Study On Treatment Of Refinery Oily Effluent By Three-dimensional Electrode Method

Oily effluent is a kind of industrial effluent with complex composition.Because of the high content of emulsified oil,it is difficult to be removed,which causes serious harm to human health and ecological environment.According to the characteristics of oily effluent from coking emptying tower in a refinery,an experimental study on the treatment of oily effluent with three-dimensional electrodes is carried out.The effects of treatment methods(adsorption method,two-dimensional electrode method,three-dimensional electrode method),electrode materials,temperature,flocculant agents and single factor conditions on oil content are investigated.Besides,Orthogonal experiments are designed to explore the influence of single factor conditions on oil content.The results show that the treatment effect of three-dimensional electrode is better than that of adsorption method and two-dimensional electrode.Considering the changes of oil content,current and water quality in the treated effluent,the graphite is selected as the anode material of the main electrode plate and the stainless steel is selected as the cathode material of the main electrode plate and the 6 mm columnar activated carbon is used as the filling particle electrode.In addition,increasing temperature appropriately can accelerate the degradation of oil pollutants,and the use of flocculant agents can improve the flocculation sedimentation rate and the treatment efficiency of oily effluent.The results of factor process experiments show that electrolysis time,voltage,quality of activated carbon,plate spacing and air intake have important effects on the treatment of oily effluent.Besides the orthogonal experiment,the order of the degree of affecting the oil content in the treated effluent is electrolysis time > activated carbon mass > air intake > voltage > electrode spacing.According to the experimental results,the technological conditions of oily effluent treatment are listed below: electrolysis time180 min,voltage 30 V,active carbon filling quality 500 g,plate spacing 6 cm and air intake 1.0 L/min.At this time,the oil content in the treated effluent is 10 mg/L,and the oil removal rate can reach 96.97%,which meets the requirement of oil contentdischarge standard for pollutant discharge in petroleum refining industry.In addition,a ceramic membrane separation device is added before the three-dimensional electrode device to improve the process plan.The oil content in oily effluent decreases with the ceramic membrane device,and the smaller the pore size of the membrane,the lower the oil content.The reaction time decreases after entering the three-dimensional electrode device,which improves the efficiency of oily effluent treatment.The micro-morphology and GC-MS atlas of oily effluent before and after treatment are compared and analyzed.The results show that the purification of coking oily effluent was realized by the improved three-dimensional electrodes.In addition,the kinetics of treating oily effluent with three-dimensional electrodes,the service life of activated carbon and the impurities after treatment are also studied.The results show that the reaction of treating oily effluent with three-dimensional electrodes is a three-stage reaction,and the mass fraction of the residual after treatment with 400 m L oily effluent is only 0.053%.At the end of this paper,the existing problems and future research directions of three-dimensional electrode method are pointed out.