Preparation of Copolymer Based on Octadecene and Maleic Anhydride as Pour Point Depressant for some Types of Gas Oil
Shaker Mabrouk Ebrahim*, Mosaad Atta EL-Kasaby*, Mohamed reda kenawy**
Institute of Graduate Studies & Research, Alexandria University*. Alexandria Mineral Oils Company**.
Paraffin wax deposition from gas oil at low temperatures is one of the serious and long standing problems in the petroleum industry. At low temperatures, the crystals of wax easily form impermeable cakes, which can block filters and eventually lead to engine failure. Many methods have been attempted for the prevention of the crystals mating together. Adding pour point depressants is one of the most important methods for improving the low temperature flow properties of gas oils.
In this work two types of pour point depressants were prepared which are polyoctadecene and Poly (α-octadecene-co- maleates) ester to treat two types of gas oils from Alexandria Mineral Oil Company which are cracked gas oil and Vacuum gas oil. The synthesized polymers characterized by Fourier transformer infrared spectroscopy and Proton nuclear magnetic resonance. The interactions between wax crystals and pour point depressants were investigated by differential scanning calorimetry and x-ray diffraction analysis.
It was found that polyoctadecene reduced pour point of cracked gas oil from (+24) to zero at 400 ppm while Poly (α-octadecene-co- maleates) ester reduce it from (+24) to (-6) at 400 ppm and polyoctadecene reduced pour point of vacuum gas oil from (+27) to (+3) at 400 ppm while Poly (α-octadecene-co- maleates) ester reduce it from (+27) to zero at 400 ppm. Results showed that pour point depressants do not completely prevent the wax from precipitating, but just shift the precipitation toward a lower temperature and the degree of crystallinity decreases with addition of pour point depressants.
A Comparison studies were carried out between the prepared polymers and a commercial one, it was found that the prepared polymers showed a better performance than the commercial one (6103) at the same concentration rate. Economically, the prepared polymers are found to be much cheaper than the commercial one (6103).