CN218025941U

CN218025941U - Catalytic cracking combination unit for producing more low-carbon olefins

Info

Publication number: CN218025941U
Application number: CN202221754298.1U
Authority: CN
Inventors: 李红波; 鲁维民
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: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-12-13
Anticipated expiration: 2032-07-07

Abstract

A catalytic cracking combination unit for increasing the yield of light olefins comprises: the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are also provided with a first heat exchanger (5) and a second heat exchanger (6), a feed pipeline of the second catalytic cracking reaction regeneration unit exchanges heat with a product oil-gas pipeline of the second catalytic cracking reaction regeneration unit through the second heat exchanger (6), exchanges heat with a catalyst from the first catalytic cracking reaction regeneration unit through the first heat exchanger (5), and then is communicated with the bottom of a reactor of the second catalytic cracking reaction regeneration unit. The device provided by the utility model is used for catalytic cracking production low carbon olefin, can show reduction reaction oil gas temperature, avoids the further polymerization of low carbon olefin among the high temperature oil gas, adjusts the thermal balance of second catalytic cracking reaction regeneration unit, reduces the energy consumption.

Description

Catalytic cracking combination unit for producing more low-carbon olefins

Technical Field

The invention relates to a combined device for producing more low-carbon olefins through catalytic cracking.

Background

The low-carbon olefin (ethylene and propylene) is a basic chemical raw material, is mainly used in the industries of polyethylene, ethylene oxide, dichloroethane/chloroethylene, ethylbenzene, polypropylene, propylene oxide, acrylonitrile and the like, and has wide market application. The catalytic cracking is one of the important sources of low-carbon olefins, except for producing gasoline, diesel oil and other products, and also produces low-carbon olefins as byproducts.

Currently, various catalytic conversion methods for producing a large amount of light olefins are available in industry, for example, chinese patent CN104560154A discloses that a heavy hydrocarbon raw material, a light gasoline component, a C4 component and a medium hydrocarbon raw material are respectively injected into different reaction regions, and catalytic cracking reaction is performed at different reaction temperatures and reaction severity levels, so as to achieve the purpose of producing a large amount of light olefins. U.S. patent No. 5009769 discloses cracking hydrocarbon feedstock of different properties in a double riser reactor, wax oil and residual oil entering the first riser, cracking under the conditions of 5-10 of self-catalyst-oil weight ratio and 1-4 seconds of residence time; injecting the straight-run gasoline, the straight-run middle distillate oil and the catalytic heavy gasoline into a second lifting pipe, and cracking under the conditions of the catalyst-oil weight ratio of 3-12 and the retention time of 1-5 seconds.

The above processes (CN 104560154A, US 5009769) generally employ a multistage reactor, using one catalyst, sharing the type of reactor settler and regenerator. However, different raw materials have different requirements on the catalyst, heavy raw materials are suitable for conversion in the presence of a catalyst containing a large-pore and medium-pore molecular sieve, and naphtha fraction with a lower boiling point is suitable for catalytic conversion in the presence of a molecular sieve catalyst with a medium-pore and small-pore diameter to produce low-carbon olefins. Therefore, a technology for carrying out independent catalytic cracking reaction on different raw materials is developed, for example, CN101362961A develops a catalytic conversion method for preparing low-carbon olefin from raw materials with a distillation range of 160-260 ℃, and under the proper catalytic condition, a set of catalytic cracking device is independently arranged, so that the yield and the selectivity of ethylene and propylene are greatly increased. However, the conversion of the high-yield low-carbon olefin requires a large reaction heat, the raw coke of the light component raw material is less, the self heat cannot be balanced, fuel oil needs to be injected, a new set of catalytic device is arranged, the equipment investment is increased, and the process technology economy is reduced.

Chinese patent CN101323798A discloses a method for sequentially carrying out catalytic conversion in a first reaction regeneration system and a second reaction regeneration system, wherein the raw material is all or part of the fraction of the reaction product of the first reaction regeneration system, and the reaction product enters the second reaction regeneration system in a gaseous form for further reaction, so as to overcome the problem of insufficient heat caused by insufficient coke formation in the low-temperature reaction regeneration system. When the second reaction regeneration system feeds by gas phase, the gas phase left after the heavy distillate oil is completely or partially removed from the first reaction regeneration system contains C1-C4 light phase generated by the first reaction regeneration system, and the generated olefin is easy to further react in the second reaction regeneration system, so that the yield of the low-carbon olefin is reduced. Meanwhile, the separately-arranged catalytic cracking for producing more low-carbon olefins usually needs a very high reaction temperature, the outlet temperature of reaction oil gas is usually over 600 ℃, and when alkadiene exists, the olefins are easy to polymerize, so that the yield of the generated low-carbon olefins is further reduced.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a catalytic cracking composite set of prolific light olefin.

The utility model provides a catalytic cracking composite set of prolific light olefin, include: the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are also provided with a first heat exchanger and a second heat exchanger, and a feed pipeline of the second catalytic cracking reaction regeneration unit exchanges heat with a product oil-gas pipeline of the second catalytic cracking reaction regeneration unit through the second heat exchanger, exchanges heat with a catalyst from the first catalytic cracking reaction regeneration unit through the first heat exchanger, and then is communicated with the bottom of a reactor of the second catalytic cracking reaction regeneration unit.

The utility model provides an application method of catalytic cracking composite set of prolific light olefin, heavy oil raw materials get into in the first catalytic cracking reaction regeneration unit with catalytic cracking catalyst contact reaction, the product oil gas heat transfer of light hydrocarbon oil feeding through second heat exchanger and second catalytic cracking reaction regeneration unit, after first heat exchanger and the high temperature catalyst heat transfer that comes from first catalytic cracking reaction regeneration unit again, contact with prolific light olefin catalyst and carry out catalytic cracking reaction; the reaction oil gas is separated to produce more light olefins.

The utility model provides a catalytic cracking composite set's beneficial effect does:

the utility model provides a catalytic cracking composite set is used for heavy oil catalytic cracking to produce low carbon olefin more, and first catalytic cracking reaction regeneration unit uses the heavy oil as the raw materials, and second catalytic cracking reaction regeneration unit uses light distillate oil as the raw materials, adopts the catalytic cracking catalyst of two kinds of differences, carries out the catalytic cracking reaction under the high severity to light distillate oil, can maximize production low carbon olefin. The high-temperature product oil gas of the second catalytic cracking reaction regeneration unit exchanges heat with the reaction feed of the second catalytic cracking reaction regeneration unit, so that the temperature of the reaction oil gas can be obviously reduced, the further polymerization of low-carbon olefins in the high-temperature oil gas is avoided, the heat balance of the second catalytic cracking reaction regeneration unit is adjusted, the fuel oil injection is reduced or cancelled, and the energy consumption is reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a schematic flow diagram of an embodiment of a catalytic cracking unit according to the present invention.

Fig. 2 is a schematic flow chart of a second embodiment of the catalytic cracking unit according to the present invention.

Fig. 3 is a schematic flow chart of a third embodiment of a catalytic cracking combination unit provided by the present invention.

FIG. 4 is a schematic flow diagram of the catalytic cracking process in comparative example 1.

Fig. 5 is a schematic flow diagram of the catalytic cracking process of comparative example 2.

Fig. 6 is a schematic flow diagram of a catalytic cracking process of comparative example 3.

Wherein:

1a first feed line; 2 a first product oil and gas pipeline; 3 a feed line; 4a second product hydrocarbon line; 5 a first heat exchanger; 6 a second heat exchanger; 7 a second feed line; 11 a first reactor; 12 a first regenerator; 13 a second reactor; 14 second regenerator.

Detailed Description

The following describes the embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

In the present application, the terms "upper", "lower" and "bottom" are used based on the relative positional relationship of the container or the member. Wherein, the bottom is 0-10% of the position of the container from bottom to top, and the top is 90-100% of the position of the container from bottom to top.

The utility model provides a catalytic cracking composite set, include: the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are also provided with a first heat exchanger and a second heat exchanger, and a feed pipeline of the second catalytic cracking reaction regeneration unit exchanges heat with a product oil-gas pipeline of the second catalytic cracking reaction regeneration unit through the second heat exchanger, exchanges heat with a catalyst from the first catalytic cracking reaction regeneration unit through the first heat exchanger, and then is communicated with the bottom of a reactor of the second catalytic cracking reaction regeneration unit.

Optionally, the first catalytic cracking reaction regeneration unit comprises a first reactor, a gas-solid separation device, a stripper and a first regenerator which are sequentially communicated, the first regenerator is communicated with the bottom of the first reactor through a regenerant inclined tube, a first feeding pipeline is arranged at the bottom of the first reactor, and a first product oil-gas pipeline is arranged at the top of the gas-solid separation device.

Optionally, the first reactor is selected from a riser reactor or a combination of two riser reactors, and the riser reactor is a riser or a combination of a riser and a fluidized bed reactor.

Optionally, the second catalytic cracking reaction regeneration unit comprises a second reactor, a gas-solid separation device, a steam stripper and a second regenerator which are sequentially communicated, the second regenerator is communicated with the bottom of the second reactor through a regenerant inclined tube, a second feeding pipeline is arranged at the bottom of the second reactor, and a second product oil-gas pipeline is arranged at the top of the gas-solid separation device.

Preferably, the feed line of the second catalytic cracking reaction regeneration unit exchanges heat with the catalyst from the regenerator of the first catalytic cracking reaction regeneration unit through the first heat exchanger after exchanging heat with the second heat exchanger.

Preferably, the first heat exchanger is a coil heat exchanger and is arranged inside or outside the first regenerator. More preferably inside the first regenerator.

Preferably, the second feed line is in communication with a coil heat exchanger disposed inside the first regenerator.

Preferably, the second heat exchanger is a shell-and-tube heat exchanger, the second feed pipeline is communicated with the shell side, and the second product oil-gas pipeline is communicated with the tube side.

Preferably, an external heat remover is arranged in the first catalytic cracking reaction regeneration unit, and the external heat remover can be arranged on the regenerant inclined tube; in the second catalytic cracking reaction regeneration unit, a fuel replenishing pipeline is arranged in the second regenerator.

Optionally, the system further comprises a fractionation unit, wherein the first product oil and gas pipeline and the second product oil and gas pipeline are communicated with the raw material inlet of the fractionation unit.

Optionally, the device further comprises an absorption stabilizing unit, and the fractionation unit is communicated with the absorption stabilizing unit.

The utility model provides a catalytic cracking composite set, first catalytic cracking reaction regeneration unit are known to the technical personnel in the field, and wherein first reactor can include fluidized bed reactor and/or riser reactor, the riser reactor can be single diameter riser reactor or reducing riser reactor.

The utility model provides a catalytic cracking composite set is used for the method of prolific low carbon system, and first catalytic cracking reaction regeneration unit adopts heavy oil catalytic cracking technology, can be conventional catalysis, or prolific liquefied gas, prolific gasoline, prolific diesel oil catalytic cracking family in the technology.

It is well known to those skilled in the art to use a feedstock oil, which may be at least one selected from the group consisting of vacuum gas oil, atmospheric residue, vacuum residue, deasphalted oil, and coker gas oil.

The regeneration process is carried out according to catalyst regeneration methods conventional in the art, for example, the regeneration method may include: introducing oxygen-containing gas (such as air) from the bottom of the regenerator, contacting the catalyst to be generated with the oxygen to burn and regenerate after the oxygen-containing gas is introduced into the regenerator, carrying out gas-solid separation on the upper part of the regenerator on flue gas generated after the catalyst is burnt and regenerated, and enabling the flue gas to enter a subsequent energy recovery system. The regeneration conditions may be those conventional in the art and may include, for example: the temperature is 550-750 ℃, preferably 600-730 ℃, and more preferably 650-700 ℃; the average residence time of the spent catalyst is from 0.6 to 3 minutes, preferably from 0.8 to 2.5 minutes, more preferably from 1 to 2 minutes.

The first catalytic cracking reaction regeneration unit employs a conventional catalytic cracking catalyst, the composition and properties of which are well known to those skilled in the art, and which is selected primarily based on the feedstock being processed and the desired end product requirements, and may be any of the various commercial grades of catalytic cracking and catalytic cracking catalysts currently commercially available.

The catalytic cracking reaction conditions adopted by the first catalytic cracking reaction regeneration unit are well known to those skilled in the art, for example, the reaction temperature is 480-700 ℃, the pressure is 0-0.2MPaG, the water-oil ratio is 0.1-1, and the mass ratio of the catalyst to the raw oil is (4-15): 1.

the first catalytic cracking reaction regeneration unit is preferably provided with a catalytic cracking reaction device with an external heat collector for heat.

The second catalytic cracking reaction regeneration unit adopts a catalytic cracking process for producing more low-carbon olefins, the raw material adopts light distillate oil, the light distillate oil does not contain components with the carbon number less than or equal to 4, and the distillation range dry point is less than or equal to 250 ℃. The catalyst can be obtained by fractionating and cutting a product of a first catalytic cracking reaction regeneration unit, and can also be obtained by cutting external coking gasoline, naphtha, biomass oil, plastic thermal degradation oil and Fischer-Tropsch synthetic oil.

Catalytic cracking units for the second catalytic cracking reaction regeneration unit are well known to those skilled in the art, wherein the second reactor may comprise a fluidized bed reactor and/or a riser reactor, which may be a single diameter riser reactor or a variable diameter riser reactor.

The regeneration process is carried out according to catalyst regeneration methods conventional in the art, for example, the regeneration method comprises: introducing oxygen-containing gas (such as air) from the bottom of the regenerator, contacting the catalyst to be generated with the oxygen to burn and regenerate after the oxygen-containing gas is introduced into the regenerator, carrying out gas-solid separation on the upper part of the regenerator on flue gas generated after the catalyst is burnt and regenerated, and introducing the flue gas into a subsequent energy recovery system. The regeneration conditions are those conventional in the art, and include, for example: the temperature is 550-750 ℃, preferably 600-730 ℃, and more preferably 650-700 ℃; the average residence time of the spent catalyst is from 0.6 to 3 minutes, preferably from 0.8 to 2.5 minutes, more preferably from 1 to 2 minutes.

The second catalytic cracking reaction regeneration unit adopts a productive low-carbon olefin catalyst, and preferably, the catalyst contains 1-60 wt% of zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay based on the total weight of the catalyst. The zeolite is preferably a medium pore zeolite and/or a large pore zeolite as an active component, and preferably the medium pore zeolite is present in an amount of 50 to 100 wt% based on the total weight of the zeolite, preferably the medium pore zeolite is present in an amount of 70 to 100 wt% based on the total weight of the zeolite. The medium and large pore zeolites are defined as conventional in the art, i.e., the medium pore zeolite has an average pore size of 0.5 to 0.6nm and the large pore zeolite has an average pore size of 0.7 to 1.0nm. The large-pore zeolite can be one or more of rare earth Y, rare earth hydrogen Y, ultrastable Y obtained by different methods and zeolite composed of high-silicon Y.

Wherein the medium pore zeolite can be selected from zeolites with MFI structure, such as ASM series zeolite and/or ZRP zeolite, and the medium pore zeolite can be modified by nonmetal elements such as phosphorus and/or transition metal elements such as iron, cobalt, nickel, etc., the ZRP is described in more detail in U.S. Pat. No. 5,232,675, the ZSM series zeolite is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites with similar structure, and the ZSM-5 is described in more detail in U.S. Pat. No. 3,702,886. The inorganic oxide is preferably selected from silicon dioxide and/or aluminum oxide as a binder. The clay is preferably selected from kaolin and/or halloysite as a matrix.

The reaction temperature of the second catalytic cracking reaction regeneration unit is 570-750 ℃, preferably 600-730 ℃, and more preferably 650-700 ℃. The reaction time is from 1 to 10s, preferably from 2 to 6s, more preferably from 2 to 4s. The weight ratio of the agent oil is 1-100, preferably 10-50, more preferably 20-40.

The first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit respectively select different catalytic cracking processes and dedicated catalysts, and are provided with independent reaction regeneration systems conforming to the respective processes, and the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are not interfered with each other.

And exchanging heat between the high-temperature oil gas of the product of the second catalytic cracking reaction regeneration unit and the reaction feed of the second catalytic cracking reaction regeneration unit to cool the reaction oil gas and reduce the further polymerization reaction of olefin generated by the reaction at high temperature, wherein the temperature of the reaction oil gas after heat exchange is lower than 400 ℃, and preferably lower than 350 ℃. The heat exchange equipment can be industrial common heat exchange equipment, such as a shell-and-tube heat exchanger, a plate heat exchanger and the like.

The reaction heat required by the second catalytic cracking reaction regeneration unit is higher than that of the conventional catalytic cracking, but the coke formation amount is less, the heat release during the catalyst regeneration cannot balance the heat requirement of a reaction system, and fuel oil needs to be additionally sprayed. The reaction feeding is vaporized and heated through the heat exchange between the reaction feeding and high-temperature oil gas, so that the vaporization heat of the raw materials required by a reaction system can be reduced, the heat requirement of the reaction system is reduced, and finally fuel oil is sprayed less or not. After heat exchange, the reaction feed temperature is greater than or equal to 300 ℃, preferably greater than or equal to 400 ℃.

In order to further balance the reverse reheating balance of the second catalytic cracking reaction regeneration unit, the feeding of the second catalytic cracking reaction regeneration unit and the product oil gas of the second catalytic cracking reaction regeneration unit are subjected to heat exchange and temperature rise, and then the feeding is continuously subjected to heat exchange with the hot catalyst of the regenerator of the first catalytic cracking reaction regeneration unit, so that the feeding of the second catalytic cracking reaction regeneration unit is further heated, and the final reaction feeding temperature is more than or equal to 400 ℃, and preferably more than or equal to 500 ℃.

The heat exchange can be carried out outside the reactor or by arranging a coil pipe in the first regenerator.

The product oil gas of the first catalytic cracking reaction regeneration unit and the product oil gas of the second catalytic cracking reaction regeneration unit can be processed in a centralized mode, the product oil gas of the first catalytic cracking reaction regeneration unit and the product oil gas of the second catalytic cracking reaction regeneration unit are mixed and then enter a separation absorption stabilizing system, and dry gas, liquefied gas, stable gasoline, catalytic diesel and oil slurry products can be obtained through separation.

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings, but the present invention is not limited thereto.

Fig. 1 is a schematic flow diagram of a first embodiment of a catalytic cracking unit according to the present invention, and as shown in fig. 1, the catalytic cracking unit includes: the device comprises a first catalytic cracking reaction regeneration unit and a second catalytic cracking reaction regeneration unit, wherein in the first catalytic cracking reaction regeneration unit, a first feeding pipeline 1 is arranged at the bottom of a first reactor 11, an outlet of the first reactor 11 is communicated with a settler and a stripper, the bottom of the stripper is communicated with a first regenerator 12 through a spent catalyst inclined pipe, and the bottom of the first regenerator 12 is communicated with the bottom of the first reactor 11 through a regeneration inclined pipe. In the second catalytic cracking reaction regeneration unit, a second feeding pipeline 7 is arranged at the bottom of a second reactor 13, an outlet of the second reactor 13 is communicated with a settler and a stripper, the bottom of the stripper is communicated with a second regenerator 14 through a spent catalyst inclined tube, and the bottom of the second regenerator 14 is communicated with the bottom of the second reactor 13 through a regeneration inclined tube. The feed pipeline 3 of the second catalytic cracking reaction regeneration unit exchanges heat with the product oil gas pipeline 4 of the second catalytic cracking reaction regeneration unit through the second heat exchanger 6, exchanges heat with the catalyst from the regenerator of the first catalytic cracking reaction regeneration unit through the first heat exchanger 5, and is communicated with the bottom of the second reactor through the second feed pipeline 7.

Fig. 2 is a schematic flow diagram of a second embodiment of a catalytic cracking unit according to the present invention. In the first catalytic cracking reaction regeneration unit, unlike the attached fig. 1, the first reactor includes a first riser, a second riser and a fluidized bed, wherein the first riser and the second riser are connected in parallel and then connected in series with the fluidized bed.

Fig. 3 is a schematic flow diagram of a third embodiment of a catalytic cracking unit according to the present invention. Different from the attached figure 1, in the first catalytic cracking reaction regeneration unit, the first reactor is a two-section riser reactor connected in series, and comprises a first reaction zone and a second reaction zone with an enlarged tube diameter, which are connected in series, wherein the second reaction zone is communicated with a gas-solid separation device through a riser with the same diameter as the first reaction zone.

The following examples further illustrate the specific embodiments of the catalytic cracking unit provided by the present invention and the technical effects of the present invention applied to the high yield of low carbon olefins.

Catalyst preparation example 1

The preparation method of the catalyst for producing more light olefins comprises the following steps:

(1) 20gNH ₄ Cl was dissolved in 1000g of water, and 100g (dry basis) of a crystallized product ZRP-1 zeolite (produced by catalyst works of Qilu petrochemical Co., si/Al (molar ratio) =30, rare earth content RE) was added to the solution ₂ O ₃ =2.0 wt%), exchanged at 90 ℃ for 0.5h, filtered to obtain a filter cake; 4.0gH was added ₃ PO ₄ (concentration 85 mass%) and 4.5g Fe (NO) ₃ ) ₃ Dissolving in 90g of water, mixing with a filter cake, soaking and drying; then roasting at 550 deg.C for 2 hr to obtain MFI structure mesoporous zeolite containing phosphorus and iron, and its element analytical chemical composition is 0.1Na ₂ O·5.0Al ₂ O ₃ ·2.4P ₂ O ₅ ·1.5Fe ₂ O ₃ ·3.8RE ₂ O ₃ ·88.1SiO ₂ 。

(2) Pulping 75.4kg of halloysite (industrial product of Suzhou china clay, with a solid content of 71.6 wt%) with 250kg of decationized water, adding 54.8kg of pseudoboehmite (industrial product of Shandong aluminum plant, with a solid content of 63 wt%), adjusting pH to 2-4 with hydrochloric acid, stirring, standing at 60-70 deg.C for aging for 1 hr, maintaining pH at 2-4, cooling to below 60 deg.C, and adding 41.5kg of alumina sol (product of catalyst plant of Qilu petrochemical company, al) ₂ O ₃ Content 21.7 wt%), and stirred for 40 minutes to obtain a mixed slurry.

(3) The phosphorus and iron containing MFI structure mesoporous zeolite prepared in step 1) (22.5 kg on a dry basis) and DASY zeolite (iso-zeolite)Industrial products of catalyst plants of Shandong petrochemical company, unit cell constant of 2.445-2.448nm, dry basis of 2.0 kg) are added into the mixed slurry obtained in the step 2), the mixture is stirred evenly, spray-dried and formed, washed by ammonium dihydrogen phosphate solution (phosphorus content is 1 weight percent), and free Na is washed off ⁺ Drying to obtain a catalytic conversion catalyst sample, wherein the catalyst comprises 18 wt% of MFI structure mesoporous zeolite containing phosphorus and iron, 2 wt% of DASY zeolite, 28 wt% of pseudo-boehmite, 7 wt% of alumina sol and the balance of kaolin.

The properties of the light distillate used in the examples and comparative examples are shown in table 1:

TABLE 1

The properties of the heavy oil feeds used in the examples and comparative examples are shown in table 2.

TABLE 2

	Heavy oil feedstock A	Heavy oil feedstock B
			Density (20 ℃ C.), g/cm ³	0.9340	0.8950
Carbon residue, by weight%	5.54	6.05
			Hydrogen content	12.15	13.1
Distillation range, deg.C
			IBP	310	278
10％	385	393
			30％	460	447
50％	530	503
			70％	630	539(57.8)
90％	850

Example 1

Example 1 illustrates the use of the catalytic cracking unit of the present invention.

As shown in fig. 2, the catalytic cracking combination unit comprises a first catalytic cracking reaction regeneration unit and a second catalytic cracking reaction regeneration unit, wherein a feed pipeline 3 of the second catalytic cracking reaction regeneration unit exchanges heat with a second product oil gas through a second heat exchanger 6, exchanges heat with a catalyst of a first regenerator 12 through a first heat exchanger 5, and then enters the bottom of a second reactor through a second feed pipeline 7.

In the first catalytic cracking reaction regeneration unit, the first reactor comprises a first riser, a second riser and a fluidized bed, wherein the first riser and the second riser are connected in parallel and then connected with the fluidized bed in series. In order to achieve heat balance, an external heat collector is arranged in the first regenerator.

The first catalytic cracking reaction regeneration unit uses a heavy oil raw material B as a raw material, uses an MMC-2 catalyst (produced by catalyst plant of Qilu petrochemical company), and performs a catalytic conversion test with the aim of producing more low-carbon olefins.

The high-temperature regenerant respectively enters the bottoms of the two lifting pipes and flows upwards under the action of a pre-lifting medium (water vapor), and the raw oil enters the first lifting pipe through the feeding nozzle to contact with the regenerant to carry out catalytic conversion reaction after being preheated and mixed with atomized water vapor. The mixture containing reaction oil gas and catalyst ascends along the riser and is introduced into the fast separation equipment for gas-solid separation. The reaction oil gas enters a reaction product separation system from a first product oil gas pipeline for separation, and the separated light gasoline fraction and the cracked heavy oil fraction are recycled as the feed of a second lifting pipe. Introducing the spent catalyst into the fluidized bed, mixing with the catalyst and oil gas therein, carrying out contact reaction, then flowing into a stripper communicated with the fluidized bed, and carrying out gas-solid separation on the hydrocarbon products adsorbed on the spent catalyst extracted by steam through the fluidized bed in a settler. The stripped spent agent enters a first regenerator through a spent inclined pipe for scorching and regeneration. The regenerated catalyst returns to the two riser reactors through the regeneration inclined tube for recycling.

The light gasoline and the atomized steam are mixed and then enter a second riser through a nozzle at the bottom of the second riser to be in contact reaction with a high-temperature catalyst, the cracked heavy oil and the atomized steam are mixed and then enter a fluidized bed reactor through a nozzle at the bottom of the fluidized bed reactor to be in contact reaction with the high-temperature catalyst, the reaction oil gas enters a settler through a fluidized bed, the catalyst carried in the reaction oil gas is separated, and then the reaction oil gas is introduced into a product separation system to be separated. The operating conditions and product distribution of the first catalytic cracking reaction regeneration unit are shown in table 3.

TABLE 3

The second catalytic cracking reaction regeneration unit takes the light distillate oil A as a feed, and uses the catalyst for producing more light olefins in the catalyst preparation example. After the heat exchange between the fed material and the material in the second oil-gas pipeline reaches 400 ℃, the fed material and the high-temperature regenerated catalyst in the first regenerator continuously exchange heat and the temperature rises to 500 ℃. The light distillate oil enters a second reactor through a second feeding pipeline to carry out catalytic conversion reaction, reaction oil gas and spent catalyst enter a closed cyclone separator from the outlet of a riser reactor, the oil gas and the spent catalyst are quickly separated, and the reaction oil gas and the feeding oil gas enter a subsequent separation system together with the oil gas from a first product oil gas pipeline after heat exchange to 320 ℃.

The spent agent enters a stripping section under the action of gravity, hydrocarbon products adsorbed on the spent agent are stripped by steam, and the stripped spent agent enters a second regenerator for coke burning regeneration; the regenerant enters a degassing tank to remove non-hydrocarbon stripping impurities adsorbed and carried by the regenerant; the degassed regenerant is returned to the riser reaction for recycling. In order to reach the heat balance, the second regenerator is injected with fuel oil for heat compensation. The second catalytic cracking reaction regeneration unit operating conditions and product distribution are shown in table 4.

TABLE 4

Example 2

An experiment was conducted according to the flow scheme of fig. 3, which is different from example 1 in that in the first catalytic cracking reaction regeneration unit, the first reactor was a riser reactor comprising a first reaction zone and a second reaction zone with an enlarged tube diameter connected in series, wherein the diameter of the second reaction zone was 2.62 times that of the first reaction zone, and the second reaction zone was communicated with a settler of the first reactor through a riser having the same diameter as that of the first reaction zone. The raw material of the first catalytic cracking reaction regeneration unit adopts a heavy oil raw material A and uses a CGP-1 catalyst (produced by catalyst factory of Qilu petrochemical company).

The high-temperature regenerant enters the bottom of the riser reactor and flows upwards under the action of a pre-lifting medium (water vapor), and the raw oil enters a first reaction zone through a feed nozzle to contact with the regenerant to perform catalytic conversion reaction after being preheated and mixed with atomized water vapor. The reaction product enters a second reaction zone to continue catalytic conversion reaction, the mixture of the reacted reaction oil gas and the catalyst ascends along the lifting pipe, and the reaction oil gas and the catalyst are introduced into a quick separation device through the outlet of the lifting pipe to carry out gas-solid separation. The reaction oil gas is led out of the reactor and then enters a reaction product separation system to separate gas and liquid products. Introducing the spent agent into a stripper, feeding the stripped spent agent into a first regenerator through a spent inclined tube, and contacting with air to perform high-temperature coke-burning regeneration. The regenerated catalyst returns to the riser reactor through the regenerated inclined tube for recycling. In order to achieve heat balance, an external heat collector is provided in the first regenerator. The operating conditions and the product distribution are shown in Table 5.

TABLE 5

The second catalytic cracking reaction regeneration unit uses the light distillate oil A as a feed, uses the catalyst with high yield of low-carbon olefin obtained in the catalyst preparation example 1, and the second reactor is a riser reactor. The reaction was operated as in the second catalytic cracking reaction regeneration unit of example 1. The operating conditions and the product distribution are shown in Table 6.

TABLE 6

	Second catalytic cracking reaction regeneration unit
		Riser outlet temperature,. Deg.C	675
Reaction time in seconds	2
		Steam/feedstock oil weight ratio	0.3
Ratio of agent to oil	25
		Distribution of the product,% by weight
H ₂ -C2	36.20
		C3-C4	32.46
C5+ pyrolysis gasoline	27.02
		Cracking diesel oil	2.76
Coke	1.56
		In total	100
Ethylene (CO) process	18.50
		Propylene (PA)	19.36
Injection of fuel oil, kg/t feedstock	21.3

Comparative example 1

The reaction flow of the comparative example 1 is shown in the attached figure 4, the structure, the raw materials and the reaction operating conditions of the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are the same as those of the example 1, the difference of the example 1 is that the feeding of the second catalytic cracking reaction regeneration unit does not exchange heat with the first catalytic cracking reaction regeneration unit, and the second feeding and the second product oil gas exchange heat to 400 ℃, and then enter the bottom of a riser to perform catalytic conversion reaction.

Compared with the example 1, the first catalytic cracking reaction regeneration unit regenerates the external heat 42kW/t of raw material, and the second catalytic cracking reaction regeneration unit sprays fuel oil 28.9kg/t of raw material.

Comparative example 2

The reaction flow of the comparative example 2 is shown in the attached figure 5, the structure, the raw materials and the reaction operating conditions of the first catalytic cracking reaction regeneration unit and the second catalytic cracking reaction regeneration unit are the same as those of the example 2, the difference of the example 2 is that the feeding of the second catalytic cracking reaction regeneration unit does not exchange heat with the first catalytic cracking reaction regeneration unit, and the second feeding and the second product oil gas exchange heat to 400 ℃, and then enter the bottom of a riser to perform catalytic conversion reaction. Compared with the example 2, the first catalytic cracking reaction regeneration unit regenerates the external heat of 216.9kW/t of raw material, and the second catalytic cracking reaction regeneration unit sprays the fuel oil of 28.9kg/t of raw material.

Comparative example 3

The reaction flow of the comparative example 3 is shown in the attached figure 6, the first and second catalytic cracking reaction regeneration units have the same structure, raw materials and reaction operation conditions as those of the example 1, and the difference from the example 1 is that the feed of the second catalytic cracking reaction regeneration unit does not exchange heat with other material flows, and directly enters the bottom of a riser to perform catalytic conversion reaction, and the heat balance is respectively calculated. Compared with the example 1, the first catalytic cracking reaction regeneration unit takes 42kW/t of external heat, and the second catalytic cracking reaction regeneration unit sprays 58.8kg/t of fuel oil.

Claims

1. A catalytic cracking combination unit for increasing the yield of light olefins comprises: the device is characterized by further comprising a first heat exchanger (5) and a second heat exchanger (6), wherein a feed pipeline of the second catalytic cracking reaction regeneration unit exchanges heat with a product oil-gas pipeline of the second catalytic cracking reaction regeneration unit through the second heat exchanger (6), exchanges heat with a catalyst from the first catalytic cracking reaction regeneration unit through the first heat exchanger (5), and then is communicated with the bottom of a reactor of the second catalytic cracking reaction regeneration unit.

2. The catalytic cracking combination unit for the high yield of light olefins as claimed in claim 1, wherein the first catalytic cracking reaction regeneration unit comprises a first reactor, a gas-solid separation device, a stripper and a first regenerator which are sequentially communicated, the first regenerator is communicated with the bottom of the first reactor through a regenerant inclined tube, the bottom of the first reactor is provided with a first feeding pipeline, and the top of the gas-solid separation device is provided with a first product oil gas pipeline.

3. The combined catalytic cracking apparatus for producing more lower olefins according to claim 2, wherein the first reactor is selected from a riser reactor or a combination of two riser reactors, and the riser reactor is a riser or a combination of a riser and a fluidized bed reactor.

4. The catalytic cracking combination unit for increasing the yield of light olefins according to claim 1, 2 or 3, wherein the second catalytic cracking reaction regeneration unit comprises a second reactor, a gas-solid separation device, a stripper and a second regenerator which are sequentially communicated, the second regenerator is communicated with the bottom of the second reactor through a regenerant inclined tube, the bottom of the second reactor is provided with a second feeding pipeline, and the top of the gas-solid separation device is provided with a second product oil gas pipeline.

5. The catalytic cracking combination for the increased production of lower olefins according to claim 4, wherein the first heat exchanger is an internal coil heat exchanger and is disposed inside the first regenerator.

6. The catalytic cracking combination for high yield of lower olefins according to claim 5, wherein the second feed line is in communication with a coiled heat exchanger disposed inside the first regenerator.

7. The combined catalytic cracking unit for increasing the yield of light olefins according to claim 1, 2 or 3, wherein the second heat exchanger is a shell-and-tube heat exchanger, wherein a feed pipeline of the second catalytic cracking reaction regeneration unit is communicated with the shell side, and a second product oil-gas pipeline is communicated with the tube side.

8. The catalytic cracking combination unit for the high yield of low carbon olefins according to claim 1, 2 or 3, wherein the first catalytic cracking reaction regeneration unit is provided with an external heat collector; in the second catalytic cracking reaction regeneration unit, a fuel replenishing pipeline is arranged in the second regenerator.

9. The catalytic cracking combination for the increased production of lower olefins according to claim 1, 2 or 3, further comprising a fractionation unit, wherein the first product hydrocarbon line and the second product hydrocarbon line are in communication with a feedstock inlet of the fractionation unit.

10. The catalytic cracking unit for increasing the yield of light olefins according to claim 9, further comprising an absorption stabilizing unit, wherein the fractionating unit is connected to the absorption stabilizing unit.