Field Application Research On New Technology Of Oil Sludge Treatment In Refinery Wastewater Treatment Plant

During the operation of the petrochemical enterprise sewage treatment plant,the bottom sludge of the grease trap,the scum of the air floatation pool and the remaining activated sludge in the biochemical pool are collectively called"three muds"."Three muds"are difficult to handle due to their fine solid particles,serious emulsification,and complex pollutant composition.Moreover,with the rapid development of industry,the total amount of“three muds”is increasing.How to efficiently clean up the stock and deal with the increment has become an urgent problem to be solved by the refinery.This paper takes the“three muds”produced during the production and operation of a refinery in Guangdong coast as the research object,analyzes its physical and chemical properties,and conducts research and exploration on pretreatment and electrochemical experiment parameters,and then conducts on-site pilot tests according to the best laboratory parameters commissioning confirmed the process flow of"Hot Washing-Sedimentation-Electrolysis-Separation-Pressure Filtering-Drying".The pilot plant operated continuously for 100 days to determine the stability and feasibility of the process,and finally completed the design of an industrial plant with a processing capacity of24,000t/a.The specific results are as follows:(1)After adjusting the p H value of the"three mud"to 10 and heating it at 60?for45 min,the demulsification effect of the"three mud"is significant,and part of the oil and water can be initially separated to reduce the volume of sludge.The dry mud oil content dropped from 24.9%to about 20%.(2)The optimal conditions for electrochemical treatment of"three muds"are:chloride ion concentration 9000mg/L,current density 40m A/cm~2,plate spacing 2cm,electrolysis time 180min.After treatment,the color of"Three Muds"changed from black to brownish brown in normal soil,the water in the sludge gap increased,the sludge water separation rate increased,the viscosity decreased from 34c P to 14.8c P,the content of pollutants in the mud decreased significantly,and the dry mud oil content can be reduced from 24.5%to 8.25%(3)Press-filter and dry dehydration treatment of the"three mud"after electrolysis,the dosage of flocculant is determined to be 20L/t,the drying time is 2h,and the final moisture content of dry sludge is 24%.The volume of mud has been reduced by about 20times,and the reduction is obvious.(4)Based on the results of the pilot test,an industrial plant with a processing capacity of 24,000t/a designed for the refinery,with a total investment of approximately 13.0956million yuan.The treatment cost per ton of"three sludge"can be reduced to about 191yuan,which can save the refinery an average of nearly 7 million yuan in sludge outlay costs per year,which not only solves the problem of"three sludge"disposal in the refinery,but also brings good environment and economic benefits.