Method for preparing low-carbon olefin by coupling methanol and mixed hydrocarbon

Abstract

The invention discloses a method for preparing low-carbon olefin by coupling methanol and mixed hydrocarbon. The gasified methanol and mixed hydrocarbon raw materials are introduced into a reaction zone to be subjected to a contact reaction with a catalyst, and a material flow I containing product gas and the catalyst is generated; after the material flow I is subjected to gas-solid separation, the catalyst enters a catalyst retention zone, and product gas enters a downstream workshop section; part of the catalyst in the catalyst staying area enters the reaction area, part of the catalyst is fed into the fluidized bed regenerator for regeneration, and the regenerated catalyst enters the fluidized bed reactor. According to the method, the low-carbon olefin is prepared by continuously coupling methanol and mixed hydrocarbon through a fluidized bed reaction-regeneration process; the reaction for preparing the low-carbon olefin from the methanol releases heat, heat is provided for preparing the low-carbon olefin from the mixed hydrocarbon through catalytic cracking, and self-heat balance is realized. The reaction contact time of the product gas in the reactor is 1t; the selectivity of ethylene and propylene carbon groups is greater than or equal to 75% wt, the conversion per pass of methanol is greater than or equal to 99% wt, and the conversion per pass of mixed hydrocarbon is greater than or equal to 50% wt.

Description

Technical Field

[0001] The present application relates to the technical field of chemical catalysis, and particularly to a method for coupling methanol and mixed hydrocarbons to produce light olefins. Background Art

[0002] Olefins are important basic organic chemical raw materials and the cornerstone of the modern chemical industry. The technical routes for olefin production mainly include naphtha cracking to produce olefins, methanol to olefins, propane dehydrogenation to produce propylene, alkane cracking to produce olefins, olefin cracking to produce olefins, etc. Light olefins are very reactive and prone to polymerization, alkylation, aromatization and other reactions, generating by-products and reducing the yield of light olefins.

[0003] The methanol to olefins (MTO) technology targets ethylene and propylene. Methanol is converted into a mixture containing components such as ethylene, propylene, butene, pentene and alkanes under the action of a molecular sieve catalyst. The methanol to olefins reaction is a strongly exothermic reaction, and usually the heat released from the reaction and coking needs to be removed by a heat exchanger.

[0004] UOP Company has developed the olefin catalytic cracking (OCP) technology. C4-C8 olefin raw materials are converted into ethylene and propylene under high temperature and low pressure conditions, and the ratio of propylene to ethylene is about 4:1. The OCP unit has two radial flow reactors, one of which is operating online and the other is on standby after regeneration. The regeneration cycle of the reactor is 48 hours. The state switching between the reactor operating online and offline regeneration is achieved through a valve group arranged at the inlet and outlet of the reactor.

[0005] Sinopec has developed the olefin catalytic cracking (OCC) technology. The olefins contained in the mixed C4-C6 raw materials are cracked into propylene, ethylene, etc. under the action of a molecular sieve catalyst. The OCC unit has two fixed bed reactors, one in operation and one in standby, and the reaction system operates in a continuously switched manner. The regeneration process of the catalyst is controlled by an automatic switching regeneration program.

[0006] The catalytic cracking reaction to produce light olefins is a strongly endothermic process. For radial flow reactors and fixed bed reactors, heat supply is generally achieved by increasing the feed temperature of the raw materials. However, if the preheating temperature of raw material components such as olefins, diolefins and alkynes is too high, coking will occur, affecting the continuous operation of the device. In addition, the catalyst gradually loses its activity during the reaction process, and continuous operation needs to be achieved by switching reactors. The problems of heat supply and deactivation limit the development and progress of radial flow reactor technology and fixed bed reactor technology. Summary of the Invention

[0007] In view of this, the present application provides a method for coupling methanol and mixed hydrocarbons to produce light olefins, and the main purpose is to solve the technical problems of low light olefin yield, low mixed hydrocarbon conversion rate and heat supply for mixed hydrocarbon cracking.

[0008] Light olefins are very reactive and prone to polymerization, alkylation, aromatization and other reactions, resulting in by-products and reducing the yield of light olefins. The reaction contact time is an important factor affecting the selectivity of light olefins in the reaction process of catalytic cracking of mixed hydrocarbons to prepare light olefins. Increasing the apparent linear velocity in the reaction zone of the fluidized bed reactor can reduce the reaction contact time and improve the selectivity of light olefins. However, the bed density in the reaction zone usually decreases significantly at the same time, and the catalyst inventory also decreases significantly, which in turn leads to a decrease in the conversion rate of the cracking raw material. That is, there is a negative correlation between the selectivity of light olefins and the raw material conversion rate.

[0009] In order to improve the yield of light olefins and the conversion rate of raw materials, the present application provides a high-density fast fluidized bed reactor, which includes a reactor outer shell, a reactor inner shell and a delivery pipe;

[0010] At least a raw material inlet, a catalyst inlet, a gas-phase product outlet and a catalyst outlet are provided on the reactor outer shell;

[0011] The reactor outer shell encloses an internal area;

[0012] The reactor inner shell is located in the lower part of the internal area, and the area enclosed by the reactor inner shell is the reaction zone;

[0013] The delivery pipe is located in the upper middle part of the internal area, and the bottom of the delivery pipe communicates with the reaction zone;

[0014] The area enclosed by the reactor outer shell and the delivery pipe is the gas-solid separation zone;

[0015] An outlet is provided on the delivery pipe, and the delivery pipe communicates with the gas-solid separation zone;

[0016] The annular area enclosed by the reactor outer shell and the reactor inner shell is the catalyst residence zone;

[0017] The bottom of the reaction zone communicates with the bottom of the catalyst residence zone;

[0018] The catalyst residence zone communicates with the gas-solid separation zone and is located below the gas-solid separation zone.

[0019] Optionally, the high-density fast fluidized bed reactor includes a catalyst distribution pipe, a fluidizing steam distributor, and a raw material distributor;

[0020] The catalyst distribution pipe passes through the reactor inner shell to communicate the catalyst residence zone and the reaction zone;

[0021] The fluidizing steam distributor is provided at the bottom of the catalyst residence zone;

[0022] The raw material distributor is arranged at the bottom of the reaction zone.

[0023] Optionally, through holes are formed in the lower surface of the catalyst distribution pipe.

[0024] Optionally, the high-density fast fluidized bed reactor includes a first gas-solid separation device and a second gas-solid separation device;

[0025] The first gas-solid separation device and the second gas-solid separation device are located in the gas-solid separation zone;

[0026] The inlet of the first gas-solid separation device is communicated with the outlet of the conveying pipe;

[0027] The catalyst outlet of the first gas-solid separation device is located in the lower part of the gas-solid separation zone, and the gas outlet of the first gas-solid separation device is located in the upper part of the gas-solid separation zone;

[0028] Preferably, the inlet of the second gas-solid separation device is located in the upper part of the gas-solid separation zone;

[0029] The catalyst outlet of the second gas-solid separation device is located in the lower part of the gas-solid separation zone;

[0030] Optionally, the first gas-solid separation device is an inertial separator.

[0031] Optionally, the second gas-solid separation device is one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

[0032] Optionally, the high-density fast fluidized bed reactor includes a reactor gas collecting chamber and a product gas conveying pipe;

[0033] The reactor gas collecting chamber is located at the top of the high-density fast fluidized bed reactor;

[0034] The product gas conveying pipe is connected to the top of the reactor gas collecting chamber;

[0035] The gas outlet of the second gas-solid separation device is communicated with the reactor gas collecting chamber.

[0036] In a second aspect, the present application provides a device for producing lower olefins from methanol and mixed hydrocarbons, and the device includes the above-mentioned high-density fast fluidized bed reactor and a fluidized bed regenerator;

[0037] The catalyst extraction pipe passes through the reactor outer shell and is located in the lower part of the catalyst residence zone, and the catalyst extraction pipe is communicated with the reactor stripper;

[0038] The inlet of the spent catalyst slide valve is connected to the bottom of the reactor stripper, the outlet of the spent catalyst slide valve is connected to the inlet of the spent catalyst transfer pipe, and the outlet of the spent catalyst transfer pipe communicates with the fluidized bed regenerator;

[0039] The regenerator stripper is located at the bottom of the fluidized bed regenerator; the inlet of the regenerated catalyst slide valve is connected to the bottom of the regenerator stripper, the outlet of the regenerated catalyst slide valve is connected to the inlet of the regenerated catalyst transfer pipe, and the outlet of the regenerated catalyst transfer pipe is connected to the lower part of the gas-solid separation zone of the high-density fast fluidized bed reactor.

[0040] Optionally, the fluidized bed regenerator includes a regenerator shell, a regenerator distributor, a third gas-solid separation device, a regenerator gas collection chamber, and a flue gas transfer pipe;

[0041] The regenerator distributor is located at the bottom of the fluidized bed regenerator;

[0042] The third gas-solid separation device is located in the upper part of the fluidized bed regenerator. The inlet of the third gas-solid separation device is located in the upper part of the fluidized bed regenerator. The gas outlet of the third gas-solid separation device communicates with the regenerator gas collection chamber. The catalyst outlet of the third gas-solid separation device is located in the lower part of the fluidized bed regenerator. The regenerator gas collection chamber is located at the top of the fluidized bed regenerator. The flue gas transfer pipe is connected to the top of the regenerator gas collection chamber.

[0043] Optionally, the inlet pipe of the regenerator stripper penetrates the regenerator shell and opens above the regenerator distributor.

[0044] Optionally, the third gas-solid separation device employs one or more groups of gas-solid cyclone separators. Each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

[0045] In a third aspect, the present application provides a method for coupling methanol and mixed hydrocarbons to produce light olefins, which is carried out using the above-mentioned device.

[0046] Optionally, the method for producing light olefins includes the following steps:

[0047] The gasified raw material including methanol and mixed hydrocarbons is introduced into the reaction zone, contacts with the catalyst, reacts, and generates a product gas containing light olefins and a catalyst stream I;

[0048] The stream I is subjected to gas-solid separation to obtain a product gas and a catalyst;

[0049] The product gas is transported to the downstream section;

[0050] Part of the catalyst enters the reaction zone, and another part of the catalyst is regenerated. The regenerated catalyst enters the reaction zone.

[0051] Optionally, the logistics I enters the first gas-solid separation device through a conveying pipe, and the catalyst after the first gas-solid separation enters the catalyst residence zone.

[0052] Optionally, the mixed hydrocarbon in the raw material is C4+ hydrocarbon, including alkanes and alkenes with carbon atom number ≥ 4.

[0053] Optionally, the catalyst is selected from ZSM-5 molecular sieve catalysts.

[0054] Optionally, the process operating conditions in the reaction zone of the high-density fast fluidized bed reactor include:

[0055] The apparent gas linear velocity is 1.5 - 7.0 m / s, the temperature is 500 - 680 °C, the pressure is 50 - 250 kPa, and the bed density is 150 - 500 kg / m 3 , and the reaction contact time is 0.5 - 2 s.

[0056] Optionally, the apparent gas linear velocity in the reaction zone is selected from any value among 1.5 m / s, 2 m / s, 2.5 m / s, 3 m / s, 3.5 m / s, 4 m / s, 4.5 m / s, 5 m / s, 5.5 m / s, 6 m / s, 6.5 m / s, 7 m / s or the range value between any two of them.

[0057] Optionally, the temperature in the reaction zone is selected from any value among 500 °C, 550 °C, 600 °C, 650 °C, 680 °C or the range value between any two of them.

[0058] Optionally, the pressure in the reaction zone is selected from any value among 50 kPa, 100 kPa, 150 kPa, 200 kPa, 250 kPa or the range value between any two of them.

[0059] Optionally, the bed density in the reaction zone is selected from 150 kg / m 3 , 200 kg / m 3 , 250 kg / m 3 , 300 kg / m 3 , 350 kg / m 3 , 400 kg / m 3 , 450 kg / m 3 , 500 kg / m 3 or the range value between any two of them.

[0060] Optionally, the reaction contact time in the reaction zone is selected from any value among 0.5 s, 1 s, 1.5 s, 2 s or the range value between any two of them.

[0061] Optionally, the process operating conditions of the catalyst residence zone include:

[0062] The superficial gas velocity is 0.02 - 0.2 m / s, the temperature is 500 - 680 °C, and the bed density is 600 - 800 kg / m 3 .

[0063] Optionally, the catalyst circulation intensity from the catalyst residence zone to the reaction zone is 500 - 1000 kg / m 2 ·s.

[0064] Optionally, the superficial gas velocity of the catalyst residence zone is selected from any value of 0.02 m / s, 0.05 m / s, 0.08 m / s, 0.1 m / s, 0.12 m / s, 0.15 m / s, 0.18 m / s, 0.20 m / s or the range value between any two of them.

[0065] Optionally, the temperature of the catalyst residence zone is selected from any value of 500 °C, 550 °C, 600 °C, 650 °C, 680 °C or the range value between any two of them.

[0066] Optionally, the bed density of the catalyst residence zone is 600 kg / m 3 , 650 kg / m 3 , 700 kg / m 3 , 750 kg / m 3 , 800 kg / m 3 or the range value between any two of them.

[0067] Optionally, the catalyst circulation intensity is selected from any value of 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000 or the range value between any two of them, with the unit kg / (m 2 ·s).

[0068] Optionally, the process operating conditions of the fluidized bed regenerator are: the superficial gas velocity is 0.5 - 2.0 m / s, the regeneration temperature is 600 - 750 °C, the regeneration pressure is 50 - 250 kPa, and the bed density is 200 - 800 kg / m 3 .

[0069] Optionally, the superficial gas velocity of the fluidized bed regenerator is selected from any value of 0.5 m / s, 1 m / s, 1.5 m / s, 2 m / s or the range value between any two of them.

[0070] Optionally, the regeneration temperature of the fluidized bed regenerator is selected from any value of 600, 650, 700, 750 or the range value between any two of them.

[0071] Optionally, the regeneration pressure of the fluidized bed regenerator is any value among 50 kPa, 100 kPa, 150 kPa, 200 kPa, 250 kPa or a range value between any two of them.

[0072] Optionally, the bed density of the fluidized bed regenerator is 200 kg / m 3 , 250 kg / m 3 , 300 kg / m 3 , 350 kg / m 3 , 400 kg / m 3 , 450 kg / m 3 , 500 kg / m 3 , 550 kg / m 3 , 600 kg / m 3 , 650 kg / m 3 , 700 kg / m 3 , 750 kg / m 3 , 800 kg / m 3 Any value among them or a range value between any two of them.

[0073] Optionally, the regeneration gas is air.

[0074] Optionally, steam enters the catalyst residence zone from the fluidizing steam distributor, and the steam carries a part of the catalyst in the catalyst residence zone into the gas-solid separation zone; the product gas and a part of the catalyst carried by the steam in the gas-solid separation zone enter the second gas-solid separation device, and the gas after the second gas-solid separation enters the reactor gas collection chamber, and the separated catalyst returns to the catalyst residence zone.

[0075] Optionally, the product gas and steam after the second gas-solid separation enter the downstream section through the product gas transfer pipe; the first part of the catalyst in the catalyst residence zone enters the reaction zone through the catalyst distribution pipe; the second part of the catalyst in the catalyst residence zone enters the bottom of the reaction zone through the bottom of the catalyst residence zone; the third part of the catalyst in the catalyst residence zone enters the reactor stripper through the catalyst extraction pipe.

[0076] The present application provides a specific methanol and mixed hydrocarbon to lower olefins device, including: a reactor outer shell, a reactor inner shell, a transfer pipe, a raw material distributor, a first gas-solid separation device, a fluidizing steam distributor, a catalyst distribution pipe, a second gas-solid separation device, a reactor gas collection chamber, a product gas transfer pipe, a catalyst extraction pipe, a reactor stripper, a spent catalyst slide valve and a spent catalyst transfer pipe;

[0077] The area enclosed by the inner shell of the reactor is the reaction zone, and the annular area enclosed by the outer shell of the reactor and the inner shell of the reactor is the catalyst residence zone. The bottom of the reaction zone is connected to the bottom of the catalyst residence zone. The area enclosed by the outer shell of the reactor and the delivery pipe is the gas-solid separation zone. The catalyst residence zone is connected to the gas-solid separation zone and is located below the gas-solid separation zone;

[0078] The raw material distributor is located at the bottom of the reaction zone. The delivery pipe is located in the central area of the middle and upper parts of the high-density fast fluidized bed reactor. The bottom end of the delivery pipe is connected to the top end of the reaction zone, and the outlet of the delivery pipe is connected to the inlet of the first gas-solid separation device. The first gas-solid separation device is located in the gas-solid separation zone. The catalyst outlet of the first gas-solid separation device is located in the lower part of the gas-solid separation zone, and the gas outlet of the first gas-solid separation device is located in the upper part of the gas-solid separation zone;

[0079] The fluidizing steam distributor is located at the bottom of the catalyst residence zone. The catalyst distribution pipe passes through the inner shell of the reactor to connect the catalyst residence zone and the reaction zone, and the lower surface of the catalyst distribution pipe is provided with openings;

[0080] The second gas-solid separation device is located in the gas-solid separation zone. The inlet of the second gas-solid separation device is located in the gas-solid separation zone. The gas outlet of the second gas-solid separation device is connected to the reactor gas collection chamber. The catalyst outlet of the second gas-solid separation device is located in the lower part of the gas-solid separation zone. The reactor gas collection chamber is located at the top of the high-density fast fluidized bed reactor, and the product gas delivery pipe is connected to the top of the reactor gas collection chamber;

[0081] The catalyst extraction pipe passes through the outer shell of the reactor and is located in the lower part of the catalyst residence zone. The reactor stripper is connected to the catalyst extraction pipe. The inlet of the spent catalyst slide valve is connected to the bottom of the reactor stripper, and the outlet of the spent catalyst slide valve is connected to the inlet of the spent catalyst delivery pipe. The outlet of the spent catalyst delivery pipe is connected to the fluidized bed regenerator;

[0082] The first gas-solid separation device adopts an inertial separator to achieve rapid separation of the product gas and the catalyst. The second gas-solid separation device adopts one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator;

[0083] The fluidized bed regenerator for regenerating the catalyst includes: a regenerator shell, a regenerator distributor, a third gas-solid separation device, a regenerator gas collection chamber, a flue gas delivery pipe, a regenerator stripper, a regenerated catalyst slide valve and a regenerated catalyst delivery pipe;

[0084] The regenerator distributor is located at the bottom of the fluidized bed regenerator; the third gas-solid separation device is located at the upper part of the fluidized bed regenerator. The inlet of the third gas-solid separation device is located at the upper part of the fluidized bed regenerator. The gas outlet of the third gas-solid separation device is connected to the regenerator gas collection chamber. The catalyst outlet of the third gas-solid separation device is located at the lower part of the fluidized bed regenerator. The regenerator gas collection chamber is located at the top of the fluidized bed regenerator. The flue gas delivery pipe is connected to the top of the regenerator gas collection chamber;

[0085] The regenerator stripper is located outside the regenerator shell. The inlet pipe of the regenerator stripper penetrates the regenerator shell and opens above the regenerator distributor. The inlet of the regeneration slide valve is connected to the bottom of the regenerator stripper. The outlet of the regeneration slide valve is connected to the inlet of the regenerated catalyst delivery pipe. The outlet of the regenerated catalyst delivery pipe is connected to the lower part of the gas-solid separation zone of the high-density fast fluidized bed reactor;

[0086] The third gas-solid separation device employs one or more groups of gas-solid cyclone separators. Each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

[0087] This application provides a specific method for coupling methanol and mixed hydrocarbons to produce light olefins, including:

[0088] a. The catalyst from the regenerated catalyst delivery pipe enters the gas-solid separation zone of the high-density fast fluidized bed reactor and then enters the catalyst residence zone;

[0089] The gasified raw material enters the reaction zone from the raw material distributor, contacts the catalyst, and generates product gas containing light olefins. The product gas carries the catalyst and enters the first gas-solid separation device through the delivery pipe. After gas-solid separation, the catalyst enters the catalyst residence zone; steam enters the catalyst residence zone from the fluidizing steam distributor. The steam carries a small amount of catalyst and enters the gas-solid separation zone from the catalyst residence zone; the product gas and steam carrying the catalyst in the gas-solid separation zone enter the second gas-solid separation device. After gas-solid separation, the gas enters the reactor gas collection chamber, and the catalyst returns to the catalyst residence zone; the product gas and steam enter the downstream section through the product gas delivery pipe; the catalyst in the catalyst residence zone enters the reaction zone through the catalyst distribution pipe; the catalyst in the catalyst residence zone enters the bottom of the reaction zone through the bottom of the catalyst residence zone; the catalyst in the catalyst residence zone enters the reactor stripper through the catalyst extraction pipe. After stripping, the catalyst then enters the middle part of the fluidized bed regenerator through the spent catalyst slide valve and the spent catalyst delivery pipe;

[0090] b. The regenerated gas enters the bottom of the fluidized bed regenerator from the regenerator distributor. In the fluidized bed regenerator, the regenerated gas contacts the catalyst, and the carbon deposition in the catalyst is burned off. The flue gas formed by the combustion carries the catalyst into the third gas-solid separation device. After gas-solid separation, the flue gas enters the regenerator gas collection chamber and then enters the downstream flue gas treatment system through the flue gas transfer pipe. The catalyst returns to the bottom of the fluidized bed regenerator. The catalyst in the fluidized bed regenerator enters the regenerator stripper. After stripping, it enters the high-density fast fluidized bed reactor through the regenerator slide valve and the regenerated catalyst transfer pipe;

[0091] The raw materials are methanol and mixed hydrocarbons. Preferably, the mixed hydrocarbons are C4+ hydrocarbons, including alkanes and olefins with carbon atom number ≥4; the catalyst is a ZSM-5 molecular sieve catalyst;

[0092] The process operating conditions in the reaction zone of the high-density fast fluidized bed reactor are as follows: the superficial gas linear velocity is 1.5 - 7.0 m / s, the temperature is 500 - 680 °C, the pressure is 50 - 250 kPa, and the bed density is 150 - 500 kg / m 3 , and the reaction contact time is 0.5 - 2 s;

[0093] The process operating conditions in the catalyst residence zone are as follows: the superficial gas linear velocity is 0.02 - 0.2 m / s, the temperature is 500 - 680 °C, and the bed density is 600 - 800 kg / m 3 ; the catalyst circulation intensity of the catalyst flowing from the catalyst residence zone to the reaction zone is 500 - 1000 kg / (m 2 ·s); the regenerated gas is air;

[0094] The process operating conditions of the fluidized bed regenerator are as follows: the superficial gas linear velocity is 0.5 - 2.0 m / s, the regeneration temperature is 600 - 750 °C, the regeneration pressure is 50 - 250 kPa, and the bed density is 200 - 800 kg / m 3 .

[0095] In the method described in this application, the single-pass conversion rate of methanol ≥ 99% wt, the single-pass conversion rate of mixed hydrocarbons ≥ 50% wt, the carbon-based selectivity of "ethylene + propylene" ≥ 75% wt, and the propylene / ethylene (mass ratio) ≥ 3.

[0096] In the method described in this application, the calculation methods of the single-pass conversion rate of methanol, the single-pass conversion rate of mixed hydrocarbons, and the carbon-based selectivity of "ethylene + propylene" are as follows:

[0097] Single-pass conversion rate of methanol = (1 - mass flow rate of methanol in product gas / mass flow rate of methanol feed) × 100%

[0098] Single-pass conversion rate of mixed hydrocarbons = (1 - mass flow rate of C4+ hydrocarbons in product gas / mass flow rate of C4+ hydrocarbons feed) × 100%;

[0099] “Ethylene + propylene” carbon-based selectivity = mass flow rate of “ethylene + propylene” in the product gas / (mass flow rate of the product gas - mass flow rate of water in the product gas - mass flow rate of methanol in the product gas - mass flow rate of C4+ hydrocarbons in the product gas) × 100%

[0100] Compared with the prior art, the present application has the following beneficial effects:

[0101] (1) The present application discloses a high-density fast fluidized bed reactor, which mainly includes a reaction zone, a catalyst residence zone and a gas-solid separation zone. The catalyst circulation intensity flowing from the catalyst residence zone to the reaction zone is as high as 500 - 1000 kg / (m 2 ·s), thereby increasing the bed density of the reaction zone, achieving a high bed density under high apparent linear velocity conditions, and overcoming the negative correlation between the selectivity of light olefins and the raw material conversion rate.

[0102] (2) In the method of the present application, the reaction contact time of the product gas in the high-density fast fluidized bed reactor < 2 s, effectively improving the “ethylene + propylene” carbon-based selectivity.

[0103] (3) In the method of the present application, the methanol-to-light olefins reaction is exothermic, providing heat for the C4+ hydrocarbon catalytic cracking to light olefins reaction, and achieving self-thermal balance.

[0104] (4) In the method of the present application, a continuous process of coupling methanol and mixed hydrocarbons to produce light olefins is achieved through a fluidized bed reaction-regeneration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Figure 1 It is a schematic diagram of the device according to an embodiment of the present application.

[0106] Figure 1 The description of the reference numerals in

[0107] 1 - High-density fast fluidized bed reactor;

[0108] 1 - 1 Reactor outer shell, 1 - 2 Reactor inner shell, 1 - 3 Delivery pipe, 1 - 4 Feed distributor, 1 - 5 First gas-solid separation equipment, 1 - 6 Fluidizing steam distributor, 1 - 7 Catalyst distribution pipe, 1 - 8 Reactor heat extractor, 1 - 9 Reactor gas collecting chamber; 1 - 10 Product gas delivery pipe; 1 - 11 Catalyst extraction pipe; 1 - 12 Reactor stripper; 1 - 13 Spent catalyst slide valve; 1 - 14 Spent catalyst delivery pipe;

[0109] 2 - Fluidized bed regenerator;

[0110] 2-1 Regenerator shell, 2-2 Regenerator distributor, 2-3 Third gas-solid separation equipment, 2-4 Regenerator gas collection chamber, 2-5 Flue gas transfer pipe, 2-6 Regenerator stripper, 2-7 Regeneration slide valve, 2-8 Regenerated catalyst transfer pipe. Detailed implementation manners

[0111] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0112] Unless otherwise specified, the raw materials and catalysts in the embodiments of the present application are all purchased through commercial channels.

[0113] In a specific implementation manner, the present application provides a device of an implementation manner, and its structural schematic diagram is as Figure 1 shown. The device includes a high-density fast fluidized bed reactor (1) and a fluidized bed regenerator (2).

[0114] a. The high-density fast fluidized bed reactor (1) includes: a reactor outer shell (1-1), a reactor inner shell (1-2), a conveying pipe (1-3), a raw material distributor (1-4), a first gas-solid separation device (1-5), a fluidizing steam distributor (1-6), a catalyst distribution pipe (1-7), a second gas-solid separation device (1-8), a reactor gas collecting chamber (1-9), a product gas conveying pipe (1-10), a catalyst extraction pipe (1-11), a reactor stripper (1-12), a spent catalyst slide valve (1-13), and a spent catalyst conveying pipe (1-14); the area enclosed by the reactor inner shell (1-2) is the reaction zone (A), the annular area enclosed by the reactor outer shell (1-1) and the reactor inner shell (1-2) is the catalyst residence zone (B), the bottom of the reaction zone (A) is connected to the bottom of the catalyst residence zone (B), the area enclosed by the reactor outer shell (1-1) and the conveying pipe (1-3) is the gas-solid separation zone (C), the catalyst residence zone (B) is connected to the gas-solid separation zone (C) and is located below the gas-solid separation zone (C); the raw material distributor (1-4) is located at the bottom of the reaction zone (A), the conveying pipe (1-3) is located in the central area of the middle and upper parts of the high-density fast fluidized bed reactor, the bottom end of the conveying pipe (1-3) is connected to the top end of the reaction zone (A), and the outlet of the conveying pipe (1-3) is connected to the inlet of the first gas-solid separation device (1-5); the first gas-solid separation device (1-5) is located in the gas-solid separation zone (C), the catalyst outlet of the first gas-solid separation device (1-5) is located in the lower part of the gas-solid separation zone (C), and the gas outlet of the first gas-solid separation device (1-5) is located in the upper part of the gas-solid separation zone (C); the fluidizing steam distributor (1-6) is located at the bottom of the catalyst residence zone (B); the catalyst distribution pipe (1-7) passes through the reactor inner shell (1-2) to connect the catalyst residence zone (B) and the reaction zone (A), and the lower surface of the catalyst distribution pipe (1-7) is provided with openings; the second gas-solid separation device (1-8) is located in the gas-solid separation zone (C), the inlet of the second gas-solid separation device (1-8) is located in the gas-solid separation zone (C), the gas outlet of the second gas-solid separation device (1-8) is connected to the reactor gas collecting chamber (1-9), and the catalyst outlet of the second gas-solid separation device (1-8) is located in the lower part of the gas-solid separation zone (C); the reactor gas collecting chamber (1-9) is located at the top of the high-density fast fluidized bed reactor, and the product gas conveying pipe (1-10) is connected to the top of the reactor gas collecting chamber (1-9); the catalyst extraction pipe (1-11) passes through the reactor outer shell (1-1) and is located in the lower part of the catalyst residence zone (B); the reactor stripper (1-12) is connected to the catalyst extraction pipe (1-11), the inlet of the spent catalyst slide valve (1-13) is connected to the bottom of the reactor stripper (1-12), the outlet of the spent catalyst slide valve (1-13) is connected to the inlet of the spent catalyst conveying pipe (1-14), and the outlet of the spent catalyst conveying pipe (1-14) is connected to the fluidized bed regenerator (2).

[0115] b. The fluidized bed regenerator (2) includes: a regenerator shell (2-1), a regenerator distributor (2-2), a third gas-solid separation device (2-3), a regenerator gas collecting chamber (2-4), a flue gas conveying pipe (2-5), a regenerator stripper (2-6), a regenerating slide valve (2-7), and a regenerant conveying pipe (2-8); the regenerator distributor (2-2) is located at the bottom of the fluidized bed regenerator (2); the third gas-solid separation device (2-3) is located at the upper part of the fluidized bed regenerator (2), the inlet of the third gas-solid separation device (2-3) is located at the upper part of the fluidized bed regenerator (2), the gas outlet of the third gas-solid separation device (2-3) is connected to the regenerator gas collecting chamber (2-4), the catalyst outlet of the third gas-solid separation device (2-3) is located at the lower part of the fluidized bed regenerator (2), the regenerator gas collecting chamber (2-4) is located at the top of the fluidized bed regenerator (2), and the flue gas conveying pipe (2-5) is connected to the top of the regenerator gas collecting chamber (2-4); the regenerator stripper (2-6) is located outside the regenerator shell (2-1), the inlet pipe of the regenerator stripper (2-6) penetrates the regenerator shell (2-1) and opens above the regenerator distributor (2-2), the inlet of the regenerating slide valve (2-7) is connected to the bottom of the regenerator stripper (2-6), the outlet of the regenerating slide valve (2-7) is connected to the inlet of the regenerant conveying pipe (2-8), and the outlet of the regenerant conveying pipe (2-8) is connected to the lower part of the gas-solid separation zone (C) of the high-density fast fluidized bed reactor (1).

[0116] In a preferred embodiment, the first gas-solid separation device (1-5) adopts an inertial separator to achieve rapid separation of the product gas and the catalyst.

[0117] In a preferred embodiment, the second gas-solid separation device (1-8) adopts one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

[0118] In a preferred embodiment, the third gas-solid separation device (2-3) adopts one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

[0119] In a specific embodiment, a method for coupling methanol and mixed hydrocarbons to produce light olefins according to the present application includes the following steps:

[0120] a. The catalyst from the regenerant delivery pipe (2-8) enters the gas-solid separation zone (C) of the high-density fast fluidized bed reactor (1), and then enters the catalyst retention zone (B); the gasified feedstock enters the reaction zone (A) from the feedstock distributor (1-4), contacts the catalyst, generates product gas containing light olefins, and the product gas carries the catalyst through the delivery pipe (1-3) into the first gas-solid separation device (1-5). After gas-solid separation, the catalyst enters the catalyst retention zone (B); steam enters the catalyst retention zone (B) from the fluidizing steam distributor (1-6), and the steam carries a small amount of catalyst from the catalyst retention zone (B) into the gas-solid separation zone (C); the product gas and steam carrying the catalyst in the gas-solid separation zone (C) enter the second gas-solid separation device (1-8). After gas-solid separation, the gas enters the reactor gas collection chamber (1-9), and the catalyst returns to the catalyst retention zone (B); the product gas and steam enter the downstream section via the product gas delivery pipe (1-10); the catalyst in the catalyst retention zone (B) enters the reaction zone (A) through the catalyst distribution pipe (1-7); the catalyst in the catalyst retention zone (B) enters the bottom of the reaction zone (A) from the bottom of the catalyst retention zone (B); the catalyst in the catalyst retention zone (B) enters the reactor stripper (1-12) through the catalyst extraction pipe (1-11). After stripping, the catalyst then enters the middle of the fluidized bed regenerator (2) via the spent catalyst slide valve (1-13) and the spent catalyst delivery pipe (1-14).

[0121] b. The regeneration gas enters the bottom of the fluidized bed regenerator (2) from the regenerator distributor (2-2). In the fluidized bed regenerator (2), the regeneration gas contacts the catalyst, and the coke deposited on the catalyst is burned off. The flue gas formed by combustion carries the catalyst into the third gas-solid separation device (2-3). After gas-solid separation, the flue gas enters the regenerator gas collection chamber (2-4), and then enters the downstream flue gas treatment system via the flue gas delivery pipe (2-5). The catalyst returns to the bottom of the fluidized bed regenerator (2). The catalyst in the fluidized bed regenerator (2) enters the regenerator stripper (2-6). After stripping, it then enters the high-density fast fluidized bed reactor (1) via the regenerated catalyst slide valve (2-7) and the regenerant delivery pipe (2-8).

[0122] Example 1

[0123] This Example 1 uses Figure 1 the device shown

[0124] In this Example 1, the feedstock is methanol and C4-C6 hydrocarbons. The methanol feed rate / C4-C6 hydrocarbon feed rate is about 1. The olefin content in C4-C6 hydrocarbons is 91% wt, and the paraffin content is 9% wt. The catalyst is a ZSM-5 molecular sieve catalyst.

[0125] The process operating conditions of the reaction zone (A) of the high-density fast fluidized bed reactor (1) are as follows: the superficial gas linear velocity is 1.5 m / s, the temperature is 500 °C, the pressure is 250 kPa, and the bed density is 500 kg / m 3 , and the reaction contact time is 2 s.

[0126] The process operating conditions of the catalyst residence zone (B) are as follows: the superficial gas linear velocity is 0.10 m / s, the temperature is 500 °C, and the bed density is 670 kg / m 3 . The catalyst circulation intensity flowing from the catalyst residence zone (B) to the reaction zone (A) is 500 kg / (m 2 ·s).

[0127] The regeneration gas is air. The process operating conditions of the fluidized bed regenerator (2) are as follows: the superficial gas linear velocity is 0.5 m / s, the regeneration temperature is 600 °C, the regeneration pressure is 250 kPa, and the bed density is 800 kg / m 3 .

[0128] The single-pass conversion rate of methanol is 99% wt, the single-pass conversion rate of mixed hydrocarbons is 79% wt, the carbon-based selectivity of "ethylene + propylene" is 87% wt, and the propylene / ethylene (mass ratio) is 3.1.

[0129] Example 2

[0130] This Example 2 uses the Figure 1 device shown.

[0131] In this Example 2, the raw materials are methanol and C4-C6 hydrocarbons. The methanol feed rate / C4-C6 hydrocarbon feed rate is approximately 1. The olefin content in C4-C6 hydrocarbons is 46% wt, and the alkane content is 54% wt. The catalyst is a ZSM-5 molecular sieve catalyst.

[0132] The process operating conditions of the reaction zone (A) of the high-density fast fluidized bed reactor (1) are as follows: the superficial gas linear velocity is 2.6 m / s, the temperature is 600 °C, the pressure is 170 kPa, and the bed density is 310 kg / m 3 , and the reaction contact time is 1.2 s.

[0133] The process operating conditions of the catalyst residence zone (B) are as follows: the superficial gas linear velocity is 0.2 m / s, the temperature is 600 °C, and the bed density is 600 kg / m 3 . The catalyst circulation intensity flowing from the catalyst residence zone (B) to the reaction zone (A) is 720 kg / (m 2 ·s).

[0134] The regeneration gas is air. The process operating conditions of the fluidized bed regenerator (2) are as follows: the apparent gas linear velocity is 2.0 m / s, the regeneration temperature is 650 °C, the regeneration pressure is 170 kPa, and the bed density is 200 kg / m 3 .

[0135] The single-pass conversion rate of methanol is 99.8% wt, the single-pass conversion rate of the mixed hydrocarbons is 50% wt, the carbon-based selectivity of "ethylene + propylene" is 78% wt, and the propylene / ethylene (mass ratio) is 4.4.

[0136] Example 3

[0137] This Example 3 uses Figure 1 the device shown.

[0138] In this Example 3, the raw materials are methanol and C5-C 12 hydrocarbons, the methanol feed rate / C5-C 12 hydrocarbon feed rate is about 1, and the olefin content in the C5-C 12 hydrocarbons is 64% wt and the paraffin content is 36% wt. The catalyst is a ZSM-5 molecular sieve catalyst.

[0139] The process operating conditions of the reaction zone (A) of the high-density fast fluidized bed reactor (1) are as follows: the apparent gas linear velocity is 4.1 m / s, the temperature is 650 °C, the pressure is 110 kPa, and the bed density is 190 kg / m 3 , and the reaction contact time is 0.8 s.

[0140] The process operating conditions of the catalyst residence zone (B) are as follows: the apparent gas linear velocity is 0.08 m / s, the temperature is 650 °C, and the bed density is 720 kg / m 3 . The catalyst circulation intensity flowing from the catalyst residence zone (B) to the reaction zone (A) is 810 kg / (m 2 ·s).

[0141] The regeneration gas is air. The process operating conditions of the fluidized bed regenerator (2) are as follows: the apparent gas linear velocity is 1.6 m / s, the regeneration temperature is 690 °C, the regeneration pressure is 110 kPa, and the bed density is 340 kg / m 3 .

[0142] The single-pass conversion rate of methanol is 99.9% wt, the single-pass conversion rate of the mixed hydrocarbons is 77% wt, the carbon-based selectivity of "ethylene + propylene" is 81% wt, and the propylene / ethylene (mass ratio) is 7.8.

[0143] Example 4

[0144] This Example 4 uses Figure 1 the device shown.

[0145] In Example 4 of the present invention, the raw materials are methanol and C5-C 12 hydrocarbons. The ratio of the methanol feed rate to the C5-C 12 hydrocarbon feed rate is approximately 1. The olefin content in the C5-C 12 hydrocarbons is 8% wt, and the paraffin content is 92% wt. The catalyst is a ZSM-5 molecular sieve catalyst.

[0146] The process operating conditions in the reaction zone (A) of the high-density fast fluidized bed reactor (1) are as follows: the superficial gas linear velocity is 7.0 m / s, the temperature is 680 °C, the pressure is 50 kPa, and the bed density is 150 kg / m 3 . The reaction contact time is 0.5 s.

[0147] The process operating conditions in the catalyst residence zone (B) are as follows: the superficial gas linear velocity is 0.02 m / s, the temperature is 680 °C, and the bed density is 800 kg / m 3 . The catalyst circulation intensity flowing from the catalyst residence zone (B) to the reaction zone (A) is 1000 kg / (m 2 ·s).

[0148] The regeneration gas is air. The process operating conditions of the fluidized bed regenerator (2) are as follows: the superficial gas linear velocity is 0.9 m / s, the regeneration temperature is 750 °C, the regeneration pressure is 50 kPa, and the bed density is 520 kg / m 3 .

[0149] The single-pass conversion rate of methanol is 99.9% wt, the single-pass conversion rate of the mixed hydrocarbons is 65% wt, the carbon-based selectivity of "ethylene + propylene" is 75% wt, and the propylene / ethylene (mass ratio) is 9.3.

[0150] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent embodiments and all fall within the scope of the technical solution.

Claims

1. A method for coupling methanol and mixed hydrocarbons to produce light olefins, characterized in that, The method includes the following steps: The gasified feedstock including methanol and mixed hydrocarbons is introduced into the reaction zone, contacts with the catalyst, and reacts to generate a product gas containing light olefins and a catalyst stream I; The stream I is subjected to gas-solid separation to obtain the product gas and the catalyst; The product gas is transported to the downstream section; Part of the catalyst enters the reaction zone, and the other part of the catalyst is regenerated, and the regenerated catalyst enters the reaction zone.

2. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 1, characterized in that, The mixed hydrocarbons in the feedstock are C4+ hydrocarbons, including alkanes and olefins with carbon atom number ≥4; Preferably, the catalyst is selected from ZSM-5 molecular sieve catalysts; Preferably, the process operating conditions of the reaction zone include: The superficial gas linear velocity is 1.5 to 7.0 m / s, the temperature is 500 to 680 °C, the pressure is 50 to 250 kPa, and the bed density is 150 to 500 kg / m 3 , and the reaction contact time is 0.5 to 2 s.

3. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 1, characterized in that, The method is carried out in a methanol and mixed hydrocarbons to light olefins unit, and the unit includes a high-density fast fluidized bed reactor and a fluidized bed regenerator.

4. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 3, characterized in that, The high-density fast fluidized bed reactor includes a reactor outer shell, a reactor inner shell and a transfer pipe; at least a feedstock inlet, a catalyst inlet, a gas-phase product outlet and a catalyst outlet are provided on the reactor outer shell; The reactor outer shell encloses an internal area; The reactor inner shell is located at the lower part of the internal area, and the area enclosed by the reactor inner shell is the reaction zone; The transfer pipe is located in the upper-middle part of the internal area, and the bottom of the transfer pipe communicates with the reaction zone; The area enclosed by the reactor outer shell and the transfer pipe is the gas-solid separation zone; An outlet is provided on the transfer pipe, and the transfer pipe communicates with the gas-solid separation zone; The annular area enclosed by the reactor outer shell and the reactor inner shell is the catalyst residence zone; The bottom of the reaction zone communicates with the bottom of the catalyst residence zone; The catalyst residence zone communicates with the gas-solid separation zone and is located below the gas-solid separation zone.

5. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, The process operating conditions of the catalyst residence zone include: The superficial gas linear velocity is 0.02 to 0.2 m / s, the temperature is 500 to 680 °C, and the bed density is 600 to 800 kg / m 3 ; Preferably, the catalyst circulation intensity of the catalyst flowing from the catalyst residence zone to the reaction zone is 500 - 1000 kg / m 2 ·s.

6. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, The high-density fast fluidized bed reactor includes a catalyst distribution pipe, a fluidizing steam distributor, and a feedstock distributor; The catalyst distribution pipe passes through the reactor inner shell to connect the catalyst residence zone and the reaction zone; The fluidizing steam distributor is arranged at the bottom of the catalyst residence zone; The feedstock distributor is arranged at the bottom of the reaction zone; Preferably, through holes are formed on the lower surface of the catalyst distribution pipe.

7. The method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, The high-density fast fluidized bed reactor includes a first gas-solid separation device and a second gas-solid separation device; The first gas-solid separation device and the second gas-solid separation device are located in the gas-solid separation zone; The inlet of the first gas-solid separation device communicates with the outlet of the transfer pipe; The catalyst outlet of the first gas-solid separation device is located at the lower part of the gas-solid separation zone, and the gas outlet of the first gas-solid separation device is located at the upper part of the gas-solid separation zone; Preferably, the inlet of the second gas-solid separation device is located at the upper part of the gas-solid separation zone; The catalyst outlet of the second gas-solid separation device is located at the lower part of the gas-solid separation zone; Preferably, the first gas-solid separation device is an inertial separator; Preferably, the second gas-solid separation device is one or more groups of gas-solid cyclone separators, and each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator; Preferably, the high-density fast fluidized bed reactor includes a reactor gas collecting chamber and a product gas delivery pipe; The reactor gas collecting chamber is located at the top of the high-density fast fluidized bed reactor; The product gas delivery pipe is connected to the top of the reactor gas collecting chamber; The gas outlet of the second gas-solid separation device communicates with the reactor gas collecting chamber.

8. A method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, The device includes a catalyst extraction pipe that passes through the reactor outer shell and is located at the lower part of the catalyst residence zone. The catalyst extraction pipe communicates with the reactor stripper; The inlet of the spent catalyst slide valve is connected to the bottom of the reactor stripper, the outlet of the spent catalyst slide valve is connected to the inlet of the spent catalyst delivery pipe, and the outlet of the spent catalyst delivery pipe communicates with the fluidized bed regenerator; The regenerator stripper is located at the bottom of the fluidized bed regenerator; the inlet of the regenerated catalyst slide valve is connected to the bottom of the regenerator stripper, the outlet of the regenerated catalyst slide valve is connected to the inlet of the regenerated catalyst delivery pipe, and the outlet of the regenerated catalyst delivery pipe is connected to the lower part of the gas-solid separation zone of the high-density fast fluidized bed reactor; Preferably, the fluidized bed regenerator includes a regenerator shell, a regenerator distributor, a third gas-solid separation device, a regenerator gas collecting chamber, and a flue gas delivery pipe; The regenerator distributor is located at the bottom of the fluidized bed regenerator; The third gas-solid separation device is located in the upper part of the fluidized bed regenerator. The inlet of the third gas-solid separation device is located in the upper part of the fluidized bed regenerator. The gas outlet of the third gas-solid separation device communicates with the regenerator gas collecting chamber. The catalyst outlet of the third gas-solid separation device is located in the lower part of the fluidized bed regenerator. The regenerator gas collecting chamber is located at the top of the fluidized bed regenerator. The flue gas delivery pipe is connected to the top of the regenerator gas collecting chamber; Preferably, the inlet pipe of the regenerator stripper penetrates the regenerator shell and opens above the regenerator distributor; Preferably, the third gas-solid separation device employs one or more groups of gas-solid cyclone separators. Each group of gas-solid cyclone separators includes a first-stage gas-solid cyclone separator and a second-stage gas-solid cyclone separator.

9. A method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, The process operating conditions of the regenerator are as follows: the apparent gas linear velocity is 0.5 to 2.0 m / s, the regeneration temperature is 600 to 750 °C, the regeneration pressure is 50 to 250 kPa, and the bed density is 200 to 800 kg / m 3 ; Preferably, the regeneration gas of the fluidized bed regenerator is air; Preferably, the stream I enters the first gas-solid separation device through a delivery pipe, and the catalyst after the first gas-solid separation enters the catalyst residence zone.

10. A method for coupling methanol and mixed hydrocarbons to produce light olefins according to claim 4, characterized in that, Steam enters the catalyst residence zone from the fluidizing steam distributor. The steam carries a part of the catalyst in the catalyst residence zone into the gas-solid separation zone; the product gas and a part of the catalyst carried by the steam in the gas-solid separation zone enter the second gas-solid separation device. The gas after the second gas-solid separation enters the reactor gas collecting chamber, and the separated catalyst returns to the catalyst residence zone; Preferably, the product gas and steam after the second gas-solid separation enter the downstream section through the product gas delivery pipe; The first part of the catalyst in the catalyst residence zone enters the reaction zone through the catalyst distribution pipe; The second part of the catalyst in the catalyst residence zone enters the bottom of the reaction zone through the bottom of the catalyst residence zone; The third part of the catalyst in the catalyst residence zone enters the reactor stripper through the catalyst extraction pipe.

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