KR-20260065807-A - Method for producing liquid hydrocarbons from synthesis gas

Abstract

A method for producing liquid hydrocarbons from synthesis gas, the method comprising: providing synthesis gas containing hydrogen cyanide and sulfur compounds; dividing the synthesis gas containing hydrogen cyanide and sulfur compounds into a first synthesis gas portion and a second synthesis gas portion; passing a mixture of the first synthesis gas portion and steam through a water-gas-shift reaction chamber to provide a hydrogen-rich first synthesis gas portion; combining the hydrogen-rich first synthesis gas portion with the second synthesis gas portion to provide a combined synthesis gas; passing the combined synthesis gas through a hydrolysis reaction chamber containing a titania catalyst to convert at least a portion of the hydrogen cyanide in the combined synthesis gas into ammonia to provide an ammonia-rich, hydrogen cyanide-depleted synthesis gas; A step of transferring an ammonia-rich, hydrogen cyanide-depleted synthesis gas to a first scrubber and contacting the ammonia-rich, hydrogen cyanide-depleted synthesis gas with a first scrubbing liquid, thereby retaining at least a portion of the ammonia contained in the ammonia-rich, hydrogen cyanide-depleted synthesis gas in the first scrubbing liquid to form an ammonia-depleted, hydrogen cyanide-depleted synthesis gas; a step of passing the ammonia-depleted, hydrogen cyanide-depleted synthesis gas through a carbon dioxide removal unit to form a carbon dioxide-depleted synthesis gas; a step of transferring the carbon dioxide-depleted synthesis gas to a reaction chamber containing a zinc oxide material to convert at least a portion of the hydrogen cyanide in the carbon dioxide-depleted synthesis gas into ammonia and adsorbing residual sulfur compounds present in the carbon dioxide-depleted synthesis gas to provide an ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas; The method comprises the steps of: transferring an ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas to a second scrubber and bringing the ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas into contact with a second scrubbing liquid, thereby retaining at least a portion of the ammonia contained in the ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas in the second scrubbing liquid to form an ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas; and passing the ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas through a Fischer-Tropsch reaction chamber to produce a liquid hydrocarbon product.

Inventors

• 앨런, 스튜어트 윌리엄
• 코, 앤드루 제임스
• 장, 추이제
• 니예메이슬란트, 미힐

Assignees

• 존슨 매티 데이비 테크놀로지스 리미티드

Dates

Publication Date

20260511

Application Date

20240704

Priority Date

20230904

Claims (20)

1. As a method for producing liquid hydrocarbons from synthesis gas, A step of providing synthesis gas containing hydrogen cyanide and sulfur compounds; A step of dividing the synthesis gas containing hydrogen cyanide and sulfur compounds into a first synthesis gas portion and a second synthesis gas portion; A step of passing the mixture of the first synthesis gas portion and steam through a water-gas-shift reaction chamber to provide a hydrogen-rich first synthesis gas portion; A step of providing a combined synthesis gas by combining the hydrogen-rich first synthesis gas portion with the second synthesis gas portion; A step of passing the combined synthesis gas through a hydrolysis reaction chamber containing a titania catalyst to convert at least a portion of the hydrogen cyanide in the combined synthesis gas into ammonia to provide an ammonia-rich, hydrogen cyanide-depleted synthesis gas; A step of transferring the ammonia-rich, hydrogen cyanide-depleted synthesis gas to a first scrubber and bringing the ammonia-rich, hydrogen cyanide-depleted synthesis gas into contact with a first scrubbing liquid, thereby forming an ammonia-depleted, hydrogen cyanide-depleted synthesis gas by retaining at least a portion of the ammonia contained in the ammonia-rich, hydrogen cyanide-depleted synthesis gas in the first scrubbing liquid; A step of passing the above-mentioned first ammonia-depleted, hydrogen cyanide-depleted synthesis gas through a carbon dioxide removal unit to form a carbon dioxide-depleted synthesis gas; A step of transferring the carbon dioxide-depleted synthesis gas to a reaction chamber containing a zinc oxide material to convert at least a portion of the hydrogen cyanide in the carbon dioxide-depleted synthesis gas into ammonia and adsorbing residual sulfur compounds present in the carbon dioxide-depleted synthesis gas to provide an ammonia-rich, hydrogen cyanide-depleted desulfurized synthesis gas; A step of transferring the ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas to a second scrubber and bringing the ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas into contact with a second scrubbing liquid, thereby forming an ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas by retaining at least a portion of the ammonia contained in the ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas in the second scrubbing liquid; and A method comprising the step of passing the ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas through a Fischer-Tropsch reaction chamber to produce a liquid hydrocarbon product.
2. A method according to claim 1, wherein the liquid hydrocarbon product comprises an alkane.
3. A method according to claim 1 or 2, wherein the step of providing hydrogen cyanide-containing synthesis gas comprises the gasification of biomass and/or municipal waste.
4. A method according to any one of claims 1 to 3, wherein the ratio of the hydrogen-rich first synthesis gas portion to the second synthesis gas portion is controlled to provide a molar ratio of hydrogen to carbon monoxide in the combined synthesis gas of 1.5 to 2.5, preferably 1.8 to 2.2.
5. A method according to claim 4, wherein the first synthesis gas portion comprises 50 to 60 volume% of the hydrogen cyanide-containing synthesis gas and the second synthesis gas portion comprises 40 to 50 volume% of the hydrogen cyanide-containing synthesis gas.
6. A method according to any one of claims 1 to 5, wherein the first synthesis gas portion is preferably heated to a temperature of 200°C to 400°C by adding steam to the first synthesis gas portion before being transferred to the aqueous gas shift reaction chamber.
7. A method according to any one of claims 1 to 6, wherein the aqueous gas shift reaction chamber comprises a catalyst comprising supported cobalt oxide and molybdenum oxide.
8. A method according to any one of claims 1 to 7, wherein the hydrolysis in the hydrolysis reaction chamber containing the titania catalyst is carried out at a temperature greater than 100°C, preferably between 150°C and 200°C.
9. A method according to any one of claims 1 to 8, wherein the synthesis gas further comprises ammonia.
10. A method according to any one of claims 1 to 9, wherein the hydrogen cyanide-containing synthesis gas comprises carbonyl sulfide, and at least a portion of the carbonyl sulfide is hydrolyzed into hydrogen sulfide in the hydrolysis reaction chamber to produce a hydrogen sulfide-rich, carbonyl sulfide-depleted synthesis gas.
11. A method according to any one of claims 1 to 10, wherein the carbon dioxide removal unit to which the ammonia-depleted, hydrogen cyanide-depleted synthesis gas is delivered is an acid gas removal unit that removes carbon dioxide and optionally hydrogen sulfide and hydrogen cyanide from the ammonia-depleted, hydrogen cyanide-depleted synthesis gas before delivering the ammonia-depleted, hydrogen cyanide-depleted synthesis gas to the reaction chamber containing the zinc oxide material.
12. A method according to any one of claims 1 to 11, wherein the second ammonia-rich, hydrogen cyanide-depleted desulfurization synthesis gas comprises less than 10 ppbv of hydrogen cyanide.
13. A method according to any one of claims 1 to 12, wherein the ammonia depletion, hydrogen cyanide depletion desulfurization synthesis gas comprises less than 10 ppbv of ammonia.
14. A method according to any one of claims 1 to 13, wherein the temperature of the Fischer-Tropsch reaction chamber is 150°C to 300°C.
15. A method according to any one of claims 1 to 14, wherein the step of passing the ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas through a Fischer-Tropsch reaction chamber to produce a liquid hydrocarbon product comprises the step of contacting the ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas with a catalyst comprising cobalt, iron, or ruthenium.
16. In any one of paragraphs 1 through 15, The step of passing the above ammonia-depleted, hydrogen cyanide-depleted desulfurization synthesis gas through the above Fischer-Tropsch reaction chamber produces a liquid hydrocarbon product and simultaneously produced water; A method in which at least the second scrubbing liquid comprises water simultaneously generated and recovered from the Fischer-Tropsch reaction chamber.
17. A method according to claim 15 or 16, wherein the simultaneously generated water is saturated with carbon dioxide under the temperature and pressure conditions of the scrubber used.
18. A method according to any one of claims 1 to 17, wherein the synthesis gas containing hydrogen cyanide and sulfur compounds further comprises a particulate material incorporated into the synthesis gas containing hydrogen cyanide and sulfur compounds, and, preferably as a first purification step upstream of the water gas shift reaction chamber, the synthesis gas containing hydrogen cyanide and sulfur compounds is passed through a particulate filter.
19. A method according to any one of claims 1 to 18, wherein the synthesis gas containing hydrogen cyanide and sulfur compounds further comprises a hydrogen halide compound, and the synthesis gas containing hydrogen cyanide and sulfur compounds is passed through a layer of a hydrogen halide adsorbent upstream of the aqueous gas shift reaction chamber, preferably downstream of a particulate filter.
20. In paragraph 19, the method wherein the first synthesis gas portion passes through a layer of hydrogen halide adsorbent upstream of the aqueous gas shift reaction chamber.

Description

Method for producing liquid hydrocarbons from synthesis gas The present invention relates to a method for producing liquid hydrocarbons from synthesis gas. The Fischer-Tropsch process is a set of chemical reactions that convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at temperatures of 150 to 300°C and pressures of 1 to several tens of atmospheres. The Fischer-Tropsch process ideally involves a series of chemical reactions that produce various hydrocarbons having the chemical formula (C n H 2 n + 2 ). More useful reactions produce alkanes as follows: (2 n + 1) H 2 + n CO → C n H 2 n +2 + n H 2 O In the equation, n can be from 1 to 100 or more. The formation of methane ( n = 1) is undesirable. Most of the alkanes produced tend to be straight-chain, making them suitable for upgrading to produce intermediate fraction fuels such as diesel and jet fuels. In addition to alkane formation, the competing reaction provides small amounts of alkenes as well as alcohols and other oxygenated hydrocarbons. The co-produced water is a byproduct and is separated from the products of the Fischer-Tropsch reaction. The Fischer-Tropsch reaction is a highly exothermic reaction due to a standard reaction enthalpy (ΔH) of -165 kJ per mole of CO combined. The synthesis gas (syngas) feed for a Fischer-Tropsch unit can be derived from a number of feedstocks; for example, natural gas via steam reforming and/or autothermal reforming, municipal solid waste and biomass via hot gasification, or carbon dioxide and hydrogen via reverse-water-gas-shift. The synthesis gas produced by these processes typically contains hydrogen cyanide and ammonia at ppm levels; since this deactivates the Fischer-Tropsch catalyst, ideally, hydrogen cyanide and ammonia are removed to single-digit ppb levels. To remove these species from the synthesis gas, hydrogen cyanide is typically converted to ammonia via hydrolysis and subsequent removal using a wet scrubber. Achieving ppb levels of ammonia is technically difficult. Synthesis gas can also contain a number of different sulfur compounds, including carbonyl sulfide (COS), mercaptan (RSH), and hydrogen sulfide ( H₂S ). Sulfur compounds are toxic to Fischer-Tropsch catalysts. Carbonyl sulfide poses a particular problem because it is not easily removed by adsorption; therefore, it has been found that conversion to hydrogen sulfide by hydrolysis is necessary to effectively remove it from synthesis gas. US9422492B2 relates to an integrated process for the production of liquid hydrocarbons. Syngas is split into two, one undergoing a water-gas-shift reaction and the other undergoing catalytic hydrolysis to hydrolyze HCN and COS, which are then recombined. The recombined synthesis gas then undergoes scrubbing and acid gas removal, which is then transferred to a Fischer-Tropsch reaction chamber. The process is complex as it requires separate water sources for the water-gas-shift and hydrolysis steps. US10518210B2 and EP3546053B1 relate to a gas scrubbing unit in which synthesis gas undergoes an HCN hydrolysis step, a subsequent COS hydrolysis step, and subsequent gas scrubbing and desulfurization steps. The purpose of these documents is to provide a gas scrubbing unit and a gas purification method capable of effectively reducing the concentration of carbonyl sulfide in the treated gas even when the concentration of carbonyl sulfide in the treated gas is high. This method will not be able to reduce the HCN content in the final synthesis gas to less than 10 ppbv, especially without the use of a large amount of hydrolysis catalyst, and therefore the washed synthesis gas will be prone to poisoning the Fischer-Tropsch catalyst. The present invention aims to solve at least some of the problems associated with the prior art or at least provide a commercially acceptable alternative solution thereto. One aspect of the present invention relates to a method for producing liquid hydrocarbons from synthesis gas, wherein the method comprises: A step of providing synthesis gas containing hydrogen cyanide and sulfur compounds; A step of dividing the synthesis gas containing hydrogen cyanide and sulfur compounds into a first synthesis gas portion and a second synthesis gas portion; A step of passing a mixture of the first synthesis gas portion and steam through a water gas shift reaction chamber to provide a hydrogen-rich first synthesis gas portion; A step of providing a combined syngas by combining a hydrogen-rich first syngas portion with a second syngas portion; A step of passing the combined synthesis gas through a hydrolysis reaction chamber containing a titania catalyst to convert at least a portion of the hydrogen cyanide in the combined synthesis gas into ammonia to provide an ammonia-rich, hydrogen cyanide-depleted synthesis gas; A step of transferring an ammonia-rich, hydrogen cyanide-depleted synthesis gas to a first scrubber and