Effects of some treatment chemicals on the quality of a crude oil blend in Nigeria

Abstract

Quality assurance parameters of untreated and treated samples of a crude oil blend in the Niger Delta area of Nigeria were analyzed with SVM 3000 densitometer, Normalab cloud / pour point test Cabinet, hydrometer and Rotanta 460R petroleum centrifuge using standard methods (American standard for testing and materials). Crude oil samples were treated with chemicals using pour point depressant, wax inhibitor and demulsifier at different concentrations of 10, 20, 30, 40 and 50 ppm respectively with the gross production of the crude as the reference fluid. Results obtained for the treated crude; cloud point (22.0000 - 9.0000 ⁰C), pour point (-12.0000 - 11.0000 ⁰C), specific gravity (0.8222 - 0.8500), API gravity (34.9700 – 40.60000), density (821.8000 – 850.0000 Kg/m³), kinematic viscosity (1.0870 – 4.0000 cSt), wax recovered (5.0000-20.0000 Kg), (BS&W)basic sediment and water (8.0100 – 17.0500 %) compared with those of the untreated crude; cloud point (23.0000 ⁰C), pour point (11.0000 ⁰C), specific gravity (0.8537), API gravity (34.2500 0), density (853.7000 Kg/m³), kinematic viscosity (4.0102 cSt), wax recovered (35.0000 Kg), basic sediment and water (19.1000 %) showed that all the measured parameters of the crude except the API gravity reduced with increasing concentration of the treatment chemicals used. The increased API gravity of the crude was a reflection of the increased market value of the crude and it is inversely proportional to the other quality assurance parameters considered. The flow characteristics of crude oil diminished as soon as wax crystallization began to occur, this was evident from the cloud point, pour point and the weight of wax recovered after pigging. Treatment with wax inhibitor and pour point depressant reduced these parameters to an acceptable level for the production facility. Demulsifier played an important role in breaking off the water and sediment from the crude which in turn reduces the BS&W, density and specific gravity of the crude thereby optimizing crude production, transportation and delivery. Treatment chemicals in general compliment the production facility in imparting the desired quality on the crude oil.

Keywords: Hydrocarbon, pour point depressant, wax inhibitor, demulsifier, crystallization, pigging, emulsion