TWI494421B - Catalytic cracking apparatus and method - Google Patents

Description

Catalytic cracking apparatus and method

This invention relates to a catalytic cracking apparatus and method.

Heavy oil catalytic cracking is an important method for the preparation of low carbon olefins such as ethylene, propylene and butene.

Industrially used heavy oil catalytic cracking processes for the production of light olefins include the processes disclosed in U.S. Patent No. 4, 858, 053, U.S. Patent No. 5,670, 037, and U.S. Patent No. 6,210, 562, which are incorporated herein by reference. The reactor structure of bed) is reacted, but the yield of dry gas and coke is high.

In recent years, the technology for producing propylene using two riser reactors has received considerable attention.

CN101074392A discloses a method for producing propylene and high quality gasoline and diesel by two-stage catalytic cracking, using a two-stage riser, using a shape-selective molecular sieve-containing catalyst, as a heavy petroleum hydrocarbon or hydrocarbon-rich. Various animal and vegetable oils are used as raw materials, and the reaction materials of different properties are combined to control the reaction conditions of different materials to achieve the purpose of improving propylene yield, taking into account light oil yield and quality, and suppressing dry gas and coke formation. . However, the method has low propylene yield and low heavy oil conversion ability.

CN101293806A discloses a catalytic conversion process for increasing the yield of low-carbon olefins by injecting a hydrocarbon oil feedstock through a feed nozzle into a riser or/and a fluidized bed reactor, and with a shape selectivity having an average pore diameter of less than 0.7 nanometers (nm). The zeolite catalyst is contacted and reacted, and a hydrogen-rich gas is injected into the reactor to separate the reaction oil and gas from the post-reaction carbon deposition catalyst, wherein the reaction oil and gas are separated to obtain a target product containing ethylene and propylene, and the carbon deposition catalyst is stripped. Return to the reactor for reuse after regeneration. The process inhibits the re-conversion reaction of the lower olefins after formation by injecting a hydrogen-rich gas into the reactor to increase the yield of the lower olefins, particularly propylene. However, this method has little effect on reducing dry gas yield and improving heavy oil conversion ability.

CN101314724A discloses a combined catalytic conversion method of bio-oil and mineral oil, comprising contacting bio-oil and mineral oil in a compound reactor with a catalyst containing modified beta zeolite to carry out catalytic cracking reaction to obtain low-carbon olefins and gasoline, diesel oil. ,heavy oil. The method has high dry gas yield and low heavy oil conversion rate.

The technical problem to be solved by the present invention is to provide a catalytic cracking apparatus and method for increasing the yield of low carbon olefins, particularly propylene, and the conversion of heavy oil.

In one embodiment, the present invention provides a catalytic cracking process comprising: a heavier feedstock and optionally atomized water vapor with a catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm in a first riser reactor The medium contact reaction results in a stream comprising a first hydrocarbon product and a first carbonaceous catalyst, the first hydrocarbon product being separated from the first carbon catalyst by a separation device at the end of the first riser, the light feedstock and optionally the mist The steam is introduced into the second riser reactor, and is contacted with a catalyst containing a shape-selective zeolite having an average pore diameter of less than 0.7 nm to obtain a second oil and gas product, a second hydrocarbon product and a second carbon deposit. The catalyst is introduced to a fluidized bed reactor in series with the second riser reactor in the presence of a catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm, while at the same time, the heavy oil is cracked, preferably, The cracked heavy oil prepared by the method is introduced to a second riser reactor and/or a fluidized bed reactor, preferably to a fluidized bed reactor for reaction; from a fluidized bed reactor To a stream containing a third hydrocarbon product and a third carbon catalyst.

In a further embodiment, the heavy feedstock comprises a heavy hydrocarbon and/or a hydrocarbon-rich animal and vegetable oil; wherein the light feedstock comprises a gasoline fraction and/or a C4 hydrocarbon; wherein the cracking The heavy oil is a cracked heavy oil having an atmospheric distillation range of 330 to 550 °C.

In a further embodiment, the catalytic cracking process further comprises: separating the first oil and gas product by a product separation system to obtain a cracking gas, pyrolysis gasoline, cracking light recycle oil, and cracking heavy oil; and/or The third oil and gas product is separated by a product separation system to obtain a cracking gas, a pyrolysis gasoline, a cracked light cycle oil, and a cracked heavy oil.

In a further embodiment, the first riser reactor atomizing water vapor accounts for 2 to 50% by weight of the feed amount, preferably 5 to 10% by weight, and the reaction pressure is 0.15 to 0.3 MPa, preferably 0.2 to 0.25 MPa; wherein, the reaction temperature of the first riser reactor is 480-600 ° C, preferably 500-560 ° C, the ratio of the agent to the oil is 5-20, preferably 7-15, and the reaction time is 0.50-10 seconds. Preferably, it is 2 to 4 seconds.

In a further embodiment, the reaction temperature of the second riser reactor is 520-580 ° C, preferably 520-560 ° C; when the light raw material introduced by the second riser reactor includes a gasoline fraction, the gasoline raw material mist The ratio of steam to steam is 5 to 30% by weight, preferably 10 to 20% by weight; when the light raw material includes a gasoline fraction, the ratio of the ratio of the gasoline to the gasoline in the second riser is 10 to 30, Preferably, the reaction time is from 0.10 to 1.5 seconds, preferably from 0.30 to 0.8 seconds. When the light raw material comprises C4 hydrocarbons, the ratio of atomized water vapor of the C4 hydrocarbon is from 10 to 40% by weight, preferably 15 ～25 wt%, when the light raw material comprises C4 hydrocarbon, the ratio of the agent to oil of the C4 hydrocarbon in the second riser is 12-40, preferably 17-30, and the reaction time is 0.50-2.0 seconds. Preferably it is from 0.8 to 1.5 seconds.

In a further embodiment, the fluidized bed reactor has a reaction temperature of 500 to 580 ° C, preferably 510 to 560 ° C, and a WHSV of 1 to 35 hours ^-1 , preferably 3 to 30 hours ^-1 ; fluidization The reaction pressure of the bed reactor is from 0.15 to 0.3 MPa, preferably from 0.2 to 0.25 MPa.

In a further embodiment, the conditions for the reaction of the cracked heavy oil in the fluidized bed include: the ratio of the cracked heavy oil to the catalyst is from 1 to 50, preferably from 5 to 40; and the cracked heavy oil has a WHSV of from 1 to 1 in the fluidized bed. 20 hours ^-1 , preferably 3 to 15 hours ^-1 ; the ratio of atomized water vapor of the cracked heavy oil is 5 to 20% by weight, preferably 10 to 15% by weight.

In a further embodiment, the weight ratio of the cracked heavy oil introduced to the second riser reactor and/or the fluidized bed reactor to the heavy feed to the first riser reactor is from 0.05 to 0.30:1.

In a further embodiment, when the light feedstock comprises a gasoline fraction, the weight ratio of the gasoline fraction introduced to the second riser reactor to the heavy feedstock introduced to the first riser reactor is 0.05 to 0.20. When the light raw material includes a gasoline fraction and a C4 hydrocarbon, the weight ratio of the C4 hydrocarbon in the light raw material to the gasoline fraction in the light raw material is 0 to 2:1.

In a further embodiment, the gasoline feed light feedstock is an olefin-rich gasoline fraction having an olefin content of 20 to 95% by weight and a final boiling point of not more than 85 ° C; the C4 hydrocarbon light raw material is rich The olefin-containing C4 hydrocarbon has a C4 olefin content of more than 50% by weight.

In a further embodiment, the gasoline fraction light feedstock comprises pyrolysis gasoline separated by the product separation system.

In a further embodiment, the catalytic cracking process further comprises mixing the first hydrocarbon product and the third hydrocarbon product and introducing to the product separation system for separation.

In a further embodiment, the catalytic cracking process further comprises introducing the first carbon deposition catalyst to a fluidized bed reactor, mixing with the catalyst of the fluidized bed reactor, and then introducing it to a stripper, or The first coke catalyst is directed to the stripper.

In a further embodiment, the catalytic cracking process further comprises steam stripping the first carbon deposition catalyst and/or the third carbon deposition catalyst and introducing the stripped water vapor entrained in the oil and gas product to the fluidized bed reaction. Device.

In an embodiment, the invention provides a catalytic cracking unit comprising: a first riser reactor (1) for cracking heavy feedstock, the first riser reactor having one or more at the bottom of the riser a heavy feed inlet for a second riser reactor (2) for cracking light feedstock, the second riser reactor having one or more light feed inlets at the bottom of the riser and a discharge port located at the top of the riser, a fluidized bed reactor (4) having one or more feed ports, and the fluidized bed reactor is connected via a connecting member (preferably low pressure) An outlet distributor, preferably a vault distributor, is coupled to the discharge opening of the second riser reactor, a separation device disposed at the end of the first riser, preferably, the quick separation device, The separation device includes an oil and gas discharge port and a catalyst discharge port, wherein the second riser reactor and/or the fluidized bed reactor further has a feed port located above the one or more light materials One or more cracking heavy oil feed ports, preferably The split heavy oil feed port is between one-half of the length of the second riser reactor and the second riser discharge port, and more preferably, the cracked heavy oil feed port is at a bottom of a fluidized bed reactor, and optionally a product separation system (6) that separates cracked heavy oil from oil and gas products from a first riser reactor and/or a fluidized bed reactor And splitting the cracked heavy oil to the one or more cracked heavy oil feed ports via a cracking heavy oil loop.

In a further embodiment, the catalytic cracking unit further comprises: a stripper (3), a settler (5), a product separation system (6), a regenerator (7), and a cyclone separation system: the stripper An outlet having stripping water vapor, an outlet of the stripped catalyst, and an outlet of the stripped water vapor entrained with oil and gas; wherein the settler is in communication with the discharge port of the fluidized bed reactor and has one or more An inlet for receiving the reaction oil and one or more outlets connected to the product separation system; wherein the regenerator includes a regeneration section, one or more spent catalyst inclined tubes, and one or more regenerated catalysts a tube, wherein preferably a used catalyst tube is connected to the stripper, and a regenerated catalyst tube is connected to the first and/or second riser reactor; wherein the product separation system comprises C4 hydrocarbons, pyrolysis gasoline, And separating the cracked heavy oil from the oil and gas products from the first riser reactor and/or the fluidized bed reactor, and introducing the cracked heavy oil to the one or more cracked heavy oil feed ports via the cracking heavy oil circuit, and/or The pyrolysis gasoline circuit directs pyrolysis gasoline to the one or more light feedstock feed ports and/or directs C4 hydrocarbons to the one or more light feedstock feed ports through a C4 hydrocarbon loop; wherein the cyclone separation system It is placed at the top of the settler and connected to the outlet of the settler for further separation of the oil and gas products and catalyst solid particles.

The invention is based on a combined reactor composed of a double riser and a fluidized bed, is optimized by a technical method, is equipped with a suitable catalyst, and selectively converts different feeds, and significantly increases the yield of propylene and suppresses on the basis of effectively improving the conversion of heavy oil. Dry gas and coke are produced and can improve pyrolysis gasoline and light oil properties. Compared with the prior art, the separation of the first oil and gas product from the first carbon deposition catalyst through the separation device (fast branching device) at the end of the first riser reactor can reduce dry gas yield and inhibit low carbon olefins, especially propylene. Re-conversion after production; the present invention produces the olefin-rich gasoline fraction and/or C4 hydrocarbon as a feedstock to the second riser reactor connected to the fluidized bed reactor while the apparatus/method is produced The cracked heavy oil is led to the second riser reactor or the fluidized bed reactor to participate in the conversion. On the one hand, the secondary conversion of heavy oil is enhanced to increase the degree of heavy oil conversion of the whole apparatus, the cracked heavy oil fraction is used to increase the production of propylene, and the olefin-rich gasoline fraction is simultaneously The chilling of the reaction with the C4 hydrocarbon is terminated, inhibiting the conversion of the lower olefins, especially after the formation of propylene, thereby effectively maintaining a high propylene yield. In addition, the method of the invention introduces the stripped water vapor entrained with oil and gas to the fluidized bed reactor, and passes through the fluidized bed reactor and exits the reactor, thereby effectively reducing the partial pressure of the oil and gas product and shortening the oil product in the settler. The residence time increases the production of propylene while reducing the dry gas and coke yield.

In the present invention, unless otherwise indicated, the reaction temperature of the riser reactor refers to the outlet temperature of the riser reactor; the reaction temperature of the fluidized bed reactor refers to the bed temperature of the fluidized bed reactor.

In the present invention, the ratio of the agent to the oil refers to the weight ratio of the catalyst to the oil/hydrocarbon unless otherwise indicated.

In the present invention, unless otherwise indicated, the reaction pressure of the riser reactor refers to the outlet absolute pressure of the reactor.

In the present invention, the gasoline fraction is used interchangeably with the gasoline feedstock unless otherwise indicated.

In the present invention, unless otherwise indicated, the ratio of atomized water vapor of the gasoline raw material refers to the ratio of the atomized water vapor of the gasoline to the gasoline feed amount.

In the present invention, unless otherwise indicated, the C4 hydrocarbon atomized water vapor ratio refers to the ratio of the atomized water vapor of the C4 hydrocarbon to the C4 feed amount.

In the present invention, the ratio of atomized water vapor of the cracked heavy oil means the ratio of the atomized water vapor to the amount of the cracked heavy oil, unless otherwise stated.

In the present invention, unless otherwise stated, the reaction pressure of the fluidized bed reactor refers to the absolute pressure of the outlet of the reactor, and in the case where the fluidized bed reactor is connected to the settler, it means the absolute pressure of the outlet of the settler.

In the present invention, the WHSV of the fluidized bed means, in terms of the total feed of the fluidized bed reactor, unless otherwise stated.

In the present invention, the quick-distribution device is a cyclone capable of achieving rapid separation of catalyst solids and oil and gas products unless otherwise indicated. Preferably, the cyclone separator is a primary cyclone separator.

According to the present invention, the heavy raw material and the atomized water vapor are subjected to catalytic cracking reaction in the first riser reactor to obtain a stream containing the first oil and gas product and the first carbon deposition catalyst, the first oil and gas product and the first product. The carbon catalyst is separated by a separation device at the end of the first riser. In one embodiment, the separation device is a fast separation device for rapidly separating oil and gas products from a carbon deposition catalyst. In one embodiment, an existing fast dispensing device can be employed. A preferred quick-distribution device is a coarse cyclone separator.

The first riser reactor reaction operating conditions: the reaction temperature is 480 to 600 ° C, preferably 500 to 560 ° C, the ratio of the agent to the oil is 5 to 20, preferably 7 to 15, and the reaction time is 0.50 to 10 seconds. Preferably, it is 2 to 4 seconds, and the atomized water vapor accounts for 2 to 50% by weight of the feed amount, preferably 5 to 10% by weight, and the reaction pressure is 0.15 to 0.3 MPa, preferably 0.2 to 0.25. MPa.

According to the present invention, a light feedstock and optionally atomized water vapor are introduced to a second riser reactor for contact reaction with a catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm to obtain a second hydrocarbon product and a second The carbonaceous catalyst, the second oil and gas product and the second carbonaceous catalyst are introduced to a fluidized bed reactor in series with the second riser reactor, in the presence of a catalyst comprising a shape selective zeolite having an average pore diameter of less than 0.7 nm. The reaction, at the same time, will crack the heavy oil, preferably, the cracked heavy oil produced by the method is introduced to the second riser reactor and/or the fluidized bed reactor, preferably to the fluidized bed reactor for reaction; A stream comprising a third hydrocarbon product and a third carbon catalyst is obtained in a fluidized bed reactor. The third hydrocarbon product and the third carbon deposition catalyst are separated by a settler to separate the third oil product and the third carbon catalyst, and the third oil product is led to the product separation system to obtain cracking gas, pyrolysis gasoline, and cracking light. Cycle oil and crack heavy oil.

The light feedstock to the second riser reactor is a gasoline fraction and/or a C4 hydrocarbon, preferably an olefin-rich C4 hydrocarbon and/or an olefin-rich gasoline fraction. The second riser reaction temperature is about 520 to 580 ° C, preferably 520 to 560 ° C. Reaction operating conditions of the gasoline fraction introduced to the second riser reactor: the ratio of the ratio of the gasoline to the raw material operating in the second riser is 10 to 30, preferably 15 to 25; and the gasoline raw material is reacted in the second riser The time is 0.10 to 1.5 seconds, preferably 0.30 to 0.8 seconds; the proportion of the atomized water vapor of the gasoline raw material is 5 to 30% by weight, preferably 10 to 20% by weight. The reaction operating conditions of the C4 hydrocarbon: the C4 hydrocarbon operating in the second riser has a ratio of 12 to 40, preferably 17 to 30; and the reaction time of the C4 hydrocarbon in the second riser is 0.50 to 2.0 seconds. Preferably, it is from 0.8 to 1.5 seconds; the proportion of C4 hydrocarbon atomized water vapor is from 10 to 40% by weight, preferably from 15 to 25% by weight.

According to the present invention, the reaction operating conditions of the fluidized bed reactor include: a reaction pressure of 0.15 to 0.3 MPa, preferably 0.2 to 0.25 MPa; and a fluidized bed reaction temperature of about 500 to 580 ° C, preferably 510 to 560 ° C. The fluidized bed has a WHSV of 1 to 35 hours ^-1 , preferably 3 to 30 hours ^-1 .

According to the present invention, the reaction operating conditions for cracking the heavy oil fraction in the second riser reactor and/or in the fluidized bed reactor: the ratio of the catalyst to the cracked heavy oil is from 1 to 50, preferably from 5 to 40; The heavy oil has a WHSV of 1 to 20 hours ^-1 , preferably 3 to 15 hours ^-1 in the fluidized bed, and the ratio of atomized water vapor of the cracked heavy oil is 5 to 20% by weight, preferably 10 to 15% by weight.

According to the invention, the light feedstock introduced to the second riser reactor is preferably an olefin-rich gasoline fraction and/or an olefin-rich C4 hydrocarbon, the olefin-rich gasoline fraction feedstock being selected from the apparatus of the invention. The gasoline produced by the production of gasoline and other devices, preferably the pyrolysis gasoline separated by the product separation system. The gasoline fraction produced by other devices may be selected from one of the catalytic cracking petroleum brain (FCC naphtha), the catalytic cracking stabilized gasoline (FCC stabilized gasoline), the coking gasoline, the viscous pyrolysis gasoline, and other gasoline fractions produced by refinery or chemical processes. More than one mixture. The olefin-rich gasoline feedstock has an olefin content of from 20 to 95% by weight, preferably from 35 to 90% by weight, most preferably at most 50% by weight. The gasoline feedstock may be a full-range gasoline fraction having a final boiling point of no more than 204 ° C, or a narrow fraction thereof, such as a gasoline fraction having a distillation range between 40 and 85 ° C. The weight ratio of the gasoline fraction introduced to the second riser reactor to the heavy feedstock introduced to the first riser reactor is from 0.05 to 0.20:1, preferably from 0.08 to 0.15:1. The C4 hydrocarbons are low molecular hydrocarbons which are present in a gaseous form at normal temperature (0-30 ° C) and atmospheric pressure (1 atm) and which are mainly composed of a C 4 fraction, and include alkanes and olefins having 4 carbon atoms. And alkyne. It may be a gaseous hydrocarbon product rich in C4 fraction produced by the device, or a gaseous hydrocarbon rich in C4 fraction produced by other process, and the preferred one is the C4 fraction produced by the device. The C4 hydrocarbon is preferably an olefin-rich C4 fraction wherein the C4 olefin content is greater than 50% by weight, preferably greater than 60% by weight, most preferably at most 70% by weight. In one embodiment, the weight ratio of C4 hydrocarbon to gasoline fraction in the light feedstock is from 0 to 2:1, preferably from 0 to 1.2:1, more preferably from 0 to 0.8:1.

According to the present invention, the light raw material and optionally the atomized water vapor are introduced to the second riser reactor, and the second oil and gas catalyst and the second carbonaceous catalyst are obtained after the reaction in the second riser reactor, the second oil and gas The product and the second carbon deposition catalyst are introduced to the fluidized bed reactor to continue the reaction, and the cracked heavy oil obtained by the product separation system of the present invention is introduced into the second riser reactor for reaction, and/or introduced to the fluidized bed. The reactor is reacted. In one embodiment, the cracked heavy oil is introduced to a second riser reactor, the introduction position of the cracked heavy oil is higher than the introduction position of the light raw material, preferably, the introduction position of the cracked heavy oil is in the riser reaction Between one-half of the length of the riser (the portion between the riser gasoline inlet and the riser outlet) and the riser outlet. In one embodiment, the cracked heavy oil is directed to a fluidized bed reactor, preferably, the cracked heavy oil is directed to the bottom of the fluidized bed reactor. The cracked heavy oil is a cracked heavy oil obtained from the product separation system of the present invention, that is, a majority of liquid products remaining after separating gas, gasoline and diesel oil from the oil and gas products entering the product separation system, and the atmospheric distillation range is 330. Between -550 ° C, it is preferred that the atmospheric distillation range is 350 to 530 ° C. The weight ratio of the cracked heavy oil injected into the second riser or injected into the fluidized bed reactor or injected into the second riser and the fluidized bed reactor to the heavy raw material injected into the first riser reactor is 0.05 to 0.30:1. Good 0.10~0.25:1. The actual cracking heavy oil refining amount depends on the degree of reaction of the first riser, and the greater the degree of reaction, the lower the cracking heavy oil refining amount. Preferably, when the cracked heavy oil is injected, the amount of carbon deposited on the catalyst in the reactor is not more than 0.5% by weight, preferably 0.1 to 0.3% by weight. The introduction of cracked heavy oil between one-half of the length of the riser reactor and the riser outlet or in the fluidized bed reactor reduces coke and dry gas yield while increasing the selectivity to propylene.

According to the present invention, the separation device at the end of the first riser reactor separates the first hydrocarbon product from the first carbon deposition catalyst, and the first hydrocarbon product is directed to the product separation system for separation. The third oil and gas product leaving the fluidized bed reactor first enters the settler, settles and separates the catalyst carried therein, and then enters the subsequent product separation system. In the product separation system, the oil and gas products are separated to obtain cracked gas, pyrolysis gasoline, cracked light cycle oil, and cracked heavy oil. Preferably, the first oil and gas product and the third oil and gas product share a product separation system, wherein the first oil and gas product and the third oil and gas product are mixed and introduced to the product separation system. The product separation system is prior art, and the invention has no special requirements.

According to the present invention, the first coke catalyst separated by the separation device at the end of the first riser reactor can be directly introduced to the stripper for stripping, or can be first introduced to the fluidized bed reactor, and the fluidized bed reactor. After mixing the catalyst, it is then fed to a stripping system for stripping. Preferably, the first carbon deposition catalyst is first introduced to the fluidized bed reactor, passed through the fluidized bed reactor, and then introduced into the stripper for stripping. The catalyst leaving the fluidized bed reactor (i.e., the third solubilizer catalyst) is directed to a stripper for stripping. The first carbon deposition catalyst and the third carbon deposition catalyst are preferably stripped in the same stripper, the stripped catalyst is introduced to the regenerator for regeneration, and the regenerated catalyst is introduced to the first riser reactor and/or The second riser reactor is reused.

According to the present invention, the stripping water vapor and the stripped oil and gas product are led to the bottom of the fluidized bed reactor and discharged from the reactor through the fluidized bed, thereby reducing the partial pressure of the oil and gas product and shortening the residence time of the oil and gas product in the settler Increase propylene production while reducing dry gas and coke yield.

The heavy raw materials described in the present invention are heavy hydrocarbons or various animal and vegetable oil-based raw materials rich in hydrocarbons. The heavy hydrocarbons are selected from one or a mixture of one or more of petroleum hydrocarbons, mineral oils, and synthetic oils. Petroleum hydrocarbons are well known to those skilled in the art and may, for example, be vacuum wax oil, atmospheric residue, vacuum wax oil blended partially vacuum residue or other secondary processed hydrocarbon oil. The hydrocarbon oil obtained by the other secondary processing, such as one or more of a coking wax oil, a deasphalted oil, and a furfural refined raffinate oil. The mineral oil is selected from one or a mixture of one or more of coal liquefied oil, oil sand oil, and shale oil. The synthetic oil is a distillate obtained by F-T synthesis of coal, natural gas or pitch. The hydrocarbon-rich animal and vegetable oil is one or more of animal and vegetable oils and fats.

According to the present invention, there is provided a catalytic cracking unit comprising: a first riser reactor (1) for cracking heavy feedstock, the first riser reactor having one or more weights at the bottom of the riser a raw material feed port for a second riser reactor (2) for cracking light feedstock, the second riser reactor having one or more light feedstock inlets at the bottom of the riser and located at the lift a discharge port at the top of the tube, a fluidized bed reactor (4) having one or more feed ports, and the fluidized bed reactor is distributed through a connecting member, preferably a low pressure outlet More preferably, the arched distributor is connected to the discharge opening of the second riser reactor, a separation device disposed at the end of the first riser, preferably a quick separation device, the separation device including the oil and gas discharge And a catalyst discharge port, wherein said second riser reactor and/or said fluidized bed reactor further has one or more cracked heavy oils located above said one or more light feed inlets a feed port, preferably, the cracked heavy oil feed port Between one-half of the length of the second riser reactor and the second riser discharge port, more preferably, the cracked heavy oil feed port is at the bottom of the fluidized bed reactor And, optionally, a product separation system (6) that separates the cracked heavy oil from the oil and gas products from the first riser reactor and/or the fluidized bed reactor and cleaves via the cracking heavy oil circuit Heavy oil is directed to the one or more cracked heavy oil feed ports.

In a further embodiment, the present invention provides a catalytic cracking unit further comprising: a stripper (3), a settler (5), a product separation system (6), a regenerator (7), and a cyclone separation system.

In still further embodiments, the stripper has an inlet for steam for stripping, an outlet for the stripped catalyst, and an outlet for stripping steam with oil and gas.

In still further embodiments, wherein the settler is in communication with a discharge port of the fluidized bed reactor and has one or more inlets for receiving reaction oil and gas, and one or more associated with a product separation system Export.

In still further embodiments, wherein the regenerator comprises a regeneration section, one or more spent catalyst tubes, and one or more regenerated catalyst tubes, wherein preferably the used catalyst tubes and steam are used The riser is connected and the regenerated catalyst ramp is connected to the first and/or second riser reactor.

In still further embodiments, wherein the product separation system separates C4 hydrocarbons, pyrolysis gasoline, and cracked heavy oil from oil and gas products from a first riser reactor and/or a fluidized bed reactor, and via cracking heavy oil The loop directs the cracked heavy oil to the one or more cracked heavy oil feed ports, and/or directs the cracked gasoline to the one or more light feedstock feed ports via a cracking gasoline loop, and/or C4 via a C4 hydrocarbon loop Hydrocarbon is introduced to the one or more light feedstock feed ports.

In still further embodiments, wherein the cyclonic separation system is disposed at the top of the settler and is coupled to the outlet of the settler for further separation of the hydrocarbon product and catalyst solid particles.

According to the present invention, the catalytic cracking unit preferably employs a combination of a double riser and a fluidized bed, wherein one of the risers is coaxially connected in series with the fluidized bed, and is juxtaposed with the other riser, and the riser and fluidize The bed reaction coaxial series structure is further disposed coaxially with the stripper.

In the coaxial series combination of the riser and the fluidized bed reaction, the riser outlet is preferably a low pressure outlet distributor having a pressure drop of less than 10 KPa. Existing low pressure outlet distributors can be used, such as arched distributors.

According to the present invention, the riser reactor is selected from one or a combination of two of an equal diameter riser, an equal line speed riser and a variable diameter riser, wherein the first riser reactor and the second riser are The reactors can be of the same type or of different types. The fluidized bed reactor is selected from the group consisting of a fixed fluidized bed, a fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a transport bed, and a dense phase fluidized bed reactor.

According to the present invention, the shape-selective zeolite having an average pore diameter of less than 0.7 nm is selected from the group consisting of ZSM series zeolites, ZRP zeolites, ferrierites, chabazite, cyclolite, erionite, A zeolite, column zeolite, turbidite, and One or more of the above-mentioned zeolites obtained by physical and/or chemical treatment. The ZSM series zeolite is selected from one of ZSM-5, ZSM-8, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other similarly structured zeolites or More than one mixture. A more detailed description of ZSM-5 can be found in USP 3,702,886, and a more detailed description of ZRP can be found in USP 5,232,675.

The catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm may be a combination of one or more of the catalysts provided by the prior art, commercially available or prepared according to existing methods. The catalyst comprises a zeolite, an inorganic oxide and optionally a clay comprising: 5 to 50% by weight of zeolite, 5 to 95% by weight of inorganic oxide, 0 to 70% by weight of clay, said zeolite comprising an average pore diameter of less than 0.7 Shape-selective zeolite of nanometer and optionally large-pore zeolite, shape-selective zeolite having an average pore diameter of less than 0.7 nm accounts for 25 to 100% by weight, preferably 50 to 100% by weight of the active component, and the macroporous zeolite is active. 0 to 75% by weight of the component, preferably 0 to 50% by weight.

The large pore zeolite is a zeolite having a pore structure of at least 0.7 nm ring opening, and is selected from the group consisting of Y type zeolite, β type zeolite, L type zeolite, rare earth Y type zeolite (REY), rare earth hydrogen Y type zeolite (REHY). One or a mixture of two or more of ultra-stable Y-type zeolite (USY) and rare earth super-stable Y-type zeolite (REUSY).

The inorganic oxide is used as an adhesive and is selected from the group consisting of cerium oxide (SiO ₂ ) and/or aluminum oxide (Al ₂ O ₃ ). The clay acts as a substrate, ie a carrier, selected from the group consisting of kaolin and/or halloysite.

In the catalytic cracking method provided by the present invention, the catalyst containing the shape-selective zeolite having an average pore diameter of less than 0.7 nm used in the second riser reactor may be the same as or different from the catalyst used in the first riser. Preferably, the first riser reactor and the second riser reactor use the same catalyst.

The method provided by the present invention will be further described below with reference to the accompanying drawings:

In the method shown in Fig. 1, the hot regenerated catalyst enters the bottoms of the riser reactors 1 and 2 via the regenerated catalyst tubes 9 and 10, respectively, and is accelerated by the pre-lifting medium injected by the lines 22 and 23, respectively. Flow upwards. The preheated heavy raw material is mixed with the atomized water vapor from the pipeline 21 in a certain ratio through the pipeline 20, and then injected into the riser reactor 1 to be reacted to obtain a first oil and gas product and a first carbon deposit catalyst, the first oil and gas The product and the first coke catalyst are separated by a fast separation device (not shown) at the end of the riser 1; while the preheated or unpreheated olefin-rich gasoline fraction and/or C4 hydrocarbons are supplied via line 24 and The atomized water vapor of line 25 is mixed in a certain ratio, injected into the riser reactor 2, and flows upward along the riser 2 together with the catalyst, and the cracking containing a certain proportion of atomized water vapor introduced through the line 36 during the flow. The heavy oil (preferably, self-produced) stream is contacted to obtain a second oil and gas product and a second carbonaceous catalyst, and the second hydrocarbon product and the second carbonaceous catalyst are passed through an outlet distributor of the riser 2 (not shown) The fluidized bed reactor 4 is fed to continue the reaction to obtain a third oil and gas product and a third carbonaceous catalyst, and finally enters the settler 5 for separation of the oil and gas product from the catalyst. The oil and gas products including the first oil and gas product and the third oil and gas product are led to a cyclone separation system (not shown) at the top of the settler to separate solids such as catalysts carried therein, and then introduced to the product separation system 6 through line 30. The catalytic cracking product is separated in the product separation system 6 into cracked gas (derived from line 31), pyrolysis gasoline (derived from line 32), cracked light cycle oil (derived from line 33), cracked heavy oil (derived from line 34), and cracked. Slurry (extracted by line 35). The cracked gas from line 31 can be subjected to subsequent product separation and refining to obtain a polymer grade propylene product and an olefin-rich C4 fraction, wherein the olefin-rich C4 fraction can be returned to the second riser reactor 2. The pyrolysis gasoline drawn from line 32 may be partially or completely returned to the second riser reactor 2; the gasoline may be first cut into light and heavy gasoline fractions, and the light gasoline fraction may be partially or completely returned to the second riser reactor 2, preferably The light gasoline is returned to the second riser reactor 2; the cracked heavy oil from the line 34 can be returned to any reactor in the reaction system, preferably some or all of the cracked heavy oil is returned to the riser 2 or the fluidized bed 4 via line 36, More preferably, it is led to the riser 2 at a position after the introduction of the olefin-rich gasoline fraction. The first carbon deposition catalyst separated by the quick separation device at the end of the riser 1 is introduced to the fluidized bed reactor 4, mixed with the catalyst at the outlet of the riser 2, and after the reaction, is introduced to the stripper 3. The stripping water vapor is injected through the line 37, and is in countercurrent contact with the carbon deposition catalyst, and the oil and gas product entrained by the carbon deposition catalyst is stripped as much as possible, and then introduced to the settler 5 through the fluidized bed reactor 3, together with other oil and gas products. It is routed via line 30 to a subsequent product separation system. The stripped catalyst is sent to the regenerator 7 for charring regeneration through the used catalyst inclined tube 8. An oxygen-containing gas such as air is injected into the regenerator 7 via line 26, and the regenerated flue gas is withdrawn via line 27. The regenerated catalyst was returned to the riser reactors 1 and 2 via the regenerated catalyst inclined tubes 9 and 10, respectively.

In the above-described embodiment, the pre-lifting medium is introduced into the riser 1 and the riser 2 through lines 22 and 23, respectively. The pre-elevation medium is well known to those skilled in the art and may be selected from one or more of water vapor, C1-C4 hydrocarbons or conventional catalytic cracking dry gas, preferably water vapor and/or olefin-rich C4 fraction.

The invention will be further illustrated by the following examples.

The raw materials used in the examples and comparative examples include the raw material A, the raw material B, the raw material C, the raw material E, and the raw material F, and the specific properties are shown in Table 1. The raw material A is a cracked heavy oil, the raw material B is an atmospheric heavy oil, and the raw material C is an olefin-rich cracked light gasoline. The raw material E and the raw material F are different side line liquid products of the F-T device, wherein the raw material E and the raw material F correspond to light and heavy flows, respectively. The catalyst used is the MMC-2 catalyst produced by Qilu Branch of Sinopec Catalyst. The specific properties are shown in Table 2. The catalyst contains shape-selective zeolite with an average pore diameter of less than 0.7 nm.

Example 1

This example was carried out on a medium-sized apparatus in which the feedstock was a mixture of olefin-containing cracked light gasoline C and cracked heavy oil A (as C:A = 1:1.5 ratio) and the catalyst was MMC-2. In the continuous reaction-regeneration operation of the medium-sized device, the riser has an inner diameter of 16 mm and a height of 3200 mm, and the riser outlet is connected to the fluidized bed reactor. The fluidized bed reactor has an inner diameter of 64 mm and a height of 600. Millimeter. All feeds enter the unit from the nozzle inlet at the bottom of the riser.

This embodiment was carried out in a single pass operation without refining of the cracked heavy oil. The high-temperature regenerated catalyst enters the bottom of the riser reaction section from the regenerator through the regenerative catalyst inclined pipe, and flows upward under the action of the water vapor pre-lifting medium. After the preheating is mixed with the atomized water vapor, the feedstock oil enters the riser through the feed nozzle to contact the hot regenerated catalyst for catalytic conversion reaction. The reaction mixture goes up the riser through the riser outlet to the fluidized bed reaction connected to the riser, the reaction mixture continues to rise, the reaction enters the settler, and then the gas-solid separation is carried out through a quick-distribution device disposed at the top of the settler. The oil and gas products are separated into gas and liquid products by a pipeline, and the coke-containing catalyst (used catalyst) flows into the stripper by gravity, and the steam is stripped to the hydrocarbon product adsorbed on the used catalyst. Gas-solid separation is carried out through a fluidized bed into a settler. The stripped used catalyst enters the regenerator through the used catalyst tube and is exposed to air for high temperature scorch regeneration. The regenerated catalyst is reused in the riser reactor through the regenerated catalyst inclined tube.

The main operating conditions and results of this example are listed in Table 3.

Comparative example 1

The feedstock oil, the catalyst, and the feedstock oil are fed in the same manner as in Example 1 in the present embodiment. The difference is that the reactor is only a riser and there is no fluidized bed reactor. The riser reactor has an inner diameter of 16 mm and a height of 3800 mm.

This example was also carried out in a single pass operation without refining of the cracked heavy oil. The high-temperature regenerated catalyst enters the bottom of the riser reaction section from the regenerator through the regenerative catalyst inclined pipe, and flows upward under the action of the pre-lifting medium. After the preheating is mixed with the atomized water vapor, the feedstock oil enters the riser through the feed nozzle to contact the hot regenerated catalyst for catalytic conversion reaction. The reaction mixture is passed up the riser through the riser outlet into the settler where it is subsequently separated by a quick separation device located at the top of the settler. The oil and gas products are separated into gas and liquid products by a pipeline, and the coke-containing catalyst (used catalyst) flows into the stripper by gravity, and the steam is stripped to the hydrocarbon product adsorbed on the used catalyst. Enter the settler for gas-solid separation. The stripped used catalyst enters the regenerator through the used catalyst tube and is exposed to air for high temperature scorch regeneration. The regenerated catalyst is reused in the riser reactor through the regenerated catalyst inclined tube.

The operating conditions and results of this example are listed in Table 3.

Example 2

This embodiment was carried out on the medium-sized apparatus described in the first embodiment. The ratio of the olefin-rich cracked light gasoline C and the cracked heavy oil A is 1:1, wherein the raw material C is injected into the riser from the raw material nozzle at the bottom of the riser, and the raw material A is injected into the riser from the raw material nozzle at the length 1/2 of the riser. Reacted. The main operating conditions and results of this example are listed in Table 4.

Example 3

This embodiment was carried out on the medium-sized apparatus described in Embodiment 1. The olefin-containing cracked light gasoline C and the cracked heavy oil A are injected at a ratio of 1:1.2, wherein the raw material C is injected into the riser from the raw material nozzle at the bottom of the riser, and the raw material A is injected into the riser from the raw material nozzle at the bottom of the fluidized bed to participate in the reaction. The main operating conditions and results of this example are listed in Table 4.

Comparative example 2

This example was carried out on the medium-sized apparatus described in Comparative Example 1. The ratio of the olefin-rich cracked light gasoline C and the cracked heavy oil A is 1:1, wherein the raw material C is injected into the riser from the raw material nozzle at the bottom of the riser, and the raw material A is injected into the riser from the raw material nozzle at the length 1/2 of the riser. Reacted. The main operating conditions and results of this example are listed in Table 4.

It can be seen from Table 4 that the raw material C in the third embodiment is injected into the riser from the raw material nozzle at the bottom of the riser and the feed material A is injected into the riser from the bottom of the fluidized bed to participate in the reaction, and the heavy oil is compared with Comparative Example 2. Under the condition that the degree of conversion is basically equivalent, the dry gas and coke yield can be significantly reduced (reduced by 1.73 and 0.68 percentage points, respectively), while the yields of propylene and butene are still increased by 1.15 and 0.28 percentage points respectively, and the dry gas selectivity index (dry) The gas yield to conversion ratio was 6.25, which was 23.17% lower than that of Comparative Example 2.

Example 4

This embodiment is carried out on a medium-sized apparatus in which the first riser reactor has an inner diameter of 16 mm and a height of 3800 mm, the second riser has an inner diameter of 16 mm and a height of 3200 mm, and the second riser outlet connection flow. The fluidized bed reactor has a inner diameter of 64 mm and a height of 600 mm. The configuration is as shown in Fig. 1. This embodiment is operated by a refining method. The high-temperature regenerated catalyst is led to the bottom of the first and second riser reaction sections by the regenerator through the regenerated catalyst inclined tube, and flows upward under the action of the pre-lifting medium. After the feedstock oil B is preheated and mixed with the atomized water vapor, the first riser reactor 1 is injected into the first riser reactor 1 through the feed nozzle to contact the hot regenerated catalyst for catalytic conversion reaction, and the reaction mixture rises along the riser reactor 1 and passes through the riser. The quick-distribution device provided at the outlet of the reactor 1 performs gas-solid separation, and the oil and gas product is led to a settler, and then led to a product separation system to separate into gas and liquid products, wherein the light gasoline fraction is retreated as the second riser reactor 2 The feed, cracked heavy oil fraction refining continues as a feed to the fluidized bed reactor 3 for catalytic conversion. The coke-containing catalyst (used catalyst) from the riser reactor 1 is firstly dropped by gravity into the fluidized bed reactor 3 and mixed with the catalyst and oil and gas products from the outlet of the riser reactor 2, and then enters the fluidized bed. In the same stripper, the stripping steam is used to adsorb the hydrocarbon product on the used catalyst, and then enters the settler through the fluidized bed for gas-solid separation. The stripped used catalyst enters the regenerator through the used catalyst tube and is exposed to air for high temperature scorch regeneration. The regenerated catalyst is returned to the two riser reactors via a regenerated catalyst inclined tube for repeated use.

Light gasoline and atomized water vapor from the product separation system are injected through the bottom nozzle of the riser reactor 2, and the cracked heavy oil is mixed with the atomized water vapor and introduced through the bottom nozzle of the fluidized bed reactor 3 to contact with the high temperature catalyst. The reaction, the oil and gas product enters the settler through the fluidized bed, and is separated from the oil and gas product of the riser reactor 1 by a cyclone separation system at the top of the settler; the oil and gas product is taken out of the reactor through the pipeline and enters the product separation system, the catalyst Introduced to a fluidized bed reactor. The coke-containing catalyst in the fluidized bed reactor (used catalyst, including catalyst from the first riser reactor and the second riser reactor) is led to a stripper, and the used catalyst after stripping is passed The used catalyst inclined tube enters the regenerator and is heated in contact with air for high-temperature scorch regeneration.

The main operating conditions and results of this example are listed in Table 5. The properties of some liquid products are shown in Table 6.

Example 5

This embodiment was carried out in the same apparatus as in the fourth embodiment. In addition to adjusting the operating conditions, in addition to adjusting the operating conditions, the reductive conversion of the C4 fraction is increased, that is, the C4 fraction from the separation system participating in the refining enters the preheater of the riser reactor 2 in contact with the catalyst. The main operating conditions and results of this example are listed in Table 7, and the properties of some of the liquid products are shown in Table 8.

From the results of Tables 5, 6, 7, and 8, the method proposed by the present invention can be found to have the characteristics of low dry gas yield and high propylene yield, and at the same time, pyrolysis gasoline having a high aromatic content can be produced, which can be extracted as an aromatic hydrocarbon. raw material. The properties of the cracked light cycle oil (having a cetane number of 22) also have a corresponding improvement to some extent and can be used as a fuel oil component.

Example 6

This embodiment was carried out in the same apparatus as in the fourth embodiment. In comparison with Example 4, in addition to adjusting the operating conditions, the feed was changed to the raw material E and the raw material F, wherein the ratio of the raw material E to the raw material F was 1:1. This embodiment operates only in the cracked heavy oil refining mode. The high-temperature regenerated catalyst is led to the bottom of the first and second riser reaction sections by the regenerator through the regenerated catalyst inclined tube, and flows upward under the action of the pre-lifting medium. After the preheating and the atomized water vapor are mixed, the feedstock oil F is injected into the first riser reactor 1 through the feed nozzle to contact the hot regenerated catalyst to carry out a catalytic conversion reaction, and the reaction mixture rises along the riser reactor 1 and passes through the riser. The quick-distribution device provided at the outlet of the reactor 1 performs gas-solid separation, and the oil and gas product is led to a settler, and then introduced to a product separation system to separate into gas and liquid products, wherein the cracked heavy oil fraction is rectified as a feed of the fluidized bed reactor 3. Continue catalytic conversion. The coke-containing catalyst (used catalyst) from the riser reactor 1 is firstly dropped by gravity into the fluidized bed reactor 3 and mixed with the catalyst and oil and gas products from the outlet of the riser reactor 2, and then enters the fluidized bed. In the same stripper, the stripping steam is used to adsorb the hydrocarbon product on the used catalyst, and then enters the settler through the fluidized bed for gas-solid separation. The stripped used catalyst enters the regenerator through the used catalyst tube and is exposed to air for high temperature scorch regeneration. The regenerated catalyst is returned to the two riser reactors via a regenerated catalyst inclined tube for repeated use.

The raw material E and the atomized water vapor are sprayed through the bottom nozzle of the riser reactor 2, and the cracked heavy oil is mixed with the atomized water vapor and introduced through the bottom nozzle of the fluidized bed reactor 3, and reacted with the high temperature catalyst, and the oil and gas product passes through the fluidized bed. Entering the settler, the gas-solid separation is carried out together with the oil and gas products to the riser reactor 1 at the cyclone separation system at the top of the settler; the oil and gas products are led out of the reactor through the pipeline and then enter the product separation system, and the catalyst is led to the fluidized bed reactor. The coke-containing catalyst in the fluidized bed reactor (used catalyst, including catalyst from the first riser reactor and the second riser reactor) is led to a stripper, and the used catalyst after stripping is passed The used catalyst inclined tube enters the regenerator and is heated in contact with air for high-temperature scorch regeneration. The main operating conditions and results of this example are listed in Table 9.

The fresh feed described in Table 5 is the heavy feedstock that is directed to the first riser reaction.

The fresh feed described in Table 7 is the heavy feed to the first riser reaction.

1, 2. . . Tube riser

3. . . Stripper

4. . . Fluidized bed reactor

5. . . Settler

6. . . Product separation system

7. . . Regenerator

8. . . For the used catalyst inclined tube

9, 10. . . For regenerating catalyst inclined tube

The riser 2 and the fluidized bed 4 are coaxially connected in series through the settler 5 and the riser 1 to be juxtaposed, and are connected coaxially with the stripper 3 at high and low.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic flow diagram of a catalytic cracking process in accordance with the present invention.

1. . . First riser reactor

2. . . Second riser reactor

3. . . Stripper

4. . . Fluidized bed reactor

5. . . Settler

6. . . Product separation system

7. . . Regenerator

8. . . Used catalyst inclined tube

9, 10. . . Regenerative catalyst inclined tube

20. . . Pipeline

twenty one. . . Pipeline

twenty two. . . Pipeline

twenty three. . . Pipeline

twenty four. . . Pipeline

25. . . Pipeline

26. . . Pipeline

27. . . Pipeline

30. . . Pipeline

31. . . Pipeline

32. . . Pipeline

33. . . Pipeline

34. . . Pipeline

35. . . Pipeline

36. . . Pipeline

37. . . Pipeline

Claims (34)

A catalytic cracking method comprises: contacting a heavy raw material and atomized water vapor with a catalyst having a shape-selective zeolite having an average pore diameter of less than 0.7 nm in a first riser reactor to obtain a first hydrocarbon product and a first a stream of carbonaceous catalyst, the first hydrocarbon product and the first carbon catalyst are separated by a separation device at the end of the first riser, and the light raw material and the atomized water vapor are led to the second riser reactor, and the average Catalyst contact reaction of a shape-selective zeolite having a pore diameter of less than 0.7 nm to obtain a second hydrocarbon product and a second carbon deposition catalyst, and the second hydrocarbon product and the second carbon catalyst are introduced into a fluidization in series with the second riser reactor In a bed reactor, reacting in the presence of a catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm, while introducing the cracked heavy oil to a second riser reactor and/or a fluidized bed reactor for reaction; A stream comprising a third hydrocarbon product and a third carbon catalyst is obtained in a fluidized bed reactor. A catalytic cracking method comprising: contacting a heavy raw material with a catalyst containing a shape-selective zeolite having an average pore diameter of less than 0.7 nm in a first riser reactor to obtain a stream containing the first hydrocarbon product and the first carbon catalyst; The first oil and gas product is separated from the first carbon deposition catalyst by a separation device at the end of the first riser, and the light raw material and the atomized water vapor are introduced to the second riser reactor, and the average pore diameter is less than 0.7 nm. Catalyst contact reaction of the shape-selective zeolite to obtain a second hydrocarbon product and a second carbon catalyst, and the second hydrocarbon product and the second carbon catalyst are introduced into a fluidization in series with the second riser reactor In a bed reactor, reacting in the presence of a catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm, while introducing the cracked heavy oil to a second riser reactor and/or a fluidized bed reactor for reaction; A stream comprising a third hydrocarbon product and a third carbon catalyst is obtained in a fluidized bed reactor. A catalytic cracking method comprises: contacting a heavy raw material and atomized water vapor with a catalyst having a shape-selective zeolite having an average pore diameter of less than 0.7 nm in a first riser reactor to obtain a first hydrocarbon product and a first a stream of carbonaceous catalyst, the first hydrocarbon product and the first carbon catalyst are separated by a separation device at the end of the first riser, and the light raw material is led to the second riser reactor, and the average pore diameter is less than 0.7 nm. Catalyst contact reaction of the shape-selective zeolite to obtain a second oil and gas product and a second carbonaceous catalyst, the second hydrocarbon product and the second carbon catalyst being introduced into a fluidized bed reactor connected in series with the second riser reactor, Reacting in the presence of a catalyst comprising a shape-selective zeolite having an average pore diameter of less than 0.7 nm, while introducing the cracked heavy oil to a second riser reactor and/or a fluidized bed reactor for reaction; from a fluidized bed reactor A stream containing a third hydrocarbon product and a third carbon catalyst is obtained. A catalytic cracking method comprising: contacting a heavy raw material with a catalyst containing a shape-selective zeolite having an average pore diameter of less than 0.7 nm in a first riser reactor to obtain a stream containing the first hydrocarbon product and the first carbon catalyst; The first oil and gas product is separated from the first carbon deposition catalyst by a separation device at the end of the first riser, and the light raw material is led to the second riser reactor, and the average pore diameter is small. Catalyst contact reaction of a 0.7 nm shape selective zeolite to obtain a second hydrocarbon product and a second carbon deposition catalyst, the second hydrocarbon product and the second carbon catalyst being introduced to a fluidized bed in series with the second riser reactor In the reactor, the reaction is carried out in the presence of a catalyst containing a shape-selective zeolite having an average pore diameter of less than 0.7 nm, and at the same time, the cracked heavy oil is introduced to a second riser reactor and/or a fluidized bed reactor for reaction; A stream comprising a third hydrocarbon product and a third carbon catalyst is obtained in a bed reactor. The catalytic cracking process according to any one of claims 1 to 4, wherein the cracked heavy oil is a cracked heavy oil prepared by the method. A catalytic cracking process according to any one of claims 1-4, wherein the cracked heavy oil is introduced to a fluidized bed reactor for reaction. The catalytic cracking process according to any one of claims 1-4, wherein the cracked heavy oil is a cracked heavy oil prepared by the method, wherein the cracked heavy oil is introduced to a fluidized bed reactor for reaction. The catalytic cracking process according to any one of claims 1 to 4, wherein the heavy feedstock comprises a heavy hydrocarbon and/or a hydrocarbon-rich animal and vegetable oil; wherein the light feedstock comprises A gasoline fraction and/or a C4 hydrocarbon; wherein the cracked heavy oil is a cracked heavy oil having an atmospheric distillation range of 330 to 550 °C. The catalytic cracking method according to any one of claims 1-4, further comprising: separating the first oil and gas product by a product separation system to obtain a cracking gas, a pyrolysis gasoline, a cracking light cycle oil, and a cracking heavy oil; and/ Or wherein the third oil and gas product is separated by a product separation system to obtain a cracking gas, a pyrolysis gasoline, a cracked light cycle oil, and a cracked heavy oil. The catalytic cracking method according to any one of claims 1 to 4, wherein the first riser reactor atomizing water vapor accounts for 2 to 50% by weight of the feed amount, and the reaction pressure is 0.15 to 0.3 MPa. Wherein, the reaction temperature of the first riser reactor is 480-600 ° C, the ratio of the agent to the oil is 5-20, and the reaction time is 0.50-10 seconds. The catalytic cracking method according to any one of claims 1 to 4, wherein the first riser reactor atomizing water vapor accounts for 5 to 10% by weight of the feed amount, and the reaction pressure is 0.2 to 0.25 MPa. Wherein, the reaction temperature of the first riser reactor is 500-560 ° C, the ratio of the agent to the oil is 7-15, and the reaction time is 2 to 4 seconds. The catalytic cracking method according to any one of claims 1-4, wherein the reaction temperature of the second riser reactor is 520 to 580 ° C; and the light raw material introduced by the second riser reactor includes the gasoline fraction The ratio of atomized water vapor of the gasoline raw material is 5 to 30% by weight; when the light raw material includes the gasoline fraction, the ratio of the ratio of the gasoline to the gasoline in the second riser is 10 to 30, and the reaction time is 0.10~ 1.5 seconds; when the light raw material includes C4 hydrocarbon, the proportion of C4 hydrocarbon atomized water vapor is 10-40% by weight, and when the light raw material includes C4 hydrocarbon, the ratio of the solvent to the C4 hydrocarbon operating in the second riser For 12~40, the reaction time is 0.50~2.0 seconds. The catalytic cracking method according to any one of claims 1-4, wherein the reaction temperature of the second riser reactor is 520 to 560 ° C; and the light raw material introduced by the second riser reactor includes the gasoline fraction The ratio of atomized water vapor of the gasoline raw material is 10-20% by weight; when the light raw material includes the gasoline fraction, the ratio of the ratio of the gasoline to the gasoline in the second riser is The reaction time is from 15 to 25, and the reaction time is from 0.30 to 0.8 seconds. When the light raw material includes C4 hydrocarbon, the proportion of C4 hydrocarbon atomized water vapor is 15 to 25% by weight. When the light raw material includes C4 hydrocarbon, the C4 hydrocarbon is The ratio of the agent to the oil in the second riser is 17 to 30, and the reaction time is 0.8 to 1.5 seconds. The catalytic cracking method according to any one of claims 1-4, wherein the fluidized bed reactor has a reaction temperature of 500 to 580 ° C and a WHSV of 1 to 35 hours ^-1 ; the reaction of the fluidized bed reactor The pressure is 0.15~0.3MPa. The catalytic cracking method according to any one of claims 1-4, wherein the fluidized bed reactor has a reaction temperature of 510 to 560 ° C and a WHSV of 3 to 30 hours ^-1 ; the reaction of the fluidized bed reactor The pressure is 0.2~0.25MPa. The catalytic cracking method according to any one of claims 1-4, wherein the reaction conditions of the cracked heavy oil in the fluidized bed include: a ratio of the cracked heavy oil to the catalyst is from 1 to 50; and the cracked heavy oil is fluidized. The WHSV in the bed is 1~20 hours ^-1 ; the proportion of atomized water vapor in cracking heavy oil is 5~20% by weight. The catalytic cracking method according to any one of claims 1-4, wherein the reaction conditions of the cracked heavy oil in the fluidized bed comprise: a ratio of the cracked heavy oil to the catalyst is from 5 to 40; and the cracked heavy oil is fluidized. The WHSV in the bed is 3~15 hours ^-1 ; the proportion of atomized water vapor in cracking heavy oil is 10~15% by weight. The catalytic cracking process according to any one of claims 1-4, wherein the method is introduced to a second riser reactor and/or a fluidized bed reactor The weight ratio of the cracked heavy oil to the heavy feedstock introduced to the first riser reactor is 0.05 to 0.30:1. The catalytic cracking process according to any one of claims 1-4, wherein when the light raw material comprises a gasoline fraction, the gasoline fraction introduced to the second riser reactor is led to the first riser. The weight ratio of the heavy raw material of the reactor is 0.05 to 0.20:1; when the light raw material includes the gasoline fraction and the C4 hydrocarbon, the weight ratio of the C4 hydrocarbon in the light raw material to the gasoline fraction in the light raw material is 0. ~2:1. The catalytic cracking method of claim 8, wherein the gasoline raw material is an olefin-rich gasoline fraction having an olefin content of 20 to 95% by weight and a final boiling point of not more than 85 ° C; The C4 hydrocarbon light feedstock is an olefin-rich C4 hydrocarbon having a C4 olefin content of greater than 50% by weight. The catalytic cracking method of claim 8, wherein the gasoline fraction light raw material comprises pyrolysis gasoline separated by the product separation system. The catalytic cracking method of claim 9, further comprising mixing the first oil and gas product and the third oil and gas product into a product separation system for separation. The catalytic cracking process according to any one of claims 1 to 4, further comprising: introducing the first carbon deposition catalyst to a fluidized bed reactor, mixing with the catalyst of the fluidized bed reactor, and then introducing Go to the stripper or direct the first carbon catalyst to the stripper. Catalytic cracking party as claimed in any of claims 1-4 The method further includes steam stripping the first carbon deposition catalyst and/or the third carbon deposition catalyst and introducing the stripped water vapor entrained with the oil and gas product to the fluidized bed reactor. A catalytic cracking unit comprising: a first riser reactor (1) for cracking heavy feedstock, the first riser reactor having one or more heavy feedstock feed ports at the bottom of the riser, a second riser reactor (2) for cracking light feedstock, the second riser reactor having one or more light feedstock feed ports at the bottom of the riser and a discharge port at the top of the riser a fluidized bed reactor (4) having one or more feed ports and the fluidized bed reactor connected to a discharge port of the second riser reactor via a connecting member, a separation device at the end of the first riser, the separation device comprising an oil and gas discharge port and a catalyst discharge port, and wherein the second riser reactor and/or the fluidized bed reactor further have the one or One or more cracked heavy oil feed ports above the plurality of light feedstock feed ports. A catalytic cracking unit comprising: a first riser reactor (1) for cracking heavy feedstock, the first riser reactor having one or more heavy feedstock feed ports at the bottom of the riser, a second riser reactor (2) for cracking light feedstock, the second riser reactor having one or more lightweights located at the bottom of the riser a feed inlet and a discharge port located at the top of the riser, a fluidized bed reactor (4) having one or more feed ports and the fluidized bed reactor being connected via a connecting member a discharge port of the second riser reactor connected to the separation device at the end of the first riser, the separation device comprising an oil and gas discharge port and a catalyst discharge port, wherein the second riser reactor and/or the The fluidized bed reactor also has one or more cracked heavy oil feed ports located above the one or more light feedstock feed ports, and a product separation system (6) that will crack the heavy oil from The oil and gas products from the first riser reactor and/or the fluidized bed reactor are separated and the cracked heavy oil is directed to the one or more cracked heavy oil feed ports via a cracking heavy oil loop. The catalytic cracking unit of any one of claims 25-26, wherein the connecting member is a low pressure outlet distributor. The catalytic cracking unit of any one of claims 25-26, wherein the connecting member is an arched distributor. The catalytic cracking unit of any one of claims 25-26, which is a quick separation device. A catalytic cracking unit according to any one of claims 25-26, wherein the cracked heavy oil feed port is at one-half of the length of the second riser reactor and the second riser is Between the mouths. Catalytic cracking as claimed in any of claims 25-26 A device wherein the cracked heavy oil feed port is at the bottom of the fluidized bed reactor. The catalytic cracking apparatus of any one of claims 25-26, further comprising: a stripper (3), a settler (5), a product separation system (6), a regenerator (7) And a cyclone separation system: the stripper has an inlet for stripping water vapor, an outlet of the stripped catalyst, and an outlet for stripping steam with oil and gas; wherein the settler and the fluidized bed reactor The discharge ports are in communication and have one or more inlets for receiving the reaction oil and one or more outlets connected to the product separation system; wherein the regenerator comprises a regeneration section, one or more used catalysts a inclined tube and one or more regenerated catalyst inclined tubes; wherein the product separation system separates C4 hydrocarbons, pyrolysis gasoline, and cracked heavy oil from oil and gas products from the first riser reactor and/or the fluidized bed reactor And directing the cracked heavy oil to the one or more cracked heavy oil feed ports via a cracking heavy oil circuit, and/or introducing the cracked gasoline to the one or more light feedstock feed ports via a pyrolysis gasoline circuit, and/or through C4 hydrocarbon A loop directs C4 hydrocarbons to the one or more light feedstock feed ports; wherein the cyclonic separation system is disposed at the top of the settler and is coupled to an outlet of the settler for further separation of the hydrocarbon product and catalyst solids. The catalytic cracking unit of claim 32, wherein the used catalyst inclined tube is connected to the stripper, and the regenerated catalyst inclined tube is The first and/or second riser reactors are connected. The catalytic cracking apparatus according to any one of claims 25-26, wherein the first riser reactor is selected from the group consisting of an equal diameter riser, an equal line riser or a variable diameter riser reactor; The second riser reactor is selected from the group consisting of an equal diameter riser, an equal line riser or a variable diameter riser reactor; the fluidized bed reactor is selected from the group consisting of a fixed fluidized bed, a bulk fluidized bed, and a drum. Bubble beds, turbulent beds, fast beds, transport beds and dense phase fluidized bed reactors.