Abstract: A process for the purification of combustion gases from domestic heating installations, internal combustion engines and similar small combustion installations, by removal of their oxidic sulfur and nitrogen impurities by means of a material which chemically binds the impurities, wherein the combustion gas is passed through a bed of high-porosity pellets, which contain metal oxides as the active material and also manganese dioxide (MnO.sub.2), and the impurities are thus deposited on the metal oxides. For the treatment of combustion gases arising at a high temperature of about 500.degree. C. and higher, for example the waste gases taken off from the high-temperature side of power stations or from the manifold of a motor vehicle engine, the pellets contain a proportion of 3-8% by weight, advantageously 4-6% by weight, of coal dust and 5-15% by weight, advantageously 8-13.5% by weight, of iron-III oxide, whereas the pellets for the purification of combustion gases arising at a low temperature of about 120.

Abstract: Process wherein air is continuously sucked and returned in a closed cycle, the moisture of the air being reduced down to a value lower than the saturation limit value. The treatment is carried out by means of a metal carbide, preferably calcium carbide and/or a substance capable of binding water by hydrolysis or hydration, for example sodium hydrophosphate or anhydrous sodium sulfate which may be contained when mixing both substances into a quantity up to 85% by weight, preferably 35 and 65% by weight, in the substance reacting with the condensed moisture. The plant is comprised of a system of conduits (1-5) containing suction nozzles and connected to a container (7, 8) intended to receive the material reacting with the air moisture and connected to the suction nozzle of a fan (6) to which is coupled a pressure line (1-5) surrounding the limited area and comprising discharge openings.