Extraction of naphthenic acids from petroleum crude oil utilizing 2-methylimidazole in ethanol / Siti Nur Ayuni Hassan

Naphthenic acid (NA) has been recognized as one of the major sources of
corrosion in oil production and refining process. In this study, catalytic extraction
reaction was investigated in order to lowering the Total Acid Number (TAN) in
crude oil to lower than 1.00 mg KOH g-1 utilizing 2-methylimidazole with the aid
of Ni/Ca (10:90)/Al2O3 catalysts. The catalyst were supported on the alumina
through Incipient Wetness Impregnation (IWI) methods and calcined at
calcination temperature of 800, 900 and 1000°C. Ni/Ca (10:90)/Al2O3 catalyst was
characterized by using Thermogravimetry Analysis-Differential Thermal Analysis
(TGA-DTA), X-ray Diffraction Spectroscopy (XRD), Brunauer-Emmett-Teller
(BET), and Fourier Transform Infrared Spectroscopy (FTIR) to study
physicochemical properties of the catalyst. The results shows that
Ni/Ca (10:90)/Al2O3 catalyst successfully reduced number of acids in crude oil to
lower than 1.00 mg KOH g-1. Ni/Ca (10:90)/Al2O3 catalyst reduced TAN of crude
oil from original TAN of 4.22 mg KOH g-1 to 0.65 mg KOH g-1 at 1000°C
calcination temperature and catalyst loading of 7 beads (0.39%). This proven by
XRD results that proposed Al2O3 face centered cubic (fcc) was an active site for
Ni/Ca (10:90)/Al2O3 catalyst even though surface area, average pore volume and
pore diameter was lower at calcination temperature at 1000°C. Stretching of N-H
imidazole from 2-methylimidazole, C-H stretching from the NA species and pure
metal oxides (M=O) stretching modes were detected on Ni/Ca (10:90)/Al2O3
catalyst at wavelength of 1455.96, 2952.2 to 2852.61 and 566.12 cm-1 respectively
by FTIR analysis. After catalytic extraction process which indicates that there
were impurities have been adsorbed on the catalyst surface. The catalytic reaction
was fixed at reaction time of 15 minutes and temperature at 27°C.