摘要
在间歇式高压反应釜中,温度为450~500℃时,反应时间为20 min,压力在24~26MPa,以K_2CO_3和Ca(OH)_2为催化剂(助催剂),对纤维素在超临界水中的气化制氢特性进行了实验研究。结果表明:K_2CO_3和Ca(OH)_2都有较好的催化作用,并且加入量存在一最佳值。加入0.2g K_2CO_3时,H_2产率为9.456 mol·kg^(-1),约为不加入催化剂时的2倍,加入1.6g Ca(OH)_2时,H_2产率为8.265mol·kg^(-1),比加入K2CO3时的产氢效果稍差,但仍然是不加入催化剂时的1.7倍。K_2CO_3和Ca(OH)_2混合使用时效果更佳,产氢量约为不加入催化剂时的2.5倍,比单独加入K_2CO_3和Ca(OH)_2时也要分别提高25%和45%。同时随着温度的提高,H_2的产率上升而CH_4的产率下降,说明甲烷化反应在低温下为主要反应,温度的提高会促使CH_4与水反应生成H_2和CO_2。
Cellulose, one of the important compositions of biomass, was gasified in supercritical water to produce hydrogen-rich gas in a high-pressure bath autoclave. K2COa and Ca（OH）2 were selected as catalysts, and the reaction condition was controlled as follows： the temperature is 450-500℃, pressure ranges from 24-26 MPa and reaction time is 20 min. The experimental results show that two catalysts have good catalytic effect and each of them has its own optimum added amount for the gasification. Hydrogen production can reach 9.456 mol·kg^-1 when 0.3 g K2COa is added, which is 2 times the H2 amount achieved when no catalyst is used. And the H2 production of 8.265 mol·kg^-1 is achieved when 1.6 g Ca（OH）2 is added, though it is worse than that when K2COa is used, it is 1.7 times the amount achieved when no catalyst is used. Comparing with using K2COa or Ca（OH）2 alone, using the mixed catalyst composed of K2COa and Ca（OH）2 can increase the H2 production by 25% and 45% correspondingly. It was found that the methane production is dominant at relatively low temperature, and the methane might be converted to hydrogen and carbon dioxide by reacting with water when the temperature is increased.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2007年第3期436-441,共6页
Journal of Chemical Engineering of Chinese Universities
基金
国家重点基础研究发展规划资助项目(973计划)(2003CB214500)
国家自然科学基金资助项目(50323001)共同资助
关键词
生物质
制氢
超临界水
气化
氢气
biomass
hydrogen production
supercritical water
gasification
hydrogen
