Sulfur-Tolerant Methanation Catalyst Regeneration
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Solution Overview
Problem
Current methods for desulfurization in catalytic conversion of producer gases from gasification of solid feedstocks, especially low-temperature coal or biomass gasification, result in energy inefficiencies and high operational and capital costs due to the need for scrubbing and water condensation, and existing sulfur-tolerant methanation catalysts are not effective in the presence of organic sulfur compounds and olefins.
Innovation Solution
A method involving simultaneous partial sulfur removal and methanation using a metal or metal oxide catalyst, with continuous regeneration at the same temperature as methanation (300°C - 700°C), utilizing catalysts like Ni, Ru, or Mo supported on Al2O3, SiO2, etc., and oxidative regeneration with controlled temperature and oxidizing agents to maintain catalyst activity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If desulfurization is performed by scrubbing at low temperatures, then sulfur removal is achieved, but energy efficiency decreases and operational costs increase
Solution Approach 1:
The patent combines desulfurization and methanation into a single catalytic process, where the catalyst simultaneously performs both sulfur removal and methane production functions, eliminating the need for separate scrubbing units and reducing energy consumption
Solution Approach 2:
The catalyst system is designed to perform multiple functions: it acts as both a desulfurization agent and a methanation catalyst, converting sulfur compounds to H2S while simultaneously converting CO and CO2 to methane in one integrated process
2Reliability
If desulfurization is performed by scrubbing and water condensation, then sulfur removal is achieved, but capital costs and operational complexity increase
Solution Approach 1:
The patent merges multiple process units (scrubber, condenser, desulfurization reactor, methanation reactor) into a single catalytic reactor that performs all functions simultaneously, greatly simplifying the overall process flow and reducing equipment requirements
Solution Approach 2:
The patent extracts and eliminates the need for separate water condensation and scrubbing units by integrating their functions into the catalytic process, removing unnecessary process steps and equipment
3Productivity
If conventional methanation catalysts are used with sulfur-containing producer gas, then methanation can proceed, but catalyst deactivation occurs
Solution Approach 1:
The patent changes the chemical environment parameters by converting sulfur compounds to H2S and controlling the atmosphere to prevent catalyst poisoning, allowing conventional catalysts to maintain activity in sulfur-containing feeds
Solution Approach 2:
The catalyst system acts as an intermediary that transforms harmful sulfur compounds into less harmful H2S form while maintaining catalytic activity for methanation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method achieves nearly complete methanation of CO in the presence of sulfur and organic compounds with fast catalyst regeneration, reducing unit operations and maintaining high energy efficiency, thus prolonging catalyst lifespan and reducing costs.
Implementation Method 1
catalytic production of a methane-rich gas mixture from sulfur-containing synthesis gas
Implementation Method 2
oxidative regeneration with controlled temperature and oxidizing agents
Data Source
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AI summary
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 catalystby sulfur and optionally 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 Al2O3, SiO2, TiO2, CeO2, ZrO2, 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.