Gelation of waxy crude oil system with ethylene-vinyl acetate on solid surface: A molecular dynamics study

Pour point depressant is one of the effective approaches to improve the low temperature fluidity of high-wax crude oil. Understanding the gelation of waxy oil on the pipe wall and the mechanism of pour point depressant is of great significance for the transportation of crude oil. In this work, molecular dynamics simulations were employed to investigate the effects of ethylene-vinyl acetate (EVA) on the gelation of the waxy oil at different temperatures (283 K, 293 K, 303 K and 313 K) and to get insight into the wax deposition on a micro-level. The results showed that the network structures of wax crystals formed at the solid wall with temperature of 283 K, 293 K and 303 K, which caused the gelation of waxy crude oil. The wax crystals tended to be arranged horizontally near the wall and vertically away from the wall surface. Actually, the crystallization of wax molecules can not be prevented by EVA. However, the pour point of oil system was reduced by the EVA which prevented the wax crystal deposition and changed the shape of wax crystal.