Search

CN-121975560-A - Method and device for removing organic sulfur from natural gas

CN121975560ACN 121975560 ACN121975560 ACN 121975560ACN-121975560-A

Abstract

The invention discloses a method and a device for removing organic sulfur from natural gas, and relates to the technical field of natural gas purification and sulfur recovery. The removal method comprises the steps of taking natural gas containing hydrogen sulfide and mercaptan as raw material gas, removing hydrogen sulfide in the raw material gas through an alcohol amine method to obtain first hydrogen sulfide removal gas and first amine-rich liquid, continuously removing mercaptan from the first hydrogen sulfide removal gas through temperature swing adsorption to obtain purified gas and mercaptan-rich gas, converting COS into hydrogen sulfide through catalytic hydrogenation and alcohol amine method to obtain hydrogen sulfide, and returning the hydrogen sulfide to an inlet of the raw material gas for circulation. The method can overcome the defects of large solution circulation amount and high energy consumption when the natural gas with high H 2 S and mercaptan is treated by the traditional alcohol amine method, solve the problems of unstable operation of a subsequent sulfur recovery device and poor quality of sulfur products caused by mercaptan, simultaneously reduce the hydrogen consumption in the process, reduce the total investment of the device and finally realize the deep desulfurization of the natural gas with high sulfur content.

Inventors

  • ZHANG JINGTAO

Assignees

  • 成都赛普瑞兴科技有限公司

Dates

Publication Date
20260505
Application Date
20260327

Claims (10)

  1. 1. A method for removing organic sulfur from natural gas, comprising: s1, taking natural gas containing hydrogen sulfide and mercaptan as raw material gas, and removing the hydrogen sulfide in the raw material gas by an alcohol amine method to obtain first hydrogen sulfide removal gas and first rich amine liquid; s2, continuously removing mercaptan from the first hydrogen sulfide removal gas through temperature swing adsorption to obtain purified gas and mercaptan-enriched gas; S3, carrying out catalytic hydrogenation on the mercaptan-enriched gas to convert mercaptan into hydrogen sulfide, so as to obtain hydrogen sulfide-enriched gas; s4, removing hydrogen sulfide from the hydrogen sulfide-rich gas by an alcohol amine method to obtain second hydrogen sulfide-removed gas containing a byproduct COS and second rich amine liquid; s5, hydrolyzing the second dehydrosulfuration gas to convert COS into hydrogen sulfide, so as to obtain sulfur-containing hydrogen sulfide; S6, returning the hydrogen sulfide-containing gas to the inlet of the raw material gas for circulation.
  2. 2. The method for removing organic sulfur from natural gas according to claim 1, wherein the temperature swing adsorption comprises the steps of adsorbing the first de-sulfurized hydrogen through an adsorbent bed at a temperature lower than 60 ℃ to remove mercaptans in the de-sulfurized hydrogen, desorbing the mercaptans from the adsorbent at a temperature of 120-300 ℃ to obtain the mercaptan-enriched gas; Preferably, the adsorbent in the adsorbent bed comprises at least one of activated alumina, silica gel, molecular sieve and activated carbon.
  3. 3. The method for removing organic sulfur from natural gas according to claim 1, wherein the catalytic hydrogenation comprises mixing the thiol-rich gas with hydrogen, heating to hydrogenation reaction temperature, entering a hydrogenation reactor to contact with a hydrogenation catalyst, and converting the thiol into hydrogen sulfide; preferably, the molar ratio of the mercaptan-enriched gas to the hydrogen is 100:1-8; preferably, the hydrogenation catalyst comprises at least one of a cobalt molybdenum catalyst, an iron molybdenum catalyst and an iron manganese catalyst; preferably, the hydrogenation reaction temperature is 250-380 ℃.
  4. 4. The method for removing organic sulfur from natural gas according to claim 1, wherein the alcohol amine method comprises introducing the raw material gas or the hydrogen sulfide-rich gas into an absorption tower, wherein the raw material gas or the hydrogen sulfide-rich gas is in countercurrent contact with the alcohol amine aqueous solution, and hydrogen sulfide in the raw material gas or the hydrogen sulfide-rich gas is absorbed; Preferably, the aqueous alcohol amine solution comprises at least one of MEA, DEA, DGA, MDEA and AMP.
  5. 5. The method for removing organic sulfur from natural gas according to claim 1, wherein the hydrolysis comprises cooling the second de-sulfurized hydrogen gas containing by-product COS to a hydrolysis reaction temperature, introducing the gas into a hydrolysis reactor to contact with a hydrolysis catalyst, and reacting COS with water vapor to generate H 2 S and CO 2 ; Preferably, the hydrolysis reaction temperature is 40-150 ℃; Preferably, the hydrolysis catalyst comprises at least one of an activated alumina-based catalyst, a titanium-based catalyst, a composite metal oxide catalyst, and an activated carbon-based non-metal oxide.
  6. 6. The method for removing organic sulfur from natural gas according to claim 1, further comprising S7, heating and regenerating the first rich amine liquid and the second rich amine liquid to obtain high-content hydrogen sulfide acid gas, and recovering sulfur from the acid gas to obtain sulfur.
  7. 7. The method for removing organic sulfur from natural gas according to claim 6, wherein the regeneration treatment comprises feeding the first rich amine liquid and the second rich amine liquid into a regeneration tower, heating, resolving and then releasing high-concentration H 2 S as acid gas, cooling and pressurizing the desorbed lean alcohol amine liquid, returning the lean alcohol amine liquid to an absorption tower of the alcohol amine method for recycling, and preparing sulfur from the acid gas discharged from the tower top after the sulfur recovery treatment.
  8. 8. The method for removing organic sulfur from natural gas according to claim 6, wherein the sulfur recovery treatment comprises the steps of feeding the acid gas and air into a combustion furnace for incomplete combustion according to a molar ratio of H 2 S to O 2 of 2:1, and oxidizing H 2 S into sulfur step by step through a catalytic reaction.
  9. 9. A natural gas organic sulfur removal device for realizing the method for removing natural gas organic sulfur according to any one of claims 1 to 8, characterized in that it comprises a first hydrogen sulfide absorption tower, a temperature swing adsorption tower, a catalytic hydrogenation reactor, a second hydrogen sulfide absorption tower and a hydrolysis reactor; The temperature swing adsorption tower is provided with a first dehydrosulfuration inlet, a purified gas outlet and a mercaptan-rich gas outlet, the catalytic hydrogenation reactor is provided with a mercaptan-rich gas inlet and a hydrogen sulfide-rich gas outlet, the second hydrogen sulfide absorption tower is provided with a hydrogen sulfide-rich gas inlet, a second dehydrosulfuration outlet and a second amine-rich liquid outlet, and the hydrolysis reactor is provided with a second dehydrosulfuration inlet and a hydrogen sulfide-containing gas outlet; the first dehydrosulfuration outlet is communicated with the first dehydrosulfuration inlet, the mercaptan-rich gas outlet is communicated with the mercaptan-rich gas inlet, the hydrogen-rich gas outlet is communicated with the hydrogen-rich gas inlet, the second dehydrosulfuration outlet is communicated with the second dehydrosulfuration inlet, and the hydrogen sulfide-containing outlet is communicated with the feed gas inlet.
  10. 10. A natural gas organosulfur removal apparatus as recited in claim 9, further comprising a regeneration tower and a claus sulfur recovery apparatus, said regeneration tower being provided with a regeneration inlet and a regeneration outlet, said claus sulfur recovery apparatus being provided with an acid gas inlet and a liquid sulfur outlet, said first rich amine liquid outlet and said second rich amine liquid outlet being in simultaneous communication with said regeneration inlet, said regeneration outlet being in communication with said claus sulfur recovery apparatus inlet.

Description

Method and device for removing organic sulfur from natural gas Technical Field The invention relates to the technical field of natural gas purification and sulfur recovery, in particular to a method and a device for removing organic sulfur from natural gas. Background Natural gas is an energy source with clean and high efficiency, and plays an important role in energy structure transformation. However, some natural gas resources contain high-concentration hydrogen sulfide (H 2 S), mercaptan (RSH) and other organic sulfur compounds, and if the high-sulfur natural gas is directly utilized, the high-sulfur natural gas can not only seriously corrode pipelines and equipment, but also generate harmful gases such as sulfur dioxide in the combustion process, pollute the environment and harm human health. Therefore, deep desulfurization and high-efficiency sulfur recovery are indispensable key links in the development and utilization process of high-sulfur natural gas, and have important significance for guaranteeing energy safety, ecological environment protection and comprehensive utilization of resources. At present, the main stream of the technology for desulfurizing the natural gas with high sulfur content in industry is an alcohol amine method, H 2 S and part of organic sulfur in the natural gas are absorbed and removed by alcohol amine solution, and then the natural gas enters a sulfur recovery device to convert sulfur elements into sulfur products to realize resource recovery. However, when natural gas with high sulfur content is treated, the traditional alcohol amine method has the defects that firstly, a larger circulating amount of alcohol amine solution is required to be maintained to ensure the desulfurization effect, so that the energy consumption of the device is high, the operation cost is greatly increased, secondly, the existence of mercaptan can seriously interfere the normal operation of a subsequent sulfur recovery device, the fluctuation of the working condition of the device is initiated, the operation stability is reduced and the like, thirdly, the selectivity of sulfur production reaction is influenced by the intervention of mercaptan, the purity and the quality of the produced sulfur product are low, the economic value of the product is reduced, the limiting content of mercaptan in sour gas is generally 0.2%, fourthly, the route of directly hydroconverting mercaptan needs multistage hydrogenation, the hydrogen consumption is extremely large, the volume of hydrogenation equipment and heat exchange equipment is huge, and the investment is very high. Further limiting its use in high thiol-containing natural gas processing scenarios. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a method and a device for removing organic sulfur from natural gas, which can overcome the defects of large solution circulation and high energy consumption when the natural gas with high H 2 S and mercaptan is treated by the traditional alcohol amine method, solve the problems of unstable operation of a subsequent sulfur recovery device and poor quality of sulfur products caused by mercaptan, simultaneously reduce the hydrogen consumption in the process, reduce the total investment of the device, finally realize deep desulfurization of the natural gas with high sulfur content, improve the sulfur recovery rate and the quality of the sulfur products, and improve the economy and stability of the whole treatment process. The invention is realized in the following way: in a first aspect, the present invention provides a process for removal of organic sulfur from natural gas comprising: s1, taking natural gas containing hydrogen sulfide and mercaptan as raw material gas, and removing the hydrogen sulfide in the raw material gas by an alcohol amine method to obtain first hydrogen sulfide removal gas and first rich amine liquid; s2, continuously removing mercaptan from the first hydrogen sulfide removal gas through temperature swing adsorption to obtain purified gas and mercaptan-enriched gas; S3, carrying out catalytic hydrogenation on the mercaptan-enriched gas to convert mercaptan into hydrogen sulfide, so as to obtain hydrogen sulfide-enriched gas; s4, removing hydrogen sulfide from the hydrogen sulfide-rich gas by an alcohol amine method to obtain second hydrogen sulfide-removed gas containing a byproduct COS and second rich amine liquid; s5, hydrolyzing the second dehydrosulfuration gas to convert COS into hydrogen sulfide, so as to obtain sulfur-containing hydrogen sulfide; S6, returning the hydrogen sulfide-containing gas to the inlet of the raw material gas for circulation. In an optional embodiment, the temperature swing adsorption comprises the steps of adsorbing the first de-sulfurized hydrogen through an adsorbent bed at a temperature lower than 60 ℃ to remove the mercaptan in the de-sulfurized hydrogen, and desorbing the mercaptan from the adsorbent at