Study on two-step process of petroleum substances recovery from oily sludge

Oily sludge has received increasing attention for its hazardousness as well as its high potential as an energy resource. In this paper, a study, in order to obtain the essential parameters in the relevant engineering design or practices, the two-step process of thermochemical demulsification separation and air floatation separation was used for oil material recovery from oily sludge (light oily sludge and heavy oily sludge) that was obtained from an oilfield. The light oil sludge and heavy oily sludge were diluted with of 3 times and 4 times mass water respectively and heated to 75. and 80., respectively, and both adjusted pH to 6. The self-made emulsion breaking agent with the mixture mass fraction of 0.3% and 0.4% were added separately, and the thermochemical demulsification separation was carried out for 20 min and 25 min respectively under stirring. The mixture of mud and water after the thermochemical demulsification separation was further air floatation at normal temperature. The oil content of the mud cake formed by the centrifugal separation of the mixture after air floatation separation was under 2%. And the result that centrifugal separation mixture liquid for the next oily sludge treatment was great. Furthermore, the test result of planting clover on the soil sample composed of the dry mud cake and some seedbed soil showed that the seed germination and growth were normal.