Development Of Refinery Oily Sludge Oil Separation Technology

This paper analyzes the composition of oily sludge in refineries through the analysis of a large number of complex hazardous solid wastes produced in the process of crude oil extraction,production,transportation and refining in the petrochemical industry.The basic characteristics of oily sludge in smelters were obtained,and the best extractors were selected.Then the oil-containing sludge in smelters was treated by ultrasonic emulsion breaking and hot washing.The best emulsifying agent was selected,the cleaning agent was selected,and the best parameters of the process were determined.On the basis of this,the effect of ultrasonic-heat washing combined process on oil-containing sludge in the refinery was evaluated.The results show that:(1)The oily sludge in a lanzhou refinery has a water content of 82.93 %,a slag content of 1.93 %,an organic content of 9.79 %,a pH of 8.19,and a COD of 66460 mg/L,which is alkaline,high in COD,high in water content,and low in organic content and slag content.It was determined that carbon tetrachloride could be used as the most suitable extractor for determination of oil-containing sludge under the present conditions.(2)Using the crude oil removal rate as an indicator,the oil-containing sludge in the refinery is treated by ultrasonic breaking process;The concentration ratios at pH 10.0,intermittent ratio 3:1,ultrasonic frequency 20 kHz,acoustic energy density 0.8 W/mL,ultrasonic temperature 60 ℃,ultrasonic time 15 min,BX-25311 and NS-9906 were 9:8 Under the conditions,the crude oil removal rate was 76.14 %.The experimental results showed that after adding the emulsion,the ultrasonic breaking effect was improved,the stability of the oil and mud was destroyed,and the crude oil removal rate was improved.(3)Using the removal rate of crude oil as an indicator,the oil-containing sludge of the refinery is treated by heat washing technology;With a mixing speed of 250r/min,a hot washing temperature of 55 ℃,a hot washing time of 15 min,a static settling time of 60 min,a concentration ratio of sodium dodecyl benzene sulfonate and sodium metasilicate of 4:3,the crude oil removal rate is 79.86 %,The experimental results showed that the organic reagent and inorganic reagent achieved the effect of inorganic roll up and organic lactation,and improved the removal rate of crude oil.(4)Using the crude oil removal rate as an indicator,the oil-containing sludge in the smelter is treated by ultrasonic breaking and hot washing combined process;Under conditionswith an ultrasonic frequency of 30 kHz,an ultrasonic power of 400 W,a pH of 9.0,an intermittent ratio of 4:1,a hot washing temperature of 55 ℃,a hot washing time of 40 min,and a stirring strength of 300 r/min,the crude oil removal rate was 84.06 %,The removal rate of crude oil was increased by 4.2 % by thermal washing only,and 7.92 % by ultrasonic cleaning only.The experimental results show that the combined process of ultrasonic emulsion breaking and hot washing can be used as the best treatment process for bottom sludge of oil tanks in lanzhou smelter.