Technology&Application Study On Sewage Treatment Process Reconstruction For Refining High Acid Crude Oil

The topic studied on the sewage quality discharged by each unit in theproduction process, and determined the main sources of naphthenic acids in thewastewater for refining high acid crude oil. It also evaluated the effect of sewagetreatment units and accounting design parameters, which to determine the mainfactors of influencing the efficiency of processing system ability. In combination withthe practical conditions of the sewage treatment system, the topic had selective testsfor the sewage treatment technology of refining high acid crude oil, and thereconstruction program was put forward and optimized in combination with thepractical process of sewage treatment and the status. Through this topic research, thefollowing conclusion was formed:1.naphthenic acid in the wastewater that discharged by each production unitmainly came from sulfur containing wastewater in delayed coking unit, sulfurcontaining wastewater in atmospheric distillation unit, sulfur containing wastewater indiesel hydrogenation unit and drainage in the electric desalting device, in which thehighest of sulfur containing wastewater in delayed coking unit, the less of sulfurcontaining wastewater in atmospheric distillation unit and diesel hydrogenation unit,and the least of drainage in the electric desalting device. There was little naphthenicacid in sulfur containing wastewater of catalytic cracking and vacuum distillationdevice, but barely in sulfur containing wastewater of catalytic reforming unit, gasolinehydrogenation unit, and sulfur recovery unit.2. the oil removal effect by facilities in wastewater treatment plant of refineryhad a direct impact on the normal and stable operation of the subsequent biochemicalsystem. According to the analysis of wastewater processing by high acid crude oil,Wastewater emulsification, especially electric desalting wastewater emulsification(naphthenic acid) is one of the most important factors to lead to remove oil difficultlyand have the impact effect on subsequent biochemical treatment. It should beperfected by the oil demulsifier, which we should focus on.3.electrolytic floating system can complete the oil-water separation, meet therequirements of purification for the sewage, reduce the influence of the naphthenicacid on wastewater treatment process, slow down the surface foam and chroma of biochemical system, and improve the efficiency of sewage purification by thesubsequent oxidation ditch.4. in biochemical treatment unit, the effluent COD concentration is high (up to3000) after oil removal, and has a high proportion of difficult biodegradation material.It should strengthen hydrolysis acidification before the biological oxidation.5.after refining high acid crude oil, because the types of additives in the refiningprocess was more, difficult to biodegradability of organic pollutants in wastewaterwas more complex, and wastewater biodegradability was worse, it was used byadvance oxidation process coupled with the next biological treatment to improve thebiodegradability of wastewater,the effluent stability, and the purification efficiency.Through this topic, it was found out the influence of the change of water qualityin each part of refining high acid crude oil on the sewage treatment effect, and themain source of naphthenic acid in waste water had been known. Through theadjustment and transformation of the sewage treatment process, it could be able tobasically meet emissions standards and normal operation requirements for sewagereuse device, which provides the reference for wastewater treatment of other refininghigh acid crude oil.