| With With the rapid development of the petroleum industry and the continuous improvement of environmental laws and regulations,how to deal with oily sludge generated in the production process of the petroleum industry has become a prominent environmental issue.Based on the composition and properties of oily sludge from a certain oilfield in Daqing,this thesis studied the ball milling combined with chemical cleaning method to treat oily sludge.Through the combination of surfactants and the optimization of ball milling process conditions,the cleaning effect was enhanced and the cleaning mechanism was explored.The main research findings are as follows:(1)Through the screening and compounding of cleaning agents,it was found that different types of cleaning agents and different composite formulas have a significant impact on the cleaning effect.Among the 13 cleaning agents studied,chemical surfactant sodium dodecyl sulfate,biosurfactant Sophorolipid and alkaline inorganic salt sodium silicate showed better cleaning effects.The residual oil rate was less than 5% after cleaning with Sophorolipid and sodium silicate alone,and that was less than 3% after cleaning with sodium dodecyl sulfate alone.The residual oil rate and surface tension test results indicated that the ability of the cleaning agent to reduce the surface tension of the solution was positively correlated with its cleaning ability.(2)The orthogonal experiment was used to compound the chemical surfactant sodium dodecyl sulfate,biosurfactant Sophorolipid and alkaline inorganic salt sodium silicate,and the optimal compound formula of cleaning agent was determined,that was,sodium dodecyl sulfate 1.33% + Sophorolipid 0.17% + sodium silicate 2%(mass percent concentration),and it was found that the effect of the dosage of each agent on the residual oil rate was in the order of Sophorolipid>sodium dodecyl sulfate>sodium silicate.(3)By conducting experiments on ball milling process and studying the mechanism of process parameters,the optimal process conditions were determined,namely,ball milling time of 35 minutes,ball milling speed of 500 r/min,ball milling liquid-solid ratio of 5:1,and mixed solution p H of 9.Under the optimal process conditions and composite formula,the residual oil rate of oily sludge reduced from 14.70 % to 1.83% after cleaning,which could meet the national emission standards.The results indicated that ball milling technology can reduce the particle size of oily sludge,increase its contact with cleaning agents,accelerate the solubilization rate of petroleum hydrocarbons in cleaning agents,shorten the time required for solubilization,and greatly improve the cleaning efficiency and effectiveness of oily sludge. |
