阅读说明：本技术 一种新型催化裂解工艺方法 (Novel catalytic cracking process method ) 是由 王柱祥 洪伟 商恩霞 葛年春 曹卫民 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种新型催化裂解工艺方法,包括以下步骤：首先,以常规催化裂化的原料,进行选择性催化裂解反应,产物经过分离后得到干气、液化气、汽油、FGO等；其次,将FGO进行高压加氢后返回流化床反应器,最大量产出汽油和液化气；然后,将液化气和汽油中有效组份进行重组单元操作,将两者重组得到的产物单独进或与新鲜原料混合进流化床反应器；经以上反应和回炼、再反应,可最大化生产出丙烯,并同时副产出大量的BTX。本发明新型催化裂解工艺方法,具有丙烯收率为原料的40～60m％,芳烃收率为原料的15～30m％,干气和焦炭收率低等优点,同时系统所采用的设备与常规催化裂化的设备类似,可操作性强,投资小,操作费用低。(The invention discloses a novel catalytic cracking process method, which comprises the following steps: firstly, carrying out selective catalytic cracking reaction on conventional catalytic cracking raw materials, and separating products to obtain dry gas, liquefied gas, gasoline, FGO and the like; secondly, returning FGO to the fluidized bed reactor after high-pressure hydrogenation is carried out on the FGO, and producing gasoline and liquefied gas to the maximum extent; then, carrying out recombination unit operation on effective components in the liquefied gas and the gasoline, and independently feeding a product obtained by recombining the liquefied gas and the gasoline into a fluidized bed reactor or mixing the product with a fresh raw material; by the reaction, the back refining and the re-reaction, the propylene can be produced to the maximum extent, and a large amount of BTX is produced as a side product. The novel catalytic cracking process method has the advantages that the yield of propylene is 40-60 m% of the raw material, the yield of aromatic hydrocarbon is 15-30 m% of the raw material, the yield of dry gas and coke is low, and the like, and meanwhile, the equipment adopted by the system is similar to the conventional catalytic cracking equipment, so that the operability is strong, the investment is low, and the operation cost is low.)

1. A novel catalytic cracking process method is characterized by comprising the following steps:

s1 selective catalytic cracking unit operation: conveying 60-80 wt% wax oil and 20-40 wt% residual oil raw materials to a fluidized bed reactor for selective catalytic cracking reaction, and performing fractionation, absorption stabilization and other separation process operations on reaction products to obtain dry gas, liquefied gas, gasoline and FGO;

s2FGO high pressure hydrogenation unit operation: preheating the FGO obtained in the step S1, directly feeding the preheated FGO into a high-pressure hydrogenation reactor, washing the hydrogenated product with high-fraction and low-fraction water, and feeding the product into a rectifying tower, wherein the product at the top of the tower is a 3# remill product;

s3 gasoline reforming unit operation: carrying out recombination operation on the gasoline obtained in the step S1, namely carrying out olefin polymerization reaction, olefin and aromatic hydrocarbon separation and other operations to obtain a 2# remixed product;

s4 butene recombination unit operations: the liquefied gas obtained in the step S1 is firstly subjected to alkali washing and water washing, and then is separated by a gas separation process to obtain propylene, propane and C₄(ii) a Wherein C is₄Carrying out recombination unit operation including selective superposition reaction on the medium butylene to obtain a 1# remixed product;

s5 maximizes propylene production operations: circularly conveying the 3# recycle product, the 2# recycle product and the 1# recycle product obtained in the steps S2, S3 and S4 to the fluidized bed reactor in the step S1, carrying out selective catalytic cracking reaction in the fluidized bed reactor again, separating the cracking reaction product, and then continuing to carry out respective unit operation according to the steps S2, S3 and S4;

the operations finally convert products of gasoline, diesel oil, slurry oil and the like of catalytic cracking into dry gas, propylene, propane, butane, BTX and coke, wherein the yield of the propylene is 40-60 m% of the raw material, the yield of the aromatic hydrocarbon is 15-30 m% of the raw material, the yield of the ethylene is 4-10 m% of the raw material, and the balance is mainly methane and coke.

2. The novel catalytic cracking process of claim 1, wherein in step S1, the reaction conditions of the fluidized bed reactor are as follows: the reaction temperature is 400-650 ℃, the reaction pressure is normal pressure, the weight ratio of the solvent to the oil is 6-12, and the space velocity is 1-20 h^-1。

3. The novel catalytic cracking process of claim 1, wherein in step S2, the reaction conditions of the high pressure hydrogenation reactor are: the reaction temperature is 300-550 ℃, the reaction pressure is 10.0-30.0 Mpa, and the airspeed is 0.1-3 h^-1。

4. The novel catalytic cracking process of claim 1, wherein in the step S3, the reaction temperature of the olefin polymerization reaction is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1。

5. The novel catalytic cracking process of claim 1, wherein in step S4, the reaction conditions of the selective polymerization reaction are as follows: the reaction temperature is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1。

6. The novel catalytic cracking process of claim 1, wherein the ratio of the circulating amount of the 1# recycle product, the 2# recycle product and the 3# recycle product to the total mass of the fresh wax oil and the residual oil raw material is 15-25: 100. 5-10: 100 and 20-30: 100.

7. the novel catalytic cracking process of claim 1, wherein in step S1, the separation process operation comprises the steps of: firstly, conveying a catalytic cracking reaction product into a fractionating tower, wherein the operating temperature of the top of the fractionating tower is 80-120 ℃, the operating temperature of the middle section of the fractionating tower is 150-200 ℃, and the operating temperature of the bottom of the fractionating tower is 250-330 ℃; FGO is extracted from the bottom of the fractionating tower, and low-boiling fraction is ejected out of the fractionating tower; the low boiling fraction is cooled and then enters a 1# three-phase separator, a rich gas-phase substance flow at the top of the separator enters a 2# three-phase separator after being compressed and cooled, non-condensable gas at the top of the 2# three-phase separator enters the bottom of an absorption tower, crude gasoline from the 1# three-phase separator is conveyed to the upper part of the absorption tower, and the crude gasoline is used as an absorbent to absorb C₃-C₄Is composed of C in a major proportion₁-C₂From dry gas C₃-C₄Separating out the gas phase; c-rich gas extracted from the bottom of the absorption tower₃-C₄The crude gasoline of the component and the liquid phase extracted from the 2# three-phase separator are conveyed to the top of a desorption tower through a conveying pump for C₂Desorbing the components, and collecting the desorbed tail gas at the top of the tower into a cooling system in front of the 2# three-phase separator again; the material at the bottom of the desorption tower enters the middle upper part of the stabilizing tower after being preheated by the heat exchanger, the gasoline product is obtained at the bottom of the stabilizing tower, and the liquefied gas product is obtained at the top of the stabilizing tower.

8. The novel catalytic cracking process of claim 1, wherein in step S2, the FGO high pressure hydrogenation unit operation specifically comprises the steps of: firstly, preheating FGO, then feeding the preheated FGO into a high-pressure hydrogenation reactor for hydrogenation operation, cooling a hydrogenation product, and then introducing the cooled hydrogenation product into a high-pressure separator, wherein unreacted hydrogen is arranged at the top of the high-pressure separator, part of the unreacted hydrogen is returned to the high-pressure hydrogenation reactor after being compressed, and part of the unreacted hydrogen is returned to be mixed with the FGO obtained in the step S1; and after the bottom product of the high-molecular separator sequentially passes through the low-molecular separator, the alkaline cleaner and the water washer to perform the cleaning operation of the bottom product, the temperature is increased, the bottom product is introduced into the hydrogenated product rectifying tower to perform the rectifying operation, the bottom product returns to the high-pressure hydrogenation reactor, and the 3# recycle product is obtained at the top of the tower.

9. The novel catalytic cracking process of claim 1, wherein in step S3, the gasoline reforming unit operation comprises the steps of: firstly, gasoline obtained in the step S1 is introduced into a 2# polymerization reactor for olefin selective polymerization reaction, part of reaction products flow back to an inlet of the 2# polymerization reactor, and part of the reaction products are conveyed to a 2# polymerization product rectifying tower for reaction product separation operation, BTX is produced at the tower top, and 2# recycle products are obtained at the tower bottom.

10. The novel catalytic cracking process of claim 1, wherein in step S4, the butene recombination unit operation comprises the following steps: firstly, conveying liquefied gas to an alkaline washing tower to be in countercurrent contact with alkali liquor to remove sulfur in the liquefied gas, then flowing through a water washing tower to be in countercurrent contact with process water to remove water-soluble substances in the liquefied gas, and then conveying the liquefied gas to the decarbonization₃Tower for removing C₃Operation, bottom extraction of C₄A product; the overhead fraction is conveyed to the decarbonization₂Tower for removing C₂Operating; removing C₂Cooling and separating the tower top fraction to obtain C₁-C₂Conveying the dry gas and the crude propylene fraction at the bottom of the tower to a propylene tower for propylene refining operation, cooling the propylene-containing gas at the top of the propylene tower to obtain a high-purity propylene product, wherein the product at the bottom of the tower is propane;

removing C₃Bottom product C of the column₄And further sent to a downstream polymerization plant for carrying out the selective polymerization reaction of the butenes by operating as follows: introducing the butene into a 1# superimposed reactor to carry out butene selective superimposed reaction, refluxing part of reaction products to an inlet of the 1# superimposed reactor, conveying part of the reaction products to a 1# superimposed product rectifying tower to carry out separation operation of the reaction products, producing butane at the tower top, and obtaining a 1# remixed product at the tower bottom.

Technical Field

The invention belongs to the technical field of catalytic cracking, and particularly relates to a novel catalytic cracking process method.

Background

With the continuous development of the oil refining industry and the chemical industry, the market demand for basic raw materials of organic chemical industry such as ethylene, propylene, BTX (Benzene-toluene-xylene mixture) and the like is also increasing, wherein propylene is used as an important organic chemical raw material and is a synthetic monomer of products such as polypropylene, acrylonitrile and the like, and with the rapid increase of the demand for derivatives such as polypropylene and the like, the demand for propylene is also increasing year by year. However, during the development process of refinery integration, oil refining enterprises will face the following problems: 1) the mass ratio of propylene to ethylene in the steam cracking product (around 43 m%) does not match the market demand (70 m%); 2) designing and building a large amount of catalytic reforming devices to produce BTX, and robbing naphtha resources with steam cracking; 3) the steam cracking and reforming device has complex process, high design and operation difficulty coefficient and huge investment. Maximizing propylene production in a refinery integrated process is a continuing goal of those skilled in the art.

The processes for producing propylene mainly include steam cracking, catalytic cracking (FCC), and catalytic cracking (DCC); the steam cracking uses light oil such as naphtha as a raw material to produce ethylene and propylene through thermal cracking, but the yield of propylene is only about 15 wt%, while the FCC uses heavy oil such as vacuum wax oil (VGO) as a raw material. Compared with the conventional catalytic cracking FCC process and the steam cracking process, the DCC process has longer reaction time, is beneficial to the over-production of low-carbon olefin and is more beneficial to the further conversion of heavy oil, so the DCC opens up a new way for preparing the low-carbon olefin, particularly the propylene from the heavy raw material, and changes the single production scheme of the conventional catalytic cracking process which aims at producing the gasoline and the diesel oil to the maximum extent all the time; at the same time, the DCC high reaction temperature also resulted in a significant increase in dry gas and coke yields with an increase in feedstock conversion.

The improvement technology for increasing the propylene yield is developed quickly, but mainly takes the traditional fuel type catalytic cracking process as a main part, namely, while increasing the propylene yield, the other product mainly comprises gasoline and diesel oil, such as Chinese patent CN200810246522.4, which obtains a high-octane gasoline product while preparing the propylene; chinese patent CN200810225607.4, which is a patent document for obtaining light fuel oil product while producing propylene; CN200910177173.X, CN200910180372.6 and CN200910180371.1, the above patent documents produce propylene and diesel oil products in large amount.

Disclosure of Invention

In view of the defects of the prior art, the invention mainly aims to provide a novel catalytic cracking process method to solve the problems of low propylene yield and more low-value byproducts in the catalytic cracking process of residual oil blended with wax oil.

In order to achieve the purpose, the invention adopts the following technical scheme:

a novel catalytic cracking process method comprises the following steps:

s1 selective catalytic cracking unit operation: conveying 60-80 wt% of wax oil and 20-40 wt% of residual oil raw materials to a fluidized bed reactor for selective catalytic cracking reaction, and performing fractionation, absorption stabilization and other separation processes on reaction productsAfter the process operation, obtaining dry gas, liquefied gas, gasoline and FGO; reaction conditions of the fluidized bed reactor: the reaction temperature is 400-650 ℃, the reaction pressure is normal pressure, the weight ratio of the solvent to the oil is 6-12, and the space velocity is 1-20 h^-1(ii) a Rectifying the catalytic cracking reaction product in a fractionating tower to re-divide the fraction, and cutting the crude oil slurry and the diesel oil into one fraction, which is called catalytic wax oil (FGO); the catalyst filled in the fluidized bed reactor is an HY molecular sieve added with an auxiliary agent, and the auxiliary agent is a modified ZSM molecular sieve; under the reaction conditions, raw material wax oil and residual oil are introduced into a fluidized bed reactor to contact with a filled catalyst to carry out catalytic cracking reaction, the single-pass conversion rate of the catalytic cracking reaction is controlled within a reasonable range of 60-70%, a balance point exists between the conversion rate of the raw material and the yield of dry gas coke, and the increase amplitude of the dry gas yield and the coke yield is smaller along with the increase of the conversion rate of the raw material; but when the single-pass conversion rate of the raw material is lower than 60%, the catalytic cracking conversion efficiency is low, the target products produced by the raw material in unit scale are less, the input-output ratio of the whole device is not economical, and the production cost for producing propylene to the maximum extent is increased; when the conversion rate per pass of the raw materials is more than 70%, the dry gas yield and the coke yield are greatly improved along with the increase of the conversion rate, the dry gas and the coke belong to low-value products, the higher the yield is, and the worse the device benefit is;

s2FGO high pressure hydrogenation unit operation: preheating the FGO obtained in the step S1 by a No. 6 heater, then directly feeding the FGO into a high-pressure hydrogenation reactor, washing the hydrogenated product with high-fraction, low-fraction and water, and feeding the product into a rectifying tower, wherein the product at the tower top is a No. 3 remixed product; reaction conditions of the high-pressure hydrogenation reactor: the reaction temperature is 300-550 ℃, the reaction pressure is 10.0-30.0 Mpa, and the airspeed is 0.1-3 h^-1；

S3 gasoline reforming unit operation: carrying out recombination operation on the gasoline obtained in the step S1, namely carrying out olefin polymerization reaction, olefin and aromatic hydrocarbon separation and other operations to obtain a 2# remixed product; the reaction conditions of the olefin polymerization reaction are as follows: the reaction temperature is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1；

S4 butene recombination unit operations: the liquefied gas obtained in the step S1 is firstly subjected to alkali washing and water washingThen separating by a gas separation process to obtain propylene, propane and C₄(ii) a Wherein C is₄Carrying out recombination unit operation including selective superposition reaction on the medium butylene to obtain a 1# remixed product; reaction conditions of the selective polymerization reaction: the reaction temperature is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1(ii) a Wherein C is₂～C₆The alkane can further produce ethylene and propylene by thermal cracking;

s5 maximizes propylene production operations: circularly conveying the 3# recycle product, the 2# recycle product and the 1# recycle product obtained in the steps S2, S3 and S4 to the fluidized bed reactor in the step S1, carrying out selective catalytic cracking reaction in the fluidized bed reactor again, separating the cracking reaction product, and then continuing to carry out respective unit operation according to the steps S2, S3 and S4;

the operations finally convert products of gasoline, diesel oil, slurry oil and the like of catalytic cracking into dry gas, propylene, propane, butane, BTX and coke, wherein the yield of the propylene is 40-60 m% of the raw material, the yield of the aromatic hydrocarbon is 15-30 m% of the raw material, the yield of the ethylene is 4-10 m% of the raw material, and the balance is mainly methane and coke.

As a preferable technical scheme, the ratio of the circulating amount of the No. 1 recycle product, the No. 2 recycle product and the No. 3 recycle product to the total mass of the fresh wax oil and the residual oil raw material is respectively 15-25: 100. 5-10: 100 and 20-30: 100.

as a preferred technical solution, in the step S1, the separation process operation includes the following steps: firstly, conveying a catalytic cracking reaction product into a fractionating tower, wherein the operating temperature of the top of the fractionating tower is 80-120 ℃, the operating temperature of the middle section of the fractionating tower is 150-200 ℃, and the operating temperature of the bottom of the fractionating tower is 250-330 ℃; FGO is extracted from the bottom of the fractionating tower, and low-boiling fraction is ejected out of the fractionating tower; cooling the low boiling point fraction, feeding the low boiling point fraction into a 1# three-phase separator, compressing and cooling a gas-phase material flow of rich gas (mainly a mixture of dry gas and liquefied gas) at the top of the separator, feeding the gas-phase material flow into a 2# three-phase separator, feeding non-condensable gas at the top of the 2# three-phase separator to the bottom of an absorption tower, conveying the crude gasoline from the 1# three-phase separator to the upper part of the absorption tower, and taking the crude gasoline as an absorbent to absorb C₃-C₄Is composed of C in a major proportion₁-C₂From dry gas C₃-C₄Separating out the gas phase; c-rich gas extracted from the bottom of the absorption tower₃-C₄The crude gasoline of the component and the liquid phase extracted from the 2# three-phase separator are conveyed to the top of a desorption tower through a conveying pump for C₂(part C)₂Absorbed simultaneously) the components, and the tail gas at the top of the tower after desorption is converged into a cooling system in front of a 2# three-phase separator again; the material at the bottom of the desorption tower enters the middle upper part of the stabilizing tower after being preheated by the heat exchanger, the gasoline product is obtained at the bottom of the stabilizing tower, and the liquefied gas product is obtained at the top of the stabilizing tower.

As a preferred technical solution, in the step S2, the FGO high pressure hydrogenation unit operation specifically includes the following steps: firstly, preheating FGO, then feeding the preheated FGO into a high-pressure hydrogenation reactor for hydrogenation operation, cooling a hydrogenation product, and then introducing the cooled hydrogenation product into a high-pressure separator, wherein unreacted hydrogen is arranged at the top of the high-pressure separator, part of the unreacted hydrogen is returned to the high-pressure hydrogenation reactor after being compressed, and part of the unreacted hydrogen is returned to be mixed with the FGO obtained in the step S1; and after the bottom product of the high-molecular separator sequentially passes through the low-molecular separator, the alkaline cleaner and the water washer to perform the cleaning operation of the bottom product, the temperature is increased, the bottom product is introduced into the hydrogenated product rectifying tower to perform the rectifying operation, the bottom product returns to the high-pressure hydrogenation reactor, and the 3# recycle product is obtained at the top of the tower.

Operating pressure of the high and low separators: 0.1 to 20.0 MPa;

the operating pressure of the alkali scrubber and the water scrubber is as follows: 0.1-0.5 MPa;

the operating conditions of the hydrogenated product rectifying tower are as follows: the pressure is 0.1-0.2 MPa; the temperature is 100-200 ℃.

The conversion rate of the raw oil is controlled to be less than 70%, and at the moment, the yield of coke and dry gas is less than 1%; when the conversion rate is more than 70%, the yield of dry gas and coke is synchronously and greatly improved, and the final yield of high-value chemical raw materials is influenced;

as a preferred technical solution, in the step S3, the operation of the gasoline reforming unit specifically includes the following steps: firstly, gasoline obtained in the step S1 is introduced into a 2# polymerization reactor for olefin selective polymerization reaction, part of reaction products flow back to an inlet of the 2# polymerization reactor, and part of the reaction products are conveyed to a 2# polymerization product rectifying tower for reaction product separation operation, BTX is produced at the tower top, and 2# recycle products are obtained at the tower bottom.

The reaction conditions of the 2# polymerization reactor are as follows: the reaction temperature is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1(ii) a The filling catalyst is as follows: an MCM-type molecular sieve or a ZSM-type molecular sieve; the material after the selective polymerization is prepared from₈The above-mentioned main composition and unreacted material; the unreacted materials include C₅-C₁₂The alkane and BTX, the alkane and BTX with low boiling point are rectified by a 2# superimposed product rectifying tower and are separated from the top of the 2# superimposed product rectifying tower, and the alkane with high boiling point and C₈The above-mentioned main laminated material is used as the return product and transferred into fluidized bed reactor to make secondary catalytic cracking reaction.

The operating conditions of the 2# superimposed product rectifying tower are as follows: the operation temperature is 80-200 ℃, and the operation pressure is 0.2 MPa;

as a preferred technical solution, in the step S4, the butene recombination unit operation specifically includes the following steps: firstly, conveying liquefied gas to an alkaline washing tower to be in countercurrent contact with alkali liquor to remove sulfur in the liquefied gas, then flowing through a water washing tower to be in countercurrent contact with process water to remove water-soluble substances in the liquefied gas, and then conveying the liquefied gas to the decarbonization₃Tower for removing C₃Operation, bottom extraction of C₄A product; the overhead fraction is conveyed to the decarbonization₂Tower for removing C₂Operating; removing C₂Cooling and separating the tower top fraction to obtain C₁-C₂Conveying the dry gas and the crude propylene fraction at the bottom of the tower to a propylene tower for propylene refining operation, cooling the propylene-containing gas at the top of the propylene tower to obtain a high-purity propylene product, wherein the product at the bottom of the tower is propane;

removing C₃Bottom product C of the column₄And further sent to a downstream polymerization plant for carrying out the selective polymerization reaction of the butenes by operating as follows: introducing the butylene into a 1# polymerization reactor for carrying out butylene selective polymerization reaction, and refluxing part of reaction products to the 1# polymerization reactorPart of the mixture is conveyed to a No. 1 superimposed product rectifying tower to separate reaction products, butane is produced at the top of the tower, and a No. 1 remixed product is obtained at the bottom of the tower.

The reaction conditions of the 1# polymerization reactor are as follows: the reaction temperature is 30-150 ℃, the reaction pressure is 1.0-6.0 MPa, and the weight hourly space velocity is 0.1-6 h^-1(ii) a The filling catalyst is as follows: an MCM-type molecular sieve or a ZSM-type molecular sieve; the material after the selective polymerization reaction is composed of₈The above-mentioned layered product and unreacted C₄Alkane composition; unreacted C of low boiling point₄Rectifying the alkane in a 1# superimposed product rectifying tower to obtain C with high boiling point separated from the top of the 1# superimposed product rectifying tower₈The above-mentioned main superimposed compound is used as the return product and conveyed into fluidized bed reactor to make secondary catalytic cracking reaction;

the operating conditions of the 1# superimposed product rectifying tower are as follows: the operation temperature at the top of the tower is 50-80 ℃, the operation temperature at the bottom of the tower is 180-250 ℃, and the operation pressure is 0.5 MPa;

the butene and gasoline components have recombinant meanings in this application: 1) to C₄-C₈The olefin is not directly recycled as before, but is firstly recombined and then processed by adopting a proper catalytic cracking technology; 2) the recombination lengthens the carbon chain, the reaction activity of the recombination product is obviously increased, the severity of the cracking reaction is obviously reduced, the one-way conversion rate is high, and the dry gas and the coke are low, so that the yield of the high-value product is maximized;

the operation of the butylene and gasoline recombination unit mainly carries out the following two reaction processes:

the first reaction process is the recombination of the monomeric olefins:

NC_M ^＝→C_K ^＝wherein N ═ 2,3, or 4; m ═ 4, or M ═ 5, 6,7, or 8; k ═ N × M;

the second reaction process is recombination between the monomeric olefins:

NC_G ^＝+MC_K ^＝→C_L ^＝wherein N ═ 1,2, or 3; m ═ 1,2, or 3; n + M is less than or equal to 4; g ═ 4 or 5; k is 6,7 or 8; l ═ N × G + M × K;

the recombinant product enters a fixed bedFluidized bed reactor for catalytic cracking reaction; controlling the propylene yield of the butylene heavy component to be 80-90 m%, and the propylene yield of the gasoline component heavy component to be 70-80 m%; during the recombination reaction of butylene and gasoline, C₁-C₄The total yield of alkanes was less than 5.4%.

According to the process for producing propylene to the maximum extent, the catalytic cracking reaction in the fluidized bed reactor of the step S1 does not pursue high conversion rate of heavy oil any more, but better selectivity is determined, which is represented by that the primary conversion rate of the heavy oil is reduced from 80-85% to 60-70%, and the yield of dry gas and coke is minimized; in addition, the high selectivity of the catalytic cracking reaction in the step S1 is combined with the FGO high-pressure hydrogenation unit operation in the step S2, so that the high-efficiency utilization of heavy oil resources is realized, the catalytic material can extend to the intermediate cycloalkyl group, the high selectivity of the catalytic material is shown in that polycyclic aromatic hydrocarbon is converted into monocyclic aromatic hydrocarbon, and further, the high-yield BTX high-value chemical raw material is realized.

The invention has the beneficial effects that:

(1) the novel catalytic cracking process method disclosed by the invention takes residual oil and wax oil with high proportion as raw materials, combines a catalytic cracking process with high selectivity, a butylene recombination process, a gasoline recombination process, an FGO high-pressure hydrogenation process and a corresponding separation and purification process, and maximally produces propylene, wherein the propylene yield is more than 40 m%.

(2) The novel catalytic cracking process method of the invention can produce the propylene to the maximum extent, meanwhile, can also produce chemical raw materials such as butane, propane, BTX and the like, and can control the generation of dry gas and coke to the maximum extent.

(3) Compared with the process for preparing propylene by adopting steam cracking and propane dehydrogenation, the novel catalytic cracking process method of the invention achieves the same scale of propylene, and has the advantages of small system investment, low operation cost and high benefit.

Drawings

FIG. 1 is a process flow diagram of the operation of a selective catalytic cracking unit in accordance with an embodiment of the present invention;

FIG. 2 is a process flow diagram of the operation of a FGO high pressure hydrogenation unit in accordance with an embodiment of the invention;

FIG. 3 is a process flow diagram of the operation of a gasoline reforming unit in an embodiment of the present invention;

FIG. 4 is a process flow diagram of the operation of a butene recombination unit in accordance with an embodiment of the present invention;

wherein, the fluidized bed reactor 1, the fractionating tower 2, the # 1 three-phase separator 3, the # 1 compressor 4, the # 2 three-phase separator 5, the absorption tower 6, the desorption tower 7, the stabilization tower 8, the # 3 three-phase separator 9, the stripping tower 10, the caustic wash tower 11, the water wash tower 12, the deC 3 tower 13, the deC 2 tower 14, the propylene tower 15, the # 1 superimposed reactor 16, the # 1 superimposed product rectifying tower 17, the # 2 superimposed reactor 21, the # 2 superimposed product rectifying tower 22, the hydrogenation reactor 26, the high-molecular separator 27, the low-molecular separator 28, the caustic wash 29, the water wash 30, the hydrogenated product rectifying tower 31, the # 4 compressor 32, the liquefied air pump 111, the # 3 delivery pump 121, the # 4 three-phase separator 130, the # 1 reflux pump 131, the # 4 cooler 132, the # 5 three-phase separator 140, the # 2 reflux pump 141, the # 5 cooler 142, the # 6 three-phase separator 150, the # 3 reflux pump 151, the # 6 reflux cooler 152, A 5# circulation pump 161, a diesel pump 201, a 1# slurry pump 202, a light ends pump 203, a 1# heater 204, a 2# heater 205, a 3# heater 206, a 1# cooler 207, a 2# circulation pump 211, a 6# heater 261, a 1# sewage pump 301, a crude gasoline pump 302, a 4# circulation pump 311, a 2# cooler 401, a 2# sewage pump 501, a 1# delivery pump 601, a 2# delivery pump 701, a gasoline pump 801, a 5# heater 802, a 1# circulation pump 901, a 3# sewage pump 902, a 2# slurry pump 1001, a 4# heater 1002, and a 7# heater 3001.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.