Abstract:
Crude oil spillages on the oceans cause huge financial losses to businesses and harm to the
environment and the species that depend on the oceans for survival. In order to cut down the
losses caused by spillages, decision was made to distill the crude oils for consumption. Before
distilling the crude, salt and sulphur had to be removed from it in order to avoid the destruction
of the distillation column during fractionation and the emission of sulphur compounds into the
atmosphere when the oil is used. Chemical desalting and oxidative extractive desulphurisation
methods were used for those processes. The distillation column used in the research was
designed and built by the researcher. The crude oil used for the work was obtained from Tema
Oil Refinery (TOR) and the seawater was fetched from the New Amanfrom Beach. The crude oil
was medium dark sour compound having a density of 900.8 kg/m3
. The American Petroleum
Institute (API) index of the crude was 25.47o
. Before desalting and desulphurisation, testing
the unspilled crude oil for salt and sulphur contents gave 13.2 g/m3
of salt and 3000 ppm of
sulphur in the unspilled crude oil. The test of the spilled crude oil also showed 89 g/m3 of salt
and 3530 ppm of sulphur contents. After two successive desulphurisation processes, the sulphur
in the spilled and the unspilled crude reduced by about 92 % and 88.82 % correspondingly.
Similarly, after five desalting processes, the salt in the spilled and the unspilled crude reduced
by about 63.13 % and 27.27 % respectively. The samples obtained from the distillation were
analysed using Fourier Transform Infrared (FTIR) Spectrometry and Gas Chromatographic
/Mass Spectrometry (GC-MS). The major fractions identified included gasoline, naphtha,
kerosene, diesel, fuel oil, and bitumen. The value of the API, the size of the distillation column,
the relative volatility of the crude components, and the surface area for the vapour and liquid
available in column influenced the fractions obtained. The total energy consumed to fractionate
the 2 liters of the crude was 1.813 x 103
kJ. The specific energy consumed by the crude fractions
are presented in an increasing order as follows: Gasoline, 388 J/g ˂ naphtha, 502.8116 J/g ˂
kerosene, 543.15 J/g ˂ diesel, 611.4441 J/g ˂ fuel oil, 763.7259 ˂ bitumen, 863.2596 J/g. The
analysis of the specific energy consumed by the crude oil fractions showed that more energy
was needed to fractionate the less volatile crude oil fractions than to fractionate the more volatile
crude oil fractions.
