CaO对褐煤在超临界水中制取富氢气体的影响

以褐煤在超临界水中制取富氢气体为目的，利用小型高压间歇反应装置，在Ca/C 摩尔比为0～0.60、温度450℃～680℃、压力23MPa～38MPa和停留1min～30min下，考察了小龙潭褐煤的反应特性。研究表明，CaO不仅可以固定气相中的CO2，提高H2的体积分数，而且可以提高碳转化率和气体产率。600℃、28MPa，Ca/C摩尔比为0.42时，气相产物中的CO2趋于完全固定，H2产率比无添加剂时提高2.5倍，H2体积分数为48％，其余为CH4和烃类气体。升高反应温度使CaO的催化作用更为显著, 碳转化率和气体产率（H2、CH4、烃类气体）随着反应温度的升高而逐渐增加，液相收率减少。增大反应压力可以促使煤转化率和气体产率升高，停留时间对反应的影响相对较小。以900℃热解焦为反应原料进行了气化实验，结果表明，在600℃和650℃反应5min后，碳转化率分别为8.6％和12.5％，CaO对气化反应和甲烷化反应起不同程度的催化作用。

Effect of CaO on conversion of lignite to hydrogen-rich gas in supercritical water

Conversion of Xiaolongtan lignite to hydrogen rich gas was performed in supercritical water under conditions of 450℃~680℃, 23MPa~38MPa, and 1min~30min in the presence of CaO. The effects of Ca/C mol ratio and reaction conditions on the product distribution and yields of gas products were investigated. The yield of CO2 in gas product decreased and that of hydrogen increased with the increase of Ca/C mol ratio. At a Ca/C mol ratio of 0.42, nearly all CO2 is fixed and the mol fraction of hydrogen in gas product is about 48 ％. The increase in temperature leads to an increase in the carbon conversion and the yield of hydrogen, and the performance of CaO is significant at higher temperatures. Higher reaction pressure favors the conversion of coal and the formation of H2 and CH4. The effect of residence time is less significant compared with Ca/C mol ratio and temperature. Experiments of char gasification in SCW were also conducted. It shows that the addition of CaO can promote carbon gasification reaction and increase the yields of H2 and CH4.