Triblock copolymers functionalized with quaternary ammonium salts as dehydrating agents for heavy and extra-heavy crude oils

摘要

Block copolymers PEO-PPO-PEO α,ω-functionalized with tertiary aliphatic or aromatic amines were synthesized to obtain a new type of ammonium salt. The compounds were evaluated as demulsifying agents in extra-heavy and heavy Mexican crude oils, 7.5° and 17.8° API. The grafting at the copolymer ends with trioctylamine and quinoline demonstrated to be the best functionalization for increasing the demulsifying efficiency in both crude oils. It was evidenced, for copolymers functionalized with aliphatic amines, that the length of the alkyl chain of the amine plays an important role in the potential to remove emulsified water. Furthermore, it was observed that higher positive value of log P parameter has a strong correlation with the performance of block copolymers functionalized with aliphatic amines. In the case of aromatic amines, the atomic charge of nitrogen proved to be an important factor to provoke the coalescence of the water drops. Finally, the molecular mass of block copolymer was also evaluated, showing that copolymers with higher M_n are more efficient to remove the water from crude oils with huge amounts of asphaltenes.