An Experimental Study On Recovery Of Crude Oil From The Sediment In Petroleum Tanks By Solvent-extraction Process

At present,pyrolysis and profile control are ubiquitously used to treat and dispose oily sludge for its good performance,yet spot operators hastate to choose such methods hurriedly since they have discerned the risk of them.Aimed at sediment in petroleum tanks from Dagang oilfield,this paper investigated the solvent-extraction method and process for its high efficiency and security.In this paper,some conclusions are drawn.(1)Oil content,water content and sand content of Dagang-oily sludge are 34.23%,38.89% and 26.92% respectively.The two typical solvents are diesel oil and xylene.The compound solvent DD-1 is based on the volume fraction of Diesel/Xylene 0.75,which is significantly better than the single solvent,with the extraction rate of 63.94%.Four-stage countercurrent extraction is recommended for extraction technology,the extraction rate can reach 90%.(2)At 20?,the best treatment effect are obtained by high-speed rotation of 190 r/min at the maximum influencing factor time of 20 min after mixing at the solid-liquid ratio of 1:5.The optimum operating parameters of Extraction residue that cleaning Time is 15 min,solid-liquid ratio is 3:1,stirring speed is 500 r/min,temperature is 60?,p H value is 8.The operating parameter influence order is Time over solid-liquid ratio over stirring speed over temperature over p H value.(3)The dry oil content of four stage extraction residue is 13.01% ? 13.34%,and the residual solvent content is 12.10% ? 12.87%.Tween 80 is selected as the washing surfactant,and the oil content of the first cleaning reached 2.35%,and the oil content of the second cleaning reached 1.68%.(4)To study the desorption process of oily sludge in DD-1 extraction,the correlation coefficient of Langmuir model is higher than Temkin model,Freundlich model and Herny model,reaching 0.9984.Comparing the four components before extraction,it is found that DD-1 has a certain degree of adsorption capacity for saturated hydrocarbons and aromatic hydrocarbons,but stronger adsorption capacity for gum and asphaltene.X-ray fluorescence spectrum analysis of solid particles of the main ingredients in the sludge SiO2 is 67.625%,each element has no obvious change after the smoke in advance.High temperature simulated distillation solvents show that extraction can reduce the organic matter between C20 to C40,but C15 to C20 increases significantly.The main residual solvents after extraction are residual solvents.GC-MS analysis shows that the main components of organic matter in the residue are distributed between C6 to C20,mainly pentadecane,hexadecane and xylene.The main residue was extractant.(5)Solvent extraction is the main process.Surfactant-assisted water washing can remove residual solvents,which can make the total petroleum hydrocarbons of tank bottom mud in Dagang Oilfield less than 2%.It has good economic value and practicability.