脱水污泥/松木锯末水蒸气共气化研究

Steam co-gasification of dewatered sewage sludge and pine sawdust

以城市污水处理厂机械脱水后的污泥(含水率约为80%)和松木锯末的混合物为原料,进行了共气化制取富氢燃气的研究.同时,采用热重分析(TGA)研究了混合样品的热失重特性,并在固定床反应器上考察了不同掺混比对燃气成分、燃气产量和碳转化率的影响.TGA结果表明,随着锯末掺混比的增加,样品的失重量、最大失重率及挥发分析出特性指数增大.在固定床反应器中,脱水污泥中的水分在高温条件下形成蒸气气氛,与产生的半焦发生了蒸气气化反应.实验结果表明,最佳掺混比为40%～60%,此时氢气含量、燃气产量、碳转化率分别为40%、0.70m·3kg-1、64.1%.此外,借助BET和SEM对残余半焦的比表面积及表面形貌特征进行了分析.

The blends of dewatered sewage sludge and pine sawdust was used as feedstock. Co-gasification of the blends for hydrogen production was studied. TGA was used to analyze the thermal-decomposition characteristics of the sample. Co-gasification process was performed in lab-scale fixed bed gasifier to investigate the effect of adding ratio on fuel gas composition, fuel gas yield and carbon conversion. TGA results showed that weight loss, the maximum weight loss rate and characteristic index volatile release increased with the increase of sawdust amount. In the fixed bed gasifier, the char was gasified with steam that generated from the moisture content in dewatered sewage sludge. The results indicated that the optimal adding ratio of sawdust ranged from 40% to 60%. H2 concentration, fuel gas yield and carbon conversion were 40%, 0.70 m3·kg^-1, and 64.1%, respectively. Moreover, BET and SEM were employed to analyze the surface characteristics of the residue char.