Removal of Benzoic Acid in Heavy Oils by Esterification Using Modified Ferrierite: Roles of Brønsted and Lewis Acid Sites

A utilization of heavy crude oils having a high total acid number (TAN) has been increased recently as a result of its lower price, and deacidification processes by esterification or thermal decarboxylation using heterogeneous catalysts can be a possible way to remove or neutralize acidic components in heavy oils. A conversion of benzoic acid as a model component of naphthenic acids was investigated using metal-modified H-form ferrierite in a batch reactor to verify the separate contributions of Brønsted and/or Lewis acid sites for esterification and decarboxylation reactions with methanol. The surface acid properties of metal-modified ferrierite with K, Zr, and P species significantly altered the extent of decarboxylation and esterification activities by showing a higher removal rate of benzoic acid on K-modified ferrierite. The amount of Lewis acid sites on metal-modified ferrierite wa…