预水解时间对蔬菜类废物机械破碎能耗的影响  

Effect of Pre-hydrolysis Time on Energy Consumption during Mechanical Size Reduction of Vegetable Wastes

作　　者：邵立明[1,2] 彭伟[1] 邱伟坚[1] 何品晶[1,2] 

机构地区：[1]同济大学固体废物处理与资源化研究所,上海200092 [2]住房和城乡建设部村镇建设司农村生活垃圾处理技术研究与培训中心,上海200092

出　　处：《农业环境科学学报》2014年第3期608-612,共5页Journal of Agro-Environment Science

基　　金：国家973重点基础研究发展计划课题(2012CB719801);国家自然科学基金项目(21177096;51178327);上海市科技创新行动计划项目子课题(12231202003)

摘　　要：为降低蔬菜类废物机械破碎能耗,采用泔水浸泡工艺对其进行预处理。在初始pH=8.12的条件下,分别设置预水解时间为1、2、4 h和8 h共4个预处理工况,采用隔栅刀和万能试验机评价经预处理后蔬菜类废物的机械破碎能耗。结果表明,预水解时间1、2、4 h和8 h工况下蔬菜类废物单位能耗相比未经预水解的蔬菜类废物(破碎能耗0.322 J·g-1湿基)分别提高12.12%、下降19.56%、下降22.67%和下降20.19%。随着预水解时间的增加,水解液的pH从初始8.12下降至7.31(8 h后);总有机碳从初始984mg·L-1上升至2 h的1009 mg·L-1,随后再下降至600 mg·L-1(8 h后)。生物质组成分析表明,破碎能耗的降低主要是由于浸泡过程中纤维类有机物因吸胀作用吸水导致植物组织强度下降所致。Mechanical size reduction could improve anaerobic digestion efficiency of vegetable wastes, but might increase energy consump- tion. An experiment was designed to examine energy consumption of mechanical size-reduction of vegetable wastes after pre-hydrolysis by steeping the wastes in swill（initial pH=8） for different times（ l h, 2 h, 4 h, 8 h）. A knife grid size reduction device and a universal test machine were used to measure the energy consumption during size reduction of the pretreated vegetable wastes. After pre-hydrolysis for 1 h, 2 h, 4 h and 8 h, the maximum load of size reduction of vegetable wastes decreased by 0.07%, 4.85%, 16.28%, 12.55%, and the mass- based energy consumption reduced by -12.12%, 19.56%, 22.67% and 20.19%, respectively, as compared to the untreated control. There were no significant differences in the mass-based energy consumption and the maximum load of vegetable wastes between 4 h and 8 h of pre-hydrolysis, suggesting that it is unnecessary or uneconomical to extend pre-hydrolysis time over 4 h, The total contents of cellulose, hemicellulose and lignin in the wastes decreased by 10.99%, 11.88%, 23.61% at 1 h, 4 h and 8 h of pre-hydrolysis, respectively, with cel- lulose decreasing most. The hydrolysate pH decreased from 8.12 at the control to 7.31 at the 8 h pre-hydrolysis; TOC slightly increased from initial 984 mg L-1 to 1009 mg L-1 during the first two hours of pre-hydrolysis, and then decreased to 600 mg L-1 at 8 h pre-hydrolysis. Component analysis showed that reduced energy consumption by pre-hydrolysis mainly resulted from weakened structural strength of plant tissues by imbibited water.

关 键 词：蔬菜类废物 预处理 水解时间 机械破碎 能耗 

分 类 号：X712[环境科学与工程—环境工程]