Abstract: According to the needs of crude oil processing and coke quality upgrading, processes of organic acid extraction, extractant regeneration, organic acid recovery and stripper were used to treat the wastewater generated in the process of electric desalination and decalcification. Taking the wastewater samples with organic acid concentration of 3.0% as the object of investigation, based on the extraction equilibrium data of isopropyl acetate, isobutyl acetate, ethyl acetate and other ester extractants, isopropyl acetate was determined as the extractant. According to the requirements of treatment efficiency and acid concentration in water less than 0.2%, the appropriate extraction ratio (oil/water volume ratio) was determined to be 3:1, and the corresponding extraction level was 6. Under this condition, the organic acid recovery rate was 95%, and the acid concentration in the lower layer of water after extraction was 0.149%. The azeotropic distillation method was used to treat the upper layer extract, and the recovered acetic acid concentration was 96.81%. After stripping, the COD value of water quality decreased from the initial 29300mg/L to 4710 mg/L, and the COD value decreased by 83.9%. The water quality can meet the influent water quality requirements of the existing industrial wastewater treatment units of the company, and realize the reuse of organic wastewater or meet the discharge standards. At the same time, the implementation of this process can get economic benefits of 1.828 million Yuan per year.

Key words: electricity desalination, decalcification, extraction, industrial wastewater