| Oily sludge is a semi-solid waste containing oil,water and mud.along with the whole process of oil production.Oily sludge is a hazardous waste,it has enormous harmful to the environment.Recycling oil not only can reduce the environment pollution,but also can carry out secondary utilization of resource.This article introduces the advantages and disadvantages of various methods,combining with the environmental requirements of the industry now,Finally,the method of thermochemical cleaning was selected to deal with hazardous oily sludge.This article takes the oily sludge of the Xinjiang Tahe’s oilfield as the main treatment target object,using the high efficient non-emulsion cleaning agents to deal with the oily sludge,then make the oil and sludge separation.Further,the oil content of sludge is reduced to below the prescribed emission level.At the same time,we can recover useful resources and obtain some economic benefits.Differences in oil composition in oily sludge lead to large differences in chemical cleaning.In this study,the total content of saturated and aromatic components of TH-0 is 53.66%,which is greater than that of TH-1,TH-2,and LN.The sum of aromas,under the same chemical cleaning conditions,the solid phase oil content after treatment was 0.36%,less than the treated oil content of TH-1,TH-2,and LN.The results of elemental analysis also showed that O/C and(O+N)/C are slightly smaller than those of the other three types of oily sludge,and TH-0 is slightly more polar and hydrophilic than the other three kinds of sludge.Strong,conducive to chemical cleaning.For the preferred chemical cleaning agent,integrated infrared spectroscopy analysis,Raman spectroscopy analysis and liquid chromatography-mass spectrometry analysis show that the main components of the cleaning agent are somewhat similar in function to the structure of the rhamnolipid surfactant.Has oil and water amphiphilicity,can reduce the water surface tension,can change the wettability of the solid surface.According to different conditions of solid-liquid ratio,agitation strength,concentration of cleaning agent,stirring time,reaction temperature and particle size distribution of solid phase,conditions affecting chemical cleaning of oily sludge were investigated.For the cleaning process,the influence of temperature,concentration,solid-liquid ratio and agitation intensity were based on four factors,and the process conditions were optimized based on the orthogonal design.The results showed that the optimum processing conditions were as follows:the washing temperature was 65,and the stirring intensity was For 350r/min,the optimum cleaning agent concentration is 10 g/L,the oil content measured after optimal conditions for treating TH-0 oily sludge is 0.31%,and the analysis of the range of the orthogonal process shows that The influence of various factors on the effect of sludge cleaning is from large to small:temperature,dosing concentration,solid-liquid ratio,and agitation strength.Through the coagulation and sedimentation treatment of the cleaning liquid,the content of petroleum in the circulating cleaning liquid can be effectively reduced,thereby reducing the re-adsorption of the residual petroleum in the cleaning liquid system by the solid phase,and the cleaning liquid is processed in 7 cycles.Under the conditions used,the oil content of the solid phase after treatment is not more than 1.5%.GC-MS was used to analyze the composition of petroleum in the cleaning process.Oily sludge contains complex oils,contains dozens of peaks,and has many miscellaneous peaks.In the aqueous phase,GC-MS spectrum analysis showed that the number of peaks was less,mainly the lighter molecular weight part.The alkane peak in the oil phase washed out by the cleaning agent is strong,and there are also many heavy components.The comprehensive analysis shows that after NY-1 cleaning agent treatment,petroleum oils do not exist in the aqueous phase in large quantities by emulsification.The reaction mechanism may be that the interface properties between oil and solid two phases are changed under the effect of cleaning agent.The surface of the solid phase is wetted and turned into a hydrophilic surface,thereby achieving the separation of oil and solid phases.The interfacial contact measurement system was used to analyze the three-phase interface behavior of oil,water and mud during cleaning.When the mass concentration of NY-1 reagent was 15 g/L,the interfacial tension had a minimum value of 4.26 mN/m.The contact angles between aqueous solution of NY-1 reagent and shale with different mass concentrations were determined.When the mass concentration was 10 g/L,the contact angle had a maximum value of 62.12°.The contact angle between NY-1 detergent and Tahe No.0 oily sludge before treatment was large,and the contact angle with the treated oil sludge was significantly smaller.It shows that the sludge after treatment has a hydrophilicity and the contact angle gradually becomes smaller. |
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