Compositional Changes in Aliphatic and Aromatic Fractions of Agbabu Natural Bitumen under Low Temperature Heating

ABSTRACT The compositions of aliphatic and polycyclic aromatic hydrocarbons in Agbabu natural bitumen (ANB) sample subjected to heating at low temperatures were examined. The raw flow type of ANB was obtained from the observatory well in Agbabu, and subsequently purified. The purified sample was divided and each division heated in an air oven for five hours at a specific temperature. The heated samples were cooled, separated and their aliphatic and polycyclic aromatic hydrocarbons contents were quantified using gas chromatograh coupled with flame ionization detector (GC-FID). The total aliphatic hydrocarbons (TALPH) found in the unheated sample of the bitumen was 484 g/kg, but samples subjected to heating at 50 70, 90,100, 110,120 and 140 o C contained 484, 467 , 462 , 420, 414, 388 and 350 g/Kg respectively. Similarly, the total polycyclic aromatic hydrocarbons (TPAHs) in the control sample was 708 µg/g while samples heated at 50, 70, 90, 100, 110,120, 140 and 160 o C contained 600, 523, 387, 307, 245, 213, 168 and 689 ug/g respectively. Distribution of these hydrocarbon compounds in the unheated sample was at variance with what was found in the heated samples. This implies that exposure of ANB to heating at low temperatures is sufficient enough to qualitatively and quantitatively alter the composition of the aliphatic and polycyclic aromatic hydrocarbons of the bitumen