title: Removal of H2S using molten carbonate at high temperature.
abstract: Gasification is considered to be an effective process for energy conversion from various sources such as coal, biomass, and waste. Cleanup of the hot syngas produced by such a process may improve the thermal efficiency of the overall gasification system. Therefore, the cleanup of hot syngas from biomass gasification using molten carbonate is investigated in bench-scale tests. Molten carbonate acts as an absorbent during desulfurization and dechlorination and as a thermal catalyst for tar cracking. In this study, the performance of molten carbonate for removing H2S was evaluated. The temperature of the molten carbonate was set within the range from 800 to 1000 °C. It is found that the removal of H2S is significantly affected by the concentration of CO2 in the syngas. When only a small percentage of CO2 is present, desulfurization using molten carbonate is inadequate. However, when carbon elements, such as char and tar, are continuously supplied, H2S removal can be maintained at a high level. To confirm the performance of the molten carbonate gas-cleaning system, purified biogas was used as a fuel in power generation tests with a molten carbonate fuel cell (MCFC). The fuel cell is a high-performance sensor for detecting gaseous impurities. When purified gas from a gas-cleaning reactor was continuously supplied to the fuel cell, the cell voltage remained stable. Thus, the molten carbonate gas-cleaning reactor was found to afford good gas-cleaning performance.
authors.affiliation: Central Research Institute of Electric Power Industry (CRIEPI), 2-6-1 Nagasaka, Yokosuka-Shi, Kanagawa 240-0196, Japan. Electronic address: kawase@criepi.denken.or.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawase
authors.forename: Maromu
authors.initials: M
authors.lastname: Otaka
mesh_terms: D056804:Biofuels; D018533:Biomass; D002245:Carbon Dioxide / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry*; D005740:Gases / Q000737:chemistry*; D006358:Hot Temperature; D006862:Hydrogen Sulfide / Q000302:isolation & purification*
chemical_list: D056804:Biofuels; D002254:Carbonates; D005740:Gases; D002245:Carbon Dioxide; D006862:Hydrogen Sulfide
keywords: Desulfurization; Gasification; H(2)S; Hot gas cleaning; Molten carbonate