The photo is sourced from temp-pro.com
Gas-turbine power units convert the energy of the in-coming air generated by combustion of natural gas into the mechanical shaft work providing for movement of the electric power generator. However, their work is accompanied by the atmospheric emissions of the combustion products including nitrogen oxide – colourless gas, which in high concentration may lead to the nervous system incitement (“laughing gas”).
According to the environmental regulations currently effective in Russia, the nitrogen oxide concentration in the exhaust gas should not exceed 30 mg per 1 cubic metre. However, in reality only the new generation of power units meet this requirement, because they are equipped with the special combustion chambers. For the purposes of decontamination of the exhaust gases at the old power units specialised chemicals are added, but this method is not free of drawbacks due to the difficulty of receiving homogenous mix for high-quality purification.
Scientists from Perm Polytechnic University proposed to resolve this problem using the so-called catalytic reduction method. It means that in addition to traditional chemicals (ammonia liquor, urea) catalysts are added to the combustion gas at different stages of purification. At first, the chemicals help to reduce the exhaust gas to elementary components (steam, carbon dioxide, nitrogen), then the catalyst is added to the flow resulting in the process of purification taking place on the surface.
“We defined the concentrations of nitrogen oxide at different modes of the gas-turbine power unit operation before and after the reduction system. We changed the consumption rate of the chemical agent injecting it into the exhaust gases. All the theoretical calculations and the experiments confirmed 100% efficiency of the exhaust gases purification (removal of nitrogen oxide) by using the reduction system at the mode of 0.5 capacity of the unit”, the Perm Polytechnic University is citing Nikita Cherepanov, the postgraduate student of the Microprocessor Automation Department.
According to the calculations by the authors of the research, the purification efficiency is pro rata the amount of the used chemical agent. The ammonia liquor is better than urea for these purposes.