MOSCOW, May 31.Russian scientists have assembled the world's largest installation, which allows using electrical discharges to effectively process heavy oil and at the same time obtain products used in the chemical industry, the Russian Science Foundation (RSF) reported.
Heavy oil reserves account for 70% of the world's reserves. However, its processing is difficult due to the high density and viscosity, a large number of sulfur-containing compounds. Modern methods have a number of disadvantages: they require high temperatures and pressures, large amounts of hydrogen, and special equipment. At the same time, for heating and maintaining high temperatures, it is necessary to burn significant volumes of hydrocarbon fuel, which leads to significant emissions of carbon dioxide.
This can be avoided if plasma reactors are used instead of high-temperature plants and furnaces. They do not require expensive catalysts and hydrogen, operate on electricity from nuclear and hydroelectric power plants, and do not emit carbon dioxide during their operation. For example, during plasma pyrolysis of oil under the action of electrical discharges, highly reactive compounds are formed: radicals and ions. They excite molecules of organic compounds in oil, as a result of which specific reactions are triggered, leading to the splitting of large molecules into smaller ones, which can then be used in many chemical processes. Despite the advantages of such oil treatment, the industrial application of this method is limited by the small size of the reactors.
Scientists from the Nizhny Novgorod State Technical University named after Alekseev (NSTU, Nizhny Novgorod) assembled an installation for plasma pyrolysis of oil. It consisted of a reactor, a control system and registration of electrical discharges, as well as a system for collecting the resulting gases. The reactor volume was 300 cubic centimeters, which is 7.5 times more than previous models.
To test the operability of the installation, the researchers used fuel oil, which was poured between two electrodes. The authors showed that an increase in the power of the energy impact leads to an increase in productivity, energy efficiency of the process and the yield of gaseous products, and also affects their quantity. So, during the process, hydrogen, acetylene, ethylene, methane, as well as hydrocarbons containing from three to five carbon atoms were released. All of them are widely used in the chemical industry.
In addition, energy consumption was the lowest and the yield of valuable gaseous hydrocarbons was the highest. In solid phase products, scientists have found disordered graphite and multilayer carbon nanotubes that can be used in electronics. In addition, the solid products contained sulfur, oxygen, vanadium, and nickel atoms, which makes these structures attractive for use in industry as accelerators of chemical reactions.
«In our future work, we will try to increase the depth of fuel oil processing, increase the productivity and profitability of plasma-chemical pyrolysis. We also plan to study carbon nanostructures for use as catalysts and adsorbents,» says the project manager, candidate (Engineering), leading researcher at NSTU Evgeniy Titov.
Scientists from the Federal Research Center «Crystallography and Photonics» of the Russian Academy of Sciences, the Kurchatov Institute and the Moscow Institute of Physics and Technology also took part in the study, supported by a grant from the Russian Science Foundation.