活性污泥混合木屑制备生物质燃料及其燃烧特性的研究

Biomass fuel prepared by activated sludge mixed sawdust and its combustion characteristics

以活性污泥混合木屑为原料制备生物质燃料,考察成型压力、物料含水率和活性污泥占比对生物质燃料的抗破碎强度和松弛密度的影响,并研究生物质燃料的燃烧特性。研究结果表明:生物质燃料的抗破碎强度和松弛密度均随着成型压力和活性污泥占比的增大而增大,物料含水率控制在15%～20%较为合适;成型压力和物料含水率对生物质燃料的抗破碎强度有显著影响,而成型压力和活性污泥占比对生物质燃料的松弛密度有显著影响;活性污泥的燃烧过程可分为水分析出、挥发分燃烧及无机盐分解3个阶段,木屑的燃烧过程可分为水分析出、挥发分析出及剩余挥发分和固定碳燃烧3个阶段;生物质燃料的燃烧过程因活性污泥占比的多少而有所差异。生物质燃料的综合燃烧性能随着木屑占比的增加而逐渐提高,活性污泥的加入可以改善生物质燃料的着火性能,合理的活性污泥混合木屑工艺和配方能够制备出燃烧性能较好的生物质燃料。

The biomass fuel was prepared by activated sludge and sawdust.The effects of molding pressure,moisture content and activated sludge ratio on the shatter resistance and relaxed density were investigated,and the combustion characteristics of biomass fuel were also studied.The results show that the shatter resistance and the relaxed density of biomass fuel were increased with the molding pressure and activated sludge ratio.The moisture content of biomass fuel is preferably controlled in the range of 15%to 20%to meet the acceptable values of shatter resistance and relaxed density.The molding pressure and moisture content have a strong influence on shatter resistance of biomass fuel,while the molding pressure and activated sludge ratio significantly determine the relaxed density.The thermogravimetric analysis reveals that the combustion process of activated sludge includes three stages of dehydration,combustion of volatile and decomposition of inorganic matter,and the combustion process of sawdust can be divided into three stages of dehydration,combustion of volatile,combustion of residual volatile and fixed carbon,while the combustion stages of biomass fuel rely on the blend ratio of activated sludge.The general combustion performance of biomass fuel was improved by the increase of sawdust ratio,while the flammability was bettered by the increase of activated sludge.The biomass fuel with better combustion characteristics depends on an optimized process and recipe.