ORGANIC MATTER IN PETROLEUM SLUDGES: A SOURCE OF USEFUL MATERIALS Part 1: Separation of Organics and Fractionation by Alkane Solvents

Abstract

ABSTRACT The environmental impact of organics in crude oil sludge discharges and their potential loss as valuable resources, necessitates investigations on their recovery and use. Organics in sludges deposited from two high API, low sulfur and low asphaltenes, parafinic Libyan crude oils: (Sedra CO., API = 37, S = 0.39%, Asphaltenes = 0.73%; and : Hamada CO., API = 39, S = 0.08%, Asphaltenes = 0.28%) were extracted with toluene using a modified Soxhlet system (MSS). In addition to organics extraction, toluene azeotroped water impurity, which was then separated in a specially designed side-arm graduated tube receiver in the MSS. Toluene was removed from TSO under low pressure distillation which effected loss of light ends. TSO, 89.3 ±1.6% (Hamada) and 95.4 ±1.2% (Sedra) were determined by evaporation of toluene in a rotavapor under 20 mm Hg ; and after readjusting for lightends loss. TSO was sub-fractionated with normal pentane (n-C5) and normal heptane (n-C7) to insolubles and maltenes fractions. The n-C5 insolubles were 25.6 ±2.5% and 27.8 ±5.0% and the n-C7 insolubles were 24.2 ±3.9% and 22.0 ±1.1% in TSO from Hamada and Sedra sludges respectively. Toluene insoluble matter (TIM) and azeotroped water content (AzW) were also determined. Thus the values of TIM: 8.6 ±1.8%, 2.9±1.1%; and AzW : 1.8 ±0.3%, 1.9±0.4for Hamada and Sedra sludges respectively were obtained. Ultimate analysis and ash contents of TSO's, n-C5 and n-C7 insolubles and maltenes were also conducted.The big increase in the n-C5 and n-C7 insolubles in the TSO from the two, low asphaltenes crude oils is discussed and a mechanism of deposits formation is proposed.