基于AspenPlus的污泥干化-热解耦合工艺模拟及放大实验

Simulation Study and Scale-up Tests of Sludge Drying Coupled withPyrolysis Based on Aspen Plus

针对污泥干化能耗高的问题,提出了污泥干化-热解耦合新工艺。通过采用Aspen Plus软件进行模拟,分析了可燃气传热量的影响因素(热解温度和杨木屑添加率)以及升温速率对热解产物和系统能耗的影响。结果表明:当采用杨木屑和污泥进行共热解时,杨木屑添加率须达43.5%,才能维持系统正常稳定地运行。当热解温度为550℃时,作为可燃气主要成分的热解油得率达到最大,为51.7%,此时系统有最大的供热量12.619 MJ/h。此外,发现随着升温速率的增加,固体残渣的得率下降,而热解油和可燃气的总得率上升;当升温速率降低时,热解油和可燃气的得率也降低。中试放大实验研究表明,当污泥进料量为3 kg/h时,停留时间必须≥45 min、通气流量40 L/min,才能达到预期的干化目标。

In the light of high energy consumption in sludge drying,a new process for sludge drying coupled with pyrolysis was proposed.The factors affecting the heat transfer of combustible gas(such as pyrolysis temperature and addition rate of poplar sawdust)and the influence of heating rate on pyrolysis products and system energy consumption were analyzed through the simulation with Aspen Plus software.The results indicated that when the co-pyrolysis of poplar sawdust and sludge was carried out,the addition rate of poplar sawdust must reach 43.5%to maintain a normal and stable operation of the system.When the pyrolysis temperature was 550℃,the yield of pyrolysis oil as the main component of combustible gas reached the maximum of 51.7%,and the system had the maximum heating capacity of 12.619 MJ/h.Additionally,it was found that when the heating rate increased,the yield of solid residue decreased,while the overall yield of pyrolysis oil and combustible gas increased.And when the heating rate decreased,the yield of pyrolytic oil and gas also decreased.Finally,the pilot plant scale-up test results showed that at a sludge feeding rate of 3 kg/h,the desired drying goal could be achieved at a minimum of residence time of 45 min and air flowrate of 40 L/min.