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CN-121971995-A - Deep desulfurization system for preparing methanol from coke oven gas and use method

CN121971995ACN 121971995 ACN121971995 ACN 121971995ACN-121971995-A

Abstract

The invention relates to the technical field of gas treatment, and discloses a deep desulfurization system for preparing methanol from coke oven gas and a use method thereof, wherein the deep desulfurization system comprises a photoelectrocatalysis desulfurization module, a nano molecular sieve adsorption module and a regeneration module which are sequentially arranged according to the movement direction of the coke oven gas, wherein the photoelectrocatalysis desulfurization module consists of a reaction tower, a photoanode, a photocathode and an electrolyte, the photoanode is a TiO 2 -ZrO 2 heterojunction nanotube array, the photocathode is a NiFe-LDH/carbon felt composite electrode, and the electrolyte adopts ionic liquid [ BMIM ] [ BF 4 ] to couple Fe 3+ /EDTA redox medium; through the integration of the photoelectric coupling technology and the deep desulfurization system, the high-efficiency desulfurization, pollutant removal, equipment service life extension, service life improvement of a methanol synthesis catalyst and environmental protection benefit maximization in the process of preparing methanol from coke oven gas are realized, and the photocatalysis desulfurization module promotes sulfide oxidation/hydrogenation reaction kinetics and reduces energy consumption through the synergistic effect of light energy excitation and electric field driving.

Inventors

  • Xia Xuefa
  • GAO YANG
  • ZHANG LINA
  • CHEN XIANG
  • HE JIANHONG
  • MENG XIANGSHUAI
  • MA BOWEN
  • ZHANG YUSHENG

Assignees

  • 淮北矿业绿色化工新材料研究院有限公司

Dates

Publication Date
20260505
Application Date
20260324

Claims (9)

  1. 1. The deep desulfurization system for preparing methanol from coke oven gas is characterized by comprising a photoelectric catalytic desulfurization module, a nano molecular sieve adsorption module and a regeneration module which are sequentially arranged according to the movement direction of the coke oven gas; The photoelectrocatalysis desulfurization module consists of a reaction tower, a photo-anode, a photo-cathode and an electrolyte, wherein the photo-anode is made of TiO 2 -ZrO 2 heterojunction nanotube arrays, the photo-cathode is made of NiFe-LDH/carbon felt composite electrodes, and the electrolyte is an ionic liquid [ BMIM ] [ BF 4 ] coupled Fe 3+ /EDTA redox medium; The nano molecular sieve adsorption module adopts a NaX molecular sieve, the sulfur capacity is improved to 30mg/g, the regeneration module is provided with a microwave unit and an air supply unit, and the air conveyed by the air supply unit is nitrogen.
  2. 2. A deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein the microwave unit is a 2.45GHz microwave generator, and the penetration depth is 1.5m.
  3. 3. The deep desulfurization system for preparing methanol from coke oven gas according to claim 2, wherein the gas supplied by the gas supply unit is replacement low-pressure nitrogen, 200-250 ℃ nitrogen and purge nitrogen.
  4. 4. The deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein the TiO 2 -ZrO 2 heterojunction nanotube array in the photo-anode expands the light response range to 450nm through ZrO 2 quantum dot modification.
  5. 5. The deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein Pt nano particles are loaded on the surface of a NiFe-LDH/carbon felt composite electrode in the photocathode.
  6. 6. The deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein the reaction tower consists of a 316L stainless steel shell and a polytetrafluoroethylene lining.
  7. 7. The deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein a honeycomb-shaped guide plate is arranged inside the reaction tower.
  8. 8. The deep desulfurization system for preparing methanol from coke oven gas according to claim 1, wherein the nano molecular sieve adsorption module is provided with three towers, and the three towers are used for realizing adsorption, regeneration and standing respectively for standby.
  9. 9. The method for using the deep desulfurization system for preparing methanol from coke oven gas according to any one of claims 1 to 8, which is characterized by comprising the following steps: S1, pre-irradiating ultraviolet light for 30 minutes to a TiO 2 -ZrO 2 heterojunction photo-anode before starting to activate the photo-anode; s2, injecting an ion liquid [ BMIM ] [ BF 4 ] and 0.1mol/L Fe 3+ /EDTA mixed solution, and maintaining pH=8.5-9.5, wherein the conductivity is more than 10mS/cm; S3, starting the xenon lamp, enabling the photo anode to absorb photons to excite electron-hole pairs, and simultaneously applying 1.2-1.5V bias to drive charge separation; S4, enabling coke oven gas to enter from the bottom of the tower at a flow rate of 0.5-1.5m/S, enabling the coke oven gas to contact with electrolyte sprayed from the top in a countercurrent manner, enabling the gas to stay for more than 60 seconds through a honeycomb guide plate design, ensuring that sulfide is fully diffused to the surface of a catalyst, and obtaining desulfurized coke oven gas after reaction; s5, coke oven gas enters from the top of the nano molecular sieve adsorption module, and uniformly flows through a buffer screen plate with the aperture of 0.5-1mm, so that the scouring speed of the NaX molecular sieve is reduced; S6, adsorbing residual hydrogen sulfide and carbonyl sulfide through a NaX molecular sieve at the airspeed of 1800-3000h -1 to obtain coke oven gas with the sulfur content less than or equal to 0.05ppm, and feeding the coke oven gas into a subsequent methanol synthesis unit; S7, the regeneration module monitors the concentration of the outlet sulfur in real time through a laser gas analyzer, and triggers a switching signal when the concentration exceeds the standard; s8, introducing low-pressure nitrogen with purity of more than 99.99% to replace residual gas; S9, starting a 2.45GHz microwave generator, wherein the penetration depth is 1.5m, selectively heating sulfide, and finally, the sulfur desorption rate is more than 98%; S10, carrying desorbed sulfide carried by 200-250 ℃ hot nitrogen into a sulfur recovery system; s11, reversely purging with 80% of adsorption gas through nitrogen, cooling to below 20 ℃, introducing purified gas of the other adsorption tower into a regeneration tower, and slowly boosting to 0.3-0.5MPa; And S12, keeping standing for 2 hours, balancing the temperature and pressure gradient in the tower, and ensuring the recovery activity of the adsorbent.

Description

Deep desulfurization system for preparing methanol from coke oven gas and use method Technical Field The invention relates to the technical field of gas treatment, in particular to a deep desulfurization system for preparing methanol from coke oven gas and a use method thereof. Background The sulfides in the coke oven gas exist in the forms of inorganic sulfur and organic sulfur, and the content is higher. Without deep desulfurization, sulfides can poison methanol synthesis catalysts, leading to catalyst deactivation, affecting methanol yield and quality, such as copper-based catalysts. In addition, sulfide emissions may cause environmental pollution, and thus the total sulfur content needs to be reduced to below 0.1 ppm. The prior desulfurization process for preparing methanol from coke oven gas has the technical challenges of complex process flow, high energy consumption, complex operation and high compression power consumption, and needs multi-stage desulfurization systems for combination, such as pre-desulfurization, hydroconversion, medium-temperature desulfurization, normal-temperature desulfurization and the like. The catalyst and the desulfurizer are insufficient in performance, the iron-molybdenum catalyst is easy to poison and inactivate, the ZnO desulfurizer has low removal efficiency on residual organic sulfur and is difficult to regenerate, and the total sulfur is difficult to reach the standard. The problems of byproduct treatment and recycling are outstanding, sulfide secondary salt generated by wet desulfurization is easy to cause equipment corrosion, the sulfur recovery rate is low, the quality is poor, and the recycling utilization rate is insufficient. In addition, equipment corrosion and operation risks are remarkable, filler blockage is easily caused by high-temperature and high-pressure operation, and the system complexity is further increased due to high pretreatment requirements of raw gas. The technical problems restrict the economy and environmental protection compliance of the desulfurization process, and technological upgrading needs to be broken through in the aspects of process optimization, novel desulfurization material development and the like. Disclosure of Invention The invention aims to provide a deep desulfurization system for preparing methanol from coke oven gas and a use method thereof, which are used for solving the technical problems of low desulfurization efficiency, high operation cost, difficult regeneration of desulfurizing agent and the like in the prior art, further prolonging the service life of a catalyst for synthesizing methanol, and improving the yield and quality of the methanol so as to solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: A deep desulfurization system for preparing methanol from coke oven gas comprises a photoelectric catalytic desulfurization module, a nano molecular sieve adsorption module and a regeneration module which are sequentially arranged according to the movement direction of the coke oven gas; The photoelectrocatalysis desulfurization module consists of a reaction tower, a photo-anode, a photo-cathode and an electrolyte, wherein the photo-anode material is a TiO2-ZrO2 heterojunction nanotube array, the photo-cathode material is a NiFe-LDH/carbon felt composite electrode, and the electrolyte is an ionic liquid [ BMIM ] [ BF 4 ] coupled Fe 3+/EDTA redox medium; The nano molecular sieve adsorption module adopts a NaX molecular sieve, the sulfur capacity is improved to 30mg/g, the regeneration module is provided with a microwave unit and an air supply unit, and the air conveyed by the air supply unit is nitrogen. As a still further proposal of the invention, the microwave unit is specifically a 2.45GHz microwave generator, and the penetration depth is 1.5m. As a still further scheme of the invention, the gas conveyed by the gas conveying unit is replaced low-pressure nitrogen, 200-250 ℃ nitrogen and purge nitrogen. As a still further scheme of the invention, the TiO 2-ZrO2 heterojunction nanotube array in the photo-anode expands the photoresponse range to 450nm through ZrO 2 quantum dot modification. As a still further scheme of the invention, pt nano particles are loaded on the surface of the NiFe-LDH/carbon felt composite electrode in the photocathode. As a still further scheme of the invention, the reaction tower consists of a 316L stainless steel shell and a polytetrafluoroethylene lining. As a still further proposal of the invention, a honeycomb-shaped guide plate is arranged inside the reaction tower. As a still further scheme of the invention, the nano molecular sieve adsorption module is provided with three towers, and the three towers respectively realize adsorption, regeneration and standing for standby. S1, carrying out ultraviolet pre-irradiation on a TiO 2-ZrO2 heterojunction photo-anode for 30 minutes before starting to carry o