煤中负载氢氧化钙对催化气化和甲烷化反应的影响

Effect of Ca(OH)2 catalyst on catalytic coal gasification and methanation

    摘要
  • 摘要: 以不连沟次烟煤为研究对象，在加压固定床中研究Ca（OH）2对煤气化及负载Ca（OH）2煤热解半焦的甲烷化反应活性。结果表明，煤中添加Ca（OH）2能够明显促进气化反应的进行和甲烷的生成，随着气化温度的升高和负载量的增加，碳转化率增加，但负载量存在饱和点。不同的催化剂负载方式对Ca的分散有一定的影响，进而影响其催化性能。含有Ca的半焦能够明显促进甲烷化的进行，出口气甲烷含量随甲烷化温度和催化剂负载量的升高而增强。采用红外光谱分析揭示了煤负载Ca（OH）2的离子交换机理和扩散过程，这一过程影响煤气化反应性能。

     

    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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