Abstract:In order to realize coordinated neutralization and disposal of liquid hydrocarbon base residue and spent ionic liquid catalyst, a chemical precipitation-flocculation process was used to pretreat liquid hydrocarbon base residue to remove sulfide and COD. The main factors affecting chemical precipitation method were systematically investigated. The removal rate of sulfide in liquid hydrocarbon spent caustic is 96.88% and COD removal rate is 74.68% under the conditions of precipitant dosage of copper sulfate of 34 g/L and reaction time of 20 min. The reaction system was further treated by flocculation method, and cationic polyacrylamide was selected. Under the conditions of flocculation reaction time of 20 min, settling time of 90 min, and dosage of 15 mg/L, the total removal rate of sulfide in liquid hydrocarbon spent caustic rises to 97.13%, and COD removal rate is 81.67%. The spent caustic treatment by chemical precipitation-flocculation process were neutralized at 20 ℃ with ionic liquid hydrolyzate by controlling volume ratio of 14︰100. After the reaction, the COD, sulfide, and oil indicators in neutralized liquid can meet the third-level sewage discharge standard of "Comprehensive Wastewater Discharge Standards" (GB 8978—1996), and realizes the coordinated neutralization treatment and utilization of liquid hydrocarbon spent caustic and ionic liquid waste catalyst.