Pusat Pengajian Kejuruteraan Kimia - Tesis

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Browsing Pusat Pengajian Kejuruteraan Kimia - Tesis by Author "Asaad Salim Bded Alibraheemi"

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    Synthesis and performance of bio additive from blending of dimethyl Ketone and sesame oil based methyl ester for enhancing heavy crude oil flowability at low temperature
    (2024-09-01)
    Asaad Salim Bded Alibraheemi
    The unique properties of natural extracts from vegetable oils serve as an alternative and effective bio-additive. In view of the need to address the issue of high viscosity and poor fluidity of heavy crude oil in pipelines during transportation at low temperatures, this study aims to synthesis a bio-additive of a dimethyl ketone with methyl esters blend extracted from vegetable sesame oil (VSO), based on optimal viscosity proportion that fulfills the standard specifications, and it assesses the impact in combination with temperature and shear rate to enhance the viscosity and rheological properties. Characteristics of bio-additive revealed that it contained 79.13% unsaturated fatty acids and 3.96 cSt kinematic viscosity. The addition of 1500 ppm of bio-additive concentration resulted in a remarkable reduction in viscosity up to 90.5%, 89.8%, 89.4%, and 88.6% at a 1.89, 46.5, 112, and 233 s−1 shear rate, respectively. The activation energy also decreased from 46.0 to 30.48 kJ/mol as the temperature increased from 5°C to 30°C. The heavy crude oil experimental data followed the Herschel-Bulkley and Power Law models, and its behaviour approached Newtonian at 1000 ppm. The consistency index decreased from 0.3099 to 0.0281, the flow behaviour index increased from 0.9428 to 1, and the yield stress decreased from 9.554 to 0.067 Pa at 30°C with the incorporation of 1000 ppm. Bio-additive effectiveness was documented by reducing the wax appearance temperature from 13 ℃ to 4.4 ℃, crystallization point shifted to the left from 19.4 to 16.9 °C, asphaltenes onset point delayed from 26 to 63 and 47 to 65.5 vol.% of n-heptane with 250 mg/L and 75 mg/L asphaltenes, respectively, and pour point temperature declined by 6.5°C using 1500 ppm. The minimum viscosity of 25.518 mPa.s was achieved at optimal conditions of bio-additive concentration of 1084 ppm, temperature of 30℃, and a shear rate of 106 s -1 via the Box-Behnken Design model. Cold surface pipe experiment revealed that deposition reduced from 0.1002, 0.1662, and 0.0988 g to 0.0619, 0.0498, and 0.068 g, respectively, at -5°C of cold flow temperatures by 1500 ppm. In short, the bio-additive has the potential to reduce viscosity and enhance the flow properties of heavy crude oil even at low temperatures.