Study On Nanofiltration Membrane For Extraction Solvent Recovery Of Crude Oil Deacidfying

The process of alcohol-ammonia chemical extraction for deacidfying curde oil and recovery for Naphthenic acids is the hotspot for research nowadays. But it has problems such as the high energy consumption, it has a long distance for industrialization. Organic solvent nanofiltration (OSN) technique for extraction solvent recovery exhibits great strongpoint for its low consumption of energy, high separating efficiency of single stage, simplicity of the whole process and non-staining to environment. The successful industrial application greatly depends on the membrane properties for the solvent extraction-nanofiltration coupling technique for deacidfying crude oil. In this dissertation, typical phase-inversion method was employed to prepare polyimide nanofiltration membrane, and carry heat treatment and grafting modification. The main aim is developing an efficient means for solvent recovery with nanofiltration membrane in crude oil extraction–deacidifying process. At first, polyimide nanofiltration membrane was prepared by phase- inversion method. The permeation flux and rejecton rate were investigated under different casting solution recipes and preparation process conditions. Then nanofiltration Membrane were grafting-modified with UV irradiation. A series of grafting modified nanofiltration membranes were obtained and their performances were tested. The suitable process condition of UV grafting modification were determined for the membrane for solvent recovery deacidfying crude oil. As a result, the prefer preparing conditions of nanofiltration membrane is as follows: apparent viscidity being 310mPa·s, volatilization time being 60s, the coagulation bath being alcohol and the post treating process is being dipped separately in alcohol, isopropanol, hexane and proportional butanone and toluene and lubricant for 24 hrs. Under the pressure of 4 MPa and the ambient temperature, the flux of membrane is 18.6L·m-2·h-1 and the rejection is 47.3%. The result after graftion is as follows: the flux of membrane being 14.8L·m-2·h-1, the remain rate being 62.9%. The above results laid a foundation for the further development of membrane for deacidfying crude oil-solvent recovery technology.