NL2032930B1

NL2032930B1 - Methods and apparatuses for plastics pyrolysis

Info

Publication number: NL2032930B1
Application number: NL2032930A
Authority: NL
Inventors: Braat Rob; Christiaan Van Der Ree Teunis; Heijmans Sem; Goldsmits Rik
Original assignee: Bluealp Innovations B V
Priority date: 2022-08-31
Filing date: 2022-08-31
Publication date: 2024-03-15
Also published as: WO2024046894A1

Abstract

A process for pyrolysis of plastics material, the process comprising the steps of: - heating plastics material to pyrolysis temperature to provide a stream of pyrolyzed gaseous hydrocarbons; - passing the stream of pyrolyzed gaseous hydrocarbons to a partial condenser and condensing a partial fraction of said stream of pyrolyzed gaseous hydrocarbons to a condensed liquid; - passing non-condensed gaseous hydrocarbons from the partial condenser to a distillation apparatus; - passing said condensed liquid from the partial condenser to a reheater, preferably a reboiler - heating said condensed liquid in the reheater to increase its temperature, preferably to a temperature greater than that of the partial condenser to provide reheated liquid hydrocarbon material; and - reintroducing at least a portion of the reheated liquid hydrocarbon material upstream of the partial condenser for pyrolysis.

Description

METHODS AND APPARATUSES FOR PLASTICS PYROLYSIS

FIELD OF THE INVENTION

The invention generally concerns methods and apparatuses to process waste plastics by means of pyrolysis, as well as the products obtained thereby. More specifically the invention concerns methods and apparatuses for treatment of preheated streams of plastic and plastic derived hydrocarbons that are undergoing pyrolysis. More particularly, the invention concerns effective phase separation and/or completion of pyrolysis of plastic-derived hydrocarbons.

BACKGROUND OF THE INVENTION

Large quantities of waste plastics are generated in the present society. While recycling of plastics is becoming ever more efficient and effective, it is still the case that much of the waste plastic cannot be effectively or efficiently recycled and is disposed of to landfill sites where it takes many years to degrade, or it may be lost to the environment where it can be damaging to ecosystems.

Plastic materials are however made of essentially useful compounds that can be used as is and/or converted for (re)use. For example, fuels such as diesel may be derived from waste plastics, or waste plastics may be converted to raw material suitable for synthesis of new materials, such as new plastics, other hydrocarbon materials, or similar. Materials recovered from waste plastics may be useful to at least partially replace hydrocarbons more traditionally obtained from natural gas or mineral oils.

The output of plastic-to-chemical plants typically includes light hydrocarbons (LHC), heavy hydrocarbons (HHC), char, and non-condensables (gases). Currently, LHC, HHC, or mixtures thereof, are the most desirable products, however, this is market dependent.

LHC and HHC fractions are required by industry to meet certain chemical and physical specifications such as vapor pressure, initial boiling point, final boiling point, Flash point, viscosity, cloud point and cold filter plugging point. Different qualities may be desired by different customers or end-uses, but it is important that plastic-to-chemical plants produce product of stable quality. The final qualities of the product fractions is controlled by a distillation column such as those well-known and commonly used in the petrochemical industry. It is desirable that the fractions are relatively pure such that light hydrocarbons fraction and heavy hydrocarbons do not contain large portions of high boiling point compounds. Such high boiling point compounds can increase cold filter plugging points, cloud point and are often unacceptable to pyrolysis oil purchasers.

In plastic-to-chemical plants, feedstock plastics, which may comprise for the most polyethylene and polypropylene for domestic sources, form the input. These plastics made up of very long chain hydrocarbons are then cracked into shorter chains, forming a wide spectrum of molecules with a variety of chain lengths. These mixtures can be distilled into various temperature-determined fractions as is known.

A known process in the art for converting waste plastic to, among other things diesel, is the thermochemical breakdown process of pyrolysis. Pyrolysis is the thermal decomposition of the waste plastics in an inert atmosphere. In effect, the long polymer chains of the plastic’s polymers are cracked through heating, resulting in shorter hydrocarbon chains, which are generally more useful as a product.

Pyrolysis is a preferred method of performing thermochemical break down of waste plastic materials. Various attempts to provide technically and cost-effective pyrolysis of waste plastic have been attempted previously.

Technically useful results have been achieved by the technologies discussed in patent publications US2018/0010050 and WO2021053139, the contents of which publications are incorporated herein by reference.

US2018/0010050A1, discusses a method for recovering hydrocarbons from plastic wastes by pyrolysis without the use of catalysts, in particular polyolefin-rich waste. The process involves melting the plastic waste in two heating devices and admixing a stream derived from a cracking reactor with the incoming molten plastic waste of a first heating device. The heated, molten plastic is passed to a cracking reactor where the plastic materials are cracked. Subsequent thereto the cracked materials are distilled into diesel and low boilers.

WO 2021/053139 A1, which offers a number of advancements in relation to

US2018/0010050A1, discusses, among other matters, a method for breaking down long- chain hydrocarbons from plastic-containing waste, comprising providing material containing long-chain hydrocarbons; heating a specific volume of the material containing long-chain hydrocarbons to a cracking temperature, at which cracking temperature the chains of hydrocarbons in the material start cracking into shorter chains; and for the specific volume having a temperature above the cracking temperature, exposing the specific volume to heat which is less than or equal to 50 °C above the temperature of the specific volume.

Although good results have been achieved based on the above technologies, there remains room for further improvement, for example it would be useful to provide systems and processes that are more versatile than previously attempted systems.

While the present invention has a general aim the overall system improvement of such pyrolysis processes and apparatuses, aspects of improvement may preferably include one or more of the following.

In an aspect of the invention, it may be useful to reduce or limit char formation in the vessel where pyrolyzed gaseous hydrocarbons are separated from liquid, partially-pyrolyzed plastic material.

In another aspect of the invention, it may be useful to achieve better control of product fractions that are sent to distillation, and which fractions are eventually distilled. For example, to achieve more commercially useful ratios of non-condensables, light hydrocarbon fractions, and heavy hydrocarbon fractions in the product streams.

In another aspect of the invention, it may be useful to provide a system and process that is compact, allowing possible ease of placement and a more acceptable format to meet governmental planning permission requirements.

In another aspect of the invention, it may be desirable to improve reliability of processes.

In another aspect of the invention, it may be desirable to improve or limit downtime of the system.

In another aspect of the invention, it may be advantageous to expand or diversify the product streams available for production by the pyrolysis process, for example, for production of heavier fractions such as paraffins at controllable quantities.

It is a non-limiting object of the present invention to provide efficient, versatile, and/or robust processes and apparatuses for conversion of waste plastic to useful product streams, e.g. non-condensable gasses, light hydrocarbons, heavy hydrocarbons, paraffins, bitumen, tar and other similar derivable fractions. In this respect the invention may address, for example, one of more of the foregoing problems or at least provide the technical arts with a useful choice.

Attempts to achieve effective pyrolysis of waste plastics have been previously made.

An example is discussed in patent publication WO11077419 A1 referring to a process for treating waste plastics, in which plastic is melted and then pyrolysed in an oxygen-free atmosphere in a jacket-heated pyrolysis vessel to provide pyrolysis gases. The pyrolysis gases upwardly flow via a pipe directly linking the pyrolysis chamber to a contactor vessel, into contact with plates in the contactor vessel so that some long chain gas components condense. The condensed liquid is directly returned by downward flow through the same pipe, to the pyrolysis zone. The condensed liquid is then reheated within the pyrolysis zone and further pyrolyzed. The short chain gas components exit the contactor in gaseous form and proceed to distillation.

It is explained in WO11077419 A1 that as a batch ends, increased load on a pyrolysis chamber agitator indicates that char drying is taking place, and that the process is ending.

The pyrolysis chambers are then purged by operating double-helical agitator blades in reverse to remove char, and nitrogen is passed up through the contactor and out directly to thermal oxidisers to flush any remaining hydrocarbons, during which phase the pyrolysis vessel and contactor are isolated from the rest of the system. Such a process and system can be problematic and suboptimal. For example, the inclusion of an agitator in the pyrolysis chamber, as well as jacketed direct heating of the pyrolysis chamber, is complex yet necessary. The system also makes use of a specific type of jacket-cooled contactor with cooled contactor baffle plates that are sloped and comprise apertures, to give direct return of condensed hydrocarbons from the contactor to the pyrolysis chamber via the same pipe by which pyrolysis gases entered the contactor. This can be complex; the pyrolysis process leads to batch completion with a dry char (carbon) product; and purging associated with extended downtime of pyrolysis reactors.

There are prior attempts in which a partial condenser has been arranged directly on top of a pyrolysis vessel to return heavy hydrocarbons for further cracking. Some of these attempts have been found to be less versatile, robust, and efficient than is optimal. Without being bound by theory, and by identification through technical investigation, it may be that the condensed liquid returning from the partial condenser directly into a pyrolysis reactor vessel can lead to temperature inconsistencies and heat loss in a pyrolysis zone, requiring complex heat input at the pyrolysis zone, with possible hot spots, charring, complex agitation, and/or energy loss. Provision of a process and system that suffers less from such disadvantages may be desirable.

Another example is discussed in CH708681A1, which refers to a process for recovering hydrocarbons from polyolefin plastic recyclables by means of pyrolytic cracking. Plastic recyclables are introduced into a mixing vessel under inert gas and mixing with diesel oil, removing water vapor in a first heating zone, removing acidic gases in a second heating zone, liquefying those not yet melted plastic recyclables in a third heating zone, cracking of the plastic recyclables in a cracking reactor at about 400°C, partial condensation to prevent the discharge of paraffins, and fractionation of the cracked products.

The partial condenser in CH708681A1 is separate and spaced from the pyrolysis reactor, with a communicating pipe leading pyrolyzed gases from the pyrolysis reactor to the partial condenser. The partial condenser is adjusted so that heavy hydrocarbons that are not of the desired product character condense and are led back into a third heating zone, via a separate pipe, where they can be further cracked. The additional cracking loop reduces the inclusion of overly heavy hydrocarbons in the product.

Attempts to implement related concepts to those disclosed in CH708681A1 were found to 5 workably result in product but showed some instability in pyrolysis and inefficiencies, for example, requiring complex heating in the pyrolysis zone. In addition, the system of

CH708681A1 may be complex to implement because of differential pressures between the partial condenser and the heating zone to which the heavy hydrocarbons are returned.

Other attempts have included US10160920 BB with a sequential cracking process for the thermal cracking of a hydrocarbon feedstock in a cascade of cracking units; US2007227874

AA discussing a method for recovering fractional hydrocarbons from recycled plastic, and

US5580443 A which discusses a process for thermally cracking a low-quality feed stock containing a considerable proportion of heavy fractions such as high-boiling fraction.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art.

SUMMARY

In accordance with an aspect of the invention there is provided a process for pyrolysis of plastics material. The process comprises the steps of - heating plastics material to pyrolysis temperature to provide a stream of pyrolyzed gaseous hydrocarbons; - passing the stream of pyrolyzed gaseous hydrocarbons to a partial condenser and condensing a fraction of said stream of pyrolyzed gaseous hydrocarbons to a condensed liquid; - passing non-condensed gaseous hydrocarbons from the partial condenser to a distillation apparatus; - passing the condensed liquid from the partial condenser to a reheater, preferably a reboiler; - heating said condensed liquid in the reheater to increase its temperature, preferably to a temperature greater than that of the partial condenser to provide reheated liquid hydrocarbon material, and - reintroducing at least a portion of the reheated liquid hydrocarbon material upstream of the partial condenser for pyrolysis.

In accordance with an aspect of the invention there is provided an apparatus for pyrolyzing waste plastics to one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising:

a heating device, preferably a heat exchanger, for receiving and heating waste plastic to pyrolysis temperature; a separator vessel downstream of the heating device, wherein the separator device comprises: an inlet arranged to receive pyrolysis temperature, gaseous and liquid plastics waste, and possibly solid particles, from the heating device, an upper outlet for exit of gaseous material, and a lower outlet for exit of liquid material; a partial condenser downstream of the separator vessel, wherein the partial condenser comprises: a partial condenser inlet arranged to receive gaseous material from the separating vessel, a partial condenser upper outlet for exit of gaseous material, and a partial condenser lower outlet for exit of condensed, liquid material, wherein the partial condenser is configured to condense a fraction of said gaseous material to a condensed liquid; a reheater vessel comprising: a heater, a reheater inlet arranged to receive condensed, liquid material from the partial condenser, and a reheater outlet in fluid communication with a return-line arranged to return liquid material for pyrolysis upstream of the partial condenser; and a distillation device having a distillation inlet arranged to receive gaseous material from the partial condenser from the partial condenser upper outlet.

In an aspect it may be that the invention provides both stable and effective pyrolysis. Without wishing to be bound by theory, using a reheater / reboiler in advance of recycling condensate from the partial condenser to a pyrolysis zone, offers a preheating of the heavy hydrocarbons recycle stream, which can assist in avoidance of heat loss at the point of pyrolysis, and/or cold spots and temperature inconsistencies in the pyrolysis zone. Such temperature variations can lead to inefficient pyrolysis and unwanted variation in product qualities. Without wishing to be bound by theory, it may be that problematic, localized or sudden temperature drops in the separation vessel or pyrolysis zones may occur due to (reintroduction of evaporable components such a low boiling fractions or fast boiling fractions, which act as a heat drain due to latent heat of vaporization.

The reheater is preferably a reboiler. Reboilers are known in the form of heat exchangers that are used to generate vapor supplied to the bottom tray of distillation columns. The liquid from the bottom of the column is partially vaporized in the exchanger. In an aspect of the present invention a reboiler provided at the bottom of a distillation column may provide both reboiling of vapours into the distillation column, as well as reheating of liquids requiring further cracking, for return to a pyrolysis zone upstream of the partial condenser.

In a further aspect, it may be useful to reduce or limit char formation in the vessel where pyrolyzed gases are separated from liquid, partially-pyrolyzed plastic material. In that respect, it may be useful to reduce, limit or avoid, direct heating of such a vessel, for example heating of the vessel wall, or inclusion of a heating element (such as a heating coil) within such a vessel. The preferred separator vessel of the present invention is not heated, e.g. no jacket heater or internal heating element is provided. The introduced stream of molten waste plastics may be provided already at pyrolysis temperature and does not require additional heating in the separation vessel. In some preferred embodiments, liquid, partially-pyrolyzed plastic material collected in the separation vessel is controllably removed from the separation vessel, preferably by pump, and reheated, preferably in a heat exchanger, to pyrolysis temperatures prior to being returned to the separation vessel, optionally together with fresh feed. Long-chain hydrocarbons in the removed liquid may thus be subjected to further pyrolysis and broken down to shorter-chain hydrocarbons, eventually exiting via the partial condenser.

It has been determined that this may assist in reducing char formation in such a vessel, as well as reducing or removing the need for an auger or other mechanical stirrer providing agitation. In that respect, it may be useful to reduce sources of heat loss from the separation volume and/or pyrolysis chambers, which then require direct heating to compensate for heat losses. Without wishing to be bound by theory, it has been identified that in a partial condenser or contactor with direct return to a separation vessel and/or pyrolysis zone, the cooled condensates are a heat drain on the system resulting in cooling and requiring compensatory (direct) heating. Inclusion of a reboiler for receipt of condensates from the partial condenser may allow controlled (partial) reheating of the condensates in the reboiler prior to return to a pyrolysis zone, with a limited impact to the heat density of the system, and a reduced need for direct heating that may result in charring or require agitation, possibly complex agitation, mechanisms. The partial condenser is in this respect preferably separated from the pyrolysis zone.

In a further aspect it may be useful to achieve better control of product fractions sent to distillation, and eventually distilled. For example, to achieve more commercially useful ratios of the non-condensables, light hydrocarbons, and heavy hydrocarbon fractions in the product streams. In that respect, it may be useful to reduce the return of light ends from a contactor or partial condenser to pyrolyzing conditions where they may be, disadvantageously, further cracked resulting in higher proportion of desired product oils, such as HHC and/or LHC fractions, or mixtures thereof. Without wishing to be bound by theory, it has been identified that in a partial condenser or contactor with direct return to a pyrolysis zone, light ends may be co-condensed with heavy boilers and sent back to the pyrolysis zone. Inclusion of a reboiler for receipt of condensates from the partial condenser may allow controlled re-evaporation of light components from the reboiler to the distillation unit and into the light hydrocarbons or heavy hydrocarbons product streams, avoiding them being further thermally degraded, for example into overly short hydrocarbon chains, such fractions that are non-condensable in distillation, also known as non-condensable gases.

Part of improving the fractions is also found in the ability to remove light fractions in the reboiler and pass these to distillation instead of back to the pyrolysis zone(s). Those light hydrocarbons that are condensed together with heavy hydrocarbons in the partial condenser, if immediately returned to the pyrolysis zone according to some prior art examples, spend very little residence time in the zone and are immediately evaporated again to the partial condenser where they are cooled to condense, and then again returned to the pyrolysis zone. It may be that the portion of this fraction of borderline light hydrocarbons increases as it is continually passed through the circuit relatively unchanged. Apart from increasing the recirculated volume of material to little gain, the repetitive cooling and reheating of a returning portion is an energy drain, and thus contributes to inefficiency. It is preferred in the present invention that the stream of pyrolyzed gaseous hydrocarbons is passed to the partial condenser via a first conduit, and the condensed liquid stream from the partial condenser is passed to the reheater via a second conduit, separate from the first conduit.

It may be advantageous that the partial condenser is provided as a unit separate and/or remote from a distillation column and/or from a pyrolysis vessel. This may allow the distillation column or cracking reactor to have a limited or reduced height. In turn this may be useful in providing a system and process that is compact, which may provide for ease of placement and more readily meet governmental planning permission requirements. In some embodiments the partial condenser is arranged as a unit separate and/or remote from any pyrolysis vessels and any distillation columns. In other embodiments, the partial condenser may be arranged as a unit separate and/or remote from any pyrolysis vessels, and be incorporated with, or made integral with, a distillation section, for example in a distillation column.

A further advantage of the invention may be found in good reliability of process and limited downtime. Without wishing to be bound by theory, provision of the combination of partial condenser and a reboiler may allow continuous circulation of condensate from the partial condenser, through a reboiler and to the separation vessel and/or pyrolysis zone. This continuous circulation decreases the chance of plugging in piping from the reboiler towards the separator vessel or pyrolysis zone, and/or provides a stable process operation. The continuous flow can also assist in improving the heat transfer from the reboiler (addition of heat) to the heavy hydrocarbons liquid in the reboiler.

A further advantage may be found in an ability to expand or diversify product streams available for production by the pyrolysis process, for example, for production of heavier fractions such as paraffins at controllable quantities. Without wishing to be bound by theory, it has been identified that in a partial condenser or contactor with direct return to a pyrolysis zone (e.g. pyrolyzed gases from the heated zone pass upwardly through the same pipe by which condensates from cooled contactors return) heavy fractions are (almost) fully cracked into lighter fractions, with loss of potentially useful materials such as paraffins or heavier hydrocarbons. Inclusion of a reboiler for receipt of condensates from a partial condenser may allow controlled removal of some or all the heavy condensates from the reboiler as valuable product. Light fractions can be boiled off for further distillation and a portion of the condensates not removed as product can be heated and returned to pyrolysis for further cracking.

Condensate at the bottom of the reboiler we thus be collected, and those heavy hydrocarbons sent as an additional product stream out of the process.

In a further aspect, the invention may assist in effective and efficient start-up operations.

Without wishing to be bound by theory, provision of a partial condenser may allow system operation in which (partially pyrolyzed) liquid is retained inside the separator vessel, and or pyrolysis reactors during startup operations. In this manner, during startup the separation vessel is (partially) filled with hydrocarbon liquid such of a diesel or similar heavy hydrocarbon fraction. This liquid may then be heated via an external heat exchanger, to cause its partial evaporation. Inclusion of a partial condenser may assist in returning the heavy fractions of this startup liquid to the separation vessel and/or pyrolysis zone, while gradual heating is attained and plastic for pyrolysis is gradually added to the system. Such a startup may assist in providing a smooth and stable startup.

Furthermore, without wishing to be bound by theory, it may be advantageous to achieve local preheating or temperature control of components at startup. This may also assist in achieving a smooth and stable startup. Without being bound to theory it is believed that the separation of the partial condenser from the pyrolysis vessel may allow a straight-forward preheating of the partial condenser prior to the startup.

In a further aspect, the invention may assist in effective and efficient provision of hot-standby operation. Without wishing to be bound by theory, provision of a partial condenser may allow system operation in which (partially pyrolyzed) liquid is retained inside the separator vessel, and or pyrolysis reactors during standby operations. In this manner, during standby the separation vessel remains (partially) filled with hydrocarbon liquid such as diesel or similar heavy hydrocarbon fraction. This liquid may then be heated via an external heat exchanger, to cause its partial evaporation. Inclusion of a partial condenser may assist in returning the heavy fractions of this startup liquid to the separation vessel and/or pyrolysis zone, while components and content of the system are stably kept at standby temperatures. The ability to maintain the system in stable and efficient standby operation may assist in reduced need for shut-down and star-procedures.

In some embodiments, the partial condenser may be arranged to be heatable such that the majority or substantially all gaseous product from the separator vessel escapes the partial condenser. Heating may be achieved by provision of thermal oil to those elements, such as a coil, normally operated as cooling elements. Heating may bring the partial condenser to temperatures of at least 350°C, more preferably at least 400°C, preferably about 410°C.

Heating of the partial condenser may be useful to assist in regulated start-up operations.

The waste plastic feedstock may preferably comprise polyethylene and/or polypropylene plastics. Preferably the sum of polyethylene and polypropylene in the feedstock is at least 50 wt.% by weight of the feedstock, more preferably at least 60 wt. %, still more preferably at least 75 wt.%, most preferably at least 90 wt.% . These materials represent a large portion of domestic plastic waste and are treatable by pyrolysis.

The feedstock may also comprise polyvinylchloride plastics, however, the level of PVC may preferably be limited to less than 10 wt.%. PVC may be present at greater than 1 wt.%, more preferably greater than 5 wt.%. An effective absence of PVC in the feedstock may be preferred.

The feedstock may also comprise polyethylene terephthalate plastics, preferably greater than 3 wt.% of polyethylene terephthalate plastics, more preferably greater than 4 wt.%. The feedstock preferably comprises maximally 20 wt.% PET plastic. Preferably the content of polyethylene terephthalate plastics is maximally 10 wt.%, more preferably 5 wt. %.

The feedstock may comprise up to 100 wt.% polystyrene plastics. In embodiments, the feedstock may comprise at least 5 wt.%, more preferably 20 wt.%, more preferably 50wt% polystyrene.

While the most preferred pyrolysis temperature may vary within a limited range dependent upon factors such as feedstock makeup and operating pressures, preferably the plastics material is heated to a pyrolysis temperature of about 390°C or more, more preferably about 400°C or more, up to about 450°C, although higher temperatures up to about 500°C or about 550°C may be contemplated. The plastic pyrolysis may also start from about 360°C, and so such temperatures may also be contemplated. Pyrolysis is, however, more significant at or above about 390°C, which may allow for a more economically attractive process.

The term “pyrolysis zone” as used herein refers to zones in which materials that are processed by the process or system (e.g. waste plastic or the derivates thereof generated by pyrolysis in the process or system) are at pyrolysis temperatures, for example at temperatures at or above 360°C, more preferably at temperatures at or above 390°C, still more preferably at or above 400°C. Pyrolysis zones are preferably those zones in the process or system in which the processed materials are at temperatures from about 360°C to about 550°C, more preferably from about 390°C to about 500°C, still more preferably from about 400°C to about 500°C. The process and system may comprise pyrolysis zones of different activity. For example, there may be primary pyrolysis zones in which the majority of pyrolysis occurs, which are preferably at temperatures above 390°C, and second pyrolysis zones in which the temperatures are above 360°C but below 390°C. Pyrolysis zones may be present in the initial heater, in the separation vessel and in a heated recycling loop.

The pyrolysis is, as commonly understood, carried out in the absence of oxygen, most preferably under an inert atmosphere, such as under nitrogen gas. The operating pressure of the separator vessel is preferably above ambient to ensure that ambient air does not enter the system. The pressure may be from 1 bar abs. to 5 bar abs., 1 bar abs. to 3 bar abs., 1 bar abs. to 2 bar abs., or 1 bar abs. to 1.5 bar abs.

The pyrolyzed gaseous material from the separator vessel is preferably supplied to the partial condenser via a packed column. This lengthens the path for separating the hydrocarbons that have not yet been sufficiently cracked (typically having more than 22 C atoms). This has the beneficial effect that the partial condenser may be operated at a higher temperature without a significant fraction of hydrocarbons of excessive length being able to leave the partial condenser, or so that the temperature in the partial condenser does not have to be set so low that a significant fraction of hydrocarbons having 22 or fewer C atoms are condensed.

The partial condenser may be settable in a range of about 150°C to about 400°C, more preferably the partial condenser may be operated at a temperature from about 220°C to about 380°C, or still more preferably from about 290°C to about 330°C. Setting the temperature of the partial condenser may assist in adjusting the chain length of the selectively condensed hydrocarbons, as particular needs of a user demand. It may be preferable for condensation of chain lengths of 22 C atoms and more, more preferably 25 C and more, more preferably 28 C and more, that the temperature be set to a temperature from 300°C to 330°C, preferably about 330°C, about 320°C, about 300°C or about 290°C.

The operation temperature of the partial condenser is the temperature to which the partial condenser is to cool the condensable incoming gas and so selectively condense a higher boiling point fraction from a lower boiling peint fraction which remains as a gas. The partial condenser temperature is measured as the outlet temperature of the partial condenser, for example it may be measured at the upper portion of the partial condenser downstream of a final cooling zone or element. The condensed liquid in the partial condenser is sent to the reboiler.

The gases/vapors exiting from the partial condenser are preferably supplied to a distillation unit. The distillation unit may comprise at least in part a packed column and be provided with an intermediate tray. The gases/vapors are fractionated into a gaseous fraction and a liquid fraction in this distillation unit. The liquid fraction is stripped off at the intermediate tray as

HHC product, and the gaseous fraction is stripped off at the top of the distillation column.

The gaseous fraction is cooled, so that LHC such as light boilers may condense and be stripped off as a liquid fraction. The uncondensed gases are preferably used as fuel, or feedstock for chemical processes, sent to a refinery for recycling, or sent to a gas treater such as a Fischer-Tropsch process.

The lengths of the hydrocarbons in the individual fractions may be well controlled on the one hand via the temperature of the partial condenser, and on the other hand via the length of the distillation column and the temperature therein and in the cooler.

The reboiler is preferably operated at a temperature from 340°C to 400°C, preferably at about 360°C to 380°C. Operating the reboiler at these temperatures may evaporate or boil off short chain hydrocarbons carried along with the condensate from partial condenser e.g. about <22 C atoms or more preferably <25 C, more preferably <28 C. These short chain hydrocarbons can be sent for distillation in the distillation device where they are taken up as product. This is preferable to them being cracked further or remaining in a heating/cooling loop. The particular operation temperature of the reheater is preferably higher than the operating temperature of the partial condenser in order to evaporate or boil off a portion of the material that condensed in the partial condenser. It is preferred that pyrolysis not take place or be limited in the reheater, the reheater operation temperature is thus preferably below the pyrolysis temperature. The operation temperature of the reboiler is determined as the temperature of the liquid body within the reboiler during operation. The temperature may be selected to drive off lower volatility fractions, while leaving heavier fractions as a liquid in the reboiler.

Preferably the hydrocarbons having more than 22 C atoms, more preferably more than 25 C, more preferably more than 28 C, remain in the reboiler and are returned upstream of the partial condenser for further pyrolysis. The return may be to the separator vessel and/or to the heating device, e.g. a heat exchanger. Alternatively, these longer hydrocarbons may be removed as product e.g. as paraffin product.

In some embodiments the reheater vessel may be provided with an upper outlet for exit of gaseous material to the distillation device. Preferably the distillation device may be provided atop the reheater vessel in fluid communication with the upper outlet thereof. It may be particularly advantageous to position the reboiler within the distillation column, more specifically at the bottom of the distillation column. This may allow improved capture of portions of lighter hydrocarbons from the partial condenser condensate, with their transfer to the distillation column for inclusion in product streams. This has been found to possibly by preferable to return of these lighter hydrocarbons to pyrolysis, where these already light hydrocarbons may be cracked further, representing energy wastage and loss of valuable product. The upper temperature (i.e. at the upper section of the distillation column prior to exit of non-condensed gases from a distillation column) may be a set temperature of from about 60°C to about 150°C, more preferably from about 80°C to about 120°C. The upper distillation column temperature may be measured as the upper outlet stream of the distillation column, for example it may be measured at the upper portion of the distillation column downstream of a final cooling zone or element.

Downstream of a distillation column gas release, there may be provided an LHC condenser for condensation of light hydrocarbons from the gas stream exiting the distillation column.

The condensed LHC fraction may be a useful product. The operating temperature of the

LHC condenser may be a set temperature of from about 35°C to about 60°C, more preferably from about 40°C to about 55°C. The LHC condenser temperature may be is measured as the temperature of the condensed liquid.. The LHC condensed in the LHA condenser may usefully be employed a reflux medium in the distillation unit.

Prior to the partial condenser, the plastics material heated to pyrolysis temperature is preferably passed to a gas-liquid separation vessel in which pyrolyzed gaseous and liquid materials diverge. This is preferably done under gravity with pyrolyzed gaseous material passing upwardly to the partial condenser via a separation vessel upper outlet, and liquid material passing downwardly.

In preferred embodiments, the liquid material that separates downwardly in the separation vessel is removed from the separation vessel, (re)heated to pyrolysis temperature and returned to the separation vessel. The liquid material is so further cracked to eventually provided gaseous material that is passed to the partial condenser and eventually to distillation.

The pyrolysis of the invention preferably provides one or more hydrocarbon products, preferably wherein the hydrocarbon products include one or more of butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha, or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel, or mixtures thereof, heavy distillates and residuum such as fuel ail, lubricating oils, paraffin, wax, asphalt, or mixtures thereof. Hydrocarbon products may be saturated, unsaturated, straight, cyclic or aromatic.

Further product may include non-condensable gases, comprising methane, ethane, ethene and/or other small molecules. The products may be a source of feedstock for steam crackers of the manufacture of plastics.

The term “non-condensables” or “non-condensable gases” as variously referred to, identifies hydrocarbon fractions that are too volatile to condense in the distillation section, and that may, preferably will, exit the process as a gas. It is generally considered that non- condensable hydrocarbons in the pyrolysis process have from about 1 to about 7 carbon atoms. The non-condensables may include hydrocarbons that are saturated, unsaturated, straight, cyclic and/or aromatic.

The term “light hydrocarbons” or “LHC” as variously referred to, identifies hydrocarbon fractions that are condensable in the process and so obtainable as a liquid, yet which comprise short-chain molecules. It is generally considered that LHCs in the pyrolysis process have from about 3 to about 8 carbon atoms, possibly with some smaller portion of

C2 molecules and/or C10 molecules. The LHCs may include hydrocarbons that are saturated, unsaturated, straight, cyclic and/or aromatic.

The term “heavy hydrocarbons” or “HHC” as variously referred to, identifies hydrocarbon fractions that are condensable in the process and so obtainable as a liquid, with generally longer chain composition than LHCs. It is generally considered that HHCs in the pyrolysis process have at least about 7 carbon atoms (possibly with some smaller portion of C6 molecules), preferably up to about 35 carbon atoms. Preferred ranges may include low range products of about 7 to about 20 carbon atoms, possibly with some smaller portion of

C6 and/or C21 molecules. For the low range product, the final boiling point of the HHC may be about 430°C. Another preferred range may include medium range products of from about 8 to about 28 carbon atoms. For the medium range product, the final boiling point of the

HHC may be about 450°C. Another preferred range may include high range products from about 10 to about 35 carbon atoms. For the high range product, the final boiling point of the

HHC may be about 550°C. HHCs may include hydrocarbons that are saturated, unsaturated, straight, cyclic and/or aromatic.

It will be appreciated by the skilled reader dealing with petrochemicals, that there may be some variation in the boundary between non-condensables, LHC and HHC in a distillation process. Overlap and/or variation may be dependent, inter alia, upon chosen temperature, pressures and flow settings, and product specification may be adjusted to accommodate desired product qualities.

Possible settings leading to low range product compositions may include: a partial condenser outlet temperature of about 290°C; a reboiler (liquid) temperature of about 360°C, an upper distillation column outlet temperature of about 80°C, an LHC condenser temperature of the condensed LHC liquid of about 42°C about

Final Boiling Point of HHC: 430°C

Possible settings leading to medium range product compositions may include: a partial condenser outlet temperature of about 320°C; a reboiler (liquid) temperature of about 380°C, an upper distillation column outlet temperature of about 100°C, an LHC condenser temperature of the condensed LHC liquid of about 42°C about

Final Boiling Point of HHC: 450°C

Possible settings leading to high range product compositions may include:

a partial condenser outlet temperature of about 330°C; a reboiler (liquid) temperature of about 380°C, an upper distillation column outlet temperature of about 120°C, an LHC condenser temperature of the condensed LHC liquid of about 55°C about

Final Boiling Point of HHC: 550°C

While the invention is defined in the independent claims, further aspects of the invention are set forth in the dependent claims, the drawings and the following description.

BRIEF DESCRIPTION OF THE FIGURES

The features and advantages of the invention will be appreciated upon reference to the following drawings, in which:

Fig. 1 shows an assembly for cracking long chained hydrocarbons;

Fig. 2 shows an embodiment of a separation vessel, partial condenser and reboiler of Fig.1 in greater detail;

Fig. 3A shows an alternative arrangement of the separation vessel, partial condenser and reboiler; and

Fig. 3B shows a detailed partial further embodiment of the reboiler of Fig. 3.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements or steps. In addition, numerous specific details are set forth to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. Furthermore, this description is not to be considered as limiting the scope of the embodiments described herein in any way, but rather as merely describing the implementation of the various embodiments described herein. The following is a description of certain embodiments of the invention, given by way of example only and with reference to the drawings.

Fig. 1 shows an apparatus comprising a heating device 11 and a separation vessel 12. The heating device 11 is in communication with the separation vessel 12 to feed fluids (liquids and gases) into the separation vessel 12. More specifically, the heating device 11 feeds fluids containing (partially) cracked hydrocarbons in both gaseous and liquid states into the separation vessel 12 at pyrolysis temperatures.

In some embodiments a feeding device 7 is arranged to fill material containing long chained hydrocarbons such as waste plastics as discussed, into the heating device 11. In some embodiments the feeding device comprises an effector 8 for heating and/or forwarding the material containing long chained hydrocarbons. In some embodiments the effector is a screw auger 8 arranged to forward, and preferably also heat, the material containing long chained hydrocarbons. In some embodiments the screw auger 8 moves the material, and internal friction in the material causes the material to heat up and to melt. In further embodiments the feeding device 7 comprises a heating device such as an electrical heater or a heating device perfused by a heating medium such as thermal oil. The feeding device 7 drives the material containing long chained hydrocarbons to the heating device 11.

The heating device 11 receives the material containing long chained hydrocarbons. In various embodiments the heating device comprises at least one heating zone 1, 2, 3, 4. The heating zone 1, 2, 3, 4 is arranged to expose the material containing long chained hydrocarbons to a temperature increase, and thereby raise the temperature of the material to a pyrolysis temperature. Pyrolysis temperatures may be 360°C or greater, more preferably 390°C or greater, preferably 395°C or greater, preferably 400°C or greater, more preferably 410°C or greater. A pyrolysis temperature may be in the range of 360-550°C more preferably 390-450°C.

In the illustrated embodiment, four heating zones are illustrated. Each of the heating zones 1, 2, 3, 4, may be a heat exchanger, preferably a tube in shell heat exchanger. The heating zones 1, 2, 3, 4 provide a flow path for the plastics material containing long chained hydrocarbons. The heating zones 1, 2, 3, 4 continuously or gradually increase the exposure temperature along the flow path. Heating is preferably done gradually to reduce or avoid char formation through excessive temperature differentials.

The heating device 11 heats and melts plastic material feedstock, raising its temperature to a pyrolysis temperature. Cracking may start in any of the heating zones 1, 2, 3, 4, with most cracking in the heating zones preferably occurring in heating zone 4, zone 4 being the hottest heating zone of the four. The molten, partially pyrolyzed plastic material exits heating zone 4 at a pyrolysis temperature and passes into separation vessel 12 via separation vessel inlet 14.

The combination of the separation vessel, partial condenser and reboiler is illustrated more clearly in Fig. 2.

In the illustrated embodiment, the separation vessel 12 is unheated, the term “unheated” meaning that the separation vessel 12 is not heated by any source other than heat carried by incoming heated material, for example, heated material entering the inner volume of the separation device from a heating device such as the heating device 11 or another heating device as may be provided on a recycling or return loop.

It has been found to be useful to avoid provision of heating means on or in the separation vessel, as may be found in some prior attempts. This may assist in reducing char formation in the separation vessel 12 and reduces or avoids requirements for special agitation means.

For example, it has been found in prior attempts that an internal heater, such as a heating coil, can cause charring of pyrolyzing material at the surface of the heating element. That char may represent loss of product, and may collect on the heating element requiring downtime for cleaning and maintenance. The same may be true in cracking reactor type vessels wherein the wall of the vessel is heated to bring or maintain the treated material at pyrolysis temperature. Charring may occur at the inner surface of the cracking reactor wall resulting in the need for complex mixing, cleaning and downtime.

Referring again to Fig.1, a recycling loop 26 is provided to remove liquid, partially-pyrolyzed plastic material collected in the separation vessel 12 by way of pump 27. The removed liquid is reheated to a pyrolysis temperature by the heat exchanger 28, and then returned to the separation vessel 12, in the illustrated case together with fresh feed. This recycle loop 26 increases the residence time for long-chain hydrocarbons at pyrolysis temperature so that they are subjected to further pyrolysis and broken down to shorter-chain hydrocarbons, eventually exiting via the partial condenser 5. The returned stream of partially-pyrolyzed plastic material carries heat into the separation vessel 12, in which there is thus pyrolysis zone. The plastics material in the separation vessel 12 so continues to pyrolyse.

At the point of entering the separation vessel 12 via inlet 14 the plastics material is undergoing pyrolysis because it is at a pyrolysis temperature. The cracking of the plastic material results in generation of a wide spectrum of substances with a wide range of boiling points. The plastics material exiting the heating device 11 and entering the separation vessel 12 via inlet 14 comprises both gaseous and (partially cracked) liquid components.

The illustrated separation vessel 12 is elongate and arranged substantially vertically. Non- vertical arrangements may also be envisioned, such as slanted or horizontal. Pyrolyzed gaseous material rises in the separation vessel 12 and liquid (partially) pyrolyzed material falls under gravity. In this manner, gaseous and liquid materials diverge and so separate in the separation vessel 12. Phase separation of gases and liquids within the separation vessel 12 may be enhanced by provision if a cyclone separator arrangement.

The gaseous hydrocarbon materials rising in the separation vessel 12 discharge via upper outlet 23 and pass via line 6 to a partial condenser 5. Partial condenser 5 is remote from the separation vessel 12 and is positioned downstream from the separation vessel 12. It is in fluid communication with the separation vessel 12 via the line 6.

The partial condenser 5 is arranged and/or configured to remove heavy fractions (lower boiling point fractions) from the exiting gas, prior to the exiting gas being further passed to full distillation or condenser sections of the apparatus and process. In the partial condenser the gas is cooled as discussed below. As the gas is cooled, heavier fractions condense and can be collected, while lighter fractions remain gaseous and are passed via line 7 to further processing. 5

The partial condenser 5 is preferably provided with a packed column 28 with (optional) random packing material such as rings e.g. raschig rings, which increases the contact surface area between the gas and the liquid which is condensed in the partial condenser. As is known in condensation processes, this may assist in effective condensation by providing a large solid surface area for condensing gases.

The partial condenser 5 is also preferably provided with a temperature-controlled cooling element 29, such as a cooling coil supplied with temperature regulated cooling medium. The temperature of the cooling element 8 is controlled to cause condensation of long-chain hydrocarbons (longer than C22, for example), which condensed materials fall under gravity to the lower part of the partial condenser 5. The cooling element 29 is preferably downstream of the packed column 28.

As alternatives, or additionally, selective condensation may be achieved by a cooling jacket (not shown) acting as a cooling element, or the partial condenser may be an external (full reflux) condenser.

The gases that do not condense (C1-C20/C22) in the unheated packed column 28 or in the cooling element 29 discharge via a partial condenser upper outlet 37 and pass via line 30 to a downstream distillation unit of a type commonly known for distillation use in the petrochemical arts, for example as used in distillation of crude or mineral oil fractions.

The downstream distillation section can be designed according to industrial standards as known to those skilled in the art. The gases can be fractionated into gaseous fractions and liquid fractions. A liquid fraction may be stripped off as middle distillate, and a gaseous fraction may be stripped off as light boilers in a distillation unit. Hydrocarbon products from the distillation unit may comprise butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha, or mixtures thereof; middle distillates such as kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residuum such as fuel oil, lubricating oils, paraffin, wax, asphalt, or mixtures thereof; or any mixtures thereof. Hydrocarbon products may be saturated, unsaturated, straight, cyclic or aromatic. Further products may include non-condensable gases, comprising methane, ethane, ethene and/or other small molecules. The products may be a source of feedstock for steam crackers of the manufacture of plastics.

The hydrocarbons that condense in the partial condenser 5 (=C22) collect as a liquid 31 at the bottom of the partial condenser 5.

The liquid level at the bottom of the partial condenser is controlled by one or more level control sensors and may be discharged batchwise or continuously. The level control in the partial condenser 5 can be achieved continuously by way of a flow control valve.

The condensed liquid 31 in the partial condenser is preferably discharged via a partial condenser lower outlet 32 and is passed to a reboiler 16 via line 33 controlled by optional valve 34. Valve 34 can be any of an open close valve or a control valve.

The condensed liquid 31 collects in the reboiler 16, where it is reheated by a heater 13, preferably an internal heating element or an internal heat exchanger. The reboiler heater 13 can be heated electrically, with thermal oil or other types of heating medium. The condensed liquid in the reboiler 16 is heated to a temperature higher than the temperature of the partial condenser.

Light hydrocarbon fractions which may unavoidably be carried along with the partial condenser condensate liquid can in this manner be evaporated or boiled off and sent to the distillation apparatus via a reheater vessel upper outlet 15. These can then be included in the distilled products. This may improve product yields as compared to a system or process in which partially condensed material is directly returned to a pyrolysis zone. This may also be considered preferable to returning light hydrocarbons to a pyrolysis zone, where they may further crack or form a relatively useless heat drain as they are circularly heated to re- evaporate and thereafter recondensed.

The reboiler 16 is preferably comprised as a component of a distillation section and joined in fluid communication for gases via reheater vessel upper outlet 15.

Liquid 35 that is collected in the reboiler, and which does not evaporate through reheater vessel upper outlet 15 for distillation, may be pumped back into the separator vessel 12 via line 9 using pump 10, with optional further heating prior to entry into the separator vessel 12.

The liquid may in this manner be further pyrolyzed to useful lighter products than those that condense in the partial condenser 5. For example, the liquid is returned to the separating vessel 12 and or pyrolysis zone and cracked until they are reduced to chain lengths of C20 to C22 or less. The product yield may thus be improved, and or the ratio of light to heavy products be more specified to customer requirements.

Alternatively, the liquid collected in the reboiler, and which does not evaporate through reheater vessel upper outlet 15 for distillation, may be collected as a useful product, for example the product may be paraffin, and be transported to a collecting vessel via valve 21.

The partial condenser coil 29 is typically operated at temperatures between 220°C and 380°C and the reboiler is typically operated at temperatures between 340°C and 400°C.

These temperatures are both lower than the typical crack reactor operating temperature of 390°C and 450°C.

The liquid pyrolyzed material present in the separator vessel 12 is continuously circulated, preferably by means of an external pump 27. As the liquid is circulated it may be reheated to a pyrolysis temperature for further cracking by a heat exchanger 28.

A distillation column (not shown) is preferably provided atop reheater vessel upper outlet 15.

The distillation column may be provided with a region designed as a packed column, and optionally within this region containing packing or preferably above this region, an intermediate tray on which the liquid fraction (diesel product or HHC) is collected and may be discharged. The HHC, for example diesel, product discharged from the distillation unit is preferably cooled by means of a heat exchanger, and a portion of this cooled diesel product may be recirculated to the distillation unit via a recycle stream line in order to set optimal temperature conditions.

Referring to FIGs.3A and 3B, an alternative embodiment is shown having an alternative liquid level control mechanism for the reboiler 16 in which liquid 35 collected in the reboiler 16 may be selectively sent to the separation vessel 12, or (re)circulated in a loop 40 out of and back to the reboiler 16.

FIG. 3B shows in greater detail the recirculating flow from and to the reboiler 16. The reboiler liquid is pumped by pump 10 and fed back into the reboiler 18. The flow may be flow controlled by a flow or pressure control valve 18. The pump 10 may be a centrifugal pump, although other pumps may also be considered. Where the pump is a centrifugal pump, the valve 18 may be utilized to ensure that the pump 10 operates on its pump curve.

A level control valve 19 in line 9 may be provided and may control the liquid 35 level in the reboiler 16. Valve 19 is variably opened to release liquid to the separation vessel 12 when the liquid level in the reboiler 16 is at or above a predetermined level, and variably closes when the liquid level is below a predetermined level. It is believed that such a (re)circulation of liquid assists in the provision of a continuous flow from the reboiler 16 to the separator vessel 12. This may allow control to provide constant pressure and as a result control and application of a stable temperature within the separation vessel 12. This may be because the heavy fraction liquid from the reboiler can be fed continuously to the separation vessel 12 as opposed to in distinct batches.

The liquid level in the partial condenser 5 may be controlled by level control valve 34, which allows release of condensed liquid to the reboiler 186.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “20°” is intended to mean “about 90°”.

It should be understood that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

CONCLUSIESCONCLUSIONS

1. Werkwijze voor pyrolyse van kunststofmateriaal, de werkwijze omvattende de stappen van: - het verwarmen van kunststofmateriaal tot pyrolysetemperatuur voor het verschaf- fen van een stroom van gepyrolyseerde gasvormige koolwaterstoffen; - het passeren van de stroom van gepyrolyseerde gasvormige koolwaterstoffen naar een partiële condensor en het condenseren van een partiële fractie van genoemde stroom van gepyrolyseerde gasvormige koolwaterstoffen tot een gecondenseerde vloeistof; - het passeren van niet-gecondenseerde gasvormige koolwaterstoffen uit de partiële condensor naar een destillatie-apparaat; - het passeren van genoemde gecondenseerde vloeistof uit de partiële condensor naar een herverwarmer, bij voorkeur een reboiler; - het verwarmen van genoemde gecondenseerde vloeistof in de herverwarmer voor het verhogen van de temperatuur ervan, bij voorkeur tot een temperatuur hoger dan deze van de partiële condensor voor het verschaffen van herverwarmd vloeibaar koolwaterstof- materiaal; en - het herinbrengen van ten minste een gedeelte van het herverwarmde vloeibare koolwaterstofmateriaal stroomopwaarts van de partiële condensor voor pyrolyse.CLAIMS 1. Method for pyrolysis of plastic material, the method comprising the steps of: - heating plastic material to pyrolysis temperature to provide a stream of pyrolyzed gaseous hydrocarbons; - passing the stream of pyrolyzed gaseous hydrocarbons to a partial condenser and condensing a partial fraction of said stream of pyrolyzed gaseous hydrocarbons into a condensed liquid; - passing uncondensed gaseous hydrocarbons from the partial condenser to a distillation apparatus; - passing said condensed liquid from the partial condenser to a reheater, preferably a reboiler; - heating said condensed liquid in the reheater to raise its temperature, preferably to a temperature higher than that of the partial condenser to provide reheated liquid hydrocarbon material; and - reinserting at least a portion of the reheated liquid hydrocarbon material upstream of the partial condenser for pyrolysis.

2. Werkwijze volgens elke voorgaande conclusie, waarbij het kunststofmateriaal verwarmd wordt tot een pyrolysetemperatuur van ongeveer 360°C tot ongeveer 550°C, bij voorkeur van ongeveer 390°C tot ongeveer 450°C.A method according to any preceding claim, wherein the plastic material is heated to a pyrolysis temperature of about 360°C to about 550°C, preferably from about 390°C to about 450°C.

3. Werkwijze volgens elke voorgaande conclusie, waarbij de partiële condensor bedreven wordt bij een temperatuur van ongeveer 150°C tot ongeveer 400°C, met meer voorkeur bij een temperatuur van ongeveer 220°C tot ongeveer 380°C, met nog meer voorkeur van ongeveer 290°C tot ongeveer 330°C.A method according to any preceding claim, wherein the partial condenser is operated at a temperature of from about 150°C to about 400°C, more preferably at a temperature of about 220°C to about 380°C, even more preferably from about 290°C to about 330°C.

4. Werkwijze volgens elke voorgaande conclusie, waarbij de herverwarmer bedreven wordt bij een temperatuur van ongeveer 340°C tot ongeveer 400°C, bij voorkeur van ongeveer 360°C tot ongeveer 380°C.A method according to any preceding claim, wherein the reheater is operated at a temperature of from about 340°C to about 400°C, preferably from about 360°C to about 380°C.

5. Werkwijze volgens elke voorgaande conclusie, waarbij het verwarmen van genoemde ge- condenseerde vloeistofstroom in de herverwarmer het verdampen van een stroom van koolwaterstoffen omvat, en de werkwijze het passeren van genoemde stroom van ver- dampte koolwaterstoffen naar het destillatie-apparaat of naar een verder destillatie-appa- raat omvat.A method according to any preceding claim, wherein heating said condensed liquid stream in the reheater includes vaporizing a hydrocarbon stream, and the method passing said vaporized hydrocarbon stream to the distillation apparatus or to a further comprises distillation apparatus.

6. Werkwijze volgens elke voorgaande conclusie, waarbij de stap van het herinbrengen van het herverwarmde vloeibare koolwaterstofmateriaal stroomopwaarts van de partiële con- densor het passeren van het herverwarmde vloeibare koolwaterstofmateriaal naar een gas-vloeistofscheidingsvat stroomopwaarts van de partiële condensor omvat.A method according to any preceding claim, wherein the step of reintroducing the reheated liquid hydrocarbon material upstream of the partial condenser includes passing the reheated liquid hydrocarbon material to a gas-liquid separation vessel upstream of the partial condenser.

7. Werkwijze volgens elke voorgaande conclusie, waarbij de stroom van gepyrolyseerde gasvormige koolwaterstoffen gepasseerd wordt naar de partiële condensor via een eerste leiding, en de gecondenseerde vloeistofstroom uit de partiële condensor gepasseerd wordt naar de herverwarmer via een tweede leiding, gescheiden van de eerste leiding.A method according to any preceding claim, wherein the stream of pyrolyzed gaseous hydrocarbons is passed to the partial condenser via a first conduit, and the condensed liquid stream from the partial condenser is passed to the reheater via a second conduit, separate from the first conduit.

8. Werkwijze volgens elke voorgaande conclusie, waarbij de herverwarmer bedreven wordt bij een temperatuur hoger dan de bedrijfstemperatuur van de partiële condensor en lager dan de temperatuur van de gepyrolyseerde gasvormige koolwaterstoffen die passeren naar de partiële condensor.A method according to any preceding claim, wherein the reheater is operated at a temperature higher than the operating temperature of the partial condenser and lower than the temperature of the pyrolyzed gaseous hydrocarbons passing to the partial condenser.

9. Werkwijze volgens elke voorgaande conclusie, waarbij de partiële condensor afgeschei- den is, bij voorkeur op afstand, van de pyrolysezone.Method according to any preceding claim, wherein the partial condenser is separated, preferably remotely, from the pyrolysis zone.

10. Werkwijze volgens elke voorgaande conclusie, waarbij de stap van het verwarmen van kunststofmateriaal tot pyrolysetemperatuur voor het verschaffen van een stroom van ge- pyrolyseerde gasvormige koolwaterstoffen, het verwarmen van kunststofmateriaal tot py- rolysetemperatuur in één of meer warmtewisselaars, bij voorkeur meerdere in serie opge- stelde warmtewisselaars, omvat voor het verschaffen van een stroom van gepyrolyseerd gasvormig materiaal en vloeibaar materiaal.A method according to any preceding claim, wherein the step of heating plastic material to pyrolysis temperature to provide a stream of pyrolyzed gaseous hydrocarbons is heating plastic material to pyrolysis temperature in one or more heat exchangers, preferably several in series arranged heat exchangers, included to provide a flow of pyrolyzed gaseous material and liquid material.

11. Werkwijze volgens conclusie 10, verder omvattende het passeren van het kunststofmate- riaal dat verwarmd werd tot pyrolysetemperatuur in de één of meer warmtewisselaars naar een gas-vloeistofscheidingsvat waarin gepyrolyseerde gasvormige en vloeibare ma- terialen divergeren, bij voorkeur onder zwaartekracht, waarbij genoemd gepyrolyseerd gasvormig materiaal omhoog passeert naar een partiële condensor, en genoemd vloei- baar materiaal naar beneden passeert.A method according to claim 10, further comprising passing the plastic material heated to pyrolysis temperature in the one or more heat exchangers to a gas-liquid separation vessel in which pyrolyzed gaseous and liquid materials diverge, preferably under gravity, said pyrolyzed gaseous material passes upwards to a partial condenser, and said liquid material passes downwards.

12. Werkwijze volgens conclusie 11, verder omvattende het verwijderen van vloeibaar materi- aal uit het scheidingsvat, het herverwarmen van genoemd vloeibaar materiaal tot pyroly- setemperatuur en het terugvoeren ervan naar het scheidingsvat.The method of claim 11, further comprising removing liquid material from the separation vessel, reheating said liquid material to pyrolysis temperature and returning it to the separation vessel.

13. Werkwijze volgens één van de voorgaande conclusies, omvattende het verschaffen van een kunststofmateriaal grondstof, waarbij de kunststofmateriaal grondstof polyethyleen en/of polypropyleen kunststof omvat, bij voorkeur waarbij de som van polyethyleen en po- lypropyleen in de grondstof ten minste 50 gew.% op gewichtsbasis van de grondstof be- draagt, met meer voorkeur ten minste 60 gew.%.Method according to any of the preceding claims, comprising providing a plastic material raw material, wherein the plastic material raw material comprises polyethylene and/or polypropylene plastic, preferably wherein the sum of polyethylene and polypropylene in the raw material is at least 50% by weight. by weight of the raw material, more preferably at least 60% by weight.

14. Werkwijze volgens conclusie 13, waarbij de grondstof polyvinylchloridekunststof omvat, bij voorkeur meer dan 1 gew.% polyvinylchloridekunststof, met meer voorkeur meer dan 5 gew.%.Method according to claim 13, wherein the raw material comprises polyvinyl chloride plastic, preferably more than 1% by weight polyvinyl chloride plastic, more preferably more than 5% by weight.

15. Werkwijze volgens conclusie 13 of conclusie 14, waarbij de grondstof polyethyleenterefta- laatkunststof omvat, bij voorkeur meer dan 3 gew.% polyethyleentereftalaatkunststof, met meer voorkeur meer dan 4 gew.%.A method according to claim 13 or claim 14, wherein the raw material comprises polyethylene terephthalate plastic, preferably more than 3% by weight polyethylene terephthalate plastic, more preferably more than 4% by weight.

16. Werkwijze volgens conclusie 13, 14 of 15, waarbij de grondstof polystyreenkunststof om- vat, bij voorkeur meer dan 1 gew.% polystyreenkunststof, met meer voorkeur meer dan 5 gew.%.A method according to claim 13, 14 or 15, wherein the raw material comprises polystyrene plastic, preferably more than 1% by weight polystyrene plastic, more preferably more than 5% by weight.

17. Werkwijze voor de productie van koolwaterstofmateriaal, omvattende de stappen van één van voorgaande conclusies, en de verdere stap van het destilleren van genoemde niet- gecondenseerde gasvormige koolwaterstoffen uit de partiële condensor in een destillatie- apparaat om het koolwaterstofproduct op te leveren, bij voorkeur waarbij het koolwater- stofproduct omvat: butaan, propaan, kerosine, diesel, stookolie; lichte destillaten, zoals LPG, benzine, nafta, of mengsels daarvan; middendestillaten zoals kerosine, vliegtuig- brandstof, diesel, of mengsels daarvan; zware destillaten en residuen zoals stookolie, smeeroliën, paraffine, was, asfalt, of mengsels daarvan; of alle mengsels daarvan; kool- waterstoffen die verzadigd, onverzadigd, met een rechte keten, cyclisch of aromatisch zijn; niet-condenseerbare gassen omvattende methaan, ethaan, etheen en/of andere kleine moleculen; en mengsels daarvan.A method for the production of hydrocarbon material, comprising the steps of any preceding claim, and the further step of distilling said uncondensed gaseous hydrocarbons from the partial condenser in a distillation apparatus to yield the hydrocarbon product, preferably wherein the hydrocarbon product includes: butane, propane, kerosene, diesel, fuel oil; light distillates, such as LPG, gasoline, naphtha, or mixtures thereof; middle distillates such as kerosene, aviation fuel, diesel, or mixtures thereof; heavy distillates and residues such as fuel oil, lubricating oils, paraffin, wax, asphalt, or mixtures thereof; or any mixtures thereof; hydrocarbons that are saturated, unsaturated, straight-chain, cyclic or aromatic; non-condensable gases including methane, ethane, ethylene and/or other small molecules; and mixtures thereof.

18. Apparaat voor het pyrolyseren van afvalkunststof tot één of meer koolwaterstofproducten, bij voorkeur ten minste één of meer vloeibare koolwaterstofproducten, het apparaat om- vattende: een verwarmingsinrichting, bij voorkeur een warmtewisselaar, voor het ontvangen en verwarmen van afvalkunststof tot pyrolysetemperatuur; een scheidingsvat, stroomafwaarts van de verwarmingsinrichting, waarbij de schei- dingsinrichting omvat: een ingericht voor het ontvangen van pyrolysetemperatuur, gasvormig en vloeibaar kunststofafval uit de verwarmingsinrichting,18. Apparatus for pyrolyzing waste plastic into one or more hydrocarbon products, preferably at least one or more liquid hydrocarbon products, the apparatus comprising: a heating device, preferably a heat exchanger, for receiving and heating waste plastic to pyrolysis temperature; a separation vessel, downstream of the heating device, the separation device comprising: a device for receiving pyrolysis temperature, gaseous and liquid plastic waste from the heating device,

een bovenste uitlaat voor het afvoeren van gasvormig materiaal, en een onderste uitlaat voor het afvoeren van vloeibaar materiaal; een partiële condensor stroomafwaarts van het scheidingsvat, waarbij de partiële condensor omvat: een partiële condensorinlaat ingericht voor het ontvangen van gasvormig ma- teriaal uit het scheidingsvat, een bovenste partiële condensoruitlaat voor het afvoeren van gasvormig ma- teriaal, en een onderste partiële condensoruitlaat voor het afvoeren van gecondenseerd, vloeibaar materiaal, waarbij de partiële condensor geconfigureerd is voor het condenseren van een partiële fractie van genoemd gasvormig materiaal tot een gecondenseerde vloeistof; een herverwarmervat, bij voorkeur een reboiler, omvattende: een verwarmer, een herverwarmerinlaat, ingericht voor het ontvangen van geconden- seerd, vloeibaar materiaal uit de partiële condensor, en een herverwarmeruitlaat in fluidumverbinding met een terugvoerleiding ingericht voor het terugvoeren van vloeibaar materiaal voor pyrolyse stroom- opwaarts van de partiële condensor; en een destillatie-inrichting met een destillatie-inlaat ingericht voor het ont- vangen van gasvormig materiaal van de partiële condensor uit de bovenste partiële condensoruitlaat.an upper outlet for discharging gaseous material, and a lower outlet for discharging liquid material; a partial condenser downstream of the separation vessel, the partial condenser comprising: a partial condenser inlet adapted to receive gaseous material from the separation vessel, an upper partial condenser outlet for discharging gaseous material, and a lower partial condenser outlet for discharging condensed liquid material, wherein the partial condenser is configured to condense a partial fraction of said gaseous material into a condensed liquid; a reheater vessel, preferably a reboiler, comprising: a heater, a reheater inlet adapted to receive condensed liquid material from the partial condenser, and a reheater outlet in fluid communication with a return line adapted to return liquid material for pyrolysis flow - upwards from the partial condenser; and a distillation apparatus having a distillation inlet configured to receive partial condenser gaseous material from the upper partial condenser outlet.

19. Apparaat volgens conclusie 18, waarbij de verwarmingsinrichting geconfigureerd is voor het verhitten van de afvalkunststof tot een pyrolysetemperatuur van van ongeveer 360°C tot ongeveer 550°C, bij voorkeur van ongeveer 390°C tot ongeveer 450°C.The apparatus of claim 18, wherein the heating device is configured to heat the waste plastic to a pyrolysis temperature of from about 360°C to about 550°C, preferably from about 390°C to about 450°C.

20. Apparaat volgens conclusie 18 of 19, waarbij de partiële condensor geconfigureerd is voor het bedrijven bij een temperatuur van ongeveer 150°C tot ongeveer 400°C, met meer voorkeur bij een temperatuur van ongeveer 220°C tot ongeveer 380°C, met nog meer voorkeur van ongeveer 290°C tot ongeveer 330°C.The apparatus of claim 18 or 19, wherein the partial condenser is configured to operate at a temperature of about 150°C to about 400°C, more preferably at a temperature of about 220°C to about 380°C, with even more preferably from about 290°C to about 330°C.

21. Apparaat volgens conclusie 18, 19 of 20, waarbij de herverwarmer geconfigureerd is voor het bedrijven bij een temperatuur van ongeveer 340°C tot ongeveer 400°C, bij voorkeur van ongeveer 360°C tot ongeveer 380°C.The apparatus of claim 18, 19 or 20, wherein the reheater is configured to operate at a temperature from about 340°C to about 400°C, preferably from about 360°C to about 380°C.

22. Apparaat volgens één van de conclusies 18 tot 21, waarbij het scheidingssysteemvat een cycloonafscheider omvat.An apparatus according to any one of claims 18 to 21, wherein the separation system vessel comprises a cyclone separator.

23. Apparaat volgens één van de conclusies 18 tot 22, waarbij de verwarmingsinrichting één of meer warmtewisselaars omvat, bij voorkeur "tube-in-shell" warmtewisselaars, met meer voorkeur een aantal warmtewisselaars opgesteld in serie.Apparatus according to any one of claims 18 to 22, wherein the heating device comprises one or more heat exchangers, preferably "tube-in-shell" heat exchangers, more preferably a number of heat exchangers arranged in series.

24. Apparaat volgens één van conclusies 18 tot 23, waarbij de partiële condensor een koel- /verwarmingsinrichting omvat, geconfigureerd voor het verschaffen van een instelbare temperatuur voor selectieve condensatie van koolwaterstoffen volgens de condensatie- temperatuur.An apparatus according to any one of claims 18 to 23, wherein the partial condenser comprises a cooling/heating device configured to provide an adjustable temperature for selective condensation of hydrocarbons according to the condensation temperature.

25. Apparaat volgens één van conclusies 18 tot 24, waarbij de partiële condensor een ge- pakte kolom omvat.An apparatus according to any one of claims 18 to 24, wherein the partial condenser comprises a packed column.

26. Apparaat volgens één van conclusies 18 tot 25, waarbij het herverwarmervat verder een bovenste uitlaat omvat voor het afvoeren van gasvormig materiaal naar de destillatie-in- richting, bij voorkeur waarbij de herverwarmer de destillatie-inrichting zich boven op het herverwarmervat bevindt.An apparatus according to any one of claims 18 to 25, wherein the reheater vessel further comprises an upper outlet for discharging gaseous material to the distillation apparatus, preferably wherein the reheater and distillation apparatus is located on top of the reheater vessel.

27. Apparaat volgens één van conclusies 18 tot 26, waarbij de terugvoerleiding ingericht is voor het terugvoeren van vloeibaar materiaal voor pyrolyse naar het scheidingsvat, of naar de verwarmingsinrichting.Apparatus according to any one of claims 18 to 26, wherein the return line is adapted to return liquid material for pyrolysis to the separation vessel or to the heating device.

28. Apparaat volgens één van conclusies 18 tot 27, waarbij het scheidingsvat langwerpig en verticaal ingericht is voor het divergeren van gepyrolyseerde gasvormige en vloeibare ma- terialen onder zwaartekracht, waarbij gepyrolyseerd gasvormig materiaal naar boven naar de bovenste uitlaat passeert en vloeibaar materiaal naar beneden passeert.An apparatus according to any one of claims 18 to 27, wherein the separation vessel is elongated and vertically arranged for diverging pyrolyzed gaseous and liquid materials under gravity, with pyrolyzed gaseous material passing upwards to the upper outlet and liquid material passing downwards .