(490e) Surface and Structural-Modified Pyroxene Nanoparticles for Adsorption and Catalytic Thermal Decomposition of Visbroken Residue Asphaltenes

The energy demand is growing worldwide due to the increase in population and quality of life. Oil will continue to be a major source of current and future non-renewable energy. However, the current upgrading and recovery technologies are energy and water intensive. Hence new cost-effective technologies for enhancing upgrading and recovery of conventional and unconventional oils are needed and of paramount importance.

Asphaltenes are the largest, densest, most polar and surface-active compounds present in crude oil. Asphaltene association and destabilizing problems affect the utilization and recovery of oil from reservoirs, resulting in major complications in the pipelines and wellbores. Consequently, operational costs will be vastly increased and the production rates will be adversely influenced. Various techniques are currently used for removing asphaltenes after deposition. These methods involve production scheme alteration techniques, chemical treatment, mechanical methods, thermal and biological methods. These treatment techniques are expensive and may cause many environmental problems.

To this end, nanotechnology, in the form of nanoparticles, has emerged as an attractive area for the oil industry. The unique physical and chemical properties of the nanoparticles promote their adsorptive and catalytic behaviors towards heavy hydrocarbons. Thus, nanoparticles could be employed as adsorbents and catalysts â??nanosorbcatsâ? for in-situ and ex-situ application processes.

This study presents a new environmentally sound and low-cost, yet highly efficient surface and structural-modified pyroxene (PY) nanoparticles. Low temperature hydrothermal synthesis route was used to prepare PY nanoparticles, which were characterized by different characterization techniques like XRD, BET, TGA, TPD-CO₂, TPD-NH₃, and XPS. The prepared nanoparticles were employed for the adsorptive removal of visbroken residue asphaltenes (VR-C₅), and the solid-liquid-equilibrium (SLE) model was used to describe the adsorption isotherms. The catalytic thermo-oxidative decomposition of adsorbed VR-C₅ asphaltenes was investigated using TGA coupled with mass spectrometry. The catalytic behavior of the nanoparticles was compared based on the significant shift of the oxidation temperature, CO₂ evolution profiles, and the kinetic triplets of the oxidation reaction (i.e., Eα, Aα and f(α)). The isoconversional corrected method of Ozawa, Flynn, and Wall (OFW) was used to describe the reaction mechanism and estimate the kinetic triplets. After that the transitional thermodynamic parameters, such as â??S^â?¡, â??H^â?¡, and â??G^â?¡ were investigated to get rise to the meaningful kinetic prediction.