WO2021186168A1

WO2021186168A1 - Method and apparatus for hydrocarbon processing

Info

Publication number: WO2021186168A1
Application number: PCT/GB2021/050660
Authority: WO
Inventors: Igor VOZYAKOV; Aleksandr SHCHEBLANOV
Original assignee: Vozyakov Igor; Shcheblanov Aleksandr
Priority date: 2020-03-16
Filing date: 2021-03-16
Publication date: 2021-09-23
Also published as: WO2021186155A1; GB202013075D0; GB2593955B; GB2593243A; GB2593241A; GB2593256A; GB2593243B; WO2021186157A2; WO2021186159A1; WO2021186157A3; GB2593242A; CH717232A1; GB202013078D0; GB202018405D0; GB2593241B; GB2593955A; GB2593242B; GB202013079D0; GB202016345D0

Abstract

An aquacracking method of cracking hydrocarbons is provided. The method comprises steps of providing a liquid comprising hydrocarbons; and forming a flow with toroidal vortices in the liquid comprising hydrocarbons, such that the liquid comprising hydrocarbons is exposed to alternating flow velocities and alternating pressures, thereby initiating cracking of the hydrocarbons. A method of processing hydrocarbons is also provided.

Description

Method and apparatus for hydrocarbon processing

The present invention relates to the field of refining and chemical processing of cracking hydrocarbons. The present invention relates to the field of processing hydrocarbons, in particular for producing gasoline and other hydrocarbon products.

Crude oil is a liquid mixture of hydrocarbons featuring various structures and properties; the number of individual compounds runs into billions. Annually, the world produces in excess of 4.2 billion tons of crude oil. The bulk of crude oil is used to produce gasoline and diesel. The number of motor vehicles around the world stands at 1.1 billion; to power them, in excess of 1.0 billion tons of mogas and 1.5 billion tons of diesel (including diesel for ships, agricultural, construction, military and industrial machinery) is produced annually. Every year, 100 million units of newly built motor vehicles are sold around the world, while gasoline and diesel consumption is rising. By 2035, in excess of 1.2 billion tons of gasoline and up to 1.8 billion tons of diesel will be consumed worldwide on an annual basis.

Gasoline consumption per capita: in the USA it exceeds 1 ,000 kg annually, as opposed to less than 100 kg in China. Being one of the world’s largest economies and the world’s top refining nation, China is expected to catch up with the USA in terms of motor fuel consumption levels.

A present-day refinery operation comprises a totality of several complex sequential process chains, each of which ends in producing a certain component of would-be market-grade fuel or other petroleum product. A refinery separates crude oil into various cuts and treats those to meet preset parameters. Each link in this chain, i.e. , each process unit, has a clear and well-defined purpose. Figure 1 shows a schematic flow diagram of a typical oil refinery (noting that each refinery is designed to process a particular crude grade/blend into a certain set of products, and therefore a specific refinery generally uses a different specific arrangement). The process units typically include:

Initial processing of crude oil by way of treatment and fractionation:

• Crude dewatering and desalting

• Crude oil fractionation

In-depth oil processing:

• Coking

• Catalytic cracking processes

• Hydrocracking

Motor fuel quality upgrades (also referred to as secondary processing): • Isomerization of light gasoline cuts:

• Catalytic reforming

• Hydrotreatment of kerosene and diesel cuts

• Hydrotreatment of gasoline and diesel cuts obtained by catalytic cracking.

The finishing process involves blending of components from different streams in required proportions to produce market-grade motor fuels, such as gasoline.

Crude oil is separated into various fractions depending on boiling point. A mix of hydrocarbon vapours and liquids is fed into an atmospheric refining tower. Such a tower is referred to as atmospheric because atmospheric pressure is maintained inside it. As a result, crude oil is separated into a number of cuts: gasoline, kerosene, diesel, and atmospheric residue. The following fractions (also referred to as cuts) of crude oil are commonly distinguished:

• Gasoline with boiling point at atmospheric pressure in the range of 26-200 °C; in the example illustrated in Figure 1 the gasoline fraction is further divided into a light gasoline fraction (26-80 °C) and a heavy gasoline fraction (80-200 °C)

• Kerosene with boiling point at atmospheric pressure in the range of 120-240 °C

• Diesel with boiling point at atmospheric pressure in the range of 200-350 °C

• Atmospheric residue with boiling point at atmospheric pressure in excess of 350 °C

All methods for determining the fractional composition of crude oils and petroleum products rely on the process of evaporating and then condensing hydrocarbon vapours as selected cuts are extracted.

In addition to density and sulphur content, one key characteristic of crude oil is its fractional composition.

The aggregate amount of gasoline, kerosene, and diesel cuts in crude oil is referred to as light hydrocarbons content; this is a crucial process characteristic of crude oil. A refinery separates crude oil into various cuts and treats those to meet preset parameters. To that end, it uses exceedingly powerful, energy-intensive, dangerous, and complex process units that cost in the hundreds of millions of dollars to build and require highly skilled personnel to operate.

Crude oil is separated into various cuts depending on their boiling point. To that end, oil has to be heated to a temperature not exceeding 350 °C. If crude oil is heated to a higher temperature, a thermal cracking process would start at atmospheric pressure as crude oil breaks down into gaseous and solid coke-like products, which would cause heat exchanger malfunctioning, reduce light hydrocarbons yield, and degrade the quality of such light hydrocarbons due to an increased content of unsaturated hydrocarbons. A mix of hydrocarbon vapours and liquids is fed into an atmospheric refining tower. Such a tower is referred to as atmospheric because atmospheric pressure is maintained inside it. As a result, crude oil is separated into a number of cuts: gasoline, kerosene, diesel, and atmospheric residue. Atmospheric residue, i.e. , a mixture of hydrocarbons with boiling points above 350 °C, is then conventionally fed to a vacuum tower for fractionation. Given that atmospheric residue cannot be heated more than 350 °C yet must be fractionated, the pressure in the vacuum tower is reduced to a residual pressure of 0.025-0.05 atmospheres. As a liquid’s boiling point drops as pressure is reduced, the atmospheric residue can be heated without exceeding 350 °C. The hydrocarbons of the atmospheric residue that would not evaporate at 350 °C in the atmospheric tower begin to evaporate at the same temperature in the vacuum tower, while heavier hydrocarbons nevertheless remain liquid. Therefore, in the vacuum tower atmospheric residue can be separated, without cracking, into a cut referred to as vacuum gasoil that would evaporate at 350-550 °C under atmospheric pressure (which may also be split into a lighter and a heavier vacuum gasoil fraction, as indicated in Figure 1), and a cut referred to as vacuum residue that would begin to evaporate at above 490 °C at atmospheric pressure and that does not boil in the vacuum tower at temperatures up to 350 °C.

Normally, the following amount of light and dark cuts can be extracted from the Urals blend:

Gasoline, 28-200 °C, up to 20% wt Diesel, 200-360 °C, up to 30% wt Vacuum gasoil, 360-490 °C, up to 25% wt,

Vacuum distillation residue above 490 °C, up to 25% wt

Oil refining depth is a key indicator of a refinery’s perfection. Refineries that only feature fractionation units attain a mere 50% refining depth. This primary refining ends with crude oil fractionation.

To improve refining depth to 96%, secondary in-depth processing units are used.

Cokers use vacuum residue as feedstock. The diesel and gasoline cuts produced this way make up to 75-80% of the vacuum distillation residue used as feedstock, but those contain a lot of sulphur and unsaturated hydrocarbons and therefore require additional hydrotreatment before they can be blended into market grade gasolines or diesels. Coker processing of vacuum distillation residue can improve refining depth by 4-7% in terms of feedstock crude.

One of the most widely used processes for in-depth oil refining involves catalytic cracking of vacuum gasoil. The catalysts used in catalytic cracking come in the form of microsphere grains. The catalysts contain an active component, such as zeolite, a crystalline substance with microporous structure that enables key cracking reactions, and a matrix, the grainy body substance comprised of aluminium silicate and aluminium oxide with mesoporous structure to maintain the process conditions. The catalyst has to be regenerated because, in the course of cracking, catalyst surfaces are quickly fouled up with coke that prevents proper contact between the catalyst and the feedstock. Such coke is burnt off the catalyst’s surface as air heated to 500 °C is introduced into the regenerator unit.

The aggregate amount of catalyst loaded into a single catalytic cracking unit could be up to 400 tons. Catalyst regeneration and organization of its continuous movement within a unit are among the most complex and expensive issues in the catalytic cracking process. Combined improvement in crude refining depth thanks to catalytic crackers stands at 20% minimum. Worldwide, total capacity of catalytic crackers exceeds 500 million tons in feedstock terms.

Since vacuum gasoil contains a lot of sulphur, it has to be hydrotreated prior to catalytic cracking, as sulphurous compounds would otherwise destroy the catalyst and reduce the process quality dramatically. The hydrotreatment process is carried out using catalyst loaded into the reactor tower with hydrogen pressures up to 50 atmospheres and at temperatures of up to 400 °C. Here, sulphurous compounds break down, and sulphur turns into gaseous hydrogen sulphide that is separated away subsequently.

Hydrocracking is the world’s fastest-developing in-depth refining process. The fundamental difference between hydrocracking and conventional catalytic cracking is found in high hydrogen pressures within the system, up to 300 atmospheres. The higher the process pressure, the deeper and more useful transformations of feedstock can be achieved. However, high hydrogen pressure translates into exceedingly demanding requirements as to equipment quality. The walls of hydrocracker reactors are up to half a meter thick, comprising several layers of highly alloyed steel that comes in different grades. This is meant to prevent any leak of hydrogen that is capable of penetrating crystalline lattice defects in all known structural materials.

Should any hydrogen leak through a tiny hole and mix with air, it would produce extremely explosive fire damp gas and unavoidably create an incredibly powerful dagger of flame, akin to a blowtorch, capable of cutting any process unit within 100 meters and blowing it up. For instance, a process unit to produce hydrogen from methane using water vapour conversion at temperatures in excess of 1000 °C may be located in immediate proximity, within the refinery compound, and represents a potential blockbuster bomb. With hydrocracker units, vacuum gasoil could be used to produce up to 80% wt of high-quality diesel cuts and up to 15% of sweet gasoline cuts, as well as jet fuel.

With a combination of hydrocrackers and catalytic crackers, combined refining depth at a refinery could be improved to 91%. However, this also requires another group of secondary processing units, built to upgrade the quality of resultant straight-run and secondary components to the required standards.

To attain the required quality level, streams and in particular diesel cuts may be hydrotreated. At temperatures under 400 °C and at pressures of up to 100 atmospheres, hydrogen on the catalyst binds with sulphur to convert it into hydrogen sulphide and reduce the content of unsaturated hydrocarbons.

Reforming produces aromatic hydrocarbons from linear hydrocarbons, and can provide a gasoline for blending high-octane gasoline blends. Isomerisation produces branched molecules from linear hydrocarbons, and can provide a gasoline for blending high- octane gasoline blends. Alkylation produces alkylate end groups in hydrocarbons, and can provide a gasoline for blending high-octane gasoline blends.

To heat process unit feedstock to the required temperature, specialized tubular fired heaters are used, and these are found at all of the refinery’s process units. All the fired heaters are fuelled using refinery-wide fuel gas and liquid fuel circuits, to achieve the following process temperatures:

Initial processing of crude oil by way of treatment and fractionation:

• Oil dewatering and desalting, 130 °C

• Crude fractionation, 350 °C

In-depth crude refining:

• Coking: 490 °C

• Catalytic cracking processes, 515-520 °C (regenerator 650-670 °C)

• Hydrocracking, 380-450 °C

Motor fuel quality upgrades.

• Isomerization of light gasoline cuts: 120-440 °C

• Catalytic reforming, 495 °C

• Hydrotreatment of kerosene and diesel cuts, 340-400 °C

• Hydrotreatment of gasoline and diesel cuts obtained from the catalytic cracker, 500 °C

The above process modes clearly show that the highest temperatures are used for secondary processes of in-depth crude refining; combined with high operating pressures and the use of hydrogen, and given the processes of hydrogen production in immediate vicinity within the refinery compound, such as methane conversion at 1000 °C, they act as a focus of costs incurred to build such units, operating expenses, and industrial hazards, all the way to manmade catastrophes. Considering that existing groups of plants, complexes, and facilities were previously built in line with the production cooperation rationale and that, as cities grew, they ended up within city limits and the impact of air and water intake as well as waste discharge may have become problematic. Refinery operation without hazardous or detrimental impact on nature and humans can only be achieved through huge capital expenditures into improving the processes, reducing atmospheric discharges, and eliminating any discharges into aquatic basins and soil. Often such efforts are not successful, and refinery operations can remain a source of elevated industrial hazard, all the way to manmade catastrophes.

There is a need for approaches for refining and cracking of that are safe and efficient.

Gasoline blending is a refinery operation that blends different gasoline streams into various grades of gasoline blends. A typical refinery has many different gasoline streams available as blend stocks, with each gasoline stream having different characteristics. The available blend stock is blended into a gasoline product such that it meets simultaneously 10 to 15 different quality specifications. Each of the individual gasoline streams contributes according to its individual characteristics to each of these quality areas and each bears a different cost of manufacture. For example a summer gasoline blend might consist of 40% FCC gasoline, 25% straight-run gasoline, 15% alkylate, 18% reformate, and 2% butane.

Market-grade gasoline blends are required to comply with specific requirements regarding composition and properties, such as octane measurements; vapour pressure; initial, intermediate, and final boiling points; sulfur content; colour; stability; aromatics content; olefin content; for several different portions of the blend; and other local governmental or market requirements. Typical blend grades of gasoline include 85 octane (research octane number) for subsequent blending with ethanol or other nonpetroleum fuels, and around 90-100 octane (research octane number) for regular and premium motor fuels. The octane number is a measure of a fuel's resistance to auto- igniting (knocking) when compressed with air in a spark ignition engine. In addition to octane number, the Ried Vapor Pressure (RVP) of a blend is usually prescribed, depending on the average temperature of the location the gasoline will be used (cold temperatures require higher RVP than warmer climates). Sulfur content is generally limited, e.g. to 10 ppm by weight in the European Union. Aromatics content, benzene content, and olefins content is also often prescribed.

The following table summarises a set of requirements for gasoline in the EU as an example:

Notes:

1. Test methods shall be those specified in EN 228:2004. Member States may adopt the analytical method specified in replacement EN 228:2004 standard if it can be shown to give at least the same accuracy and at least the same level of precision as the analytical method it replaces.

2. The values quoted in the specification are ‘true values’. In the establishment of their limit values, the terms of EN ISO 4259:2006 ‘Petroleum products — Determination and application of precision data in relation to methods of test’ have been applied and in fixing a minimum value, a minimum difference of 2R above zero has been taken into account (R = reproducibility). The results of individual measurements shall be interpreted on the basis of the criteria described in EN ISO 4259:2006.

3. Member States may decide to continue to permit the placing on the market of unleaded regular grade petrol with a minimum motor octane number (MON) of 81 and a minimum research octane number (RON) of 91.

4. The summer period shall begin no later than 1 May and shall not end before 30 September. For Member States with low ambient summer temperatures the summer period shall begin no later than 1 June and shall not end before 31 August.

5. In the case of Member States with low ambient summer temperatures and for which a derogation is in effect in accordance with Article 3(4) and (5), the maximum vapour pressure shall be 70 kPa. In the case of Member States for which a derogation is in effect in accordance with Article 3(4) and (5) for petrol containing ethanol, the maximum vapour pressure shall be 60 kPa plus the vapour pressure waiver specified in Annex III.

6. Other mono-alcohols and ethers with a final boiling point no higher than that stated in EN 228:2004

Typical streams (also referred to as hydrocarbon gasoline cuts) that are blended into gasoline, some of which are illustrated in Figure 1 , include:

• Straight-run gasoline cut

• Hydrocracked 28-225 °C gasoline cut

• Hydrocracked 35-170 °C gasoline cut

• Hydrocracked 40-85 °C gasoline cut

• Hydrocracked 85-170 °C gasoline cut

• Catalytic reformed gasoline cut (also referred to as reformate)

• Catalytic cracked gasoline cut (also referred to as FCC gasoline)

• Coker derived gasoline cut

The abovementioned streams may be subject to further processing in order to improve the characteristics of the stream for gasoline blending, for example with hydrotreatment, alkylation (producing alkylate), and/or isomerisation (producing isomerate). Other streams may be included in a blend, for example toluene, benzene, butane and/or xylene streams. These streams are used for blending or compounding into finished fuel gasoline of a specific grade.

Straight-run gasoline is a distillation fraction of crude oil with a boiling temperature in the range of e.g. 26-200 °C. For straight-run gasolines, low values of octane numbers and a high concentration of sulphur are typical, which can limit the concentration of their inclusion in blended gasolines.

A hydrocracked gasoline stream is a vacuum gasoil fraction of crude oil which is hydrocracked and subsequently fractionated according to a boiling temperature in a certain range (e.g. 28-225 °C). Fractions with different boiling point ranges of 28-225 °C, 35-170 °C, 40-85 °C and 85-170 °C may be used. Hydrocracked streams typically exhibit relatively low values of octane numbers (60-81 units), contain relatively low sulphur (e.g. up to 10 mg / kg = 10 ppm) and have a low concentration of aromatics (e.g. up to 15% by volume) and olefins (e.g. up to 3% by volume). Due to the relatively high content of naphthenic hydrocarbons, the gasoline fraction of the hydrocracking process has a higher specific heat of combustion (at least 32.0 MJ/L) than straight-run gasoline. The use of the hydrocracked gasoline stream in blended gasolines can be limited due to low octane numbers.

A catalytic reformed gasoline stream can have a high octane number and a relatively high concentration of aromatics.

FCC gasoline can generally have suitable properties for market-grade gasoline blends, and in particular can have appropriate octane numbers and vapor pressures.

Diesel fuels also have requirements of their properties, such as a minimum cetane number (a measure of the delay of ignition of a diesel fuel). For example European EN 590 standard specifies that road diesel fuel must have a minimum cetane number of 51. Fuels with higher cetane numbers can form premium diesel fuels.

There is a need for approaches permitting provision of high quality streams for petroleum fuels, including gasoline.

Summary

Aspects of the invention are set out in the independent claims and preferred features are set out in the dependent claims.

According to a first aspect there is provided an aquacracking method of cracking hydrocarbons, comprising steps of: providing a liquid comprising hydrocarbons; and forming a flow with toroidal vortices in the liquid comprising hydrocarbons, such that the liquid comprising hydrocarbons is exposed to alternating flow velocities and alternating pressures, thereby initiating cracking of the hydrocarbons. The flow conditions in the flow with toroidal vortices can initiate cracking safely and efficiently.

According to another aspect there is provided an aquacracking method of refining crude oil, comprising cracking a portion of crude oil (preferably an atmospheric distillation residue) according to the aquacracking method set out in the first aspect. The flow conditions in the flow with toroidal vortices can initiate cracking safely and efficiently, and thereby enable the efficient refining of crude oil to useful products.

According to another aspect there is provided a method of refining crude oil, comprising: • flowing a portion of a distillation residue from a distillation device; • forming a flow with toroidal vortices in the distillation residue, such that the distillation residue is exposed to alternating flow velocities and alternating pressures, thereby initiating cracking of the distillation residue; and

• recycling the flow back to the distillation device.

The flow conditions in the flow with toroidal vortices can initiate cracking safely and efficiently, and thereby enable the efficient refining of crude oil to useful products.

According to another aspect there is provided aquacracking apparatus for cracking hydrocarbons, comprising a flow generator adapted to form a flow with toroidal vortices in a liquid comprising hydrocarbons such that the liquid comprising hydrocarbons is exposed to alternating flow velocities and alternating pressures for initiating cracking of the hydrocarbons. The flow conditions provided by the flow generator can initiate cracking safely and efficiently. The apparatus may comprise one or more nozzles for introducing water vapour into the flow and/or a fixed catalyst for catalysing cracking.

According to another aspect there is provided an oil refinery comprising aquacracking apparatus according to the previous aspect. The flow conditions provided by the flow generator can initiate cracking safely and efficiently. The oil refinery preferably includes a distillation device, a conduit arranged to provide a portion of a distillation residue from the distillation device to the aquacracking apparatus, and a further conduit arranged to recycle the flow from the aquacracking apparatus back to the distillation device. Such an oil refinery can enable particularly safe and efficient refining.

According to further aspects there may be provided an oil refining method by way of low- temperature aquacracking that includes one or more of:

• oil heating using waste heat

• initial separation in a first atmospheric tower for stripping out of light gasoline cuts from the tower top

• heating the residue from the first atmospheric tower, for example using recuperation heat

• feeding residue from the first atmospheric tower into the feed zone of a second atmospheric tower

• separating stripped oil into a heavy gasoline cut, kerosene, diesel and atmospheric residue

• extracting a portion of atmospheric residue from the bottom section of the second atmospheric tower

• feeding the atmospheric residue portion into a generator

• injecting water vapour in the atmospheric residue portion at the generator

• recycling the generator-processed atmospheric residue back into the bottom section of the atmospheric tower below the level of stripped oil feed from the first atmospheric tower to the second tower • in the second atmospheric tower extracting the gasoline and diesel cuts additionally formed in the generator -processed atmospheric residue.

The mass ratio of the atmospheric residue from the second tower, which is fed into the generator, to water vapour, may be 100:0.1 to 100:0.5. The generator pressure may be maintained at 8 atmosphere (810 kPa) minimum. High efficiency of the catalytic processes that occur downstream of the generator may be achieved thanks to the pressure and flow conditions created by the generator. The pressure and flow conditions may include a dispersion of toroid vortices. The toroid vortices may be 20-40 micrometres in diameter. The toroid vortices may have peripheral speeds of 200-400 meters per second. The linear velocity of the bulk flow may be 20-60 meters per second. The generator may provide numerous contacts with a solid catalyst. The solid catalyst may contain 17-19% chromium, 9-11% nickel, 0.8% titanium, 1.5% manganese, and 0.03% copper.

According to another aspect there is provided a method of processing hydrocarbons, comprising steps of: providing a liquid comprising hydrocarbons and a hydrogen source, preferably water; forming a flow with toroidal vortices in the liquid, such that the hydrocarbons and hydrogen source are exposed to alternating flow velocities and alternating pressures; thereby initiating reactions of the hydrocarbons and water. The flow conditions in the flow with toroidal vortices can initiate reactions to enhance the characteristics and increase the mass quantity of for example a gasoline stream safely and efficiently.

According to another aspect there is provided apparatus for processing hydrocarbons, comprising a flow generator adapted to form a flow with toroidal vortices in a liquid comprising hydrocarbons and a hydrogen source, preferably water such that the hydrocarbons and hydrogen source are exposed to alternating flow velocities and alternating pressures for initiating reactions of the hydrocarbons and hydrogen source. The flow conditions provided by the flow generator can initiate reactions safely and efficiently. The apparatus may comprise one or more nozzles for introducing water into the flow and/or a fixed catalyst for catalysing cracking.

According to another aspect there is provided an oil refinery or a hydrocarbon storage facility comprising apparatus according to the previous aspect. The flow conditions provided by the flow generator can initiate cracking safely and efficiently. The oil refinery or hydrocarbon storage facility preferably includes a tank, a conduit arranged to provide a portion of a gasoline from the tank to the apparatus, and optionally a further conduit arranged to recycle the flow from the apparatus back to the tank. Such an oil refinery or hydrocarbon storage facility can enable particularly safe and efficient enhancement of the characteristics and increase of the mass quantity of for example a gasoline stream. According to further aspects there is provided a process for refining hydrocarbon gasoline cuts in a refinery setting. The process may be for producing hydrocarbon gasoline cuts in amounts exceeding the original quantities by 25-30%. The quality of the cuts is preferably preserved. The burning of such cuts in any internal combustion engines, including automotive ones, does not adversely affect harmful atmospheric discharges, greenhouse effect, or other types of environmental pollution. The process may include simultaneously feeding water to a flow generator. Addition of e.g. around 30% water to the hydrocarbons at the flow generator units, and reaction of that water with the hydrocarbons under the influence of toroidal vortices in the flow, can reduce by 50% or more the pollutants from internal combustion engine going in to the atmosphere, whilst preserving all the qualities of market fuels. The process may take place at ambient temperature. The feedstock may be provided at atmospheric pressure.

The mass ratio of the hydrocarbon stream, which is fed into the generator, to water, may be 100:0.1 to 100:50. The generator pressure may be maintained at 8 atmosphere (810 kPa) minimum. High efficiency of the catalytic processes that occur downstream of the generator may be achieved thanks to the pressure and flow conditions created by the generator. The pressure and flow conditions may include a dispersion of toroid vortices. The toroid vortices may be 20-40 micrometres in diameter. The toroid vortices may have peripheral speeds of 200-400 meters per second. The linear velocity of the bulk flow may be 20-60 meters per second. The generator may provide numerous contacts with a solid catalyst. The solid catalyst may contain 17-19% chromium, 9-11% nickel, 0.8% titanium, 1.5% manganese, and 0.03% copper.

According to another aspect there is provided a method of generating toroidal and spatial vortices in a liquid, by a generator for generating toroidal and spatial vortexes in a liquid, the generator comprising a substantially rotationally symmetrical stator housing with an axis and an axial inlet opening and an eccentric outlet opening directed in a plane that is oriented normal to the axis, and a rotor rotatably arranged around the axis in the stator housing with radially outwardly extending channels in constant fluid connection to the inlet opening, characterized by a rotor disc, which is attached to the rotor in a rotationally fixed manner radially outside the rotor, comprising a side surface of the rotor disc normal to the axis with inner notches spaced apart from one another and equidistant from the axis and in constant fluid connection to the rotor channels, for portion and temporarily blocking the liquid, as well as a stator disc attached with torque proof connection to the stator housing comprising a side surface of the stator disc facing the side surface of the rotor disc, the side surface of the stator disc comprising stator notches spaced apart from one another and equidistant from the axis, for providing passages for the liquid to form a periodical liquid flow from the inner notches to the stator notches, when these notches face each other due to rotation of the rotor disc in operation, for generating toroidal vortexes in the portioned liquid during use by shear stress as the portions of liquid pass from the inner notches to the stator notches and move back and forth, and for providing passages radially outside of the stator disc to the outlet opening, contributing between 70 and 95% of a total liquid flow through the generator, wherein the rotor disc and the stator disc are spaced apart by a gap to allow a permanent liquid flow through that gap from the inner notches to the outlet opening, for generating spatial vortexes during use in the laminar liquid flow due to the velocity difference of the side surfaces defining the gap and due to periodical disruptions by the portioned liquid passing the gap in axial direction, contributing between 5% and 30% of the total liquid flow through the generator; the method comprising operation of the generator for generating toroidal and spatial vortexes in a liquid, by the steps of a) bringing the liquid to the inlet opening; b) bringing the rotor with the rotor disc attached into rotation; c) producing a permanent liquid flow and a periodical liquid flow between the stator disc and the rotor disc; d) generating toroidal vortices in the portioned liquid of the periodical liquid flow by shear stress as the portions of liquid pass from the inner notches to the stator notches; e) generating spatial vortices in the permanent liquid flow in the gap between the side surfaces due to the velocity difference of the side surfaces and due to periodical disruptions by the portioned liquid passing the gap in axial direction; f) combining the permanent liquid flow and the periodical liquid flow to a total liquid flow; g) conducting the total liquid flow to the outlet opening of the generator to let it exit the generator; whereas the liquid brought to the inlet opening is fuel oil with 3-5% sulphur and up to 3% water, and the total liquid flow conducted away from the outlet opening is fuel oil with 0.3-0.5% sulphur, up to 5% colloidal sulphur and up to 1% liquid hydrocarbon. The total liquid flow may be filtered after conducted away from the outlet opening for obtaining fuel oil separated from colloidal sulphur.

According to another aspect there is provided a method of producing fuel oil with colloidal sulphur from fuel oil with sulphur, the method comprising exposing the fuel oil with sulphur, to toroidal and spatial vortexes in a liquid. The method may further comprise filtering to separate the fuel oil from the colloidal sulphur. According to another aspect there is provided a method of precipitating an impurity out of a hydrocarbon fluid, comprising steps of: providing a hydrocarbon fluid with an impurity; and forming a flow with toroidal vortices in the hydrocarbon fluid, such that the hydrocarbon fluid is exposed to alternating flow velocities and alternating pressures, thereby initiating precipitation of the impurity from the hydrocarbon fluid. The flow may be as aforementioned. The impurity may by sulphur, and precipitation may include formation of colloidal sulphur. The hydrocarbon may be fuel oil with 3-5% sulphur. The flow may comprise up to 3% water. The method may further comprise filtering to separate the hydrocarbon from the impurity.

As used herein, the term “light gasoline” preferably refers to hydrocarbons with a boiling point at atmospheric pressure in the range from 26 °C to 80 °C.

As used herein, the term “stripped oil” preferably refers to hydrocarbons after removal of a light gasoline fraction.

As used herein, the term “heavy gasoline” preferably refers to hydrocarbons with a boiling point at atmospheric pressure in the range from 80 °C to 200 °C.

As used herein, the term “gasoline” preferably refers to hydrocarbons with a boiling point at atmospheric pressure in the range from 20 °C to 220 °C, preferably from 26°C to 200 °C. The term ‘straight-run gasoline’ preferably refers to gasoline obtained by fractionation of crude oil without further processing. As used herein, the term “gasoline fraction obtained from crude oil” preferably encompasses straight-run gasoline, but also gasoline obtained from cracking of a crude oil fraction (e.g. coker processing of a residue fraction, hydrocracking of a residue fraction, fluid catalytic cracking of a residue fraction). The term also includes gasoline obtained using one or more processing steps including but not limited to hydrotreatment, reforming, isomerisation, alkylation, and any other secondary in-depth processing step suitable for gasoline.

As used herein, the term “kerosene” preferably refers to hydrocarbons with a boiling point at atmospheric pressure in the range from 120 °C to 240 °C.

As used herein, the terms “diesel” and “diesel oil” are used synonymously and preferably refer to hydrocarbons with a boiling point at atmospheric pressure in the range from 180- 360 °C, preferably from 200 °C to 350 °C. The term ‘straight-run diesel’ preferably refers to diesel obtained by fractionation of crude oil without further processing. As used herein, the term “diesel fraction obtained from crude oil” preferably encompasses straight-run diesel, but also diesel obtained from cracking of a crude oil fraction (e.g. hydrocracking of a residue fraction). The term also includes diesel obtained using one or more processing steps including but not limited to hydrotreatment and any other secondary in-depth processing step suitable for diesel. As used herein, the term “atmospheric distillation residue” preferably refers to hydrocarbons with a boiling point at atmospheric pressure above 350 °C. Atmospheric distillation residue is also known as ‘reduced crude oil’.

As used herein, the term “heavy hydrocarbons” preferably refers to hydrocarbons with a boiling point at atmospheric pressure above 350 °C. Heavy hydrocarbons may include atmospheric distillation residue, heavy crudes and extra-heavy crudes.

As used herein, the term “blending” may include providing a composition formed to 100% of a single source, or may refer to blending two or more streams.

Unless specified otherwise, percentages provided herein are by mass, also referred to as % wt or wt %.

As used herein, a ‘low’ temperature is preferably a temperature below a boiling point of a processed material. For example for a gasoline a ‘low’ temperature is preferably below 30 °C, optionally below 25 °C, optionally an ambient temperature, optionally a temperature in the range of 4-25 °C. For example for an atmospheric distillation residue a ‘low’ temperature is preferably a temperature below 400 °C, optionally below 380 °C or below 360 °C; and further optionally a temperature above 120 °C or above 300 °C or above 320 °C or above 340 °C.

Brief Description of the Drawinqs

Example embodiments are illustrated in the accompanying figures in which:

Figure 1 shows a schematic flow diagram of a typical oil refinery;

Figure 2a shows a schematic flow diagram of an oil refinery with aquacracking;

Figure 2b shows an aquacracking unit;

Figure 3 shows a schematic flow diagram of a typical oil refinery with process components that are omitted in the refinery shown in Figure 2a marked;

Figure 4 shows a schematic flow diagram of another example of an oil refinery with aquacracking;

Figure 5 shows a cross sectional view of a generator

Figure 6 illustrates a perspective view of a rotor disc of a generator;

Figure 7 illustrates a perspective view of a stator disc of a generator;

Figure 8 shows a cross sectional view of a portion of the generator of Figure 5;

Figure 9 shows a cross sectional view along the section A-A of Figure 8;

Figure 10 shows a cross sectional view of a generator with outlet duct;

Figures 11 illustrates a perspective view of a permanent flow generated by conditions in a generator;

Figure 12 illustrates a perspective view of a periodical flow generated by conditions in a generator;

Figure 13 shows a sectional and plan view schematic of flows when a stator notch is aligned with a rotor notch; Figure 14 shows a sectional and plan view schematic of flows when a rotor notch has no overlap with a stator notch;

Figure 15 shows a sectional and plan view schematic of flows when a stator notch has no overlap with a rotor notch;

Figures 16a, 16b and 16c show graphs of local flow velocity, acceleration and absolute pressure in flow in a generator during different phases of operation;

Figure 17 shows a schematic illustration of another rotor ring;

Figure 18 shows a perspective drawing of flows with the rotor ring of Fig. 17;

Figure 19 shows a schematic view of another rotor ring;

Figure 20 shows another view of the rotor ring of Fig. 19;

Figure 21 shows a perspective drawing of another rotor ring and stator ring;

Figure 22 shows a schematic illustration of an alternative generator with axial flow; Figure 23 shows a cross sectional side view of a generator with a nozzle;

Figure 24 shows a cross sectional front view of the generator with a nozzle of Figure 23; Figure 25 shows another nozzle;

Figure 26 shows a schematic flow diagram of the aquacracking process with an atmospheric distillation process;

Figure 27 shows a graph comparing yields of atmospheric distillation process and an aquacracking process;

Figure 28 shows a graph of yields of atmospheric distillation with aquacracking for different densities of crude oil;

Figure 29 shows a graph comparing sulphur content of residue from atmospheric distillation for a process with vacuum distillation against a process with aquacracking; Figure 30 shows a graph comparing coking fraction of residue from atmospheric distillation for a process with vacuum distillation against a process with aquacracking; Figure 31 shows a graph comparing softening temperature of residue from atmospheric distillation for a process with vacuum distillation against a process with aquacracking; Figure 32 shows a graph where the kinematic viscosity of residue is shown against its softening temperature for different densities of crude oil;

Figure 33 shows a schematic flow diagram of an oil refinery with flow generators for enhancing stream quality;

Figure 34 shows a schematic flow diagram of a flow generator unit of Figure 33;

Figure 35 shows another schematic flow diagram of a flow generator unit of Figure 33.

In the drawings, like reference numerals are used to indicate like elements.

Detailed Description

Aquacrackinq Figure 2a shows a schematic flow diagram of an oil refinery with an aquacracker process unit 100 instead of a vacuum distillation unit and its associated downstream processing units as shown in Figure 1. Figure 2b shows an aquacracker process unit 100 in more detail. In brief, a portion of atmospheric residue 35 from an atmospheric distillation tower 101 is fed to a generator 36, and following processing in the generator 36 it is fed back in to the atmospheric distillation tower 101.

In Figure 3 the process units of the conventional oil refinery of Figure 1 that are omitted in the oil refinery of Figure 2a are circled and crossed out.

Aquacracking (also referred to herein as ‘low temperature aquacracking’) is a process of cracking hydrocarbons at typically 340-360 °C and with a feed at approximately atmospheric pressure. Aquacracking can be used to produce straight-run light hydrocarbon cuts from extra-heavy and heavy crudes as well as in heavy oil residues, including in atmospheric residue, followed by extraction of the straight-run light hydrocarbon cuts so formed using the standard atmospheric distillation process. With aquacracking refining depth of up to 91 % can be achieved with an aquacracking residue of 7-8% that could be transferred by a pipeline directly to a coker unit to deepen refining to 96%.

In aquacracking of hydrocarbons (e.g. extra-heavy or heavy crudes, heavy oil residues, atmospheric residue) a liquid flow is flowed through a generator 36 as illustrated in Figure 2b. The generator creates flow conditions in the liquid flow that initiate and promote cracking. The generator causes formation of a vortex braid in the flow. The vortex braid splits up into toroid and spatial vortices that subject the liquid stream to alternating accelerations varying from +16,000,000 to -16,000,000 m/sec² and create pressures in various portions of the liquid flow varying from 500 bar (50 megapascal (MPa) or 510 atmospheres (atm)) overpressure to 0.1 bar (0.01 MPa) vacuum. These conditions create a stress state in the liquid and maintain it for a short period. These conditions initiate and promote cracking of the hydrocarbons.

The aquacracking process unit 100 includes a generator 36 that can generate toroidal and spatial vortices in a liquid flow. More details of the generator 36 and how it is operated are provided below.

Cracking refers to the breaking-down of long chain hydrocarbons into short ones, to the point of depletion of the original long hydrocarbon molecules. Aquacracking refers to the use of water molecules in cracking as a source of hydrogen to block uncontrolled merging of broken-down hydrocarbon chains without formation of coke or naphthenic substances. In aquacracking both water dissociation occurs, as well as cracking of hydrocarbons. The combination of water dissociation and hydrocarbon cracking can enable minimal formation of unsaturated compounds and minimal gas formation. The generator creates flow conditions in the liquid flow that initiate and promote water dissociation as well as cracking in combination with the water dissociation. By virtue of the generator and the flow conditions created by the generator aquacracking can occur at 340-360 °C and in a feed provided at atmospheric pressure or near-atmospheric pressure, e.g. 1.2-1.5 atm (122-152 kPa).

Hydration reaction of unsaturated hydrocarbons can be enabled by providing water molecules in the form of water vapour that is fed to the generator through a special nozzle; further details of the nozzle are described below.

Selectivity is achieved by a process catalyst as further described below.

Aquacracking can include a number of chemical processes that can take place in parallel and sequentially, including:

• decomposition of water vapour molecules to provide hydrogen;

• hydrogenation of light hydrocarbon radicals that are formed during aquacracking by hydrogen atoms;

• cracking of heavy hydrocarbons and predominance of recombination processes to obtain stable light hydrocarbon molecules and minimize gas formation; and

• hydration by water vapour molecules of any unsaturated hydrocarbons formed by cracking.

The reactions develop and take place downstream of the generator. In the example illustrated in Figures 2a and 2b the reactions continue in the atmospheric distillation unit.

In the example illustrated in Figure 2a product streams of straight-run heavy gasoline, kerosene, and diesel cuts are extracted using the standard process at the atmospheric distillation unit. Oil refining depth improves to 91% in terms of feedstock crude, simultaneously with the primary process of atmospheric refining. Aquacracking residue can be directly conveyed to a coker to improve the oil refining depth to 94-96%. Characteristics of the aquacracking process residue enable transfer of the aquacracking residue via process pipelines without any problems or early coking, making for problem- free coking processes in a coker unit.

With the aquacracking process in use, a number of secondary in-depth refining processes can be omitted from the refinery’s operational flowchart, as marked in the flowchart in Figure 3; these include vacuum distillation, hydrocracking, catalytic cracking, and hydrotreatment of gasoline, kerosene, and diesel cuts obtained by catalytic cracking.

The aquacracking process can be particularly beneficial with heavier crude oil feedstock, as such feedstock can give relatively low yields of fractions boiling below 350 °C (and a high proportion of atmospheric distillation residue), and the atmospheric distillation residue can have a relatively high density.

Overview of Atmospheric Distillation Concept: Figure 4 shows a schematic flow diagram of an example of an oil refinery with aquacracking.

In brief, feedstock crude is distilled in a first distillation tower 4 at 120-150 °C to extract light gasoline cuts with initial boiling points of 26-80 °C. Remaining feedstock crude, usually referred to as “stripped oil,” proceeds to a second distillation tower 14 for distilling products with higher initial and end boiling points; in the second distillation tower 14 oil is separated into the following fractions: heavy gasoline, kerosene, diesel, and atmospheric residue.

A portion of atmospheric residue, amounting to at least 25% of the total atmospheric residue at the second distillation tower 14, is extracted from the atmospheric distillation unit below the hydrocarbon feedstock input level and is fed to the generator 36. This portion forms the generator feedstock stream. This stream is provided under the pressure of the liquid column in the atmospheric tower, i.e. at a pressure slightly above atmospheric pressure. Pressure of the liquid column in the atmospheric tower is determined by the pressure of the petroleum products’ vapours and column height; in general, the pressure of the generator feedstock stream exceeds atmospheric pressure by a small margin. The generator feedstock stream is therefore at a near-atmospheric pressure of for example 1.2-1.5 atm (122-152 kPa).

The generator 36 produces toroid and spatial vortices in the flow of atmospheric residue so that the hydrocarbons in the flow are subjected to the resultant alternating high frequency oscillations in flow velocity (acceleration) and pressure, whereby a “stress” condition is created and momentarily maintained. The stream is brought into contact with water, e.g. by injecting water vapour, and with one or more catalysts to initiate a number of processes that take place in parallel and sequentially. The processes initiated in the generator 36 include:

• Low-temperature (340-360 °C) catalytic aquacracking of wax and paraffin found in atmospheric residue, with predominant recombination processes that form stable light hydrocarbon molecules with minimum gas production.

• Hydrogenation of light hydrocarbon radicals produced in the course of low- temperature catalytic aquacracking of wax and paraffin substances with hydrogen atoms in branched saturated hydrocarbons and on periphery of aromatics compounds with high hydride mobility.

• Hydration of unsaturated hydrocarbons produced in the course of cracking, as water molecules in water vapour dissociate.

• Prevention of coking processes in the bottom section of the atmospheric tower as atmospheric residue is recycled to the tower bottom, thanks to the generator operation that increases turbulence of the residue flow at the tower bottom to reduce coke fouling potential; an effect whereby any produced coke is dispersed while any radicals formed in low temperature aquacracking are hydrogenated and hydrated as per the foregoing points.

• Evaporation of stable light hydrocarbon cuts produced in the course of those processes, as the processed residue is recycled back into the atmospheric tower and those cuts are separated out.

As a result straight-run cuts, such as heavy gasoline, kerosene, and diesel cuts, are produced and can be separated from that portion of the atmospheric residue. The formation of “light cuts” out of atmospheric residue and the offtake of the additionally created lighter cuts at the second atmospheric tower reduces the yield and, accordingly, output of atmospheric residue from the tower bottom; this reduces the consumption of fuel required to heat up that residue before it is fed to either a downstream vacuum tower or a coker.

The temperature of atmospheric residue processed in the generator 36 is consistent with the temperature of the atmospheric residue fed into the same, within 340-350 °C.

The pressure of saturated water vapour fed into the generator 36 ranges from around 2 to 6 atmosphere (203-608 kPa, or around 200-600 kPa). For example, saturated water vapour obtained from the refinery’s process equipment is typically readily available at around 3-4 atmosphere (304-405 kPa, or around 300-400 kPa) pressure.

Atmospheric residue and water vapour are normally fed into the generator 36 at a mass ratio ranging from 100:0.1 to 100:0.5.

Following its processing in the generator 36, atmospheric residue is recycled to the second atmospheric distillation unit 14 below the level at which stripped oil is fed into the second atmospheric distillation unit 14. The average pressure in the flow downstream of the generator may be several atm (e.g. 8 or 10 or 12 atm), and this pressure is released on recycling of the stream back into the second atmospheric distillation unit 14, dropping the average pressure to the working pressure at that position in the second atmospheric distillation unit 14. Local pressure variations may exist due to toroidal vortices persisting.

When a portion of the atmospheric residue, following its processing in the generator 36, is recycled back to the second atmospheric distillation unit 14, the chemical reactions so initiated continue and proliferate in the atmospheric residue inside the second atmospheric distillation unit 14; as a result, shorter-chain hydrocarbons are formed, including straight-run cuts, such as heavy gasoline, kerosene, and diesel cuts; in addition, other shorter-chain hydrocarbons may form as well.

Thereafter, straight-run cuts, such as heavy gasoline, kerosene, and diesel cuts, plus other hydrocarbon cuts with a shorter chain are extracted at the second atmospheric distillation unit 14, using standard methods, in parallel with the aquacracking. With refining depth increased to 91% right at the second atmospheric distillation unit 14, the amount of atmospheric distillation residue as a percentage of feedstock crude can be reduced to 7-8% aquacracking residue. Meanwhile, aquacracking residue can be pumped via process pipelines with no risk of early coking, so it is transferred to the standard coking process to achieve a final refining depth of 96-97% in terms of feedstock crude.

The entire sequence thus described occurs as a continuous process.

By virtue of the approach involving aquacracking with the generator 36 as described, 90% of all known crudes with densities of 820-960 kg/m³ can be refined. Meanwhile, the oil refining depth using the described approach can reach 91% in terms of feedstock crude while maintaining straight-run quality in resultant distillate fractions, which is significantly higher compared to the standard refining process that encompasses all processes of in-depth crude refining, including vacuum distillation, said fractions containing a high amount of unsaturated hydrocarbons as a result of using secondary refining processes.

An added advantage of the described approach comes from the fact that the processes of aquacracking longer chain hydrocarbons into shorter chain hydrocarbons, such as straight-run cuts, i.e. , heavy gasoline, kerosene, and diesel cuts, takes place at lower temperatures, 340-360 °C, and at atmospheric pressure. By contrast, conventional cracking processes require higher temperatures, in excess of 400 °C. If temperatures below 400 °C are used in the standard cracking process, the reaction rate slows down unacceptably and the unit’s throughput reduces the refinery’s aggregate throughput.

An added advantage of the described approach involves the fact that the percentage of unsaturated hydrocarbons in the resultant straight-run cuts, such as gasoline, kerosene, and diesel cuts, is consistent with unsaturated hydrocarbon content of the original feedstock crude. By contrast, in conventional processes hydrocarbon cracking produces a large amount of light unsaturated hydrocarbons that can dramatically degrade the quality of end fuel if not further treated.

Yet another advantage of the described approach consists in the fact that existing groups of plants, complexes and facilities were previously built in line with the production cooperation rationale; as cities grew, they ended up within city limits and the impact of air and water intake as well as waste discharge may have become problematic. Attempts to reorganize a refinery operation or to set up a new refinery operation involve huge capital expenditures into improving the processes, reducing atmospheric discharges, eliminating any discharges into aquatic basins and soil as to prevent or minimize harmful impact on the human being and the nature, even though such expenditures often remain unsuccessful and result in manifold production cost increases. Vacuum distillation units, hydrocrackers, catalytic crackers, and hydrotreaters for catalytic cracker gasoline, kerosene and diesel cuts rely on temperatures in excess of 670 °C in combination with operating pressure of 100+ atmospheres and use hydrogen at operating pressures of up to 300 atmospheres. These processes require hydrogen production in the immediate vicinity within the refinery compound, such as by way of methane conversion at 1000 °C. By enabling the omission of these process concentration of costs on building new units can be avoided, operating expenses can be reduced, and fundamentally the industrial hazards associated with refinery operations can be reduced.

Yet another advantage comes from the fact that the described approach can radically reduce the risks of unit malfunction or operational failure at a facility, along with the risks of repairs, fires, accidents, and industrial catastrophes; it can simplify the operational management processes and fundamentally improve operational economics.

An extra advantage is found in the fact that, as the costs associated with in-depth refining processes are eliminated from the production costs of market grade fuel, the cost for market grad fuel could fall by 60% or more, given that the ratio of the present value associated with in-depth crude refining to the cost of primary processes and the processes involved in upgrading market fuels, as the percentage of the end motor fuel cost, stands at 2:1.

One other advantage may be seen in that the generator 36 used in the described aquacracking process is derived by modernizing a standard centrifugal pump found in refinery processes, as it is centrifugal pumps that serve as principal pumping units at refineries. Such pumps achieve the highest efficiency when pumping low viscosity liquids; they take little material to build while offering lower costs, design simplicity, high reliability, and ease of maintenance.

An additional advantage is found in the fact that an aquacracking generator 36 derived from a standard centrifugal pump used for petroleum product transfer may be sited at the standard pump station of an atmospheric distillation unit.

Another advantage consists in the fact that implementation of the aquacracking process at an operating existing refinery neither involves full or partial outage of such refinery nor requires any major overhaul or retrofit that would necessitate full or partial disruption of the refinery’s operating mode.

Another advantage is that the aquacracking process involves minimum production of gases.

For completeness, the process illustrated in Figure 4 is now described in more detail, though many of the details may be varied and the aquacracking process can be used in other processes.

Via line 1 , oil is fed into waste heat exchanger 2 and, via line 3, transferred into the inlet to a first atmospheric distillation tower 4. Gasoline vapours are vented from the top of the first tower 4 via line 5, to be condensed in condenser 6 and fed into separator 7. Via line 8, a portion of such condensate is recycled, from separator 7, into the first tower 4 as reflux, while the balance condensate is transferred for further refining via line 9. Non- condensed vapours are vented from separator 7 via line 10.

The residue (stripped oil) is collected from the bottom section of the first tower 4 via line 11 , heated in furnace 12 and, via line 13, fed into a second atmospheric distillation tower 14. Gasoline vapours are extracted from the top section of the second tower 14 via line 15 to be condensed in condenser 16 and fed into separator 17. A portion of such condensate from separator 17 is recycled via line 18 to the second tower 14 as reflux, while the balance condensate is transferred for further refining via line 19. Non- condensed vapours are vented from separator 17 via line 20. Kerosene sidecuts are extracted from the product concentrating section of the second tower 14 via line 21 , and diesel fuel is transferred via line 22 into stripper sections, numbered respectively 23 and 24, wherefrom kerosene and diesel are taken out via, respectively, via lines 25 and 26, while stripped light cuts from stripper sections 23 and 24 are recycled into the second tower 14 via, respectively, lines 27 and 28. Kerosene and diesel stripping is achieved as water streams are fed into stripper sections 23 and 24 via, respectively, lines 29 and 30.

Atmospheric residue from the bottom section of the second tower 14 is removed from the atmospheric distillation tower via line 33. A portion of atmospheric residue from the bottom section of tower 14 is transferred via line 35 to generator 36 as water vapour 34 is injected there simultaneously. Given the temperatures of 350-360 °C at the bottom section of the atmospheric tower 14 and in the generator 36, a portion of atmospheric residue in tower 14 and in the generator 36 undergoes aquacracking in the presence of water vapour to produce gasoline and diesel cuts. The product from generator 36 arrives to the bottom section of the atmospheric tower via line 31, so that the gasoline and diesel produced can be extracted from the generator-treated stream. As a portion of atmospheric residue is treated in the generator 36 and recycled to the bottom section of the second atmospheric tower 14, gasoline, kerosene, and diesel cuts are produced. The aquacracking of the atmospheric residue into diesel, kerosene, and gasoline cuts may primarily occur within the bottom section of the second tower 14, subject to initiation of at least 25% of atmospheric residue inside generator 36.

Generator

The following description of the generator 36 used for aquacracking will be discussed below with reference to Figures 5 to 22.

Figure 5 illustrates a cross sectional view of a generator 36 for generating toroid and spatial vortices in a liquid 102. As used herein, the term ‘spatial vortex’ is used to distinguish non-toroid vortices from toroid vortices, and includes vortices where the axis of rotation does not form a closed loop (e.g. tubular vortices, cone-shaped vortices). The generator 36 comprises: a substantially rotationally symmetrical stator housing 103, symmetrical about axis 107; an axial inlet opening 104, an eccentric outlet opening 105 directed in a plane 106 that is normal to axis 107, and a rotor 108 rotatable around axis 107 in the stator housing 103, the rotor 108 comprising radially outwardly extending channels 109 in constant fluid connection to the inlet opening 104. In an example, the rotor 108 has an outer diameter of about 30 cm ± 20%.

The generator further comprises a rotor disc 110 (also referred to as a rotor ring) rotatable about axis 107 and a stator disc 114 (also referred to as a stator ring). Figures 6 and 7 illustrate a perspective view of a rotor disc 110 and a stator disc 114 of a generator 36 respectively. Inner notches 112 are arranged periodically about the rotor disc 110, and notches 116 are arranged periodically about the stator disc 114.

The rotor disc 110, shown in Figure 6, is attached to the rotor 108 in a rotationally fixed manner radially outside the rotor 108. The rotor disc 110 comprises a side surface 111 normal to axis 107 with inner notches 112, spaced apart from one another and equidistant from the axis 107 for channelling a liquid 102. The rotor disc 110 may additionally comprise outer notches 113 on the same surface 111 as the inner notches 112. These outer notches 113 can also be spaced apart from one another and equidistant from the axis 107. It should be appreciated that the rotor disc 110 may be provided as a separate part that is distinct from the rotor 108, or it may equally be provided as an integral feature or portion of the rotor 108.

The rotor disc 110 also includes outer notches 113. By virtue of the outer notches 113 the building of toroid vortices within the periodical liquid flow 119 is further increased before the liquid 102 exits the rotor disc 110.

The stator disc 114, shown in Figure 7, is attached with torque proof connection to the stator housing 103. The stator disc 114 comprises a side surface 115 configured to face the side surface 111 of the rotor disc 110 as well as stator notches 116 spaced apart from one another and spaced equidistantly around axis 107. It should be appreciated that the stator disc 114 may be provided as a separate part that is distinct from the stator housing 103, or it may equally be provided as an integral feature or portion of the stator housing 103.

The number of each kind of notch 112, 113, 116 determines the throughput of liquid and is preferably between 16 and 42, although it will be appreciated that any number of notches can be used. It is not necessary for the notches 112, 113, 116 to be arranged equidistant from one another on the discs 110, 114, but it is preferred. The number of the inner notches 112 may equal the number of the outer notches 113 and/or the number of the stator notches 116. This is the case illustrated in Figures 6 and 7.

The generator 36 may further comprise a guide vane 121 inside the stator housing 103 radially outside the stator disc 114 and rotor disc 110 for guiding a total liquid flow 120 to the eccentric outlet opening 105. Passages radially outside of the stator disc 114 to the outlet opening 105 are provided by the spiral guide vane 121 , with blades bent in the opposite direction to the impeller blades. At the nearest point to the rotor and stator discs the guide vanes leave only a very small gap.

Figures 8 and 9 show the vanes 121 arranged in the stator housing 103 providing passages 123 for the flow downstream of the stator disc 114 and rotor disc 110. Figure

10 shows the guide vanes 121 feeding into the pump’s spiral discharge duct 124 leading to the outlet opening 105, as is well known in the art. The liquid exiting the stator disc 114 and rotor disc 110 passes through the passages 123 between the evenly spaced guide vanes 121 to enter the pump’s spiral discharge duct 124 and exits the generator via the outlet opening 105.

The guide vanes 121 are intended to reduce the velocity of liquid exiting the stator disc 114 and rotor disc 110. In this context, the stream’s kinetic energy is partially converted into pressure energy, with the pressure at the guide vane exit greater than the pressure at the entry thereto. The vanes can be optimized to meet specific desired operating parameters for a pump. The vanes can promote vortices staying intact downstream of the rotor/stator discs, for up to 3 to 5 meters within the discharge pipeline.

Figures 11 and 12 illustrate perspective views of a permanent flow 118 and a periodic flow 119 generated by conditions in a generator 36 respectively. In particular, Figures

11 and 12 illustrate how the conditions change as the rotor disc 110 and the stator disc 114 move relative to one another. A permanent flow 118 flows in a direction illustrated by arrows in Figure 11 and flows perpendicular to a periodic flow 119 illustrated by an arrow in Figure 12. Manipulation of these flows helps to create toroid vortices in the liquid 102.

A permanent liquid flow 118 between the discs 110, 114 flows between the flat parallel side surface 111 , 115 of rotor disc 110 and stator disc 114 and moves in a constant radial direction, independent of the positioning of the notches 112, 116. The rotor disc 110 and the stator disc 114 are spaced apart by a gap 117. This gap 117 allows a liquid flow, defined as the permanent flow 118, through from the inner notches 112 to the outlet opening 105. The gap 117 provides for spatial vortices to be generated in the liquid flow, in use, due to the velocity difference between the opposing side surfaces 111 , 115, which define the gap 117, and due to periodical disruptions by the portioned liquid 102 passing through the gap 117 in an axial direction from the centre of the discs outward as illustrated by arrows 118 in Figure 11. This permanent liquid flow 118 contributes between 5% and 30% of the total liquid flow 120 through the generator 36 depending on the size of the gap 117. In some examples the gap 117 between the rotor disc 110 and stator disc 114 is preferably between 0.8 mm and 1.2 mm wide. In other examples the gap 117 between the rotor disc 110 and stator disc 114 is between 1 mm and 1.8 mm wide. This permanent liquid flow 118 is independent of the actual position of the rotor 108. Inner and outer notches 112, 113 of the rotor disc 110 and stator notches 116 of the stator disc 114 provide volumes in which to form a periodic liquid flow 119 of liquid 102. The periodic liquid flow 119 flows between the inner notches 112 and the stator notches 116 as illustrated, for example, in Figure 12. When the inner notches 112 and stator notches 116 are aligned, the liquid 102 flows from the inner notches 112 to the stator notches 116, forming the periodic flow 119. Portions of liquid 102 pass back and forth from the inner notches 112 to the stator notches 116 caused by a change in volume as the rotor 108 rotates and the notches 112, 113, 116 successively align and misalign with each other. The periodic flow 119 helps to generate toroid vortices in the portioned liquid 102 by shear stress.

Liquid 102 leaves the rotor 108 to enter the inner notches 112 of rotor disc 110 when it is opposite the stator notch 116 of stator disc 114; it has roughly the same linear peripheral speed until the rotor disc 110 rotates to a position opposite the enclosed space between the notches 112, 113, 116. At that point, the passage for liquid 102 to exit the chamber of the rotor disc notch 112 closes off. This produces a pressure spike in liquid in the inner notch 112 of rotor disc 110 until an exit for the liquid 102 via a notch 116 in the stator ring 114 opens again, due to rotation, and the liquid 102 is able to flow into the stator notch 116.

Figure 11 illustrates the case after the closure point of the flow from an inner notch 112 to a stator notch 116. The periodical flow becomes further accelerated; a portion of the flow turns 180° and begins to move in the opposite direction to the principal flow within the inner notches 112, taking the shape of a twisted flow and forming a stable vortex braid 122 along the full length of the inner notches 112, which partially enters the stator notch 116.

Further rotation of the rotor disc 110 partially opens the flow passage from the inner notches 112 into the stator notches 116. Given that the opening is still very narrow, the space for the vortex braid flow 122 becomes tight, and the braid begins to break up into toroid vortex pieces. The toroid vortices so generated enter the stator notches 116, where the shape of the notches shapes the vortices into separate toroid vortices.

As the flow passage from the inner notches 112 to the stator notches 116 then gradually widens, each stator notch 116 is filled with a screw-like vortex braid that, once the total flow of liquid reverses its direction 180°, breaks up into portions, generating similar toroid vortices.

The time period when the stator notches 116 are fully aligned with the inner notches 112 is very brief, as the rotor disc 110 rotates at around 3000 revolutions per minute (50 Hz). The frequency of rotation can be adjusted to achieve variations in pressure experienced by the liquid 102. The rotor’s continued rotation tightens the spaces for the vortex braid, as the inner notches 112 gradually close. This promotes continued breakup of the vortex braid into toroid vortices. As the rotor disc 110 rotates and the stator notches 116 are closed off from the inner notches 112 again, the entire process repeats, submitting the liquid 102 to high frequency alternating flow velocities and pressures. Rotation of the rotor ring creates a suction effect and draws fluid in.

The generator 36 can be used for generating toroid and spatial vortices in a liquid 102, by: guiding the liquid 102 to the inlet opening 104 and rotating the rotor 108 with the attached rotor disc 110 to produce a permanent liquid flow 118 and a periodical liquid flow 119 between the stator disc 114 and the rotor disc 110 as described above.

Toroid vortices are generated in the portioned liquid 102 of the periodic liquid flow 119 by shear stress as the portions of liquid 102 pass from the inner notches 112 to the stator notches 116 and move back and forth therebetween. Further, spatial vortices are generated in the permanent liquid flow 118 in the gap 117 between the side surfaces 111 , 115 due to the velocity difference of the side surfaces 111, 115 and due to periodical disruptions by the portioned liquid 102 passing the gap 117 in the axial direction.

Figures 13, 14 and 15 illustrate the flows between the stator disc 110 and the rotor disc 114 in different configurations in more detail. Figure 13 shows the flows when a stator notch is aligned with a rotor notch, in sectional and plan views. Figure 14 shows the flows when a rotor notch has no overlap with a stator notch, in sectional and plan views. Figure 15 shows the flows when a stator notch has no overlap with an inner rotor notch, in sectional and plan views. In the configuration shown in Figure 15 it can be seen that in the sections between inner rotor notches fluid is blocked from entering the gap between rotor ring and stator ring. Liquid flow can only exit via an inner rotor notch, as illustrated in Figures 13 and 14.

Figure 13 shows a number of vortices being formed in the periodic flow 19 due to shear along the various notch surfaces of the rotor and stator rings. Liquid flows into the inner rotor notch 112, is redirected in the inner rotor notch 112 toward the stator 114, enters the stator notch 114, and is redirected in the stator notch 114. In the illustrated example the flow can enter the outer rotor notch 113 but in other examples the outer rotor notch

113 is omitted and the flow is redirected out of the stator notch 114. In the illustrated examples the notches provide curved surfaces to redirect the flow in the inner rotor notches 112 by approximately 60-90°, and also to redirect the flow in the stator notches

114 by 60-120° or by approximately 60-90° depending on whether or not outer rotor notches 113 are provided. As the flow moves through the notches a number of toroid vortices are formed perpendicular to the liquid flow. The redirections in the notches cause flow shearing and produce vortex zones within the notches.

Figure 14 shows the permanent liquid flow 118 between the discs 110, 114 that gets squeezed up between the flat parallel side surface 111 , 115 of rotor disc 110 and stator disc 114 and moves radially. The permanent liquid flow 118 is affected by shear stresses the rotor disc 110 generates as it moves vis-a-vis the stator disc 114.

The outer notches 112 continuously disrupt the linear nature of the inter-disc flow 118 and generate spatial vortices therein. The permanent liquid flow 118 is further disturbed by vortex flows as the inner notches 112 start to line up with the stator notches 116 and provide a flow path that passes from the inner notches 112 to the stator notches 116 perpendicular to that permanent liquid flow 118.

Figures 16a, 16b and 16c show graphs of local flow velocity, acceleration and absolute pressure in flow in an exemplary generator during different phases of operation.

Some of the details of the exemplary generator are as follows:

Pump capacity, Q = 200 m³/hour

Pressure head, H = 12 atmospheres (1216 kPa)

Impeller speed, n = 3,000 revolutions per minute Outer diameter of the impeller, D = 0.32 m Impeller width, h = 0.025 m Number of impeller blades, a = 6 Guide vane channel 0.040 m by 0.035 m

Rotor ring parameters:

Number of rotor inner notches, N_p = 18 Rotor inner notch width, h_p = 0.025 m Rotor inner notch height, L_p = 0.015 m Rotor inner notch depth, a_p = 0.025 m

Stator ring parameters:

Number of stator notches, n_c = 18 Stator notch width, h_c= 0.025 m Stator notch height, L_c = 0.020 m Stator notch depth, a_c = 0.020 m

Gap between the frontal surfaces of the rotor and stator rings, B = 0.001 m

The graphs in Figures 16a, 16b and 16c show flow conditions immediately downstream from the rotor ring / stator ring passage, from t=0 just before a rotor ring inner notch 112 starts to line up with a stator notch 116, continuing until the rotor ring notch fully opens (i.e. is in alignment with a stator notch) and further until the rotor ring notch closes. As the notch 112 starts to open up, over a duration of 0.000092 seconds (0.092 milliseconds), flow velocity increase from 10 to 160-200 meters per second (m/sec). As the rotor ring notch then comes into full alignment, over a duration of 0.00023 seconds, flow velocity drops to 30 m/sec. Subsequent movements of the rotor ring result in continued progressive closure of the notch, boosting the flow velocity to 160-200 m/sec. With further rotation of the rotor ring, the notch closes (i.e. it no longer is located at a stator notch), and the flow velocity (from flow through the gap 117) drops to 10 m/sec. As the rotor ring continues to rotate, the notch 112 is in its closed configuration (with only flow through the gap 117) for 0.00064 second. The notch 112 remains in its open configuration (fully or partially lined up with a stator notch) for 0.00046 second.

Such rapid changes in flow velocity occasioned by rotor ring rotation within the same time period produce significant alternating accelerations of the flow that change from +16,000,000 to -16,000,000 m/sec². Such accelerations affect the liquid within the rotor ring notch and the slot-like gap between the rotor and stator rings.

The forces that develop in the process produce pressure in a portion of liquid flow, which varies from 500 bar (50 Megapascal MPa or 510 atmosphere atm) overpressure to 0.1 bar (0.01 MPa) vacuum over a period of 0.00046 seconds. In a 0.000092 second timespan the pressure drops from 500 bar (50 MPa) overpressure to 0.7 bar (0.07 MPa) vacuum. Such rapid pressure changes, from overpressure to vacuum and back, can be very effective at initiating aquacracking.

In some examples, depending on the generator design, the maximum local pressure in a toroid vortex may reach 200-400 kg/cm² (around 20-40 MPa) and flow velocity change per unit of time (acceleration) is 50,000 G (around 490,000 m/sec²).

The permanent liquid flow 118 is disturbed by vortex flows that pass from the inner notches 112 to the stator notches 116 perpendicular to the permanent liquid flow 118. In this context, the permanent liquid flow 118 is affected by shear stresses the rotor disc 110 generates as it moves in relation to the freely attached stator disc 114 that is blocked to prevent its rotation. The notches 112, 113 in the rotor disc’s side surface 111 continuously disrupt the linear nature of inter-disc flow along the permanent liquid flow 118 and generate spatial vortices therein.

A conical funnel-shaped spatial vortex forms in at a rotor ring notch as the stator ring blocks the flow exit from the rotor ring. As the rotor ring exit is closed off, the outside portion of the vortex braid produces a maximum diameter funnel and unfolds towards the rotor ring entrance.

As those spatial vortices come into contact with toroid vortices, first from the inner notches 112 and then from the stator notches 116, they morph into yet smaller and more intense toroid vortices and, along with toroid vortices from the stator disc notches 112, are dispersed in total flow 120 and carried out into a discharge system. Alternating flow velocities may be produced using this technique at a frequency of at least 500 Hz, for example. Alternating pressures may also be produced using this technique at a frequency of at least 500 Hz, for example.

Contact between spatial vortices in the permanent liquid flow 118 and the spatial vortex braid for the periodical flow 119 exiting the stator notches 116 as they fully open help to cause the toroid vortices to stabilise. As the two flows 118, 119 mix, they generate a total liquid flow 120 featuring an internal volume comprising a plurality of toroid vortices.

Peripheral liquid flow velocity in a toroid vortex is greater than that of the fluid outside the toroid vortex. For example, peripheral flow velocity in a toroid vertex may be between 5 and 10 times that of the flow velocity outside the toroid vertex. Peripheral flow velocities of liquid flow in a toroid vortex may be at least 100 m/s, for example, 200 m/s to 400 m/s. Pressure of a toroid vortex may also be greater than the pressure in the fluid outside the toroid vortex. Local pressures of at least 500 kPa may be achieved.

At 3000 revolutions of the rotor ring per minute, and from 12 to 48 notches on the rotor ring, the vortex braid generation process is near enough continuous to be effectively continuous. The spatial vortices formed in the chamber comprised by rotor ring notches and stator ring notches may be deemed stable, and their number deemed consistent with the number of notches, i.e. , 12 to 48; in their turn, the spatial vortices produce a large number of smaller toroid vortices with a typical torus diameter of 20-40 micrometres. The vortex braid breaks down into toroid vortices typically ranging from 20 to 40 micrometres in diameter. Larger and smaller toroid vortices are present as well, but in lower numbers. As the toroid vortices travel in the flow they gradually dissipate and shrink. In an example at a distance of 3 meters from the outlet port of the generator 20-40 micrometre vortices are still found in the pipeline. At that point smaller vortices may have dissipated and may not be observed, whereas larger vortices may have split into smaller ones and coincide in the 20-40 micrometre size. The toroidal vortices may have a typical diameter of at least 10 μm, preferably at least 20 μm, further preferably at least 40 μm. The toroidal vortices may have a typical diameter of up to 500 μm, preferably up to 100 μm, further preferably up to 50 μm. Preferably the toroidal vortices are micrometer-scale toroidal vortices.

In an example the rotor ring rotates at 40-60 Hz and has 16-42 notches to generate toroid vortices at 640 to 2520Hz. In this example 256-1764 vortices are produced per revolution. In addition to such primary vortices formed at a primary frequency, secondary vortices are formed with an integral multiple frequency (integer N = 2, 4, 6, 8), but the efficiency of those secondary vortices is significantly less compared to efficiency of the primary vortices. In an example where the generator throughput is about 160-240 m³/hour, a density of around 190-3000 primary vortices may be generated per litre of fluid. The flow may include at least 150, preferably at least 200, further preferably at least 500 toroidal vortices per litre of suspension. The flow may include 200 to 3000 toroidal vortices per litre of suspension or 190-2940 toroidal vortices per litre of suspension.

As described above, under such conditions, in particular due to the liquid in the permanent liquid flow 118 and the sudden change of direction in the periodical liquid flow 119 (in a direction perpendicular to the permanent liquid flow 118), a vortex is built and the liquid 102 forms toroid currents therein. The liquid 102 is subjected to resulting high frequency alternating pressures and flow velocities. Conditions experienced by the hydrocarbons in the liquid 102 can initiate aquacracking, as discussed above. Conditions experienced by the hydrocarbons in the liquid 102 can lead to hydrocarbon quality improvement, as discussed in more detail below.

The example provided above discusses a rotor rotating with 3000 revolutions per minute (RPM) ± 20%, and having an outer diameter of the rotor and the rotor disc and stator disc of about 30 cm ± 20%. It should be appreciated that a toroid vortex dispersion can similarly be created at lower or higher RPM provided the rotor’s diameter is suitably increased or decreased. For instance, in a generator with an outer diameter of the rotor and the rotor disc and stator disc of about 45 cm, a suitable rotor rotation speed is around 2000 revolutions per minute. In a generator with an outer diameter of the rotor and the rotor disc and stator disc of about 90 cm, a suitable rotor rotation speed is around 1000 revolutions per minute. In all of these examples, the peripheral speed (tangential speed) of the rotating rotor, at the rotor disc (e.g. at an inlet to the rotor disc, or at an outer edge of the rotor disc), is around 47 m/sec. For a generator to produce a toroid vortex dispersion effectively, the peripheral speed of the rotor, at the rotor disc, is preferably 30 m/sec or more. A peripheral speed in the range from 20-29 m/sec is borderline and may be unstable or ineffective, though it may permit formation of a toroid vortex dispersion. A peripheral speed in the range from 15-19 m/sec may in some configurations (e.g. in otherwise particularly effective configurations) permit formation of a toroid vortex dispersion.

In some of the examples provided above the inner notches and the outer notches of the rotor ring are aligned with one another, e.g. as seen in Figures 9 and 12; in others they are not aligned, e.g. as seen in Figure 6, or some are aligned and others are not. In some of the examples provided above the inner notches and the outer notches of the rotor ring have the same or similar widths; in other examples the inner notches and the outer notches of the rotor ring do not have the same widths, e.g. as seen in Figure 9 where the inner notches are narrow than the outer notches.

Figure 17 shows another arrangement of notches that is observed to be particularly effective at creating a flow of toroid vortexes. Figure 18 illustrates the rotor ring of Figure 17 with a stator ring 114 in a generator. In this rotor ring 110, one outer notch 113 spans two inner notches 112. In the stator ring 114 the stator notches 116 are such that a stator notch 116 spans two inner notches 112. A stator notch 116 may be same or similar width as an outer rotor notch 113.

Figure 18 illustrates some flow paths in the generator with the rotor ring 110 of Figure 17. Flow from a pair of inner notches 112 of the rotor ring 110 is directed to a common rotor notch 116 of rotor ring 114. Each inner notch 112 is formed to channel liquid at an angle to its neighboring notch, such that a pair of inner notches 112 that face the same outer notch 113 channel fluid toward a common area. The central flow axes of a pair of inner notches are at a converging angle to one another; the angle is such that a point of intersection of the two flow axis is inside the volume of the notch of the stator ring, as illustrated in Figure 18.

Movement of the rotor ring 110 is now considered, starting from when two inner rotor notches 112 of the rotor ring 110 are fully aligned with a stator notch 116 of the stator ring 116, as seen in Figure 18. As the rotor ring moves, one of the pair of inner notches remains fully open, while the other of the pair of inner notches becomes partially closed. In this instant, the flow speed via the partially obstructed inner notch is significantly higher than the flow speed via the fully open inner notch. The two flows interact in the stator notch. The presence of an angle between these flows causes the faster flow to accelerate the slower flow.

With the notch design of Figures 17 and 18, the points of maximum speeds are shifted compared against the velocity plot shown in Figure 16a. What is more, the maximum flow velocity is significantly increased due to the cumulative effect of contact between two vortex braids with subsequent significant positive and negative acceleration. The number of toroid vortexes generated in the system increases exponentially, and their total peripheral speed significantly increases compared to those described above with reference to Figures 16a, 16b and 16c.

The examples illustrated in Figures 17 and 18 provide stator notches spanning two inner notches so as to commingle the periodic flows from two inner notches in a stator notch. It should be appreciated that a stator notch need not span exactly two inner notches; it may for example be sized to span more, or less, than two inner notches. In an alternative one stator notch spans one inner notch as illustrated in e.g. Figures 6 and 7, but the outer notches 116 are sized so as to span two stator notches. In this way the periodic flow from two stator notches is commingled in an outer notch. Flow interactions are promoted, and the number of toroid vortices generated is increased.

Figures 19 and 20 show plan and front view schematics of outer rotor notches 113 with a bottleneck design. In the examples previously illustrated, the outer notches of the rotor ring have approximately parallel side walls, as seen e.g. in Figure 6. As shown in Figures 19 and 20 the exit section of the outer notches 113 of the rotor ring 110 may be formed to provide channels that are progressively narrower and with smaller flow area and that resemble a bottleneck. The liquid is compressed as it moves along these channels. Flow speeds are increased as are flow interactions, and the number of toroid vortices generated is increased.

Figure 21 shows a variant where the rotor ring 110 does not provide outer notches. Instead, the outside part of the rotor ring constitutes an outer surface 28 shaped like a carved-out toroid with a certain curvature; the cross section of the outer surface 28 is same as or similar to the cross section of an outer notch, such that the outer surface 28 can provide a redirection of the flow similar to the outer notches as described above. The stator 114 includes prongs 29 between the stator notches 116 that project toward the outer surface 28 of the rotor ring 110. In this variant the gap 117 between the opposing side surfaces of the rotor disc and stator disc extends further between the prongs 29 and the outer surface 28 of the rotor, to permit movement of liquid along the outer surface 28 of the stator ring 110 and provide a passage via the gap 117 for a permanent liquid flow. The prongs 29 also form a notch-like channel for fluid to pass between the prongs 29 after exiting the stator notches, similar to the outer rotor notches in the other variants.

The features described with reference to Figures 17 to 21 can be combined for particularly effective formation of toroid vortexes in the flow.

While the examples provided above are concerned with a centrifugal pump moving fluid in radial direction toward the rotor/stator discs, it should be appreciated that a toroid vortex dispersion can similarly be created in a pump that pumps fluid in an axial direction toward suitably adapted rotor/stator discs.

Figure 22 provides a schematic illustration of an alternative generator with a rotor disc and a stator disc adapted for axial flow, rather than radial flow, with an axial flow impeller 27 instead of a radial flow impeller as described above.

In this configuration, the stator ring 26 is arranged concentrically outside the rotor ring 25 with a gap between the inner cylindrical surface of the stator ring 26 and the outer cylindrical surface of the rotor ring 25. The rotor ring 25 has inner rotor notches on a flow-facing side such that flow from the impeller can enter the inner rotor notches. The stator ring 26 has stator notches arranged on its inner cylindrical surface, facing the rotor ring. The flow is redirected by the inner rotor notches toward the stator ring, either entering the gap between the rings (in the configuration illustrated in the lower half of the cross section in Figure 22) or entering a stator notch (in the configuration illustrated in the upper half of the cross section in Figure 22). The stator notches redirect the fluid further.

For efficient formation of toroidal vortices, the flow entering the inner rotor notches has a tangential velocity (tangential to the rotational motion of the rotor) of e.g. at least 15- 25 m/sec. Suitable guide vanes can be provided upstream of the rotor ring, to ensure that the flow entering the inner rotor notches has a suitable tangential velocity, while ensuring that the generator creates a pressure of at least 5 to 7 atmospheres (506-709 kPa). In the absence of a tangential velocity component the rotor ring causes such a tangential velocity component to be produced in the flow, which can result in a relevant loss of energy and less efficient formation of toroidal vortices.

Nozzles for introducing water vapour to the generator

As described above, the atmospheric residue enters the generator 36 in liquid form at the inlet of the generator. Water vapour is introduced to the atmospheric residue via a special nozzle in the generator. The nozzle serves to deliver gas to the generator such that the gas contacts liquid as the latter leaves the stator and rotor ring structures. Nozzles of various design and configuration may be used in the process invented. Typically, the nozzle serves to deliver water vapour to the generator such that the water vapour contacts fluid (i.e. atmospheric residue) as the latter leaves the stator and rotor ring structures.

Figures 23 and 24 show an example of a nozzle 212 in a generator.

The end of the nozzle 212 that delivers the water vapour is situated in proximity to the rotor ring 108 and stator ring 114 assembly such that water vapour leaving the nozzle 212 contacts atmospheric residue as it leaves the rotor ring 108 and stator ring 114 assembly. Movement of the rotor ring’s upper portion creates suction within the generator, which draws fluid through the nozzle 212 and into the fluid flow.

A guide vane 202 is seen in Figures 23 and 24; such guide vanes are fixed relative to the housing and can define fluid flows from the pump’s impeller to its discharge line. A guide vane is not an essential element and it may be omitted. In the illustrated example the nozzle 212 passes through a guide vane 202; the nozzle 212 is not connected to the guide vane 202 and the nozzle can be provided in the absence of a guide vane.

In the illustrated example one nozzle is provided on the circumference of the rotor/stator ring assembly. In other examples two or more nozzles are distributed around the circumference of the rotor/stator ring assembly.

The diameter of the nozzle outlet is in some examples less than the width of between two outer notches of the rotor ring. The diameter of the nozzle outlet is in some examples less than the width of an outer notch of the rotor ring. The centre of the nozzle outlet is aligned with the centre of the outer notches of the rotor ring.

The water vapour is fed into the generator at 2 to 6 atmosphere (202-607 kPa), typically 3 to 4 atmosphere (304-.405 kPa). As mentioned, movement of the rotor ring’s upper portion can create suction within the generator, which draws fluid through the nozzle 212 and into the generator’s interior. The nozzle outlet is located 2-3 mm from the external blades of the rotor ring to enable this suction effect to act on the water vapour in the nozzle. Movement of the rotor ring’s upper portion creates an atmospheric vacuum zone of 0.2-0.6 atm, which ensures continuous suction of water vapour into the flow.

Figure 25 illustrates another configuration of a nozzle 212, with an angled outlet plane. Figure 25 also indicates two speeds at different positions in the housing outside the rotor/stator rings: v₁ outside the rotor ring but prior to the nozzle, and v₂ between the nozzle outlet and the rotor ring. As the nozzle obstructs flow outside the rotor ring and only permits flow to pass in the gap between the nozzle and the rotor ring, in those different positions the flow speed is different, due to the different flow cross section areas. In an example it is calculated that v₁ = 10 m/sec and v₂ = 133 m/sec. The different flow speeds give rise to the Venturi effect, and the zone in the gap between the nozzle outlet and the rotor ring is at a relatively lower pressure, causing entrainment of the gas from the nozzle into the flow.

The outer surface of the rotor ring moves at a greater speed than v₁. As the rotor ring rotates, vortexes are generated and destroyed within the stator ring notches and outer rotor notches with high intensity. This too can cause a low-pressure zone near the nozzle, similar to a vortex pump with the rotor ring acting as a vortex impeller; the rotation of the rotor also assists in drawing gas from the nozzle into the flow. In an example water from the depth of 5 to 8 meters could be lifted through the nozzle thanks to a vacuum of about 200-500 mm Hg or about 50-80 kPa at the nozzle outlet, which is generated by the synergy between the Venturi effect and the operation of the rotor ring notches.

In general water vapour is provided (or, equivalently “injected”) at a pressure below the average pressure of the hydrocarbon flow at the nozzle outlet, to prevent disruption of the flow produced by the generator and to prevent formation of gas bubbles in the hydrocarbon stream which could have detrimental effects downstream, e.g. on re-entry to the atmospheric distillation tower.

The nozzle delivers water vapour to the flow; in the conditions created by the generator dissociation of water vapour molecules provides a source of hydrogen to the hydrocarbons. Hydrogen can serve to regulate the quality of hydrocarbons cuts. Hydrogen blocks, as the generator is used, uncontrolled merging of broken-down hydrocarbon chains without formation of coke or naphthenic substances.

It should be appreciated that the nozzle can serve to introduce a second fluid into the primary flow generally. For example other gases, or liquids including water, or a fluid that is heterogenous in respect to the primary flow, or a slurry or dispersion of a solid in a liquid, or a flowable solid such a powder can by introduced into the primary flow by way of the nozzle.

Catalyst Aquacracking process selectivity is achieved by using a catalyst. Generally a catalyst may be selected as is known in the art to be useful for cracking longer-chain hydrocarbons into shorter-chain hydrocarbons. The methods for catalyst use could differ, e.g.:

• The generator’s operating components could be made of a material that contains a catalyst;

• Catalyst may be applied on contact surfaces of the generator’s internal operating components. In such cases, the core material of the generator’s internal components does not have any catalytic properties in and of itself, and any catalyst is applied on its surface appropriately;

• One or more catalysts could be introduced into the generator’s interior in liquid form through a nozzle;

• Catalyst could be used to manufacture the generator’s operating components.

In an example, the material from which the rotor and stator rings of the generator are manufactured acts as catalyst. An example of a rotor and stator ring that can have a catalytic effect is a steel that and comprises from 17% to 19% by weight chromium, from 9% to 11% by weight nickel, 0.8% by weight titanium, 1.5% by weight manganese and 0.03% by weight copper. In this case the catalytic effect arises at the stage where the working substance is handled by the rotor and stator rings, where toroid vortices are generated. Stainless steel may for example provide a suitable material, for example comprising following composition:

• Fe,

• <0.07% C,

• 16-19% Cr,

• 9-14% Ni,

• 2-3% Mo,

• 0.1-2% Mn,

• 0.1-1% Ti,

• <0.05% Cu,

• <1% Si,

• <0.05% P,

• <0.03% S

Catalyst in the form of microsphere grains that contain an active component, such as zeolites, and are mixed in with the hydrocarbons are less suitable for use with the generator. Zeolite particles could be damaged in the course of exposure to the conditions created in the generator, and consequently be difficult to extract downstream, which could result in reducing the quality of the product. Providing the catalyst bound to the contact surfaces of the generator avoids these issues. In another example a conventional catalyst, such as one or more rare earth metal salts, is applied to the working contact surfaces of the generator elements, such as the notches and blades of the rotor and stator rings, using a suitable technique such as electrolysis, sputtering or metal spraying. In another example a water-soluble salt of a suitable rare earth is used as catalyst and dispersed into the hydrocarbon flow with water vapour via the nozzle. If used this way, a low consumption of such rare earth metal could be achieved and would help eliminate the problem and high costs of their regeneration. Compared with conventional use of rare earth catalysts premature fouling with sulphur compounds of hydrocarbons cuts could be avoided by eliminating the processes of hydrofining hydrocarbons cuts.

As the aquacracking process can be operated on a continuous flow basis, if under some circumstances a fraction is not sufficiently cracked then recycling through the generator can provide the desired cracking. The processing in the generator is continuous and cyclical. Hydrocarbons that have not been sufficiently cracked are continuously and cyclically recirculated back to the generator where they are subjected to initiation and cracking development in the lower section of the second atmospheric tower to achieve depletion of long-chain hydrocarbon molecules.

Examples of aquacracking process

Now examples of the aquacracking process and its performance are provided in more detail.

Table 1 provides characteristics of atmospheric residue depending on feedstock crude density.

Table 1. Atmospheric residue characteristics depending on feedstock crude density (standard atmospheric distillation, without vacuum distillation or aquacracking).

The data in table 1 characterize 90% of all known crudes and their atmospheric residues.

As the density of crude feedstock increases from 819 to 960 kg/m³, the density of atmospheric residues in the crude distillation unit increases by an average of 10%, output under 350°C drops by 57%, coking cuts increase by a factor of 4, sulphur content rises by a factor of 5, softening point grows by a factor of 5, and kinematic viscosity at 80°C increases by a factor of 80.

Atmospheric residues with density in excess of 930 kg/m³ are hardly suitable for further refining, given the difficulties of pumping the same through process pipelines.

Two samples have been taken from each crude oil type light, medium and heavy and then subjected, alternatively, to the low temperature aquacracking process for atmospheric distillation as illustrated in Figure 26, and as described in more detail above.

In brief, refinery residue 306 from an atmospheric distillation tower 301 is transferred to a generator 36, where pretreated water vapour 304 is injected. Once exiting the generator the flow is recycled back to the atmospheric tower above a certain level 303. Light cuts additionally generated are separated out in the atmospheric tower 301. Atmospheric tower residue 305 is transferred to either a delayed coker or a desulfurization plant and a needle coking plant. Conditions of the low temperature aquacracking process:

• Process temperature 340-360°C;

• Generator capacity is double the capacity of atmospheric residue output;

• Agent ratio, crude residue to water vapour, 100 to 0.1 -0.5.

Experimental data of the aquacracking process using different crudes are summarised in Table 2. The additional yield for various fractions due to the aquacracking process is quantified, and the characteristics of residue following extraction of the under 350 °C fractions after aquacracking is shown.

Table 2. Yields of different fractions of various samples with and without aquacracking, and characteristics of residue with aquacracking. The results in Table 2 show that for various crudes subjected to the low temperature aquacracking process the yield of under-350°C cuts can be increased to 85-91% of feedstock crude. The greatest yields are observed with crudes in the 850-890 kg/m³ density range. For comparison, standard atmospheric and vacuum distillation (without aquacracking) is analysed. The process is adjusted to provide a comparable depth of light distillate output as the process with aquacracking as indicated in Table 2. Table 3 shows the characteristics of the residue resulting from such a process with vacuum distillation.

Atmospheric and vacuum distillation of crude oil to the requisite output depth

Table 3. Characteristics of the residue in with vacuum distillation instead of aquacracking.

A comparison of the residues in the two cases in terms of key properties, such as the softening point, kinematic viscosity at 80°C, and coking cuts in case of vacuum distillation, shows that only crude oils under 850 kg/m³ in density could be used; even so, 35-42% of the cuts so produced would consist of vacuum gasoil, which would require subsequent conventional cracking.

In case of crude oils above 850 kg/m³ in density, atmospheric and vacuum distillation cannot achieve the output depth of up to 90%, given that the resultant residue would have a softening point above 80°C, kinematic viscosity in excess of 30,000 mm²/sec, and a threshold coking cut of over 30%. This poses a risk of domino-effect coking in the bottom section of the vacuum tower and the pipelines.

By contrast, crude residue obtained using low temperature aquacracking such as in the example illustrated in Figure 26 is suitable for transfer via process pipelines; it is also suitable for further use in coking processes.

Low temperature aquacracking of atmospheric oil residues offers an alternative to hydrogen-based techniques of crude residue processing. It increases the depth of feedstock crude refining while boosting the yield of light distillates that boil off at temperatures under 350°C only, with minimum costs involved by way of process support. It is applied as part of the primary refining processes, using a crude distillation unit as a co-reactor. The performance of the distillation process with aquacracking is compared to the performance of the distillation process without aquacracking (with or without vacuum distillation) in Figures 27-32.

In Figure 27 the yield of an under 350°C fraction (i.e. having a boiling temperature below 350°C at atmospheric pressure) is shown for an atmospheric distillation process 310 without aquacracking, and for an aquacracking process 312, for different densities of crude oil processed. This corresponds to the data in the first three rows of Table 2.

In Figure 28 the yield of an under 350°C fraction is shown for a process 314 combining atmospheric distillation with aquacracking, for different densities of crude oil. This corresponds to the data in the fourth row of Table 2.

As crude density increases, the yield of cuts under 350°C obtained through the standard process drops by a factor of around 2.3. As crude density increases, low temperature aquacracking increases the yield of cuts under 350°C by a factor of 2.1 based on crude feedstock amount. A maximum combined yield is observed within the oil density range of 850-880 kg/m³. As crude density increases to 960 kg/m³, the combined yield declines and drops to 95% of the maximum combined yield.

In Figure 29 the sulphur content of residue from atmospheric distillation is shown for an atmospheric distillation process combined with vacuum distillation 320, and for an atmospheric distillation process combined with aquacracking 322, for different densities of crude oil processed. This corresponds to the sulphur content data in Tables 2 and 3.0verall the sulphur content in aquacracking residue is lower than in vacuum distillation residue by 35-38%.

In Figure 30 the fraction of residue that can be coked from atmospheric distillation is shown for an atmospheric distillation process combined with vacuum distillation 330, and for an atmospheric distillation process combined with aquacracking 332, for different densities of crude oil processed. This corresponds to the coking cut data in Tables 2 and 3. The coking cuts in aquacracking residues are lower than in vacuum distillation residues by 45-55%.

In Figure 31 the softening temperature of residue from atmospheric distillation is shown for an atmospheric distillation process combined with vacuum distillation 340, and for an atmospheric distillation process combined with aquacracking 342, for different densities of crude oil processed. This corresponds to the softening temperature data in Tables 2 and 3. The softening temperatures in aquacracking residues are lower than in vacuum distillation residues by 65-70%.

In Figure 32 the kinematic viscosity of residue is shown against its softening temperature for different densities of crude oil. A first line 350 represents a process combining atmospheric distillation with vacuum distillation, and a second line 352 represents a process combining atmospheric distillation with aquacracking. The data points correspond to the kinematic viscosity and softening temperature data in Tables 2 and 3. A fitted curve is plotted based on the sets of data points. The kinematic viscosity in aquacracking residue is lower than in vacuum distillation residue by 40-45%. To summarise, the process with aquacracking instead of vacuum distillation can provide a higher output of straight-run cuts under 350°C and significantly improve the quality of resultant petroleum residues.

Next the performance of the aquacracking process operated at different pressures is investigated. The characteristics of the crude oil feedstock used for the comparison are: · Density at 20°C, kg/m³ - 875.1

• Kinematic viscosity, at 20°C, mm²/sec - 19.1

• Sulphur, % wt - 1.71

• Coking tendency, % wt - 5.0

• Aromatics, % wt - 3.1 · Olefins, % - 0.7

In the aquacracking processes such as is illustrated in Figures 2a, 2b and 4 the feed to the generator is at near-atmospheric pressure, and in the generator the flow is compressed to a higher pressure (i.e. average pressure of the flow) - in one example to 8 atm (810 kPa, or approximately 800 kPa), and in another example to 12 atm (1.2 MPa). The results of the aquacracking process under the different conditions is summarised in Table 4. For comparison the performance data of a conventional process combining atmospheric distillation and vacuum distillation (labelled as ‘standard method’ in table 4) is also shown.

Table 4. Comparison of atmospheric distillation results using standard process vs. process with aquacracking operated at 8 or 12 atm pressure.

In the 12 atm mode the process was optimized by adjusting the flow rate of stripped oil feedstock to the distillation tower, to make sure the equipment stayed within its operating envelope. In particular heat exchangers for condensing light hydrocarbon cuts can limit capacity, and to avoid such heat exchangers from becoming overloaded a gradual reduction of stripped oil feed rate by 40% was implemented. As the generator fed processed atmospheric residue back to the distillation tower this flow was balanced by the reduced volume of stripped oil feed. The aggregate volume of light hydrocarbon cuts so extracted is corrected for the diminishing feedstock.

The performance of the aquacracking process under the different conditions is summarised in Table 5.

Table 5. Comparison of atmospheric distillation performance using standard process vs. process with aquacracking operated at 8 or 12 atm pressure.

In assessing efficiency of the method applied for in the context of atmospheric distillation of crude oil, due regard should be taken of gas output, comprising 1.2% wt of the crude oil feedstock, gasoline output from the first tower, at 4.1 %, and losses, at 1 %.

Table 4 shows characteristics of the products obtained in the second atmospheric tower 14 using the standard process vs. the process with aquacracking; this shows that the recirculation of generator-processed atmospheric residue into the product concentrating section of the second atmospheric tower increases the yield of gasoline and diesel cuts and reduces their sulphur content as well as aromatic and olefin content as light cuts are formed in the atmospheric residue so recirculated and pretreated in the generator. The light cut yield increases 40% to improve oil refining yield to 91 % without using either a vacuum tower or secondary processes.

Further estimates suggest that subsequent heating of atmospheric residue resulting from the process with aquacracking in a fired heater to enable vacuum distillation or coking takes 2 to 4 times less energy than in the same process without aquacracking.

The increased yield of light hydrocarbon cuts to 91% and a radical reduction of costs involved in subsequent processes make low-temperature aquacracking a useful process in crude oil refining. Low-temperature aquacracking is feasible in the context of oil fractionation at crude and vacuum distillation units. Efficiency of this process improves significantly in case of refining heavy sour grades of crude oil.

The aquacracking process described above can crack heavy hydrocarbons, for example from atmospheric residue. Processing of other hydrocarbon cuts in a similar manner can provide benefits, and in particular quality improvements to the hydrocarbon cut. Processing of other hydrocarbon cuts in a generator (as described above) is now described in more detail.

Figure 33 shows a schematic flow diagram of an oil refinery with a flow generator unit 400 included in each of the gasoline streams for blending. Figures 34 and 35 show process flow charts of examples of a flow generator unit 400 in more detail. A flow generator unit 400 may be similar to an aquacracking unit 100 described above, albeit that it is integrated in a different part of a refinery process and processes different hydrocarbon cuts.

In a flow generator unit 400 a stream of a gasoline cut 403 from the preceding processing units (e.g. from a hydrocracker) enter tank 401 , also referred to as a buffer tank 401. In an example the tank 401 is a 20-100 m³ tank of the existing tank farm. From a lower region of the tank 401 a stream 406 of hydrocarbons is fed to a generator 402. A water stream 404 is also fed to the generator 402. The generator 402 is similar or same as a generator 36 described above. After being processed in the generator 402, an onward stream 409 of hydrocarbons (now with components that have reacted) is transferred to the product tank farm for blending. In case the stream from the generator 402 exceeds the capacity of onward stream 409, discharge circulation circuit 408 is available, for returning overflow to the tank 401. More or less of the stream from the generator 402 may be recycled back to the tank 401, depending on circumstances, but ideally onward stream 409 discharges the full proportion of the stream from the generator 402 and matches the feed stream 403 in volume terms. An optional drain line 405 is shown that can permit maintaining the hydrocarbon level in the tank 401, for example in case of a spike in hydrocarbon feed volume via feed line 403. Vapours may be vented from the top of the tank 401 via line 407, to be condensed and further processed.

In the generator 402 a liquid flow of hydrocarbons is flowed under low temperature conditions, e.g. at 25 °C. The generator 402 creates flow conditions in the liquid flow that initiate and promote a variety of reactions in the hydrocarbon flow. The generator 402 can generate toroidal and spatial vortices in a liquid flow, as described above.

In brief, the generator causes formation of a vortex braid in the flow. The vortex braid splits up into toroid and spatial vortices that subject the liquid stream to alternating accelerations varying from +16,000,000 to -16,000,000 m/sec² and create pressures in various portions of the liquid flow varying from 500 bar (50 megapascal (MPa) or 510 atmospheres (atm)) overpressure to 0.1 bar (0.01 MPa) vacuum. These conditions create a stress state in the liquid and maintain it for a short period. The generator 402 produces toroid and spatial vortices in the flow so that the hydrocarbons in the flow are subjected to the resultant alternating high frequency oscillations in flow velocity (acceleration) and pressure, whereby a “stress” condition is created and momentarily maintained.

The stream is brought into contact with water, e.g. by injecting water (in liquid or in vapour phase depending on the processing temperature), and with one or more catalysts to initiate a number of processes that take place in parallel and sequentially. These conditions initiate and promote reactions of the hydrocarbons.

As the generator produces a stress condition, also referred to as a supercritical state, in the mixture of hydrocarbons and water, a number of reactions take place in parallel and sequentially, including hydrogenation, catalytic cracking (aquacracking), reforming, isomerization, and hydration. Those rely on the use of a heterogeneous process involving activation and simultaneous catalysis with preset selectivity, productivity, and operational stability in a system of “liquid - liquid - solid state catalyst”, where:

Liquid agent: hydrocarbon gasoline cuts;

Liquid agent: water;

Solid contact catalyst: e.g. containing 17-19% chromium, 9-11% nickel, 0.8% titanium, 1.5% manganese, and 0.03% copper.

Several distinct reactions of the hydrocarbons take place following processing in the generator under addition of water and exposure to a catalyst, both in parallel and sequentially, including:

• decomposition of water molecules to provide hydrogen;

• hydrogenation, taking place using ionized hydrogen obtained from water molecules;

• aquacracking, a cracking process involving water molecules (aquacracking is described in more detail above, and may include occurrence of any of the other reactions listed here in connection with the cracking products);

• reforming, including reactions converting naphthene hydrocarbons into aromatics by way of dehydrogenation; isomerization reactions converting pentatomic cycloalkane into cyclohexane derivatives; isomerization reactions converting n- alkanes into iso-alkanes; and reactions converting alkanes into aromatics by way of dehydrocyclization;

• isomerization, converting coverts n-alkanes into iso-alkanes; and

• hydration, whereby water molecules are radically attached to hydrocarbon radicals produced by way of aquacracking. Cracking refers to the breaking-down of long chain hydrocarbons into short ones. Aquacracking refers to the use of water molecules in cracking as a source of hydrogen to block uncontrolled merging of broken-down hydrocarbon chains without formation of coke or naphthenic substances. Molecules of hydrocarbon compounds are radically split to produce two short-lived or two long-lived hydrocarbon radicals. In aquacracking both water dissociation occurs, as well as cracking of hydrocarbons, both by virtue of the conditions provided by the generator. The combination of water dissociation and hydrocarbon cracking can enable minimal formation of unsaturated compounds and minimal gas formation.

Light hydrocarbon radicals that are formed during aquacracking are hydrogenated by hydrogen atoms in branched saturated hydrocarbons and on periphery of aromatics compounds with high hydride mobility. Recombination processes are predominant to obtain stable light hydrocarbon molecules and minimize gas formation. Unsaturated hydrocarbons formed by cracking are hydrated by water molecules, as water molecules in water dissociate.

The generator creates flow conditions in the liquid flow that initiate and promote water dissociation as well as cracking in combination with the water dissociation, alongside the other reactions listed above. By virtue of the generator and the flow conditions created by the generator the reactions can occur at 25 °C and in a feed provided at atmospheric pressure or near-atmospheric pressure, e.g. 1.2-1.5 atm (122-152 kPa). The generator 402 creates conditions to bring the system of hydrocarbons and water into a supercritical state with a high frequency of local time periods. In this state the “hydrocarbon fraction - water” system forms a complete mutual solution of low density. Under the conditions created in the flow reactions are initiated and take place.

Water molecules are provided in the form of a water stream (in liquid phase at the processing temperature of 25 °C as described above) that is fed to the generator 402 through a nozzle 212 as described above.

Selectivity of aquacracking is achieved by exposing the flow to an appropriate solid catalyst as described above.

The properties of supercritical water and hydrocarbons are adjustable; at higher pressures, the mixture’s dissolving capacity improves dramatically. Light and heavy hydrocarbons dissolve in supercritical water with no limit, given that the dissolving capacity of supercritical systems is much higher than otherwise.

The temperature of processing in the generator 402 is consistent with the temperature of the hydrocarbon feed, e.g. 25 °C. In the illustrated examples the hydrocarbon feed is a gasoline cut with a boiling temperature in the range of e.g. 28-180 °C and the use of a process temperatures below the lowest boiling point, e.g. a process temperature below 28 °C, can reduce potential evaporation of the hydrocarbon feed so processed. A suitable process temperature may for example be in the range of 4-25 °C for gasoline cuts, but may be higher or lower depending on the hydrocarbon feed.

The pressure of water fed into the generator 402 ranges from around 2 to 6 atmosphere (203-608 kPa, or around 200-600 kPa).

The hydrocarbon stream and water stream are fed into the generator 402 at a mass ratio that is appropriate for the type of stream, for example ranging from 100:10 to 100:40 w/w hydrocarbomwater.

The average pressure in the flow downstream of the generator may be several atm (e.g. 8 or 10 or 12 atm), and this pressure may be released to drop the average pressure to the working pressure at the flow destination. Local pressure variations may exist due to toroidal vortices persisting.

The reactions take place within the generator, substantially immediately under the influence of the toroid and spatial vortices. At temperatures above around 120^°C reactions can continue downstream of the generator 402, but at lower temperatures (e.g. at around 25 ^°C as described above) reactions do not significantly take place downstream of the generator, once the toroid and spatial vortices dissipate.

The hydrocarbon feed is a gasoline cut with a boiling temperature in the range of e.g. 28-180 °C, and therefore it does not generally contain substantial quantities of components that would inhibit radical processes (unlike for example a crude oil feed or a distillation residue feed). Reactions take place in sufficient rates at around 25 ^°C to have a measurable effect on the characteristics of the gasoline stream.

The entire sequence thus described occurs as a continuous process.

A refinery may include flow generator units 400 in all of the gasoline blending streams as illustrated in Figure 33, or alternatively a subset of gasoline blending streams may include flow generator units 400 in order to selectively improve the quality of a sub-set of streams.

Some of the secondary processing units as shown in Figure 33 (e.g. for isomerisation, hydrotreating, reforming, alkylation) may be omitted if a flow generator unit 400 is included in a particular stream. If a flow generator unit 400 is included in a particular stream in addition to the secondary processing units the resulting product has improved characteristics (and overall a refinery can produce a greater quantity of higher quality product), but depending on the intended purpose the changes in the stream provided by the processor in the absence of a particular secondary processing unit can be sufficient.

By virtue of the inclusion of flow generator units 400 the yield of market-grade gasolines may increase to exceed the original quantities by 25-30%, while their quality is preserved and the burning of such cuts in any internal combustion engines, including automotive ones, does not adversely affect atmospheric discharges, greenhouse effect, or other types of environmental pollution.

Addition of 30% water to the hydrocarbon at the flow generator units, and reaction of that water with the hydrocarbons under the influence of toroidal vortices in the flow, can reduce by 50% or more the pollutants from internal combustion engine going in to the atmosphere, whilst preserving all the qualities of market fuels.

An advantage of the described approach comes from the fact that the processes in the flow generator unit 400 can take place at lower temperatures, e.g. 25 °C, and at atmospheric pressure. By contrast, conventional quality enhancing processes generally require higher temperatures, often in excess of 400 °C.

By enabling the omission of conventional quality enhancing processes concentration of costs on building new units can be avoided, operating expenses can be reduced, and fundamentally the industrial hazards associated with refinery operations can be reduced.

One other advantage may be seen in that the generator 402 used in the described flow generator unit 400 is derived by adapting a standard centrifugal pump found in refinery processes, as it is centrifugal pumps that serve as principal pumping units at refineries. Such pumps achieve the highest efficiency when pumping low viscosity liquids; they take little material to build while offering lower costs, design simplicity, high reliability, and ease of maintenance. Such pumps are usually already located at the tank farm of a refinery, e.g. in a pump room. A 20-100 m³ tank of an existing tank farm can serve as tank 401 in a flow generator unit 400. Existing groups of plants, complexes and facilities can be easily and efficiently adapted to include flow generator units 400.

The processing steps can take place at a refinery tank farm without having to carry out a full or partial rebuild, turnaround or retrofit of the refinery or having to suspend its operations, and without using any processes involving hydrogen or chemicals or any other processes posing fire, explosion, or environmental hazards. Implementation at an operating existing refinery neither involves full or partial outage of such refinery nor requires any major overhaul or retrofit that would necessitate full or partial disruption of the refinery’s operating mode.

Another advantage is that the quality enhancement process involves minimum production of gases.

Now examples of the processing of different types of hydrocarbon stream and the quality enhancement achieved are provided in more detail.

T o test the enhancement provided by processing in the generator, a set of gasoline cuts is blended into various blends. The properties of the resulting blends are measured. The blends are then further processed with the generator under specific conditions, and the properties following processing are measured. Comparison of the properties before and after processing in the generator characterises the changes brough about by processing in the generator.

Table 1 provides characteristics of various samples of conventional gasoline cuts used for gasoline blending. The properties of these samples depend on the properties of the crude oil used and the details of the refinery operation (for which many variants are known in the art), and these samples are merely examples of possible gasoline cuts.

Table 1. Characteristics of several conventional gasoline fractions used for blending market-grade gasoline.

The ‘cat reformed’ gasoline sample was obtained from a gasoline catalytic reforming process at a real-life refinery, following a process that corresponds to the example illustrated in Figure 33; the ‘cat reformed’ sample corresponds to the stream marked ‘Reformate’ in Figure 33.

The sample of ‘straight-run’ gasoline obtained by atmospheric distillation was sampled upstream of the isomerization unit at a real-life refinery, following a process that corresponds to the example illustrated in Figure 33. Table 2 provides compositions of various conventional gasoline blends of the hydrocarbon gasoline samples of Table 1. For example Blend 1 is formed exclusively of the hydrocracked gasoline 40-85 °C fraction, and Blend 3 is formed of 83.3 wt% hydrocracked gasoline 28-225 °C fraction and 16.2 wt% straight-run gasoline.

Table 3. Measured characteristics of Blend 1 - Blend 9 of Table 2.

Table 4 provides process conditions for processing various gasoline samples as characterised in Table 1 in a generator 402 as described above.

Table 4. Process conditions of different hydrocarbon gasoline cuts in a generator. The flow is processed in the generator without any recycling of the processed flow back to a buffer tank or for re-processing in the generator.

For processing the blends as characterised in Table 3 a process temperature in the range of 4-20 °C is used and a generator pressure of 7-8 atm is used.

Table 5 quantifies the water stream at the generator 402 relative to the hydrocarbon stream for various blends as characterised in Table 2. It can be seen that the ratio varies from 100:18 to 100:34 hydrocarbon:water by weight for the different blends undergoing processing. An asterisk symbol (*) marks blends undergoing processing in the generator.

Table 5. water stream at generator per hydrocarbon flow, for different hydrocarbon blends.

The described hydrocarbon:water ratios were determined by adjusting the ratios until the resultant flow contains no unreacted water post processing. These ratios present optimum ratios for the particular samples, for which the reactions occur most efficiently without surplus water being provided and processed, but such that water availability does not limit the reactions. Processing can take place as sub-optimal conditions as well, but for efficiency the water proportion is ideally adjusted as appropriate for a particular stream. Table 5 also illustrates that the water mass is converted in the reactions, and the mass of hydrocarbon product obtained is greater than that of the hydrocarbon feedstock. For example for blend 1* 100g of hydrocarbon feed produce approximately 118g of hydrocarbon product, by virtue of 18g of water consumed in the generator.

Depending on the composition of the hydrocarbon feed a proportion of the water is consumed in side products other than hydrocarbons. For example if the sulfur content is high then a part of the water is consumed in forming hydrogen sulfide H₂S in hydration reactions. It can be seen from Table 5 that the gasoline sample with particularly high sulfur content (e.g. blend 9) can consume particularly high water mass (mass ratio 100:32 hydrocarbon:water). In case of formation of gas products such as hydrogen sulfide such gas may be collected downstream of the generator as is well known in the context of refinery operation. Table 6 provides measured characteristics of the various gasoline blends described above, following processing in the generator under the conditions indicated above. An asterisk symbol (*) marks blends following processing in the generator.

Table 6. Measured characteristics of Blend 1* - Blend 9* (corresponding to Blend 1 - Blend 9 of Table 2 following processing in a generator).

Table 7 provides further measured characteristics of Blend 1* - Blend 9* (corresponding to Blend 1 - Blend 9 of Table 2 following processing in a generator as indicated above).

Table 7. Further measured characteristics of Blend 1* - Blend 9* (corresponding to Blend 1 - Blend 9 of Table 2 following processing in a generator).

As seen from the test results summarized in Tables 6 and 7 compared against the data for unprocessed blends (summarized in Table 3) processing in the generator results in following enhancements of the blends:

• A meaningful drop in olefin hydrocarbon content as aromatic hydrocarbon content increases without benzene formation;

• A meaningful drop in sulfur content;

• A meaningful increase of octane number. Prior to processing the Research octane numbers of the blends were in the range of 53.9 to 81.3; processing increased all Research octane numbers to over 80, in the range of 81.2 to 96.1.

Blend 8* is formed to 100% of a straight-run gasoline cut, and processing in the generator with water at a mass ratio of 100:28 hydrocarbon water increases the Research octane number from 53.9 to 81.2, by approximately 50%. Processing also reduces sulfur content from 410 ppm to 7 ppm or by a factor of 58. A minor amount of a high-octane gasoline component can be blended in to increase the Research octane number further and provide a market-grade gasoline.

Blend 9* is formed to 100% of a coker-derived gasoline cut, and processing in the generator with water at a mass ratio of 100:32 hydrocarbon water increases the Research octane number from 70 to 86, by approximately 23%. Processing also: • reduces sulfur content from 4670 ppm to 12 ppm or by a factor of 400;

• reduces benzene content from 5.7% to 0.7% or by 714%; and

• reduces olefin content from 50% to 4% or by a factor of 12.5.

Blend 2* is formed to 100% of a 28-225°C cut of hydrocracked gasoline, and processing in the generator with water at a mass ratio of 100:34 hydrocarbomwater increases the Research octane number from 66 to 95 or by 44%. Processing also reduces sulfur content from 7 ppm to 4 ppm or by a factor of 1.75.

Catalytically cracked gasoline (FCC gasoline) is conventionally a relatively high quality gasoline and generally has more favorable characteristics than for example coker- derived gasoline. Test data (not shown) indicate that catalytically cracked gasoline is observed to be similarly improved by processing in the generator and can also be rendered directly suitable as a market-grade gasoline. A minor amount of a high-octane gasoline component can be blended in to increase the Research octane number further, if appropriate.

In the tested samples the olefin content typically is in the range from 0.1% to 0.4%, and the volume share of benzene typically does not exceed 0.6%.

Efficiency can improve in case heavier gasolines are processed. For heavier gasoline streams the water addition per 100g of hydrocarbon flow can rises to 35-40g water, and generator pressure increase to 12 atm can optimize the processing.

Generally processing in the generator can increase the production quantity of a particular gasoline fuel product or grade by 25-30%. In addition, the properties of otherwise low-quality gasoline blend feedstock can be improved (which could otherwise only be used in fairly low proportions).

Precipitation of impurities

Under the conditions created in the generator, and in particular under the influence of toroidal vortices created in the flow, the physicochemical properties of the liquid can be altered. A similar effect occurs in liquids near their critical point; it is known that near the critical point, the physical properties of a liquid typically change (e.g. compressibility, relative permittivity, solvent behaviour). This can tip an equilibrium toward a more favourable state and permit separation of impurities. It is observed that an impurity in a hydrocarbon, such as sulphur in a fuel oil, can be precipitated under the influence of toroidal vortices created in the flow. In the case of sulphur colloidal sulphur is formed under the influence of toroidal vortices in the flow, which can be removed form the fluid by filtration. In an example fuel oil with 3-5% sulphur and up to 3% water is processed in the generator. The resulting flow contains 0.3-0.5% sulphur and up to 5% colloidal sulphur.

Alternatives It will be appreciated from the above description that many features of the different examples are interchangeable and combinable. The disclosure extends to further examples comprising features from different examples combined together in ways not specifically mentioned. Indeed, there are many features presented in the above examples and it will be apparent that these may be advantageously combined with one another.

As used herein, the term ‘aquacracking’ preferably includes variants of the process of cracking hydrocarbons with the generator in the absence of water vapour. In some examples an alternative source of hydrogen is provided instead of the saturated water vapour described above, for example a hydrogen-containing hydrocarbon gas, an unsaturated gas containing water vapour, or hydrogen gas.

It should be appreciated that cracking of hydrocarbons generally can be achieved with the generator and process described above. In general, the process can crack a stream of hydrocarbons to a mixture of lighter hydrocarbons. The mixture of cracking products can be tailored for example by selection of catalysts, hydrogen source, and operating conditions of the generator (e.g. temperature, average pressure of the flow at the outlet of the generator).

In the examples discussed above the hydrocarbon stream is an atmospheric distillation residue that is maintained at around 340-360 °C from the outlet of the distillation tower until the stream is recycled back into the distillation tower. A range of 340-360 °C is particularly suitable for a high rate of cracking in the examples described above. More generally aquacracking (e.g. of lighter hydrocarbons or in examples where the feed is not already at around 340-360 °C) may be initiated at lower temperatures, for example in the range of 120 °C and above. The hydrocarbon stream may be heated at or downstream of the generator to increase the rate of aquacracking following initiation. At temperatures above 400 °C gases and unsaturated hydrocarbons may be formed, and temperatures lower than 400 °C are preferred.

While examples are provided of various gasoline cuts being processed in a generator prior to blending, the same benefits can be achieved if a blend is processed in a generator after blending. In some examples the generator can be arranged both to achieve blending as well as at the same time improving the characteristics of the resulting product.

In some examples an alternative source of hydrogen is provided instead of the water described above, for example a hydrogen-containing hydrocarbon gas, an unsaturated gas containing water, or hydrogen gas.

It should be appreciated that reactions of hydrocarbons generally can be achieved with the generator and process described above. In general, the process can react a stream of hydrocarbons. The mixture of products can be tailored for example by selection of catalysts, hydrogen source, and operating conditions of the generator (e.g. temperature, average pressure of the flow at the outlet of the generator).

In particular, while the described examples focus on processing gasoline streams for gasoline blending, other streams may be similarly processed to enhance the properties of the stream. For example diesel streams for diesel fuel blending, streams for aviation fuel or other kerosene products, with or without blending, or streams for naphta products may be similarly processed to enhance the properties of the stream. Also heavier hydrocarbon fuel products such as fuel oils, marine fuels, thermal power plant fuels and heating fuels can be similarly processed in order to improve the fuel properties and obtain a higher quality and value fuel. The processes described above can be adapted to hydrocarbon fuels generally (including gasoline fuels, aviation fuels, diesel fuels and fuel oils), be it before blending into a fuel product or after. Such processing can enhance the properties of hydrocarbon fuels generally. The process conditions for such hydrocarbons may be adapted, and in particular optimum processing pressure, processing temperature, water: hydrocarbon mass flow rate and catalyst may be varied from those described for the examples concerning processing gasoline streams. Generally for heavier streams the water addition per 100g of hydrocarbon flow may increase (e.g. per 100g of hydrocarbon 35-40g water or more), the processing temperature may be higher (e.g. above 25 °C, but advantageously below a boiling temperature of the flow), and the generator pressure (e.g. 12 atm) may be higher to optimize the processing.

While the described examples focus on processing hydrocarbon streams in a refinery setting, it is not essential that the processing take place at a refinery. Generally, processing can take place at any stage prior to consuming the hydrocarbon fuel. For example, processing may take place at a facility for storing petroleum products, for instance at an airport or at a river or marine port, and generally at fuel tank farms; at storage facilities of gasoline distribution systems; on tankers carrying petroleum products; and at other hydrocarbon fuel storage locations.

While gasoline from an oil refining process is provided as an example, the process is equally applicable to gasoline derived from other sources than from crude oil, for example gasoline derived from coal with a similar result.

In the examples described above a nozzle is provided at the generator for introducing the water stream into the hydrocarbon stream, substantially where the toroidal vortices are formed. In other examples the water stream is introduced to the hydrocarbon stream upstream of the generator, and the nozzle feature described above is omitted from the generator.

Claims

1. An aquacracking method of cracking hydrocarbons, comprising steps of: providing a liquid comprising hydrocarbons; and forming a flow with toroidal vortices in the liquid comprising hydrocarbons, such that the liquid comprising hydrocarbons is exposed to alternating flow velocities and alternating pressures, thereby initiating cracking of the hydrocarbons.

2. An aquacracking method according to claim 1, wherein the liquid comprising hydrocarbons is at a temperature up to 400 °C, preferably up to 380 °C, further preferably up to 360 °C.

3. An aquacracking method according to claim 1 or 2, wherein the liquid comprising hydrocarbons comprises a fraction of a crude oil, preferably an atmospheric distillation residue, further preferably a distillation fraction of a crude oil, the fraction being hydrocarbons with a boiling point above 300 °C at atmospheric pressure, preferably above 340 °C at atmospheric pressure, further preferably above 350 °C at atmospheric pressure.

4. An aquacracking method according to any preceding claim, further comprising providing a hydrogen source, preferably water vapour, to the flow.

5. An aquacracking method according to claim 4, wherein the hydrogen source, preferably water vapour, is provided to the flow at or near where the toroidal vortices are formed, preferably downstream from a rotor-stator assembly that forms the toroidal vortices.

6. An aquacracking method according to claim 4 or 5, wherein a ratio of the mass flow rates of the liquid comprising hydrocarbons to water vapour is 100:0.1 or more, preferably up to 100:0.5.

7. An aquacracking method according to any of claims 4 to 6, wherein the water vapour is injected at a pressure of 200 kPa or more, preferably 300 kPa or more, more preferably up to 700 kPa, further preferably at a pressure below an average pressure of the flow with toroidal vortices at the point of injection.

8. An aquacracking method according to any preceding claim, further comprising passing the flow over a fixed catalyst.

9. An aquacracking method according to claim 8, wherein the fixed catalyst is one or more parts of a device that forms toroidal vortices in the flow, the one or more parts being formed of a material with a catalytic effect and/or the parts having a material with a catalytic effect at a surface.

10. An aquacracking method according to claim 9, wherein the material includes one or more of: 16-19 wt % chromium; 9-14 wt % nickel; 0.1-1 wt % titanium; 1-2 wt % manganese; and 0.01-0.05 wt % copper.

11. An aquacracking method according to any preceding claim, wherein the flow comprises local pressures of at least 10 MPa, preferably at least 25 MPa, further preferably at least 50 MPa; and/or wherein the flow comprises local pressures of up to 1 mPa, preferably up to 0.1 mPa, further preferably up to 0.01 mPa; and/or wherein the flow comprises local velocities of at least 100 meters per second, preferably at least 200 meters per second, further preferably up to 400 meters per second.

12. An aquacracking method according to any preceding claim, wherein the flow with toroidal vortices has an average pressure of at least 600 kPa, preferably at least 800 kPa, further preferably up to 1.2 MPa; and/or wherein the flow with toroidal vortices has an average velocity of at least 10 meters per second, preferably at least 20 meters per second, further preferably up to 60 meters per second.

13. An aquacracking method according to any preceding claim wherein the peripheral flow velocity in a toroidal vortex is greater than the flow velocity in the fluid outside the toroidal vortex by a factor of at least 3, preferably by a factor of at least 6, further preferably by a factor of at least 10.

14. An aquacracking method according to any preceding claim, wherein the flow comprises high-frequency alternating flow velocities and/or high-frequency alternating pressures, preferably wherein high frequency is at least 500 Hz, preferably at least 1000 Hz, further preferably at least 2000 Hz.

15. An aquacracking method according to any preceding claim, wherein the toroidal vortices have a typical diameter of at least 10 μm, preferably at least 20 μm, further preferably at least 40 μm; and/or wherein the flow includes at least 150, preferably at least 200, further preferably at least 500 toroidal vortices per litre of liquid comprising hydrocarbons.

16. An aquacracking method according to any preceding claim, wherein the flow is formed by a notched rotor rotating in cooperation with a notched stator to block and open cyclically a plurality of passages for a fluid.

17. A method of refining crude oil, comprising cracking a portion of crude oil according to the aquacracking method of any preceding claim, preferably wherein the portion of crude oil is a portion of a distillation residue from a distillation device, the method preferably comprising: flowing a portion of a distillation residue from a distillation device; initiating cracking according to the aquacracking method of any of claims 1 to 16; and recycling the flow back to the distillation device for further separation of cracking products formed downstream of the formation of toroidal vortices in the flow.

18. A method according to claim 17, wherein the portion of a distillation residue is at least 25% by mass of the distillation residue.

19. A method according to claim 17 or 18, wherein the distillation device is an atmospheric distillation device, and the distillation residue is an atmospheric distillation residue; and/or wherein the distillation device further separates a heavy gasoline cut, a kerosene cut, and a diesel cut; and/or wherein the flow is recycled back to the distillation device below the level of a primary feed to the distillation device.

20. Aquacracking apparatus for cracking hydrocarbons, comprising a flow generator adapted to form a flow with toroidal vortices in a liquid comprising hydrocarbons such that the liquid comprising hydrocarbons is exposed to alternating flow velocities and alternating pressures for initiating cracking of the hydrocarbons.

21. Aquacracking apparatus according to claim 20, wherein the flow generator comprises a notched rotor rotatable in cooperation with a notched stator to block and open cyclically a plurality of passages for a fluid to form the flow.

22. Aquacracking apparatus according to claim 20 or 21 , further comprising at least one nozzle for injecting a hydrogen source, preferably water vapour, to the flow, preferably wherein the at least one nozzle is arranged to provide the hydrogen source downstream of the or a rotor-stator assembly.

23. Aquacracking apparatus according to any of claims 20 to 22, wherein at least a portion of the apparatus arranged to be in contact with the fluid comprises a fixed catalyst, preferably wherein the fixed catalyst is at a surface of one or more parts of the apparatus, preferably at a surface of a rotor and/or a stator of the apparatus.

24. Aquacracking apparatus according to any of claims 20 to 23, comprising one or more parts formed of a material with one or more of: 17-19 wt % chromium; 9-11 wt % nickel; 0.8 wt % titanium; 1.5 wt % manganese; and 0.03 wt % copper.

25. Aquacracking apparatus according to any of claims 20 to 24, adapted to perform the method of any of claims 1 to 16.

26. An oil refinery comprising aquacracking apparatus according to any of claims 20 to 25 and/or adapted to perform the method of any of claims 17 to 19.

27. An oil refinery according to claim 26 further including a distillation device, a conduit arranged to provide a portion of a distillation residue from the distillation device to the aquacracking apparatus, and a further conduit arranged to recycle flow from the aquacracking apparatus back to the distillation device.

28. A method of processing hydrocarbons, comprising steps of: providing a liquid comprising hydrocarbons and water; forming a flow with toroidal vortices in the liquid, such that the hydrocarbons and water are exposed to alternating flow velocities and alternating pressures; thereby initiating reactions of the hydrocarbons and water.

29. A method according to claim 28, wherein the liquid comprising hydrocarbons is a gasoline, preferably a gasoline fraction obtained from processing of crude oil.

30. A method according to claim 28 or 29, wherein the liquid comprising hydrocarbons is a straight-run gasoline or a gasoline obtained from cracking of a crude oil fraction, optionally a gasoline obtained from coker processing of a crude oil fraction, or a gasoline obtained from hydrocracking of a crude oil fraction, or a gasoline obtained from catalytic cracking of a crude oil fraction.

31. A method according to claim 28, wherein the liquid comprising hydrocarbons is a diesel, preferably a diesel fraction obtained from processing of crude oil; or wherein the liquid comprising hydrocarbons is an aviation fuel or a kerosene or a fuel oil or a marine fuel or a thermal power plant fuel or a heating fuel.

32. A method according to any of claims 28 to 31 , wherein a process temperature is below a boiling point of the hydrocarbons being processed, preferably at least 5 - 10 °C below a boiling point of the hydrocarbons being processed, further preferably wherein the process temperature is below 50 °C or below 25 °C or in the range of 15 to 20 °C.

33. A method according to any of claims 28 to 32, wherein a ratio of the mass flow rates of the hydrocarbons to water is 100:0.1 or more, preferably 100:10 or more, further preferably 100:15 or more.

34. A method according to any of claims 28 to 33, wherein a ratio of the mass flow rates of the hydrocarbons to water is up to 100:50, preferably up to 100:40.

35. A method according to any of claims 28 to 34, wherein the water is provided to the flow at or near where the toroidal vortices are formed, preferably downstream from a rotor-stator assembly that forms the toroidal vortices.

36. A method according to any of claims 28 to 35, further comprising passing the flow over a fixed catalyst or introducing a catalyst into the flow.

37. A method according to claim 36, wherein the fixed catalyst is one or more parts of a device that forms toroidal vortices in the flow, the one or more parts being formed of a material with a catalytic effect and/or the parts having a material with a catalytic effect at a surface.

38. A method according to claim 37, wherein the material includes one or more of: 16-19 wt % chromium; 9-14 wt % nickel; 0.1-1 wt % titanium; 1-2 wt % manganese; and 0.01-0.05 wt % copper.

39. A method according to any of claims 28 to 38, wherein the flow comprises local pressures of at least 10 MPa, preferably at least 25 MPa, further preferably at least 50 MPa; and/or wherein the flow comprises local pressures of up to 1 mPa, preferably up to 0.1 mPa, further preferably up to 0.01 mPa; and/or wherein the flow comprises local velocities of at least 100 meters per second, preferably at least 200 meters per second, further preferably up to 400 meters per second.

40. A method according to any of claims 28 to 39, wherein the flow with toroidal vortices has an average pressure of at least 600 kPa, preferably at least 800 kPa, further preferably up to 1.2 MPa; and/or wherein the flow with toroidal vortices has an average velocity of at least 10 meters per second, preferably at least 20 meters per second, further preferably up to 60 meters per second.

41. A method according to any of claims 28 to 40 wherein the peripheral flow velocity in a toroidal vortex is greater than the flow velocity in the fluid outside the toroidal vortex by a factor of at least 3, preferably by a factor of at least 6, further preferably by a factor of at least 10.

42. A method according to any of claims 28 to 41 , wherein the flow comprises high- frequency alternating flow velocities and/or high-frequency alternating pressures, preferably wherein high frequency is at least 500 Hz, preferably at least 1000 Hz, further preferably at least 2000 Hz.

43. A method according to any of claims 28 to 42, wherein the toroidal vortices have a typical diameter of at least 10 μm, preferably at least 20 μm, further preferably at least 40 μm; and/or wherein the flow includes at least 150, preferably at least 200, further preferably at least 500 toroidal vortices per litre of liquid.

44. A method according to any of claims 28 to 43, wherein the flow is formed by a notched rotor rotating in cooperation with a notched stator to block and open cyclically a plurality of passages for a fluid.

45. Apparatus for processing hydrocarbons, comprising a flow generator adapted to form a flow with toroidal vortices in a liquid comprising hydrocarbons and water such that the hydrocarbons and water are exposed to alternating flow velocities and alternating pressures for initiating reactions of the hydrocarbons and water.

46. Apparatus according to claim 45, wherein the flow generator comprises a notched rotor rotatable in cooperation with a notched stator to block and open cyclically a plurality of passages for a fluid to form the flow.

47. Apparatus according to claim 45 or 46, further comprising at least one nozzle for injecting water, to the flow, preferably wherein the at least one nozzle is arranged to provide the hydrogen source downstream of the or a rotor-stator assembly.

48. Apparatus according to any of claims 45 to 47, wherein at least a portion of the apparatus arranged to be in contact with the fluid comprises a fixed catalyst, preferably wherein the fixed catalyst is at a surface of one or more parts of the apparatus, preferably at a surface of a rotor and/or a stator of the apparatus.

49. Apparatus according to any of claims 45 to 48, comprising one or more parts formed of a material with one or more of: 17-19 wt % chromium; 9-11 wt % nickel; 0.8 wt % titanium; 1.5 wt % manganese; and 0.03 wt % copper.

50. Apparatus according to any of claims 45 to 49, adapted to perform the method of any of claims 28 to 44.

51. An oil refinery or a hydrocarbon storage facility comprising apparatus according to any of claims 45 to 50.

52. An oil refinery or a hydrocarbon storage facility according to claim 51 further including a tank for storing a gasoline or a diesel oil, a conduit arranged to provide a portion of gasoline or diesel oil from the tank to the apparatus, and optionally a further conduit arranged to recycle flow from the apparatus back to the tank.