Catalytic Effects of Nano-Size Metal Ions in Breaking Asphaltene Molecules During Thermal Recovery of Heavy-Oil

摘要

Heavy-oil or bitumen recovery requires effective recovery of many different components of hydrocarbons for an efficient process. Production of asphaltenic components and minimizing their precipitation, which may affect the ultimate recovery and rate, is of particular interest. Conventional thermal and solvent techniques are limited in breaking asphaltene components and new types of catalysts are needed for efficient recovery of heavy-oil. The presence of nano-size metal particles catalyzes the breaking of carbon-sulfur bonds within asphaltenes. This results in a reduction of asphaltene content, with an increase in saturates and aromatic content. The end effect of this process is a significant reduction in the viscosity of heavy oil and bitumen. Having a strong hydrogen donor present dramatically increases the amount of viscosity reduction, while not having any hydrogen donor present completely inhibits the reaction. The proper metals and corresponding concentrations need to be investigated before conducting displacement experiments in porous media. In this paper, we investigated the effects of microwave radiation, using a standard 2.45 GHz emitter, on viscosity reduction. Different nano-sized metal particles (Fe, Fe(III) Oxide, and Cu) were used as catalysts in concentrations ranging 0.1% weight to 1% weight. Heavy oil samples were heated to and maintained at a temperature of 200°C using inductive microwave heating for a period of 5 hours. Viscosity and mass data were obtained before and after each experiment, with viscosity being measured at 55 °C, 75°C, and 95°C. Since the heavy oil samples which contained no added hydrogen donors experienced a significant vaporization of components, they must be participating in a reaction independent of the aquathermolysis reaction.