Synthesis of ZnO for wax deposition control and oil upgrading: effect of pH

Waxes and asphaltene depositions are one of the major problem happened during oil and gas operation. Deposition of asphaltene in pipes and pipelines may cause damages to the equipment and increase the maintenance cost. To overcome this problem, several methods are invented in the industries. One of the methods is by using nanoparticles as an agent in controlling wax deposition in crude oil because of their applicable characteristics. At some point, to maximize the outcome of the method, an optimum pH of nanoparticles is vital because the higher the pH, nano-size of nanoparticles become smaller. To get the best viscosity reduction and wax deposition control, uses nanoparticles at optimum pH is important. So, objectives of this study are to synthesize and characterize zinc oxide, ZnO nanoparticles by using sol – gel method in the effect of pH and to run performance study of zinc oxide in-situ addition to heavy crude oil. Firstly, heavy crude oil is characterized to obtain physical properties and rheology characteristics. Secondly, synthesis of ZnO nanoparticles by using sol-gel method in variations of pH values (pH 2, pH 3, pH 4 and pH 5). Thirdly, the ZnO nanoparticles is characterized using X-ray diffraction (XRD) to analyze crystal structure and crystallite size of ZnO nanoparticle. Energy Dispersive X-ray (EDX) and Field Emission Scanning Electron Microscope (FE-SEM) also used to observe morphology and final composition of ZnO nanoparticles. Lastly, performance studies of insitu addition of ZnO nanoparticle to heavy crude oil by using Electronic Rheometer and cold finger method. The result showed that high pH values will produce smaller crystallites size of ZnO nanoparticles when checked by using X-ray diffraction (XRD). Performance study result showed that optimum pH for wax deposition control is at pH 2. On the other hand, pH 4 ZnO nanoparticle give the best result for viscosity reduction of the heavy crude oil. When shear rate increases, the viscosity reduction decreases. In conclusion, this study will provide the best option of pH for ZnO nanoparticle that can be used to overcome the wax and asphaltene problems and oil upgrading in industries.