The effectiveness of K/Al2O3 and Ca/Al2O3 heterogeneous catalysts in the extraction of naphthenic acid from petroleum crude oil

Abstract

The rising demand for conventional crude oil has made it a major source of energy in recent years, but raw crude oil contains Naphthenic Acids (NAs), which may cause severe operational issue for the oil refineries within the petroleum industry. The value and quality of the oil treated will also be affected by the presence of this molecule. As a result, removing NAs from crude oil is more important to avoid corrosion. The purpose of this study is to create a catalytic extraction method using ethanolic 2-methylimidazole and heterogeneous K/Al2O3 and Ca/Al2O3 catalysts to remove the NAs from crude oil with high Total Acid Number (TAN) crude oil. Aqueous Incipient Wet Impregnation (IWI) method was used to make the catalysts preparation. To improve the TAN value, various parameters such as reaction temperature (27-45°C), catalyst loading (5-20wt%), and catalyst calcination temperature (700-1000°C) were investigated. X-ray Diffraction Spectroscopy (XRD), Scanning Electron Microscopy- Energy Dispersive X-ray (SEM-EDX), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Gravimetry Analysis (TGA) were used to analyzed the catalysts were. When utilizing a Ca/Al2O3 catalyst, 89% of the TAN was removed in mg KOH/g, however when using K/Al2O3 catalyst, 83% of the TAN was removed by employing a catalyst loading at 20wt%, reaction temperature of 35°C and reaction time of 15 minutes. As a result, the treated acidic crude oil satisfies the PETRONAS criteria of having a TAN of less than 1.0 mg KOH/g.