Hydrogen and methane mixture from biomass gasification coupled with catalytic tar reforming, methanation and adsorption enhanced reforming
Jingjing Zhang, Mei Wang, Shaoping Xu⁎ , Yanchun Feng
Abstract：In order to obtain fuel gas rich of hydrogen and methane from biomass gasification, an integrated process of catalytic tar steam reforming, methanation and adsorption enhanced reforming (AER) was established. A freefall gasifier followed by a moving bed upgrading reactor loaded with bed materials was applied as the reaction device. The bed materials consisted of Ni/hematite, calcined limestone and quartz sand. The Ni/hematite was used for catalyzing both tar reforming and methanation, and the calcined limestone as CO2 capturer and the quartz sand as diluting agent. In the free fall reactor, white pine sawdust was gasified with steam to produce syngas containing tar. Then the syngas with tar was introduced upwardly into the moving bed reactor and passed through the downwardly moving bed materials. The tar in the syngas was catalytically reformed to produce a H2- rich gas, and thereafter the gas underwent WGS reaction, CO2 adsorption and methanation at the upper part of the reactor. The reactions were optimized through a decreased temperature gradient along with the up flow of reaction gas in the moving bed reactor. The influences of the mass ratio of steam to biomass (S/B) in the gasifier and the amounts of Ni/hematite and calcined limestone in the bed materials on the reactions were investigated. Under the condition of the temperature gradient from 500 to 600 °C, S/B 0.4, and bed materials composed of 20% Ni/hematite, 60% calcined limestone and 20% quartz sand, a fuel gas with H2 and CH4 mixture concentration over 97 vol% was obtained.
Key words: H2 and CH4 production； Ni/hematite； Methanation； Tar reforming； Sorption enhanced reforming
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