Abstract: In order to optimize the structure of polyether demulsifiers in slurry settling agents，carboxyl-terminated polypropylene glycol (PPG) was synthesized by means of carboxyl chain extension. Carboxyl-terminated polypropylene glycol reacts with polyethylene glycol (PEG) in the presence of a catalyst to form block polyether. The optimal conditions for the synthesis of carboxyl-terminated polypropanediol were determined by acid value, 1H NMR,FT-IR,GPC and other characterization methods. Polyether demulsifiers with different block structure, block proportion and average relative molecular weight were prepared by PEG and PPG with different average relative molecular weight, and the performance of different demulsifiers in the course of slurry de-solidifying was compared by slurry sedimentation test. The results showed that the PEG-PPG-PEG block polyether with molecular weight of 10 000 and mass ratio of PPG/PEG of 4:1 had the best performance, and the de-solidifying rate of slurry reached 92.4%, which could effectively reduce the ash content in the slurry and improved the slurry utilization rate, and had good market application prospect.

Key words: demulsifier, oil slurry, desolidation, carboxyl chain extension, block polyether