Effect of Ca(OH)2 catalyst on catalytic coal gasification and methanation
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Abstract
The catalytic gasification performance of Buliangou coal using Ca(OH)2 as catalyst was investigated at 3.5 MPa and 700-800℃ in a pressurized fixed bed. The effect of gasification temperature, Ca(OH)2 loading and loading method on coal steam gasification and methanation reaction were examined. The results show that Ca(OH)2 can enhance the reactivity of char gasification and the formation of CH4. Increasing temperature and Ca(OH)2 loading can heighten the carbon conversion, but Ca(OH)2 loading possesses a saturation point. The gasification reactivity is affected by loading method which determines the Ca(OH)2 dispersion. The coal char loaded with Ca(OH)2 shows a great catalytic activity on methanation reaction and the CH4 content in the product gas increases with the increase of methanation temperature and catalyst loading. The analysis result of coal surface function groups by FT-IR reveals the dispersion mechanism of Ca(OH)2 into the matrix of coal through ion exchange and diffusion, which is a key factor to improve coal char gasification reactivity.
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