Acceleration of the microwave pyrolysis of oily sludge

The characteristics of an accelerated microwave pyrolysis process for oily sludge containing PAC(polyaluminium chloride) were studied after the oily sludge was mixed with a microwave absorber which was produced during the microwave heat treatment of oily sludge.It was found that the microwave absorber had no effect on the characteristics of the microwave heat treatment process for oily sludge containing PAC.However,when the process was separated into five stages—rapidly-increasing temperature,microwave drying,microwave evaporation of heavy hydrocarbons,microwave pyrolysis,and microwave burning—it was found that the microwave absorber markedly accelerated the microwave pyrolysis of the oily sludge,resulting in a reduced microwave treatment time.When the amount of microwave absorber was 3%,the microwave pyrolysis time of oily sludge was decreased by almost 80% and the overall microwave treatment time was decreased by about 60%.When the amount of microwave absorber was 5%,the microwave pyrolysis time of the oily sludge was decreased by almost 90% and the overall microwave treatment time was decreased by about 67%.The variation in the yields of non-condensed gases or condensed liquids with temperature was essentially unchanged when the amount of microwave absorber was varied.The yield of recovered oil increased with increasing amount of microwave absorber below 3%,but the yield decreased with increasing amount of microwave absorber in the range 3% to 5%.When the microwave absorber content was 3.0%,the yield of recovered oil reached a maximum of about 80%.