A method for methanation of gasification derived producer gas on metal catalysts in the presence of sulfur

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This invention presents a method for converting sulfur-containing synthesis gas (obtained from gasifying coal or biomass) into methane-rich gas (synthetic natural gas) using metal-based catalysts. The key novelty is that the catalysts, which are deactivated by sulfur and carbon species over time, can be continuously or intermittently regenerated by oxidation within the same process, enabling both effective methane production and sulfur removal without the need for expensive and inefficient external scrubbing steps.

Use CasesContent extracted from patent full text and abstract with AI.

• Production of synthetic natural gas (SNG) from coal, biomass, or waste-derived synthesis gas streams that contain sulfur and other contaminants.
• Upgrading biogas or gasified biomass/coal to pipeline-quality methane for energy supply.
• Deployment in integrated gasification combined cycle (IGCC) power plants or waste-to-energy plants where sulfur-laden producer gas is common.
• Methanation processes in chemical plants with contaminated syngas feeds.
• Cleaner fuel generation for sectors requiring low-sulfur content fuels, such as urban heating or transportation.

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• Eliminates or reduces the need for costly and complex upstream gas scrubbing and water condensation steps.
• Allows efficient methane production even with sulfur-rich or contaminated gas feeds, broadening the range of acceptable feedstocks.
• Maintains catalyst activity and longevity through continuous in situ regeneration, reducing downtime and replacement costs.
• Improves overall energy efficiency by performing methanation and catalyst regeneration at similar (relatively high) temperatures.
• Simplifies process design due to integration of methanation, sulfur removal, and catalyst regeneration in a unified system.
• Enables high selectivity and nearly complete conversion of CO to methane, even in the presence of challenging impurities like tars and olefins.

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Patent Abstract

The present invention discloses a method for catalytic production of a methane-rich gas mixture from sulfur-containing synthesis gas with simultaneous at least partial sulfur removal, thereby: a) producing a synthesis gas mixture; b) bringing said synthesis gas mixture into a contact with a methanation catalyst thereby continuously deactivating the methanation catalyst by sulfur and/or carbon species comprised in the synthesis gas mixture in one part of the methanation process, while a part of said depleted methanation catalyst is simultaneously regenerated by oxidation in a different part of the process; c) the methanation catalyst is a metal, a metal oxide, a metal sulfide or a mixture of metals, metal oxides or metal sulfide/nitride/phosphide on a support; d) said metal or metals are selected from a group comprising Ni, Ru, Mo, Co, Fe, Rh, Pd, Pt, Ir, Os, W, V, wherein the support is an oxide of a group comprising Al 2 O 3 , SiO 2 , TiO 2 , CeO 2 , ZrO 2 , carbides, nitrides, phosphides or a mixture thereof, wherein e) the metal or metals can be promoted by one or more of the following elements: K, P, Na, Ba, Ni, Ru, Rh, Co, Pt, Pd, Ir, W, Os, V, Mn. The method achieves a nearly complete methanation of CO in the presence of both organic and inorganic sulfur compounds, such as olefins, tars etc., combined with an at least partial uptake of sulfur followed by a relatively fast oxidative regeneration of the methanation catalyst (bed material) and sulfur release, preferably at a temperature level near the methanation temperature.