CHARACTERIZATION AND PERFORMANCE ASSESSMENT OF A NOVEL NIO-FE3O4-POLYTHIOPHENE NANOCOMPOSITE FOR ASPHALTENE PRECIPITATION INHIBITION

Abstract

Precipitation and deposition of asphaltene represents a significant challenge in the oil industry. Nanomaterials are considered as proper candidates for asphaltene adsorption and precipitation owing to their exceptional physical and chemical features. In this dissertation, first, a novel NiO-Fe3O4-Polythiophene nanocomposite (NC) was characterized using various advanced analytical methods to ensure its authenticity. X-ray diffraction (XRD) was used to determine the crystallite size and explore structures of the NC. Scanning electron microscopy (SEM) was used to investigate surface morphology and assess the particle size of the NC qualitatively. Fourier transform infrared spectroscopy (FTIR) methods was used to identify functional groups and elemental bonding of the NC. Brunauer-Emmett-Teller (BET) method was used to determine surface area of the NC. Thermogravimetric analyzer (TGA) was used to explore thermal stability of the NC. Using the XRD data the crystallite size was determined 33.2 nm. The particle size of the NC ranges from 60 to 400 nm based on SEM images, and surface area of the NC was determined 55.83 m2/g using the BET test data. TGA analysis revealed that the NC is thermally stable with a negligible mass loss under reservoir conditions (80°C). To assess efficacy of the novel NC for adsorption and inhibition of asphaltene, UV-spectroscopy technique was used to determine Asphaltene Onset Point (AOP) in presence and absence of the NC and then supernatant obtained from TGA analysis was used for adsorption kinetics isotherm modeling. Adsorption kinetics isotherm modeling was done using the Langmuir (R2 = 0.98) and Freundlich (R2 = 0.95) isotherm models. The experimental data matched well both models which suggests monolayer and multilayer adsorption behavior for adsorption of asphaltene onto the surface of the NC. A maximum adsorption capacity of 1.116 mg/m2 was obtained for the NC. TGA analysis confirmed that oxidation of virgin asphaltene started at around 400-450℃; while oxidation of 5,000 ppm sample with NC started at around 350℃. The NC has catalyzed oxidation of the asphaltene. An optimum NC concentration of 0.3 wt% was obtained and an AOP shifting from 40% to 48% volume of n-heptane was observed for the optimum concentration. The outcomes prove that, the novel NC is an effective nano-inhibitor for asphaltene under laboratory conditions.