Solvent Blend Performance in Hydrocarbon Recovery from Nigerian Tank Bottom Sludge

Abstract

Oil sludge waste associated with crude oil production generally consists of oil, sands and untreatable emulsions segregated from the production stream, and sediment accumulated on the bottom of crude oil and water storage tanks. The use of single solvent and combination (solvent blend) was evaluated for extraction of hydrocarbon content (oil) of the Tank Bottom Sludge (TBS) associated with the crude oil production with a view to optimizing hydrocarbon recovery from the sludge. TBS samples were contacted with selected solvents blends of varying volumetric ratios, each at a time. The blend generated from xylene, hexane, cyclohexane and petroleum ether representing aliphatic and aromatic interactive combination with varying polarity. Their effects on the oil recovery from tank bottom sludge were determined, with solubility parameter as a factor. The optimum oil recovery by blend A, B and C at room temperature of 29°C, from sample 1 are respectively 54.48% (3:2), 60.33% (2:3) and 61.10% (1:1); from Sample 2, were respectively 66.25% (2:3), 60.80 (3:2) and 63.35 (1:1) at room temperature of 29°C . At room temperature Blend C has the highest performance in extracting oil from sample 1. The highest performance in recovery of oil from sample 2 was observed with blend A (66.25 %.). Solvent extraction process is very effective in recovering hydrocarbons oil from TBS. The use of solvents mixture greatly improved oil recovery from TBS and varies with blend composition and the operating temperature condition.