DOI: https://doi.org/10.55373/mjchem.v25i3.314

Keywords: Crude Oil; heterogeneous catalyst; naphthenic acid

Abstract

Naphthenic Acids (NAs) found in crude oil are the major causes of corrosion problems in oil pipelines, distillation unit, storage, and facilities. As a result, crude oil with high NA will be marketed at lower price and considered as low quality. In this study, catalytic extraction reaction was conducted to lower the Total Acid Number (TAN) in crude oil to below than one mgKOH/g utilizing 2-methylimidazole with the aid of different types of metal supported onto Alumina. The synthesized catalysts were Ca/Al2O3 and Ce/Al2O3 from alkaline earth metal and rare earth metal group. The metals were supported onto Alumina beads by using Incipient Wetness Impregnation (IWI) methods and calcined at 700℃. Thermogravimetry Analysis-Differential Thermal Analysis (TGA-DTA) was used to determine the suitable calcination temperature for both catalysts. Petronas Penapisan Melaka crude oil was selected to be tested with the original TAN being 5.30 mgKOH/g. The parameters studied were the catalysts’ loading and reaction time. The catalytic reaction was fixed at reaction temperature of 27℃. The results showed that Ca/Al2O3 and Ce/Al2O3 catalysts successfully reduced TAN value in acidic crude oil to below than 1.00 mgKOH/g. Ca/Al2O3 catalyst gave a better reduction with 0.08 mgKOH/g compared to Ce/Al2O3 catalyst which only reduced the value to 0.65 mgKOH/g. Stretching modes of (M=O) were detected before and after the reaction while CH3 stretching, carboxylic acid (C=O), CH2 and CH3 bend were detected by FTIR analysis which indicated that there were impurities that had been absorbed on both catalysts after the reaction. In summary, alkaline earth metal of Ca supported with Alumina is the best catalyst in the study. The catalytic extraction technique successfully extracts NAs from the crude oil sample thus reducing the TAN value to less than 1.00 mgKOH/g.