Microwave demulsification characteristics and product analysis of oily sludge

Abstract

ABSTRACT Oily sludge is a kind of industrial hazardous waste that contains a lot of harmful substances. It has high water content and oil content. Demulsification is the key link for its resource utilization. Based on the unique heating characteristics of microwave heating, this paper uses microwave heating method to demulsify oily sludge in refineries. The effects of microwave power, temperature, stirring time, and additives on the demulsification of oily sludge are studied. The composition of each layer of the oil phase is analyzed to explore the possibility of oil reuse. The orthogonal test results show that the order of the influence of various factors on the dehydration rate of sludge is: temperature>power>stirring time; microwave power 700 W, temperature 55°C, and stirring time 10 min, the dehydration rate of sludge reaches the maximum value of 69.3%; adding sludge pyrolysis residue can significantly improve the efficiency of sludge dehydration; based on the results of microwave primary demulsification experiments, a deep demulsification and dehydration method for sludge is proposed. Based on the carbon number method, the relative contents of the liquid phase product were corrected, and it was found that the three layers of liquid phase product composition after demulsification and centrifugation were significantly different. The upper layer was mainly composed of gasoline (69.54%), and the middle layer was mainly composed of diesel (89.55%), the lower layer was mainly heavy oil components (75.87%).