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CN-122006603-A - Aromatic hydrocarbon preparation system and method

CN122006603ACN 122006603 ACN122006603 ACN 122006603ACN-122006603-A

Abstract

The invention provides an aromatic hydrocarbon preparation system and method. The aromatic hydrocarbon preparation system comprises a methane aromatization unit, a first aromatic hydrocarbon separation unit, a CO 2 hydrogenation aromatization unit, a second aromatic hydrocarbon separation unit and a CO 2 production and heating unit, wherein a product gas outlet of the methane aromatization unit is connected with a feed inlet of the first aromatic hydrocarbon separation unit, a tail gas outlet of the first aromatic hydrocarbon separation unit is connected with a hydrogen inlet of the CO 2 hydrogenation aromatization unit, a product gas outlet of the CO 2 hydrogenation aromatization unit is connected with a feed inlet of the second aromatic hydrocarbon separation unit, a tail gas outlet of the second aromatic hydrocarbon separation unit is connected with a feed inlet of the CO 2 production and heating unit, and a product gas outlet of the CO 2 production and heating unit is connected with a CO 2 inlet of the CO 2 hydrogenation aromatization unit. According to the aromatic hydrocarbon preparation system provided by the invention, the combination of methane aromatization to prepare aromatic hydrocarbon and CO 2 hydrogenation aromatization to prepare aromatic hydrocarbon is effectively realized, so that the energy utilization efficiency is improved, and the yield and selectivity of aromatic hydrocarbon are obviously improved.

Inventors

  • ZHANG CHENXI
  • WANG ZONGBAO
  • XIAO HAICHENG
  • WEI FEI
  • LI QINGXUN
  • WANG JINGYUAN
  • LU YUYING
  • Lv kai
  • HAN XIAOLIN

Assignees

  • 中国石油天然气股份有限公司
  • 清华大学

Dates

Publication Date
20260512
Application Date
20241112

Claims (15)

  1. 1. An aromatic hydrocarbon production system, wherein the system comprises: A methane aromatization unit, a first aromatic separation unit, a CO 2 hydroaromatization unit, a second aromatic separation unit, and a CO 2 production and heating unit; The product gas outlet of the methane aromatization unit is connected with the feed inlet of the first aromatic hydrocarbon separation unit, the tail gas outlet of the first aromatic hydrocarbon separation unit is connected with the hydrogen inlet of the CO 2 hydro-aromatization unit, the product gas outlet of the CO 2 hydro-aromatization unit is connected with the feed inlet of the second aromatic hydrocarbon separation unit, the tail gas outlet of the second aromatic hydrocarbon separation unit is connected with the feed inlet of the CO 2 production and heating unit, and the product gas outlet of the CO 2 production and heating unit is connected with the CO 2 inlet of the CO 2 hydro-aromatization unit.
  2. 2. The system of claim 1, wherein the CO 2 production and heating unit is further configured to provide thermal energy to the methane aromatization unit and/or the CO 2 hydroaromatization unit.
  3. 3. The system of claim 1, wherein the methane aromatization unit comprises an induction pre-reactor, a fluidized bed aromatization reactor, a catalyst regenerator, and a fresh catalyst storage tank; The catalyst outlet of the fluidized bed aromatization reactor is connected with the catalyst inlet of the catalyst regenerator, the catalyst outlet of the catalyst regenerator is connected with the catalyst inlet of the induction pre-reactor, the catalyst outlet of the induction pre-reactor is connected with the catalyst inlet of the fluidized bed aromatization reactor, the circulating gas outlet of the fluidized bed aromatization reactor is connected with the induction gas inlet of the induction pre-reactor, the catalyst outlet of the fresh catalyst storage tank is connected with the catalyst inlet of the induction pre-reactor, the raw material inlet of the fluidized bed aromatization reactor is connected with the supply source of methane raw material gas, the regeneration gas inlet of the catalyst regenerator is connected with the supply source of regeneration gas, and the product gas outlet of the fluidized bed aromatization reactor is used for discharging the product gas obtained by methane aromatization of the methane aromatization unit.
  4. 4. The system of claim 1, wherein the recycle gas outlet of the fluidized bed aromatization reactor is further connected to the feed inlet of the fluidized bed aromatization reactor.
  5. 5. A process for the preparation of aromatic hydrocarbons using the aromatic hydrocarbon preparation of any one of claims 1-4, the process comprising: in a methane aromatization unit, carrying out methane feed gas aromatization reaction under the action of a catalyst to obtain a product gas; The product gas obtained from the methane aromatization unit enters a first aromatic hydrocarbon separation unit to carry out aromatic hydrocarbon separation to obtain aromatic hydrocarbon and tail gas; The tail gas obtained by the first aromatic hydrocarbon separation unit enters a CO 2 hydrogenation aromatization unit, in the CO 2 hydrogenation aromatization unit, CO 2 raw material gas produced by CO 2 and provided by the heating unit and hydrogen in the tail gas obtained by the first aromatic hydrocarbon separation unit are subjected to hydrogenation aromatization reaction under the action of a catalyst to obtain product gas; the product gas obtained from the CO 2 hydrogenation aromatization unit enters a second aromatic separation unit to carry out aromatic separation to obtain aromatic hydrocarbon and tail gas; the tail gas obtained by the second aromatic hydrocarbon separation unit enters a CO 2 production and heating unit for combustion to obtain product gas; The product gas obtained by burning the CO 2 production and heating unit enters the CO 2 hydrogenation aromatization unit to provide CO 2 feed gas for the reaction in the CO 2 hydrogenation aromatization unit.
  6. 6. The method according to claim 5, wherein the catalyst used in the aromatization reaction of methane feed gas is a molybdenum-based catalyst; Preferably, the mass content of the carrier in the molybdenum-based catalyst is 5% -30%; Preferably, the particle size of the molybdenum-based catalyst is no more than 150 μm, more preferably 30-90 μm; Preferably, the molybdenum-based catalyst has a specific surface area greater than 80m 2 /g.
  7. 7. The process according to claim 6, wherein the aromatization reaction is carried out at a temperature of 600-1000 ℃, preferably 750-950 ℃, during the aromatization reaction of the methane feed gas over the catalyst.
  8. 8. The process of claim 5, wherein the aromatic hydrocarbon production process comprises: In the methane aromatization unit, respectively and continuously performing catalyst pre-reaction, methane feed gas aromatization reaction and catalyst regeneration reaction, The catalyst pre-reaction comprises the steps of pre-reacting a regenerated catalyst from a catalyst regenerator and a fresh catalyst from a fresh catalyst storage tank in an induction pre-reactor by utilizing product gas generated by a fluidized bed aromatic device to obtain an activated catalyst; The methane feed gas aromatization reaction comprises the steps of introducing an activated catalyst generated by a pre-reactor into a fluidized bed aromatizer to be mixed with a catalyst in the fluidized bed aromatizer, and performing aromatization reaction on the methane feed gas entering the fluidized bed aromatizer under the action of the catalyst in the fluidized bed aromatizer to obtain product gas, wherein part of the product gas enters the pre-reactor to be used as catalyst pre-reaction gas, and part of the product gas is used as product gas of a methane aromatization unit to be discharged out of the methane aromatization unit to enter a first aromatic hydrocarbon separation unit to be subjected to subsequent reaction; The catalyst regeneration reaction comprises that part of catalyst in the fluidized bed aromaticity device enters a catalyst regenerator, in the catalyst regenerator, the catalyst is subjected to regeneration reaction under the action of catalyst regeneration gas entering the catalyst regenerator to obtain regenerated catalyst, and the regenerated catalyst is conveyed into an induction pre-reactor; Preferably, in the aromatization reaction of the methane feed gas, part of the product gas is re-introduced into the fluidized bed aromatizer as recycle gas to perform the aromatization reaction; Preferably, during the catalyst pre-reaction, the induction pre-reactor is charged with a quantity of hydrogen in a mass ratio of hydrogen to product gas from the fluidized bed aromatizer of from 5 to 30:100.
  9. 9. The method of claim 8, wherein, The reaction temperature for inducing the pre-reaction of the catalyst in the pre-reactor is 600-900 ℃; The space velocity of the catalyst pre-reaction in the pre-reactor is 2500-7500 mL.g -1 ·h -1 ; In the induction prereactor, the residence time of the catalyst is 60-6000s.
  10. 10. The method of claim 8, wherein, In the process of methane raw material gas aromatization reaction, the apparent gas velocity of the gas in the fluidized bed aromatizer is 0.05-1.2m/s; the residence time of the gas is 0.5-90s in the process of methane feed gas aromatization reaction.
  11. 11. The process of claim 8 wherein the amount of catalyst discharged per hour in the fluidized bed aromatizer is no more than 20 percent of the total amount of catalyst in the fluidized bed aromatizer.
  12. 12. The method of claim 8, wherein, In the process of carrying out the catalyst regeneration reaction, the reaction temperature of the regeneration reaction is 500-700 ℃; in the process of carrying out the catalyst regeneration reaction, the apparent gas velocity of the catalyst regeneration gas in the catalyst regenerator is 6-20m/s; In the process of carrying out the catalyst regeneration reaction, the residence time of the catalyst in the catalyst regenerator is 3-120s.
  13. 13. The method according to claim 5, wherein in the CO 2 hydroaromatization unit, the catalyst used in the process of the hydroaromatization reaction is a zinc-chromium spinel catalyst; preferably, in the zinc chromium spinel catalyst, the mass content of the carrier is 10% -40%, more preferably 30%; preferably, the particle size of the zinc chromite catalyst is no greater than 120 μm, more preferably 40-120 μm; preferably, the specific surface area of the zinc chromium spinel catalyst is greater than 50m 2 /g.
  14. 14. The process of claim 13, wherein in the CO 2 hydroaromatization unit, the reaction temperature is 250-450 ℃ and the reaction pressure is 3-5MPa during the hydroaromatization reaction.
  15. 15. The method according to claim 5, wherein the tail gas obtained from the second aromatic separation unit enters the CO 2 production and heating unit for combustion, and the combustion temperature is 500-1000 ℃.

Description

Aromatic hydrocarbon preparation system and method Technical Field The invention belongs to the technical field of aromatization, and relates to an aromatic hydrocarbon preparation system and method for preparing aromatic hydrocarbon by methane aromatization and CO 2 hydroaromatization. Background Benzene and other aromatic hydrocarbon products are important basic chemical raw materials, are mainly derived from coal coking and petroleum reforming processes at present, and in view of limited capacity of producing benzene and other aromatic hydrocarbon products by coal coking and petroleum reforming, development of new technical routes for preparing benzene or other aromatic hydrocarbons is very necessary. Currently, one of the most promising new technological routes for the production of benzene or other aromatic hydrocarbons is the aromatization of natural gas (methane as the main component) in the presence of a catalyst to produce benzene or other aromatic hydrocarbons. The catalytic dehydrogenation aromatization of methane in an anaerobic environment can directly convert methane into liquid aromatic hydrocarbon products with high added value such as benzene and the like, and simultaneously hydrogen is a byproduct. At present, research work of methane aromatization mainly focuses on the aspects of catalyst preparation and development, reaction and deactivation mechanism and the like, and is also in a laboratory microreaction research stage, and research results in engineering are not reported yet. The key bottleneck in methane aromatization reactions is the limited ability of CH 4 conversion to produce aromatics and the rapid carbon deposition leading to catalyst deactivation. The method mainly comprises the steps of introducing other gas components in the reaction process to inhibit the generation of carbon deposition by an in-situ reaction carbon elimination principle, and carrying out burning regeneration on the catalyst after the carbon deposition reaction to research an optimized regeneration process. Conventional regenerators for carbon deposition catalysts are water vapor, carbon dioxide, hydrogen and oxygen. The method is not suitable for industrial application, but is not suitable for industrial application because of the fact that the source of carbon dioxide is not wide, and the regeneration of the carbon deposition catalyst by using the carbon dioxide is not too large. In addition, after the methane aromatization catalyst is subjected to reaction activation in an induction period, the methane conversion rate of 10-20% and the aromatic hydrocarbon selectivity of 50-90% can be realized in a single time, but the induction reaction process is reduced or even eliminated in the methane conversion process as far as possible from the stability of continuous reaction and regeneration of the catalyst. In addition, the hydrogenation of CO 2 to produce aromatic hydrocarbons has attracted considerable attention in recent years as an emerging technological route. According to the method, CO 2 and hydrogen are subjected to hydrogenation aromatization reaction under the condition of a proper catalyst, so that an aromatic hydrocarbon product is directly generated, the emission of carbon dioxide can be effectively reduced, and the efficient utilization of CO 2 as a carbon source can be realized. The technical path has good sustainability and environmental friendliness, and provides a new development opportunity and technical innovation space for the chemical industry. However, this method requires a large amount of hydrogen as a reducing agent and a hydrogen source for the reaction, thereby limiting its engineering applications. In summary, the main difficulties in the application of methane aromatization engineering are that firstly, the aromatic hydrocarbon production capacity is limited, secondly, the catalyst is easy to accumulate carbon and difficult to regenerate in the aromatization process, so that the aromatization cannot continuously and stably run for a long period. The CO 2 hydrogenation process for aromatics requires the use of large amounts of hydrogen as a reducing agent for the reaction, thereby limiting its engineering applications. At present, a new aromatic hydrocarbon preparation route is still needed to be researched so as to solve the difficulty in the engineering application of methane aromatization and the difficulty in the engineering application of the technology for preparing aromatic hydrocarbon by CO 2 hydrogenation. In view of this, research is still needed at present to solve the problems that the aromatic hydrocarbon production capacity is limited in the process of methane aromatization engineering application, long-period continuous and stable operation is difficult due to easy carbon deposition of the catalyst and reaction induction period of the catalyst, and hydrogen is difficult to obtain in the process of CO 2 hydrogenation to prepare aromatic hydrocarbon engineering applica