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CN-121972098-A - Technological method and reaction system for dehydrogenation conversion of moving bed propane

CN121972098ACN 121972098 ACN121972098 ACN 121972098ACN-121972098-A

Abstract

A process method and a reaction system for dehydrogenation conversion of moving bed propane belong to the field of petrochemical industry, and comprise the steps of carrying out contact reaction on propane feed gas with a gamma-alumina/theta-alumina composite carrier pellet catalyst with the diameters of 1.5-2 mm and loaded with platinum, tin, potassium, chlorine and phosphorus under the reaction conditions that the temperature is 500-700 ℃ and the pressure is 0.01-3 MPa and the volume airspeed is 0.3-5 hours ‑1 , enabling the propane feed gas to sequentially pass through a reaction zone (2-6 zones) of a downstream moving bed zone reactor in countercurrent mode in the presence of hydrogen, enabling the propane feed gas to pass through a downstream moving bed reactor in parallel, enabling the propane feed gas to pass through a downstream moving bed reactor in series, enabling the propane feed gas to enter a regenerator, enabling a carbon-deactivated catalyst to enter a nitrogen gas containing oxygen and chlorine, and burning, oxychlorination and reduction regeneration at 500-700 ℃. The continuous reaction-regeneration process and the reaction system can improve the dehydrogenation conversion efficiency, simplify the device equipment, reduce coking, energy consumption, investment and occupied area, and improve the operability and running stability of the process.

Inventors

  • ZHUO RUNSHENG
  • LIU MIN
  • WANG GANG
  • SUN QIUSHI
  • YANG GUO

Assignees

  • 上海润和盛建设备科技有限公司

Dates

Publication Date
20260505
Application Date
20240125

Claims (9)

  1. 1. A process for the dehydrogenation conversion of moving bed propane, comprising: (1) After the propane raw material gas is heated to 300-600 ℃ by a preheating furnace, the propane raw material gas enters the reactor from the lower part of a reactor of a downstream moving bed zone (2-6 reaction zones) under the hydrogen/hydrocarbon (0.1-6) volume ratio and is in countercurrent contact with a catalyst entering from an upper port of the reactor and after the reaction of the downstream moving bed reactor in series; (2) The reacted materials coming out of the upper end of the zone reactor are heated at 300-500 ℃ and then enter from the upper end of the serially connected downstream moving bed reactor and are contacted with regenerated catalyst coming in from the upper port and (forward) flow from the regenerator; (3) The dehydrogenation conversion reaction in the two reactors is carried out by contacting the catalyst with a gamma-alumina/theta-alumina composite carrier pellet catalyst with the diameter of 1.5-2 mm and loaded with platinum, tin, potassium, chlorine and phosphorus at the temperature of 500-680 ℃, the pressure of 0.01-1 MPa and the volume space velocity of 0.1-2 hours -1 , and the product gas after the reaction conversion enters a subsequent device for separation to obtain propylene; (4) And the carbon deposition from the lower port of the zone reactor deactivates the catalyst to be regenerated, enters from the upper port of the moving bed regenerator, is filled with nitrogen containing oxygen and chlorine, is subjected to scorching and oxychlorination at 500-700 ℃, is reduced by contact with hydrogen at 500-600 ℃, and descends out of the lower port of the regenerator to enter the reaction-regeneration process of the next cycle.
  2. 2. The process method for the dehydrogenation conversion of the moving bed propane according to claim 1, wherein the catalyst is a high-pore volume and large-pore gamma-alumina and theta-alumina composite carrier pellet with a pore diameter of 3-25 nanometers, the mass ratio of gamma-alumina to theta-alumina is 1 (0.1-10), 0.3-0.6 wt% of platinum, 0.3-0.5 wt% of tin, 0.1-1.3 wt% of potassium, 0.3-1.5 wt% of chlorine and 0.1-0.5 wt% of phosphorus are loaded on the total absolute catalyst, the specific surface area of the catalyst is 95-120 square meters/gram, the pore volume is 0.5-0.9 milliliter/gram, the stacking ratio is 0.5-0.7 milliliter/gram, the diameter is 1.6-1.8 millimeters, and the crushing strength is 45-65 newtons/gram.
  3. 3. The process method for dehydrogenation and conversion of moving bed propane according to claim 1, wherein the catalyst regeneration and the oxychlorination process are carried out at 510-650 ℃, nitrogen with 0.1-8% of oxygen and 0.1-1.0% of chlorine is introduced, carbon content of 1.2-3% of spent catalyst before regeneration is reduced, and the coke is reduced to carbon content of 0.01-0.2% of regenerated catalyst after regeneration.
  4. 4. A process for the dehydrogenation conversion of moving bed propane according to claim 3, wherein the oxygen-containing element is derived from oxygen in air added to nitrogen and the chlorine-containing element is derived from tetrachloroethylene and/or dichloroethane compounds added to nitrogen.
  5. 5. The process for the dehydrogenation conversion of moving bed propane according to claim 1, wherein the regenerated catalyst is contacted with hydrogen containing 0.02-0.8% of water for 1-6 hours at a temperature of 510-570 ℃.
  6. 6. The reaction system for implementing the process method for dehydrogenation conversion of moving bed propane according to any one of claims 1 to 5 is characterized by comprising a reaction material propane (1), a platinum-tin composite alumina pellet dehydrogenation catalyst, a downstream moving bed zone reactor (4) in countercurrent contact with the catalyst, a downstream moving bed serial reactor (8) in parallel flow contact with the catalyst, a moving bed regenerator (30), a feed preheating heating furnace (9) of the zone reactor, a feed heating furnace (10) of the serial reactor, a high-temperature heat medium heating furnace (11) of the zone reactor, high-temperature heat medium heat exchange coils and grate plate internals (29) of the zone reactor zone (5 to 7) and heat supplementing, a heat exchanger (3) of a propane reaction raw material (1) and a conversion product gas material (2), a catalyst lifting hopper (12 to 14), a transfer hopper (15 to 17), a lock hopper (18 to 19), a catalyst nitrogen seal pot (20), a material conveying pipeline (27), a catalyst conveying pipeline (28), a fan, a pump, a gas-solid separator, a hydrogen separator, a dust separator and a dust separator.
  7. 7. The reaction system of the process method for the dehydrogenation conversion of the moving bed propane according to claim 6 is characterized in that the upper parts of the countercurrent downflow moving bed zoned reactor (4), the parallel downflow moving bed serial reactor (8) and the moving bed regenerator (30) respectively comprise catalyst buffer hoppers (21-22), separation hoppers (23) and sealing diplegs, and the lower parts respectively comprise blanking legs, catalyst collecting hoppers (24-26) and a catalyst flow controller.
  8. 8. The reaction system of the process method for the dehydrogenation conversion of the moving bed propane according to claim 6 is characterized in that a high-temperature heat medium in a heat exchange coil (29) of an inner component of the zone reactor (4) is selected from molten nitrate, chloride salt and caustic alkali, and the working temperature range is 550-900 ℃.
  9. 9. A process and a reaction system for carrying out the dehydrogenation conversion of moving bed propane according to the claims 1 and 6 are characterized in that the reactant flow (1) is heated by a preheating furnace (9) after heat exchange with a reaction product (2) through a heat exchanger (3), enters the reactor from the lower part of a zone moving bed reactor (4) and sequentially goes up to a reaction zone (5-7) in the reactor, the heating furnace (11) is a high-temperature heat medium heating in a coil (29) separating the reaction zone, the heat required by the dehydrogenation reaction in the reaction zone (5-7) is supplemented through heat exchange, the product of the reaction conversion is separated from the upper end of the zone reactor (4) through a hydrogen separator and then is reheated through a heating furnace (10), the reaction product is separated from the lower part of the reactor through the hydrogen separator and then enters a heat exchanger (3) after heat exchange with a fresh reactant flow (1), and then enters a later separation device for separation.

Description

Technological method and reaction system for dehydrogenation conversion of moving bed propane Technical Field The invention relates to a process method and a reaction system for dehydrogenation conversion of moving bed propane, in particular to a process method and a reaction system for dehydrogenation conversion of propane by adopting a downstream moving bed partition reactor and a serial downstream moving bed reactor, belonging to the technical field of petrochemical industry. Background Propylene is an important basic raw material next to ethylene in the petrochemical field, can be used for synthesizing polypropylene, polyacrylonitrile, acrolein, acrylic acid, epoxypropane, isopropanol, isopropylbenzene, propylene oligomers and the like, and is widely applied to various industries such as materials, medicines, textiles and the like. The current common technical routes for preparing propylene include various technological methods such as catalytic cracking, steam cracking, olefin disproportionation, olefin preparation from methanol, propane dehydrogenation and the like. The propylene prepared by the dehydrogenation of propane has the advantages of high product yield, good selectivity and the like, so that the propylene is increasingly valued, and the number of industrialized devices is steadily increasing. The industrial method for dehydrogenating propane mainly comprises an Oleflex process of UOP (Universal Oil Products), a Catofin process of ABB Lummus, a STAR process of Uhde, a PDH process of Linde/BASF and an FBD process of Snamprogetti/Yarsintez. As described in USP3978150, USP4926005, CA113133048, DE3841800, GB2177317a, etc. The catalyst has platinum series and chromium series, and is disclosed in USP4827066, GB1168342A, USP02956030 and CN113244907A. The Oleflex process is a continuous regeneration reaction process device of a moving bed, realizes industrial production in 1990, and is applied to most of propylene preparation projects of propane dehydrogenation at home and abroad. The process has the advantages of continuous operation, uniform load and high airspeed, and the propylene yield reaches 85 percent, and the USP3584060, the USP3878131, the USP4438238, the USP4595673, the USP4716143, the USP4786265 and the USP4827072. The Oleflex process employs a platinum catalyst that is recycled via isothermal regeneration as described in USP4778942, USP6756340, and the like. CN112074499a discloses a dehydrogenation process and reaction system, the moving bed reactor comprises a heat exchanger containing a heating medium, the catalyst material and the heating medium are not contacted, more than half of the enthalpy change of at least one reaction zone is provided by the heat exchanger, and the hydrocarbon feed is contacted with the catalyst in at least one reaction zone of the moving bed reactor for reaction to convert into products containing olefins, alkynes, cyclic hydrocarbons and/or aromatic hydrocarbons. CN110452085A discloses a process for dehydrogenating C 3/C4 alkane in a moving bed, wherein the flowing direction of the catalyst between each reactor is opposite to the flowing direction of the reactant flow, the process comprises that mixed hydrogen and C 3/C4 alkane feed flow through a heat-combined heat exchanger and a heating furnace, enter a first-stage reactor and sequentially flow through a second-stage reactor and a last-stage reactor in series to form reactant flow, the catalyst is regenerated through a regenerator and enters the last-stage reactor, sequentially flow through the second-stage reactor and the first-stage reactor in series to form catalyst flow, and a hydrogen permeable membrane separator is arranged at the outlet of each-stage reactor. Compared with the existing industrialized process, the method can improve the single pass conversion rate and selectivity, reduce the reaction temperature, save energy, reduce carbon deposition, prolong the service life and reduce investment. CN116020356a also discloses a method and system for dehydrogenation of light alkane by countercurrent moving bed, comprising introducing light alkane from inlet of dehydrogenation reaction zone to make countercurrent contact with dehydrogenation catalyst, said dehydrogenation reaction zone contains at least two reactors connected in series in turn so that gas phase stream can pass through each of said reactors in turn, obtaining spent catalyst from the most upstream reactor, regenerating and reducing said spent catalyst in turn to obtain regenerated catalyst, circulating said regenerated catalyst back to the most downstream reactor, and introducing sulfur-containing coking inhibitor into each reactor to ensure smooth operation of the device. The method disclosed in CN116693360A comprises the steps of contacting low-carbon alkane with a catalyst in a reaction device for dehydrogenation under the conditions of hydrogen and no water, and entering a regeneration unit for regeneration when the carbon content o