Abstract: Taking the oily sludge of certain oily sludge treatment plant as the research object, the oil washing efficiency of single chemical agent and compound agent was compared by means of thermochemical cleaning. And the experimental conditions such as experimental temperature, proportion of oily sludge to prepared water, mixing time and mixing speed were analyzed systematically. The results indicated that the highest washing efficiency of Na2SiO3 · 9H2O is 92.44% among single chemical components; linear alkylbezene sulfonates (LAS) has better washing efficiency, and non-ionic surfactant NP-10 has the best washing efficiency, which is 92.83%. In the compound agent, the cleaning agent efficiency at Na2SiO3 · 9H2O:LAS:NP-10 =6:3:1 can reach 96.58%. The washing efficiency increases with the increase of temperature; with the increase of liquid-solid ratio, the oil washing efficiency first increases and then decreases. The reasonable liquid-solid ratio is 4:1; the optimal experimental temperature is 80 ℃ , and the stirring time is 30 minutes. The oil washing efficiency can reach 96.58%. 

Key words: oily sludge, sludge cleaning agent, cleaning agent compounding, experiment optimization