污水污泥低温热解技术工艺与能量平衡分析

Analysis on Conditions and Energy Balance of Low-temperature Pyrolysis of Sewage Sludge

针对一次给料稳定运行污泥热解系统制取三相产物的工艺展开分析,并基于能流图、能源回收率、能耗比等方法和衡算指标讨论该工艺的能量平衡关系。研究发现:热解产物的产率和热值高低受热解终温影响最大,反应时间次之,升温速率最小。不同工况条件下热解过程热量损失具有明显差别,热解停留时间长、升温速率低都造成输入能量、热损失增大。热解过程能量平衡分析也验证了以制取气相产物为目标的污泥热解工艺条件的回收率和能耗比最高,分别为0.94和1.73;与高产出液相油的热解过程相比,产物总能量相差不多而系统消耗的能量能够减少35%。从能源回收、节约能源角度分析,污泥低温热解制取可燃性气相产物的工艺系统具有较高应用价值。

Process conditions of pyrolysis technology with one-time feeding and stable operation system to produce the three-phase sewage sludge pyrolysis were in detailed investigated. Energy balance relationship was analyzed through energy- flow diagram, energy recycling rate and energy consumption rate. It was found that yield and calorific value of sludge pyrolysis product were influenced with three key factors in a decreased order of final temperature, reaction time and heating rate. Heating loss has a significant difference under different pyrolysis working conditions. Residence time and lower heating rate can cause obvious increase of input energy and the heat loss. Results of the heating balance analysis showed that pyrolysis system that produce gas products with high quality has the highest energy recycling rate and energy consumption rate, which are 0.94 and 1.73 respectively. Compared with pyrolysis process to produce liquid oil product, total energy is almost the same but total energy consumption can be reduced by 35%. It can be verified that low temperature pyrolysis technology of sewage sludge is more suitable to produce gas product according to its energy recovery and saving.