An Experimental Investigation on Hydrogasification of Coal Chars in a Fixed Bed Reactor under High Pressure

Abstract

The Characteristic of Coal Hydrogasification Was Carried Out in a Fixed Bed Reactor by Using Chars of Datong Bituminous, Spain Lignite and Pingdingshan Bituminous. it Was Investigated that the Effects of Reaction Temperature (973-1123K), Reaction Pressure (3-7Mpa), the Char Preparation Temperature (973-1073K) and Catalyst (CaO) on CH4 Yield. the Three Stages Model Was Provided to Explain the Coal Hydrogasification Process. the CH4 Yield Increases Rapidly in the First Stage which Is Dominated by the Reaction of Active Groups (-O-CH3,-COOH,-CH2OH,-CH3) and H2. the CH4 Yield Keeps Constant in the Second Stage. the Releasing Rate of C-O-(C) and C-O-(H) Active Groups Dominates the CH4 Yield Rate. the CH4 Yield Decreases in the Third Stage which Is Dominated by the Reaction Rate of Carbon and Hydrogen. there Is Higher CH4 Yield under Higher Pressure which Is Related to the Higher Reaction Rate of Graphite and H2 under Higher Pressure. the Structure of Raw Coals and Chars Was Identified by FTIR. in Additional, the Influences of Char Structure and Catalyst on the CH4 Yield Are Discussed in the Paper.