Efficiency enhancement of polyols derivatives surfactants for oil and water phase separation

Noik C.¹, Dalmazzone C.¹ and Dewattines C.²

¹ IFP - 1&3 Avenue Bois-Preau, 92852 Rueil-Malmaison -cedex - France

² Oleon -Industriezone Ter Straten, Vaarstraat 130, B-2520 Oelegem, Belgium

Emulsions formation always occurs during oil production and their presence drastically increases the technical problem of phase separation in production process. Considering the physico-chemical characteristics of the water-in-oil emulsion formed, additives injection is required to destabilise emulsions and enhance coalescence phenomena between droplets. Surfactants based on polyols derivatives chemical structure exhibit some interesting properties as emulsion breakers. Moreover these products are totally safe according to the environmental regulation related to non-toxicity , biodegradation and non-bioaccumulation behaviour.

     The objective of the study is to analyse the mechanism of action of such surfactants on oil/water interface destabilisation in order to enhance their properties in relation with chemical structure modification. Complementary techniques are used. Effective separation ability of different surfactants was first evaluated according to the classical “bottle test”. From this preliminary screening, some polyols derivatives appeared to be efficient on several crude oil emulsion types and were therefore studied more intensively. Turbidimetric measurements with a vertical scanner permitted to quantify the water and oil separation kinetics and also the quality of  the separated water. Separation efficiencies were related to the chemical structure of the product such as esterification degree or molecular weight and to the interfacial properties on some products. Finally, selected products and formulations were tested through dynamic tests using a dispersion rig set-up. This experimental technique permits, for a fixed oil/water system and temperature, to control the formation of  emulsions according to an average droplet size criteria. Additives are injected in the flow line into the formed emulsion. Separation performances observed under static bottle test and dynamic experimental conditions were compared.