The effect of cationic unit structure on reverse demulsification and air flotation performance of cationic polyacrylate

Abstract

Cationic polyacrylates have efficient reverse demulsification performance and air flotation performance, which make them potentially viable for application in offshore oil fields. However, study of the relationship between their structure and performance is still lacking. In this paper, four compounds (benzyl chloride, 3-chloro-1-propanol, 3-chloro-1,2-propanediol and 3-chloro-2-hydroxytrimethylammonium chloride) were used to modify the copolymer of acrylate and tertiary amine monomer, and four cationic polyacrylates (CP-1, CP-2, CP-3 and CP-4) with different cationic unit structures were prepared. The hydrophilicity of the cationic units in these four cationic polyacrylates increased successively. The relationship between the cationic unit structure, interface properties and produced water treatment performance of products was studied. The results showed that CP-1 had the highest air flotation efficiency because it had the largest adsorption capacity on the surface of bubble and the strongest attractive force between oil droplets, while CP-2 had the highest reverse demulsification efficiency because it had the largest adsorption capacity on the surface of oil droplet and the strongest ability to reduce the elastic modulus of the O/W interface. The research results can provide a reference for chemical agent selection in the treatment of oilfield produced water.