CN117186933A

CN117186933A - Catalytic cracking reaction method and system capable of realizing heat balance light oil

Info

Publication number: CN117186933A
Application number: CN202210614121.XA
Authority: CN
Inventors: 张执刚; 魏晓丽; 崔琰; 乔瑞琪
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2023-12-08

Abstract

The application relates to a catalytic cracking reaction method and a system capable of realizing heat balance of light oil, wherein the system comprises a catalytic cracking reactor, an oil agent separation device, a settler and a regenerator, wherein the settler comprises a dense-phase settling section positioned below the oil agent separation device; and the bottom of the dense-phase sedimentation section is provided with one or more raw coke fuel oil nozzles for spraying raw coke fuel oil into the dense-phase sedimentation section, so that the spent catalyst contacts with the raw coke fuel oil in the dense-phase sedimentation section to obtain the catalyst with carbon. The catalytic cracking method of the system can improve the selectivity of ethylene and propylene, reduce methane generation, and simultaneously solve the problem of reaction heat balance without damaging the physical and chemical properties of the catalyst.

Description

Catalytic cracking reaction method and system capable of realizing heat balance light oil

Technical Field

The application relates to the technical field of fluidized catalytic cracking, in particular to a reaction method and a system suitable for light oil catalytic cracking capable of realizing heat balance.

Background

At present, the oil refining capability is excessive, the terminal consumption of the finished oil is slowed down, and the excessive structure of the finished oil becomes a urgent need for solving the problem of oil refining enterprises. In the aspect of chemical raw material market, ethylene and propylene are taken as basic chemical raw materials, and market demands are still vigorous. The consumption of ethylene and propylene rises year by year, taking China as an example, the estimated 2023 year end, the production capacity of ethylene and propylene in China can reach about 4400 ten thousand tons/year and 5200 ten thousand tons/year respectively, and the annual average composite acceleration rate is 11.5% and 8.7% respectively. Therefore, the domestic oil refining pattern and the resource flow direction can be structurally recombined, the terminal consumption of the finished oil is accelerated and slowed down, and the consumption of the chemical light oil is greatly increased. Therefore, the transformation of oil refining to chemical industry has become the necessary direction of the development of refineries, and catalytic cracking is a key technology in the transformation process of oil refining to chemical industry as a tie between oil refining and chemical industry.

The catalytic cracking process generally uses heavy petroleum hydrocarbon as raw material, such as paraffin-based vacuum fraction or atmospheric residuum, and has the characteristic of higher yield of low-carbon olefin such as propylene. With the heavy and inferior quality of global crude oil, high-quality heavy petroleum hydrocarbon resources are less and less, and the raw material application range of the catalytic cracking technology needs to be widened. Along with the structural adjustment transformation of the products, the refinery improves the quality of the oil products and simultaneously produces a large amount of light petroleum hydrocarbon resources as byproducts. For a typical ten million ton class fuel oil refinery, the light petroleum hydrocarbon yield per year of the whole plant can reach millions of tons, accounting for about 10% of the crude oil processing amount. For a refining integrated enterprise or a chemical oil refinery, as the conversion depth of crude oil resources is further improved, the yield and proportion of light petroleum hydrocarbon of the whole plant are greatly increased, and how to efficiently utilize the light hydrocarbon resources becomes the focus of attention and research of the refining industry.

In the catalytic cracking technology using low-carbon olefin as a main target product, the conversion rate of the cracking reaction is high, the reaction temperature is high, the reaction heat is large, more heat is required in the reaction aspect than that of a conventional fluidized catalytic regenerator or other catalytic conversion methods, the coke generated by self-cracking can not meet the self-heat balance requirement of a reaction-regeneration system, and if the raw materials are light, the problem of serious shortage of heat sources is aggravated. When coke formation is insufficient in the reaction process, the required heat is usually provided for the reaction by adopting a mode of slurry oil recycling or fuel oil supplementing outside the regenerator. Because the slurry oil contains more polycyclic aromatic hydrocarbon, the slurry oil is easy to be adsorbed on the active center of the catalyst, and the accessibility of the active center of the raw material molecules is influenced, so that the selectivity of the catalytic reaction is influenced; in addition, because the catalytic cracking adopts the catalyst with the molecular sieve as an active component, the aluminum of the molecular sieve framework is gradually removed by the local high temperature generated by the combustion of the fuel oil in the regenerator, so that the catalyst is damaged, the damage is irreversible, and the influence of the high-temperature hot spot generated by the local combustion of the external fuel oil on the catalyst framework structure and the reaction performance is not fundamentally solved. To solve this problem, the prior art solutions start from a regenerator system, such as an oxygen-deficient area arranged in the regenerator, and introduce fuel oil into the oxygen-deficient area to mix with the catalyst, and enter the regenerator to burn and regenerate; or disposing a heater within the regenerator and employing a fuel nozzle configured to inject a mixture of fuel and an oxygen-containing gas for combustion of supplemental heat; or injecting methane, and supplementing heat for the reaction by means of the combustion heat release of methane. The heat supplementing mode in the technology relieves the adverse effect on the catalyst, but does not fundamentally solve the influence of high-temperature hot spots generated by local combustion of the external fuel oil on the skeleton structure and the reaction performance of the catalyst, thereby seriously affecting the reaction selectivity. Therefore, developing a light oil catalytic cracking technology is a technical problem that the heat balance is insufficient while the selectivity of the low-carbon olefin is improved.

Disclosure of Invention

The application aims to provide a light oil catalytic cracking reaction method and a system capable of realizing heat balance, which can improve the yield of ethylene and propylene, reduce the yield of methane, solve the problem of heat balance in the reaction process from the aspect of reaction and improve the selectivity of catalytic reaction.

In one aspect, the present application provides a catalytic cracking reaction-regeneration system comprising:

a catalytic cracking reactor, wherein the catalyst is a catalyst,

an oil agent separating device is provided with a plurality of oil agent separating devices,

a settler, and

the regeneration device comprises a regenerator, a first heat exchanger, a second heat exchanger, a third heat exchanger and a,

wherein the cracking reactor is provided with a pre-lifting gas inlet at the bottom, a catalyst inlet, one or more cracking raw oil inlets and an oiling agent outlet at the top; the oil outlet of the cracking reactor is in fluid communication with the oil separation device such that reaction oil gas and spent catalyst from the catalytic cracking reactor are separated in the oil separation device;

the oil separating device is accommodated inside the settler so that the settler collects spent catalyst separated in the oil separating device; the settler comprises a dense phase settling section located below the oil separation device; one or more raw coke fuel oil nozzles are arranged at the bottom of the dense-phase settling section and are used for spraying raw coke fuel oil into the dense-phase settling section, so that a spent catalyst contacts with the raw coke fuel oil in the dense-phase settling section to obtain a catalyst with carbon; the dense-phase sedimentation section is provided with a spent catalyst outlet positioned on the side wall of the dense-phase sedimentation section;

The regenerator is provided with a spent catalyst inlet and a regenerated catalyst outlet; a regenerated catalyst outlet is in fluid communication with the catalyst inlet of the cracking reactor such that regenerated catalyst is recycled back to the cracking reactor; the spent catalyst inlet is in fluid communication with a spent catalyst outlet of the settler so that the coked catalyst of the settler enters the regenerator for regeneration.

In one embodiment, the spent catalyst outlet is located from 10% to 30% of the dense phase settling leg height from the bottom of the dense phase settling leg.

In one embodiment, 2-6 uniformly distributed raw coke fuel oil nozzles are arranged at the bottom of the dense-phase settling section, and jet extension lines of the raw coke fuel oil nozzles are converged on the same intersection point of the central axial line of the settling vessel.

In one embodiment, the catalytic cracking reactor comprises, in order from bottom to top:

an optional pre-lift zone;

the reaction zone comprises at least one reducing reaction section, the reducing reaction section is in a hollow cylinder shape with a cross section of a general circular shape and an opening at the bottom end and the top end, and the inner diameter of the reducing reaction section is continuously or discontinuously reduced from bottom to top; and

An outlet zone;

wherein the optional pre-lifting zone is communicated with the bottom end of the reaction zone, the top end of the reaction zone is communicated with the outlet zone, and at least one raw material feeding port is arranged on the optional pre-lifting zone and/or the bottom of the reaction zone;

the cross-sectional inner diameter of the bottom end of the reaction zone is greater than or equal to the cross-sectional inner diameter of the optional pre-lift zone, and the cross-sectional inner diameter of the top end is equal to or less than the cross-sectional inner diameter of the optional pre-lift zone and the cross-sectional inner diameter of the outlet zone; the regenerated catalyst inlet is provided at the bottom of the reaction zone and/or the optional pre-lift zone.

In one embodiment, the ratio of the inner diameter of the cross section of the bottom of the reaction zone of the catalytic cracking reactor to the total height of the catalytic cracking reactor is 0.01:1 to 0.5:1, a step of; the ratio of the total height of the reaction zone to the total height of the catalytic cracking reactor was 0.15:1 to 0.8:1.

in one embodiment, the reaction zone of the catalytic cracking reactor comprises 1-3 reduced diameter reaction sections,

preferably, the diameter-reducing reaction section of the catalytic cracking reactor is in a hollow truncated cone shape, and the longitudinal section of the diameter-reducing reaction section is in an isosceles trapezoid shape; the ratio of the inner diameter of the top cross section to the height of the reducing reaction section is respectively and independently 0.005-0.3:1, the ratio of the inner diameter of the cross section of the bottom end to the height of the reducing reaction section is respectively and independently 0.015-0.25:1, the ratio of the inner diameter of the cross section of the bottom end to the inner diameter of the cross section of the top end is respectively more than 1.2 and less than or equal to 10; the ratio of the height of the diameter-reduced reaction section to the total height of the catalytic cracking reactor is 0.15 independently: 1 to 0.8:1.

In one embodiment, the ratio of the inner diameter to the height of the pre-lift zone of the catalytic cracking reactor is from 0.02 to 0.4:1, a step of; the ratio of the height to the total height of the catalytic cracking reactor is 0.01:1 to 0.2:1.

in one embodiment, the pre-lifting area of the catalytic cracking reactor is connected with the reaction area by a first connecting section, the longitudinal section of the first connecting section is an isosceles trapezoid, and the camber angle alpha of the side edge of the isosceles trapezoid is 5-85 degrees.

In one embodiment, the reactor outlet zone has a cross-sectional inner diameter to height ratio of 0.01 to 0.3:1, the ratio of the height of the outlet zone to the total reactor height being 0.05:1 to 0.5:1.

in another aspect, the present application provides a light oil catalytic cracking process capable of achieving thermal equilibrium, said process being carried out in the above-mentioned system,

the method comprises the following steps:

1) Introducing preheated light oil from the lower part of a cracking reactor, contacting with regenerated catalyst from a regenerator and carrying out catalytic cracking reaction from bottom to top, introducing the obtained oil mixture into an oil separation device for separation to obtain a first reaction product and a spent catalyst,

2) The spent catalyst enters a dense-phase sedimentation section and reacts with raw coke fuel oil introduced from the bottom of the dense-phase sedimentation section to obtain reaction oil gas and a catalyst with carbon, wherein the reaction oil gas enters an oil-solvent separation device to be separated to obtain a second reaction product,

3) Delivering the catalyst with carbon to a regenerator for burning regeneration, and delivering the regenerated catalyst to a cracking reactor for reaction in a circulating way;

4) And introducing the first reaction product and the second reaction product into a separation system for separation to obtain dry gas, liquefied gas, pyrolysis gasoline and pyrolysis heavy oil.

In one embodiment, the light oil comprises gaseous hydrocarbons and light distillate; the light oil meets one, two, three or four of the following indexes: the density at 20 ℃ is less than 860 kg/cubic meter, the carbon residue is 0-0.5 wt%, the total aromatic hydrocarbon content is 0-30 wt%, and the final distillation point of the distillation range is less than 360 ℃.

In one embodiment, the conditions of the catalytic cracking reaction include: the reaction temperature is 510-750 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is 10:1 to 50:1, the weight ratio of the pre-lifting gas to the raw oil is 0.05:1 to 2.0:1, the catalyst density is 20-100 kg/cubic meter, the linear speed is 4-18 m/s, and the reaction pressure is 130-450 kilopascals.

In one embodiment, the process further comprises introducing a C4 hydrocarbon fraction and/or a C5-C6 light gasoline fraction into the cracking reactor for catalytic cracking reactions.

In one embodiment, the raw coke fuel oil is a self-produced cracked heavy oil and a secondary processing distillate, or a mixture thereof; preferably, the secondary processed distillate oil may be selected from the group consisting of catalytic cracked diesel, catalytic cracked slurry/cycle oil, coker gasoline, straight run diesel, coker diesel, and coker wax oil.

In one embodiment, the conditions of the coking reaction include: the reaction temperature is 460-650 ℃, the reaction time is 2-20 seconds, and the weight ratio of the catalyst to the oil is 3:1 to 30:1, the weight ratio of the fluidization gas to the raw coke fuel oil is 0.01:1 to 0.2:1, the catalyst particle density is 300-450 kg/cubic meter.

In the application, the diameter-reducing structure of the diameter-reducing reaction section, particularly the conical reaction section, arranged in the cracking reactor is beneficial to accelerating the reaction oil gas to leave the reaction zone, shortening the reaction time, reducing the back mixing of the catalyst, reducing the secondary conversion reaction of the low-carbon olefin generated by the primary reaction and improving the selectivity of the low-carbon olefin.

In the application, the stripping section of the traditional catalytic cracking device is eliminated, the space of the original stripping section is used as a coking reaction place, the characteristic that the catalyst to be regenerated still has higher cracking reaction activity is utilized, and proper reaction conditions are provided for coking raw materials, so that coking raw material oil and the catalyst react in a coking manner under the relatively low-temperature and oxygen-free fluidization condition, coke is attached to the catalyst, and then the catalyst is conveyed to a regeneration system, and the catalyst is fully burnt and released under the action of high-temperature and oxygen-enriched gas, so that heat required by the reaction is supplied, the property of the catalyst is not damaged, a coke source is supplemented from the end of the reaction system, and the problem of thermal balance of the catalytic cracking device is solved.

When the method and the system are used for catalytic cracking reaction, the contact efficiency of the raw materials and the catalyst is high, the catalytic reaction selectivity is good, the yield of high-value-added products such as ethylene and propylene is high, and the yield of byproducts such as methane is low. The transformation, development and extension of the booster refinery from oil refining to chemical raw material production not only solve the problem of petrochemical raw material shortage, but also improve the economic benefit of the refinery.

Drawings

The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, illustrate the application and together with the description serve to explain, without limitation, the application. In the drawings:

FIG. 1 is a schematic diagram of one embodiment of a catalytic cracking reactor of the present application;

fig. 2 is a schematic diagram of a catalytic cracking system according to an embodiment of the present application.

Detailed Description

The application is further described in detail below by means of the figures and examples. The features and advantages of the present application will become more apparent from the description.

The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

In addition, the technical features described below in the different embodiments of the present application may be combined with each other as long as they do not collide with each other.

Any particular value disclosed herein (including the endpoints of the numerical ranges) is not limited to the precise value of the value, and is to be understood to also encompass values near the precise value, such as all possible values within the range of + -5% of the precise value. Also, for a range of values disclosed, any combination of one or more new ranges of values between the endpoints of the range, between the endpoints and the specific points within the range, and between the specific points is contemplated as being specifically disclosed herein.

In the present application, both the terms "upstream" and "downstream" are based on the flow direction of the reaction mass. For example, when the reactant stream flows from bottom to top, "upstream" means a location below, and "downstream" means a location above.

Unless otherwise indicated, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art, and if a term is defined herein and its definition is different from the ordinary understanding in the art, then the definition herein controls.

The application provides a catalytic cracking reaction-regeneration system, comprising:

a catalytic cracking reactor, wherein the catalyst is a catalyst,

a settler, and

The application also provides a light oil catalytic cracking method capable of realizing heat balance, which can be carried out in the system of the application,

the method comprises the following steps:

FIG. 2 shows a catalytic cracking reaction-regeneration system of the present application. The catalytic cracking process of the present application is further described below in conjunction with the catalytic cracking reaction-regeneration system. The following description of the catalytic cracking process according to the application applies equally to the catalytic cracking reaction-regeneration system according to the application and vice versa.

The catalytic cracking reaction-regeneration system comprises:

the catalytic cracking reactor 100 is configured to operate,

the oil agent separating apparatus 201,

settler 200, and

regenerator 500.

As shown in fig. 1, the catalytic cracking reactor 100 may be provided with a pre-lift gas inlet 101, one or more pyrolysis feedstock oil inlets (e.g., a lower pyrolysis feedstock feed inlet 102, a C4 hydrocarbon fraction and/or C5-C6 light gasoline fraction feed inlet 105, etc.), a bottom catalyst inlet 103, and a top oil outlet 104. The oil outlet 104 of the cracking reactor is in fluid communication with the oil separation device 201 such that the first reaction oil gas and the first spent catalyst from the catalytic cracking reactor 100 are separated in the oil separation device 201.

In one embodiment, the catalytic cracking reactor 100 comprises, in order from bottom to top:

an optional pre-lift zone I is provided,

the reaction zone II comprises at least one reducing reaction section, wherein the reducing reaction section is a hollow cylinder with a cross section of a general circular shape and an opening at the bottom end and the top end, and the inner diameter of the hollow cylinder is continuously or discontinuously reduced from bottom to top; and

an outlet region III,

wherein the optional pre-lifting zone I is communicated with the bottom end of the reaction zone II, the top end of the reaction zone II is communicated with the outlet zone III, and at least one raw material feeding port 102 is arranged on the optional pre-lifting zone and/or the bottom of the reaction zone;

The cross-sectional inner diameter of the bottom end of the reaction zone II is greater than or equal to the cross-sectional inner diameter of the optional pre-lifting zone I, and the cross-sectional inner diameter of the top end is equal to or less than the cross-sectional inner diameter of the optional pre-lifting zone and the cross-sectional inner diameter of the outlet zone.

As shown in fig. 1, the catalytic cracking reactor may include the pre-lift region I provided at the lowermost portion of the catalytic cracking reactor for pre-lifting the catalyst or the like entering the reactor. As shown in fig. 1, the lower part of the pre-lift zone I is provided with a catalyst inlet 103 for inputting catalyst. The pre-lift zone I may be a hollow cylindrical structure having an inner diameter to height ratio of 0.02-0.4:1, a step of; the ratio of the height to the total height of the reactor was 0.01:1 to 0.2:1, preferably 0.05:1 to 0.15:1. in one embodiment, the pre-lift zone I may have an inner diameter of 0.2 to 5 meters, preferably 0.4 to 3 meters. In embodiments where a pre-lift zone I is present, pre-lift medium may be input to the pre-lift zone I through a pre-lift gas inlet. In embodiments where a pre-lift zone I is present, the bottom of the pre-lift zone I may also be provided with at least one catalyst inlet 103 for allowing catalyst to enter the reactor through the pre-lift zone I.

According to the application, the pre-lift zone I is not necessary, for example when the reaction zone II of the reactor according to the application is used in series with other reactors, such as riser reactors, the reaction zone II may be in direct communication with the outlet of the other reactor located upstream, without the need to employ the pre-lift zone I. In one embodiment, the catalytic cracking reactor may not include the pre-lift zone I. At this time, the bottom of the reaction zone II may be provided with at least one raw material feed port 102 to facilitate the entry of raw materials and the like into the catalytic cracking reactor. In embodiments where there is no pre-lift zone I, the bottom of the reaction zone II may be provided with at least one catalyst inlet (not shown) for allowing catalyst to enter the reactor. Of course, the reaction zone II may be provided without a catalyst inlet, wherein the catalyst may originate from catalyst carried in other reactor streams. Both of these embodiments are within the scope of the present application.

As shown in fig. 1, the catalytic cracking reactor may include a reaction zone II. The pre-lifting area I is communicated with the bottom end 110 of the reaction area II, the top end 120 of the reaction area II is communicated with the outlet area III, and at least one catalyst inlet 103 and at least one raw material feeding port 102 are arranged on the pre-lifting area and/or at the bottom of the reaction area. The cross-sectional inner diameter of the bottom end 110 of the reaction zone II is greater than or equal to the cross-sectional inner diameter of the pre-lift zone I, and the cross-sectional inner diameter of the top end 120 is equal to or less than the cross-sectional inner diameter of the pre-lift zone I and the cross-sectional inner diameter of the outlet zone III.

In the catalytic cracking reactor provided by the application, the reaction zone II is a fluidized bed, preferably, the fluidized bed is one or a combination of a plurality of conveying fluidized bed, turbulent fluidized bed and rapid bed.

In one embodiment, the pre-lift zone I is connected to the reaction zone II via a first transition section I-1. The longitudinal section of the first transition section I-1 may be an isosceles trapezoid, and the camber angle α of the sides of the isosceles trapezoid may be 5-85 °, preferably 15-75 °.

As shown in fig. 1, the raw material feed port may be provided in the upper portion of the pre-lift zone I, in the first transition section I-1, or in the lower portion of the reaction zone II. In particular, in embodiments where there is no pre-lift zone I, the lower portion of the reaction zone II may be provided with a feedstock feed port 102 for feeding feedstock.

In one embodiment, the ratio of the bottom cross-sectional inner diameter of the reaction zone II to the total reactor height is 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2:1, a step of; the ratio of the total height of the reaction zone II to the total height of the reactor was 0.15:1 to 0.8:1, for example 0.2:1 to 0.75:1.

as shown in FIG. 1, the reaction zone II comprises at least one reduced diameter reaction section which is a hollow cylinder having a substantially circular cross section and open at the bottom and top ends, and the inner diameter of which continuously or discontinuously decreases from bottom to top.

According to the application, by "reduced diameter" is meant that the inner diameter decreases in a discontinuous manner, for example in a stepwise or jump-like manner or in a continuous manner. As an example of the "reduced diameter section having a discontinuous inner diameter decreasing from bottom to top", there may be mentioned a column body composed of two or more hollow cylinders having a decreasing inner diameter.

As an example, the reaction zone II may be a cylindrical pattern comprising one or more hollow frustoconical sections, or a cylindrical pattern comprising two or more hollow cylindrical sections. According to the present application, when the reaction zone includes two or more reduced diameter reaction sections, each reduced diameter reaction section may have the same or different heights, to which the present application is not strictly limited.

In a preferred embodiment, the reaction zone II comprises a column pattern consisting of one or more hollow frustoconical sections and optionally connecting sections for connecting adjacent hollow frustoconical sections, or a column pattern consisting of two or more hollow cylindrical sections and optionally connecting sections for connecting adjacent hollow cylindrical sections.

In one embodiment, as shown in fig. 1, the reaction zone II comprises a 1-stage reduced diameter reaction stage in the form of a hollow truncated cone with a longitudinal section in the form of an isosceles trapezoid; its top cross-section inner diameter D ₁₂₀ Height h of the reduced diameter reaction section _II The ratio of each is independently 0.005-0.3:1, inner diameter D of bottom cross section ₁₁₀ Height h of the reduced diameter reaction section _II The ratio of each is independently 0.015 to 0.25:1, bottom end cross section inner diameter D ₁₁₀ With the top cross-section inside diameter D ₁₂₀ Each independently greater than 1.2 and less than or equal to 10, more preferably 1.5 to 5; the diameter-reducing reaction section h _II The ratio of the height of (2) to the total reactor height h was 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1. in one embodiment, the inner diameter D of the bottom end cross section ₁₁₀ The ratio to the total reactor height h was 0.01:1 to 0.5:1, preferably 0.05:1 to 0.2; the ratio of the height h1 of the diameter-reduced reaction section to the total height h of the reactor is 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1, and the total height h of the reaction zone II _II The ratio to the total reactor height h was 0.15:1 to 0.8:1, preferably 0.2:1 to 0.75:1. in one embodiment, the diameter D of the top cross section of the reduced diameter reaction section 100 ₁₁₀ 0.2 to 5 meters, preferably 0.4 to 3 meters. In one embodiment, the total height h of the reaction zone II _II May be about 2-50 meters, preferably about 5-40 meters, more preferably about 8-20 meters.

In the catalytic cracking reactor, the bottom space of the arranged reduced diameter reaction section, particularly the conical reaction section, is large, and can effectively improve the catalyst density in the reactor, thereby greatly improving the ratio of the catalyst to the reaction raw materials in the reactor, strengthening the primary cracking reaction of the raw materials, improving the reaction conversion rate and improving the yield of the low-carbon olefin; in addition, the diameter-reducing structure of the arranged diameter-reducing reaction section, particularly the conical reaction section, is beneficial to accelerating the reaction oil gas to leave the reaction zone, shortens the reaction time, reduces the back mixing of the catalyst, is beneficial to reducing the secondary conversion reaction of the low-carbon olefin generated by the primary reaction, and improves the selectivity of the low-carbon olefin.

In the catalytic cracking reactor provided by the application, one or more, such as one, two or more raw material feed openings can be arranged in the reactor, wherein the raw material feed openings can be independently arranged at the outlet end of the pre-lifting zone I or arranged at the bottom of the reaction zone II. Further preferably, the positions of the plurality of feedstock inlets are each independently located at the same height or at different heights of the reaction zone II. Thus, raw materials with different properties can be fed into different raw material feed ports respectively.

As shown in fig. 1, the catalytic cracking reactor may include an outlet zone III. In one embodiment, the outlet region III may be in the form of a hollow cylinder having a cross-sectional inner diameter and a height h _III The ratio is 0.01-0.3:1 height h of the outlet zone _III The ratio to the total reactor height h was 0.05:1 to 0.5:1, more preferably 0.1:1 to 0.35:1. in one embodiment, the inner diameter of the outlet zone III is from 0.2 to 5 meters, preferably from 0.4 to 3 meters.

As mentioned before, the inside diameter of the cross section at the top end of the reaction zone II is equal to or smaller than the inside diameter of the cross section of the outlet zone III. In one embodiment, the cross-sectional inner diameter of the top end of the reaction zone II is equal to the cross-sectional inner diameter of the outlet zone III.

In one embodiment, the cross-sectional inner diameter of the top end of the reaction zone II is smaller than the cross-sectional inner diameter of the outlet zone III. In this case, the reaction zone II and the outlet zone III may be connected by a third transition (not shown). The longitudinal section of the third transition section may be an isosceles trapezoid, and the camber angle of the sides of the isosceles trapezoid may be 5-85 °, preferably 15-75 °.

The outlet end 104 of the outlet zone III may be directly connected to an inlet of an oil separating device 201, such as a cyclone.

In one embodiment, the light oils used in the present application include gaseous hydrocarbons and light distillate oils. The light oil meets one, two, three or four of the following indexes: the density at 20 ℃ is less than 860 kg/cubic meter, the carbon residue is 0-0.5 wt%, the total aromatic hydrocarbon content is 0-30 wt%, and the final distillation point of the distillation range is less than 360 ℃.

In one embodiment, the gaseous hydrocarbon may be selected from one or more of saturated liquefied gas, unsaturated liquefied gas, and carbon four fractions; the light distillate oil comprises petroleum hydrocarbon with a distillation range of 25-360 ℃, oxygen-containing compounds and distillate oil of biomass or waste plastic generated oil; the petroleum hydrocarbon can be selected from one or more of straight-run naphtha, straight-run kerosene and straight-run diesel oil which are processed at one time; and mixing oil of one or more of secondary processed topped oil, raffinate oil, hydrocracking light naphtha, pentane oil, coker gasoline, fischer-Tropsch synthetic oil, catalytic cracking light gasoline, hydrogenated gasoline and hydrogenated diesel oil.

In one embodiment, the catalyst comprises 1 to 50 wt% on a dry basis and based on the weight of the catalyst on a dry basis; from 5 to 99% by weight of an inorganic oxide, and from 0 to 70% by weight of clay. The zeolite comprises a medium pore zeolite and optionally a large pore zeolite, the medium pore zeolite being selected from the group consisting of ZSM-series zeolites, ZRP zeolites, and any combination thereof; the large pore zeolite is selected from rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite, and high silicon Y-type zeolite, and any combination thereof. The medium pore zeolite comprises 10 to 100 wt%, preferably 50 to 90 wt%, of the total weight of the zeolite on a dry basis.

In the present application, the medium pore zeolite and the large pore zeolite are as defined conventionally in the art, i.e., the average pore size of the medium pore zeolite is about 0.5 to 0.6nm and the average pore size of the large pore zeolite is about 0.7 to 1.0nm.

As an example, the large pore zeolite may be selected from one or more of Rare Earth Y (REY) type zeolite, rare Earth Hydrogen Y (REHY) type zeolite, ultrastable Y type zeolite and high silicon Y type zeolite obtained by different methods. The mesoporous zeolite may be selected from zeolites having MFI structure, such as ZSM-series zeolites and/or ZRP zeolites. Optionally, the above mesoporous zeolite may be modified with a non-metal element such as phosphorus and/or a transition metal element such as iron, cobalt, nickel and the like. For a more detailed description of ZRP zeolites see U.S. patent US5,232,675A. The ZSM series of zeolites is preferably selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites of similar structure. For a more detailed description of ZSM-5, see U.S. patent US3,702,886A.

According to the application, the inorganic oxide is used as a binder, preferably silica (SiO ₂ ) And/or aluminum oxide (Al) ₂ O ₃ ). The clay is preferably kaolin and/or halloysite as a matrix (i.e., carrier).

In one embodiment, the conditions of the catalytic cracking reaction include: the reaction temperature is 510-750 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is 10:1 to 50:1, the weight ratio of the pre-lifting gas to the raw oil is 0.05:1 to 2.0:1, the catalyst density is 20-100 kg/cubic meter, the linear speed is 4-18 m/s, and the reaction pressure is 130-450 kilopascals. In one embodiment, the pre-lift gas is selected from the group consisting of steam, nitrogen, dry gas, rich gas, or carbon four fractions, or mixtures thereof.

In one embodiment, the feedstock is introduced into the cracking reactor at one location or at more than one same or different locations.

In the present application, the C4 hydrocarbon fraction refers to low molecular hydrocarbons in the form of gas at normal temperature and normal pressure, which mainly contains the C4 fraction, and include alkanes, alkenes and alkynes having 4 carbon atoms in the molecule, and may include gaseous hydrocarbon products (such as liquefied gas) rich in the C4 hydrocarbon fraction produced by the method of the present application, and may include gaseous hydrocarbons rich in the C4 fraction produced by other devices, wherein the C4 hydrocarbon fraction produced by the method of the present application is preferred. The C4 hydrocarbon fraction is preferably an olefin-rich C4 hydrocarbon fraction, and the content of C4 olefins may be greater than 50 wt%, preferably greater than 60 wt%, more preferably above 70 wt%.

In the present application, the C5-C6 light gasoline fraction may include pyrolysis gasoline produced by the method of the present application, and may also include gasoline fractions produced by other apparatuses, for example, may be at least one C5-C6 fraction selected from the group consisting of catalytic pyrolysis gasoline, straight run gasoline, coker gasoline, thermal pyrolysis gasoline, and hydrogenated gasoline. The C5-C6 light gasoline is preferably an olefin-rich fraction, wherein the olefin content is more than 50 wt%, preferably more than 60 wt%.

In one embodiment, a C4 hydrocarbon or C5-C6 light gasoline fraction is introduced at one or more locations downstream in the cracking reactor.

In the present application, the oil separating apparatus 201 is used to separate the reaction product and the catalyst in the oil from the catalytic cracking reactor 100, and the oil separating apparatus 201 is in communication with the outlet end 104 of the catalytic cracking reactor. The oil separating apparatus 201 may be a cyclone separator, or an outlet flash separator, or the like.

In the present application, the settler 200 is configured to collect spent catalyst separated in the oil separation apparatus 201. As shown in fig. 2, in one embodiment, the oil separating apparatus 201 is accommodated inside the settler 200 such that the settler 200 collects spent catalyst separated in the oil separating apparatus 201. The settler 200 comprises a dense phase settling section 205 located below the oil separation apparatus 201; the bottom of the dense-phase settling section 205 is provided with one or more raw coke fuel oil nozzles 209 for spraying raw coke fuel oil into the dense-phase settling section, so that the spent catalyst contacts with the raw coke fuel oil in the dense-phase settling section to obtain the catalyst with carbon. The dense phase settling section is provided with spent catalyst outlets 206 located in the side walls of the dense phase settling section. A fluidizing gas inlet 207 is also provided at the bottom of the dense phase settling section 205 for introducing fluidizing gas to fluidize the catalyst in the dense phase settling section. The fluidizing gas may be nitrogen, water vapor or a mixture thereof.

In one embodiment, the conditions of the coking reaction occurring within the dense phase settling section include: the reaction temperature is 460-650 ℃, the reaction time is 2-20 seconds, and the weight ratio of the catalyst to the oil is 3:1 to 30:1, the weight ratio of the fluidization gas to the raw coke fuel oil is 0.01:1 to 0.2:1, the catalyst particle density is 300-450 kg/cubic meter. In one embodiment, the injection amount of raw coke fuel oil may be 10 to 50% of the total weight of the feedstock oil introduced into the catalytic cracking reactor.

In one embodiment, the raw coke fuel oil is a plant self-produced cracked heavy oil and a secondary processing distillate, or a mixture thereof. Preferably, the secondary processed distillate oil may be selected from a mixed oil of one or more of catalytic cracking diesel, coker gasoline, straight-run diesel and coker diesel.

In one embodiment, the spent catalyst outlet 206 is located from 10% to 30% of the dense phase settling leg height from the bottom of the dense phase settling leg.

In one embodiment, 2-6 uniformly distributed raw coke fuel oil nozzles 209 are arranged at the bottom of the dense-phase settling section, and jet extension lines of the raw coke fuel oil nozzles are converged on the same intersection point of the central axial line of the settling vessel.

The regenerator 500 is used for regenerating a spent catalyst, an oxygen-containing gas inlet 501, a spent catalyst inlet 505 and a regenerated catalyst outlet 506 are arranged at the lower part, and a flue gas outlet 504 is arranged at the top part. The regenerated catalyst outlet 506 is in fluid communication with the catalyst inlet 103 of the cracking reactor such that regenerated catalyst is recycled back to the cracking reactor; the spent catalyst inlet 505 is in fluid communication with the spent catalyst outlet 206 of the settler so that the coked catalyst of the settler enters the regenerator for regeneration.

In one embodiment, the catalytic cracking reactor is generally arranged in parallel with the settler.

In the catalytic cracking system of the present application, the catalytic cracking reactor may be one or more, may be a combination of one catalytic cracking reactor of the present application and other existing catalytic cracking reactors, or may be a combination of a plurality of catalytic cracking reactors of the present application. The reactors may be connected in parallel and with an oil separation device.

In the catalytic cracking system provided by the application, the settler, the oil separation device, the regenerator, the reaction product separation device and the like can be all devices which are well known to those skilled in the art, and the connection mode between the devices can also be performed according to the known mode in the art. For example, the oil separation device may comprise a cyclone separator, an outlet flash separator.

The catalytic cracking method and the system can be used for efficiently producing the chemical raw materials such as ethylene, propylene and the like from the light petroleum hydrocarbon, so that the problem of heat balance can be fundamentally solved, the damage to a catalyst and a regeneration system caused by the traditional fuel injection mode is reduced, the cost of the catalyst is saved, the conversion, development and extension of a booster refinery from oil refining to chemical raw material production are realized, the problem of shortage of the petrochemical raw materials is solved, and the economic benefit of the refinery is improved.

The application will be further described with reference to the preferred embodiments shown in the drawings to which, however, the application is not limited.

FIG. 2 shows a preferred embodiment of the catalytic cracking reaction system of the present application.

The pre-lifting gas enters a pre-lifting zone I of the cracking reactor from the bottom of the cracking reactor 100 through a pre-lifting gas inlet 101, a high-temperature regenerated catalyst of the self-regenerator enters the pre-lifting zone I at the lower part of the cracking reactor 100 through a regenerated catalyst inlet 103, and is mixed with the pre-lifting gas to move upwards, and the mixture is contacted with raw oil from a raw oil inlet 102 to perform catalytic cracking reaction in a reaction zone II; the catalyst with carbon and the generated oil gas flow upwards and enter an outlet area III to enter the oil agent separation equipment 201 through an outlet 104;

The reaction oil gas separated by the oil agent separating device 201 enters the gas collection chamber 202 and is introduced into a product separating system (not shown) through an oil gas pipeline 203; the separated spent catalyst enters a dense phase settling section 205 of the settler 200; raw coke fuel oil is introduced through a pipeline 208, injected into a dense-phase settling section 205 through a nozzle 209, contacted with a spent catalyst and subjected to coking reaction, and the reacted spent catalyst enters a regenerator 500; the oxygen-containing gas from the oxygen-containing gas inlet 501 enters the regenerator after passing through the gas distributor 502, contacts with the coke-containing catalyst to generate complete combustion reaction, thoroughly emits heat, and the regenerated catalyst after regeneration returns to the catalytic cracking reactor 100 for recycling through the regenerated catalyst outlet 506 and the regenerated catalyst inlet 103; the regenerated flue gas is passed through a cyclone 503 to recover entrained catalyst and through a flue gas outlet 504 to a subsequent energy recovery system.

Examples

The following examples further illustrate the application, but are not intended to limit it. The industrial catalyst of the catalyst used in the test has the trade mark of NCC, and the raw oil for the cracking reaction is straight run Yanshan naphtha which is taken from a Yanshan petrochemical atmospheric and vacuum device. The raw coke fuel oil is catalytic diesel oil, which is taken from an Anqing petrochemical catalytic cracking device, and the properties of the two raw materials are shown in table 1.

Example 1

The test was performed according to the system of fig. 2: wherein the catalytic cracking reactor used has the following structure:

the total height of the reactor is 10 meters, wherein the pre-lifting area is 2 meters, and the inner diameter is 0.2 meter; the height of the reaction zone is 5 m, the inner diameter of the cross section of the top end is 0.2 m, and the inner diameter of the cross section of the bottom end is 0.3 m; the outlet zone has a height of 3 meters and an inner diameter of 0.2 meters.

The structure of the settler is as follows:

the oil agent separating equipment is accommodated in the settler, 4 evenly distributed feeding nozzles are arranged at the bottom of the dense-phase settling section, and jet extension lines of all the feeding nozzles are converged on the same intersection point of the central axial line of the settler;

and a spent catalyst outlet is arranged on the side wall of the dense-phase settling section, and the distance between the spent catalyst outlet and the bottom of the dense-phase settling section is 20% of the height of the dense-phase settling section.

And (3) carrying out a cracking reaction test of straight-run naphtha on a cracking reactor, introducing preheated raw oil from the lower part of the cracking reactor, contacting with a regenerated catalyst from a regenerator and carrying out catalytic cracking reaction from bottom to top to obtain an oil mixture of a reaction product and a spent catalyst, enabling the oil mixture to enter a cyclone separator from an outlet of the reactor, quickly separating the reaction product and the spent catalyst, and cooling and collecting the reaction product.

The spent catalyst enters a dense-phase sedimentation section under the action of gravity, is in turbulent fluidization under the action of bottom fluidization steam, and is injected into a dense-phase sedimentation section to be contacted with spent catalyst to generate coking reaction, and the spent catalyst after coking is conveyed to a regenerator to be contacted with air for regeneration; the regenerated catalyst is returned to the reactor for recycling. The operating conditions and product distribution are listed in Table 2.

As can be seen from the results in Table 2, the methane yield was 14.51%, the ethylene yield was 18.18% by weight, the propylene yield was 18.73% by weight, the coke yield was 5.99%, the methane selectivity was 17.11%, and the total selectivity of ethylene and propylene was 43.53%.

Comparative example 1

The test was performed according to the system of fig. 2, wherein the raw coke fuel oil was not injected in the dense phase settling section.

The spent catalyst enters a dense-phase sedimentation section for collection under the action of gravity, enters a regenerator through a spent vertical pipe, and is contacted with air for regeneration; the regenerated catalyst is returned to the reactor for recycling. The operating conditions and product distribution are listed in Table 2.

As can be seen from the results in Table 2, the methane yield was 14.76%, the ethylene yield was 18.01% by weight, the propylene yield was 18.40% by weight, the coke yield was 3.92%, the methane selectivity was 17.62%, and the total selectivity of ethylene and propylene was 43.46%. The comparative example had a low coke yield and insufficient green coke to maintain the thermal balance of the reaction.

From the results of the above examples, it can be seen that the catalytic cracking reaction system of the present application can not only reduce methane yield and improve ethylene and propylene selectivity, but also can produce coke with high selectivity, and provides a heat source for the regenerator from the aspect of the reaction system, without affecting the regeneration system.

In the description of the present application, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc. are directions or positional relationships based on the operation state of the present application are merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements to be referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of the present application, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly, unless otherwise specifically defined and limited. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

The application has been described above in connection with preferred embodiments, which are, however, exemplary only and for illustrative purposes. On this basis, the application can be subjected to various substitutions and improvements, and all fall within the protection scope of the application.

TABLE 1 cracking reaction raw materials and raw coke fuel oil Properties

	Straight run naphtha	Anqing oil slurry
			Density at 20 ℃ kilogram/meter ³	752.5	1068.6
Refractive index at 70 DEG C		1.6361
			Viscosity at 100 ℃ of millimeter ² Per second		11.5
Carbon residue,% (by weight)	0	4.79
			Carbon content,% (by weight)	87.47	91.22
Hydrogen content,% (by weight)	14.53	8.06
			Sulfur content,% (by weight)	0.014	0.331
Nitrogen content, mg/kg	1.2	2100
			Basic nitrogen, mg/kg	/	86
Distillation range, DEG C
			5% (volume)	/	364.5
10% (volume)	90.9	373.2
			30% (volume)	121.7	400.6
50% (volume)	145.8	425.6
			70% (volume)	167.3	464.8
95% (volume)	197.5	/

Table 2 example 1 and comparative example 1 operating conditions and results

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Claims

1. A catalytic cracking reaction-regeneration system, comprising:

a catalytic cracking reactor, wherein the catalyst is a catalyst,

a settler, and

2. The system of claim 1, wherein the spent catalyst outlet is located a distance from the bottom of the dense phase settling section that is 10% -30% of the dense phase settling section height.

3. The system of claim 1, wherein 2-6 evenly distributed raw coke fuel oil nozzles are arranged at the bottom of the dense phase settling section, and jet extension lines of the raw coke fuel oil nozzles are converged on the same intersection point of the central axial line of the settling vessel.

4. The catalytic cracking reaction-regeneration system of claim 1, wherein the catalytic cracking reactor comprises, in order from bottom to top:

an optional pre-lift zone;

an outlet zone;

5. The catalytic cracking reaction-regeneration system of claim 4, wherein a ratio of a bottom cross-sectional inner diameter of a reaction zone of the catalytic cracking reactor to a total height of the catalytic cracking reactor is 0.01:1 to 0.5:1, a step of; the ratio of the total height of the reaction zone to the total height of the catalytic cracking reactor was 0.15:1 to 0.8:1.

6. the catalytic cracking reaction-regeneration system according to claim 4, wherein the reaction zone of the catalytic cracking reactor comprises 1-3 reduced diameter reaction sections,

7. the catalytic cracking reaction-regeneration system of claim 4, wherein the ratio of the inner diameter to the height of the pre-lift zone of the catalytic cracking reactor is between 0.02 and 0.4:1, a step of; the ratio of the height to the total height of the catalytic cracking reactor is 0.01:1 to 0.2:1.

8. The catalytic cracking reaction-regeneration system according to claim 7, wherein the pre-lift zone of the catalytic cracking reactor is connected to the reaction zone by a first connection section, the longitudinal section of the first connection section is isosceles trapezoid, and the camber angle α of the side of the isosceles trapezoid is 5-85 °.

9. The catalytic cracking reaction-regeneration system of claim 4, wherein a ratio of a cross-sectional inner diameter to a height of said reactor outlet zone is between 0.01 and 0.3:1, the ratio of the height of the outlet zone to the total reactor height being 0.05:1 to 0.5:1.

10. a process for the catalytic cracking of light oils which allows thermal equilibrium to be achieved, said process being carried out in a system according to any one of claims 1 to 9,

the method comprises the following steps:

11. The method of claim 10, wherein the light oil comprises gaseous hydrocarbons and light distillate; the light oil meets one, two, three or four of the following indexes: the density at 20 ℃ is less than 860 kg/cubic meter, the carbon residue is 0-0.5 wt%, the total aromatic hydrocarbon content is 0-30 wt%, and the final distillation point of the distillation range is less than 360 ℃.

12. The method of claim 10, wherein the conditions of the catalytic cracking reaction comprise: the reaction temperature is 510-750 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is 10:1 to 50:1, the weight ratio of the pre-lifting gas to the raw oil is 0.05:1 to 2.0:1, the catalyst density is 20-100 kg/cubic meter, the linear speed is 4-18 m/s, and the reaction pressure is 130-450 kilopascals.

13. The process of claim 10, wherein the process further comprises introducing a C4 hydrocarbon fraction and/or a C5-C6 light gasoline fraction into the cracking reactor for catalytic cracking reactions.

14. The method of claim 10, wherein the raw coke fuel oil is a self-produced cracked heavy oil and a secondary processing distillate, or a mixture thereof; preferably, the secondary processed distillate oil may be selected from the group consisting of catalytic cracked diesel, catalytic cracked slurry/cycle oil, coker gasoline, straight run diesel, coker diesel, and coker wax oil.

15. The method of claim 10, wherein the conditions of the coking reaction comprise: the reaction temperature is 460-650 ℃, the reaction time is 2-20 seconds, and the weight ratio of the catalyst to the oil is 3:1 to 30:1, the weight ratio of the fluidization gas to the raw coke fuel oil is 0.01:1 to 0.2:1, the catalyst particle density is 300-450 kg/cubic meter.