Study on the oil-sludge separation by thermochemical method in rotating packed bed

• The rotating packed bed was used in the treatment of the oil sludge first. • The optimal operating conditions of the oil sludge treating in RPB were investigated. • The oil sludge separation efficiency can be greatly enhanced by RPB. • The usage of detergent solution in RPB treatment process is less than that in STR treatment process. In this work, we first introduced the high gravity technique in thermochemical method for oil-sludge separation. The effects of different operating conditions on oil content in the treated sludge were investigated. The optimal operating conditions of a reagent component of 5 wt% Na 2 SiO 3 / 2 wt% water soluble demulsifier B1 / 93 wt% H 2 O, an oil sludge/detergent solution ratio of 1:2, a cycle time of 30 min, a cleaning temperature of 80 °C, a rotating speed of 500 rpm and a settling time of 20 h was obtained. It was found that the oil content in the treated sludge could be reduced to 3.13% after thermochemical treating in a rotating packed bed (RPB) under the optimal conditions, while that in stirring tank reactor (STR) is 5.47%. In addition, the usage of detergent solution in RPB treatment process is 50% less than that in STR treatment process. This work provide a novel higee-thermochemical method for the efficient and continuous treatment of oil sludge.