分级冷凝回收城市污泥热解油

Pyrolysis oil retrieving from sewage sludge by fractional condensation

为了便于将污泥热解油中不同用途的组分分离,在一套处理量为10 kg/h的循环流化床污泥热解系统中采用分级冷凝的方法回收污泥热解油.分级冷凝装置包括两级喷淋式直接冷凝器和一级间接冷凝器,直接冷凝器中的储液段装有用于控制冷凝器出口温度的间接冷凝盘管.分析了各级热解油的pH值、高位热值、黏度等理化性质,并通过GC/MS和FTIR仪器分析各级热解油的组分分布.结果表明,第一级冷凝器得到的油相高位热值达到25.7 MJ/kg,可用作替代燃料,而第二级热解油可用于提纯化工原料,其余热解油经过调至可返回污水处理厂,经处理后排放.

In order to promote the separation of sludge pyrolysis oil＇s component for different application, a fractional-condensation process fixed in a 10 kg/h circulating fluidized bed pyrolysis system was used to retrieving sludge bio-oil. The system of fractional condensation was composed of two series spray towers and one intermediate condenser. Intermediate cooling circles were fixed at the liquid store parts of the spray towers for controlling the outlet temperature of the spray towers. The pH, higher heating value and viscosity of the bio-oil collected from different condensers were detected to realize their physicochemical characters. GC/MS （ gas chromatography mass spectrometry） and PT- IR （Fourier transform infrared spectrum） methods were used to analyze the composition of the bio- oil. The result shows that the oil-phase with a higher heating value of 25.7 MJ/kg collected from the first condenser can be used as alternative fuel. Meanwhile, the bio-oil collected from the second condenser can be used as chemical feedstock. Other bio-oil can be discharged after treated by the wastewater treatment plant.