高灰煤小型流化床混合气催化气化研究

高灰煤小型流化床混合气催化气化研究

  • 摘要: 在内径28mm流化床中,对阳泉高灰煤在碱性催化剂(固碱和黏胶废碱液)作用下进行了混合气(空气/水蒸气)催化气化研究,两种碱性催化剂的适宜添加量均为6%。不加催化剂,气化温度830℃~900℃与900℃~920℃下,气化反应的表观反应级数n分别约为2/3与1/3;有催化剂(3%固碱)时,表观反应级数有两个明显的温度段,在830℃~860℃,催化气化的表观反应级数n=1;在860℃~920℃,催化气化的表观反应级数为n=1/3。

     

    Abstract: The experimental study on the Yangquan high-ash coal catalytic gasification with mixing-gas (air/steam) by using solid alkali (sodium hydroxide) or waste liquid of viscose fiber as the catalyst in a smallscale fluidized bed with 28mm i.d. was carried out. The loading saturation levels (LSL) of two catalysts in Yangquan high-ash coal are about 6%. Under the gasification temperature ranging from 830℃ to 900℃ and from 900℃ to 920℃, the apparent reaction order of Yangquan highash coal with respect to the unreacted carbon fraction approximates to 2/3 and 1/3 for the noncatalyst case, respectively. Also, the different values of apparent reaction order in the two temperature ranges are presented for the case with 3% solid alkali catalyst loaded. At the low temperature ranging from 830℃ to 860℃, the apparent reaction order of catalytic gasification is 1 since enough active carbon sites on the coal surface are formed during the catalytic gasification by solid alkali. But at the high temperature ranging from 860℃ to 920℃, the sodium carbonate produced by the reaction of solid alkali with carbon dioxide can be easily fused, transferred and redistributed, which affects the gasification reaction rate, and the apparent reaction order of catalytic gasification is reduced to 1/3.

     

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