Abstract
The utilization of oil sludge for the creation of value-added petroleum products represents an important research direction, as certain processing routes do not incur the additional costs that are associated with more complex refining operations. The selection of the most appropriate treatment method is therefore critical for achieving cost-effective processing outcomes. The economic feasibility of a particular technology is largely determined by the physical–chemical properties and potential toxicity of oil sludge, and thus, it is essential to comprehensively characterize and assess the toxicity of this substance. In this study, the physical–chemical composition and principal characteristics of oil sludge obtained from a Kazakhstan oil company were examined. To clean the oil sludge, an alkaline solution was used as a surfactant with a solid–liquid ratio of 1:3. The solid content in the sludge was reduced from 23% to 0.76%. The results revealed that the hydrocarbon fraction of the oil sludge was predominantly composed of heavy fractions. In addition, the effects of thermal parameters on treatment efficiency were found to contribute to the secondary products present in high oil fractions. Treatment with inert gases improved processing efficiency rates by over 57%. The most efficient results included the pyrolysis of cleaned oil sludge with minimum solid residues (5.8% under CO2) and maximum gas products (37.8% under N2).