Removal of Naphthenic Acids of a Second Vacuum Fraction by Catalytic Esterification

Abstract

This article introduces a catalytic esterification process to reduce the acid number of a high acid content petroleum fraction. The fraction was treated with methanol under conditions sufficient to form the naphthenic acid esters. In this way, the acid number of the petroleum fraction could be lowered. SnO could accelerate petroleum oil esterification. The acid removal ratio was much higher in the presence of SnO than without it. The optimal reaction conditions were: reaction temperature 300°C, the quantity of methanol in oil was 5.0 wt%, the quantity of catalyst SnO was 4.0 wt%, and a longer reaction time was preferable.