Acceleration Of Microwave Pyrolysis Process Of Oily Sludge

Oily sludge containing PAC with a large number of toxic hazardous components like organic compounds and heavy metals is generated during the crude oil secondary exploitation. Therefore, it is important for oily sludge to be treated with the aims of resources, harmless and volume reduction, and it is helpful to recover oil from oily sludge in order to solve energy shortage and environment pollution.The process of microwave heat treatment and its product characteristics were studied by microwave radiation. Then, the solid residues produced during microwave heat treatment were used as the microwave absorbent to accelerate the processes of microwave pyrolysis. Finally, non-condensable gases, recycling oil, solid residues were qualitatively analyzed, and the process by which active adsorbent was produced by using the solid residues as raw materials was also studied.The results showed that microwave heat treatment process can be divided into five stages:rapidly-increasing temperature, microwave drying, hydrocarbon microwave evaporation, microwave pyrolysis and microwave burning. The whole microwave heat treatment process took a long time with high energy consumption.The addition of solid residues as microwave absorbent could markedly accelerate the microwave pyrolysis processes, resulting in decreasing the time for microwave treatment of oily sludge, and had no effect on the characteristics of the microwave heat treatment process. When 3% of solid residues were mixed with oily sludge, the time of microwave pyrolysis process was decreased by 80%, and the whole time for microwave heating treatment of oily sludge was decreased by 60%. Under these conditions, the volume of recovery oil after microwave treatment processes was up to maximum.Non-condensable gases, which have high flammability, mainly contain hydrogen, carbon monoxide, methane, ethylene, propylene and other small organic gases. Recovery oil was composed of 39.23% gasoline,39.83% diesel and 20.94% heavy oil, and mainly contained alkanes and olefin. This meant recovery oil has good quality. Besides, the production of solid residues usually in less than 10% of the oily sludge indicated that microwave treatment is a good way for the volume reduction of oily sludge.After solid residues were treated with 5% of nitrate, the surface area of solid residues was increased to above 150 m2/g.