Application of Ultrasonicated Blended Solvent for Dewaxing of Crude Petroleum Oil

Wax deposition is a serious problem in the petroleum industry that results in plugging of flow strings, formation damage, loss of hydrocarbons, increased production cost. In order to overcome wax deposition problem, this study investigated the feasibility of acetone: n-pentane as a selective solvent to dewax a Nigerian heavy crude oil using ultrasonic technique. To understand the effectiveness of selected solvent mixture for dewaxing process, the ultrasonic velocity, density, viscosity are determined experimentally at temperature 30°C. From the experimental data the acoustic parameters such as adiabatic compressibility (β), intermolecular free length (L_f), acoustic impedance (Z), interaction parameter (η) and molar volume (V_m) and their excess values are calculated. The variation of acoustic parameters and their excess values are discussed in terms of molecular interactions present in the solvent mixture which explains the physio-chemical behaviour and optimum feasibility condition of the blended solvent for dewaxing of the crude oil. Experiments were conducted on three solvent to crude oil ratios (10:1, 15:1 and 20:1) at 30°C. Each crude oil sample was weighed out and mixed with acetone: n-pentane at a predetermined mass ratio and then heated in a hot water bath and stirred until a thermal equilibrium was achieved. The results indicated that acetone: n-pentane dewaxing performance improved at 30°C temperatures.