Catalytic plasma process to limit combustion emissions affecting the environment

The main environmental problem arising from the combustion of coal in thermal power stations is pollution arising from the release of NO _x and SO₂. A number of technologies have been proposed to reduce these emissions. Here, the authors outline the plasma catalysis concept which shows great promise of being an environmentally and economically acceptable solution to this problem. The possibility of lowering the levels of nitrogen and sulphur oxides present in the flue gas, by means of medium energy electrons injected into the gas was recognised several years ago. It has also been shown that the presence of an electric field increases the efficiency of the electrons within the gas. Recent laboratory tests at ENEL in Italy have demonstrated that suitable electrons may be produced by corona discharge (or plasma catalysis)