Researchers at the Institute of applied physics RAS, for the first time were able to dispose of carbon dioxide with non-equilibrium plasma discharge that is generated and maintained by microwave radiation of a high power gyrotron. The degree of decomposition of CO2 has reached more than 30% with efficiency of around 10%. At the moment, according to these indicators, the new method outperforms all analogues. An article about developing the researchers published in the journal of CO2 Utilization.
The concentration of carbon dioxide in the Earth’s atmosphere is constantly increasing at a rate of 2-3 ppm per year. This is several times higher than that in the pre-industrial era. Such high growth may cause irreversible changes in the climate caused by the increase in temperature across the planet. So today around the world there is a growing demand for technologies for utilization of carbon dioxide on an industrial scale.
The main problem of utilization of this compound is that the molecule of carbon dioxide is very stable. To break the bond of carbon with oxygen requires a large amount of energy. To do this, however, is possible if you heat a gas to very high temperatures — 3000K and above. But for heating gas to a temperature of the energy required, in the generation which stand out greater quantities of CO2. Also high temperature gas can generate the opposite reaction. In the course of it the resulting carbon monoxide (CO) and oxygen (O2) will merge back into carbon dioxide.
One of the most promising technologies for utilization of carbon dioxide associated with decomposition in non-equilibrium plasma of microwave (MW) discharge. In it, molecules break apart due to the energy of the electrons. Through such mechanism the decomposition process can be carried out at low temperatures of the gas. This is achieved by the gain in energy compared with the equilibrium methods of heating. Russian scientists have been able to implement this method in practice, using the developed technological gyrotrons. These are the sources of electromagnetic radiation of high power, emitting waves of centimeter and millimeter range.
Scientists decomposed the carbon dioxide using a continuous focused microwave radiation of gyrotron with frequency 24 GHz and power up to 5 kW. The researchers tested the method in the flow of pure CO2 and its mixture with argon at atmospheric pressure. Scientists have shown that non-equilibrium plasma with the electron temperature not less 4000-8000 a and the temperature of the gas around 2000-3500 K, capable of destroying molecules of carbon dioxide even at atmospheric pressure.
Such mild conditions allow to abandon the use of vacuum pumps to create low pressure. The combination of the ability to carry out the process at atmospheric pressure using non-equilibrium plasma televisions.yaet significantly reduce energy consumption plant for disposal of CO2 make it advantageous for use on an industrial scale.