煤及生物质共超临界水气化过程中的协同效应

Synergistic Effect in Co-Gasification of Coal and Biomass in Supercritical Water

在自行研制的连续管流式煤及生物质共超临界水气化制氢装置上,对甘肃华亭烟煤、羧甲基纤维素钠(生物质模型化合物)及其两者的混合物在反应器壁温650℃、系统压力25 MPa、停留时间30 s、NaOH质量分数为0.1%的条件下进行了实验研究.实验表明:气体产物主要由H2、CO2和CH4组成,其中H2的体积分数可高达60%以上;气体产物中未检测到N和S,含N和S的污染物以液相排除,极大地减少了大气污染.研究发现煤与羧甲基纤维素钠共超临界水气化过程中在产氢率和气化率上出现了明显的协同效应,进一步提出协同效应主要由超临界水中的自由基反应引起.结果表明,煤及生物质共超临界水气化制氢是一种富有前景的洁净能源转化新技术.

Experiments of co-gasification of biomass and coal in supercritical water （SCW） are conducted to investigate any synergy between biomass and coal for enhancing coal gasification and hydrogen production. A thermal-catalytic reactor with continuous flow is employed to co-gasify Hua-Ting bituminous coal, sodium carboxymethylcellulose （a model compound of biomass） and their blends under a reactor with wall temperature of 650 ℃, pressure 25 MPa, and a residence time 30 s and 0.1% NaOH additive. The experimental results show that the produced gases consist mainly of H2, CO2 and CH4, and the molar fraction of hydrogen reaches in excess of 60% Nitrogen or sulfur is not detected in the produced gases, and contaminations with nitrogen or sulfur are discharged by liquid. A synergistic effect between coal and sodium carboxymethylcellulose is observed on the hydrogen yield and the gasification efficiency, and that the synergistic effect is mainly resulted from free radical reactions in SCW is proposed further. The present work indi- cates hydrogen production from co-gasification of biomass and coal in SCW is a promising new technology for clean energy conversion.