Regenerierbare feststoff-reaktions-schichten zur reinigung heisser schadstoffhaltiger gase

Abstract

A method for the purification of a hot off-gas stream by a gas-solid reaction, e.g. neutralisation, is described. A series of metal plates are continuously coated with a solution of a suitable reactant, removed from the solution and dried in the off-gas stream. The reaction between aqueous absorbing solutions or continuously generated solid reactant films and the noxious gases HCl, SO 2 and NO x has been studied with a small test model in flowing gas streams. In the test model the solid reactant film was generated on metal support plates having 800 cm 2 area, operating between 25°C and 150°C, the solid reactant films being typically regenerated 10 times per hr. With respect to purifying gas streams the solid films behave similarly, sometimes superior to aqueous scrubbers. Only the reaction of NO x with alkaline films was not satisfactory. It is likewise that it will take place only at higher temperatures. Removal of 99% of the other noxious gases was demonstrated under the above conditions for 500 1/h of air containing 2500 ppm HCl and for 100 1/h of air containing 2000 ppm SO 4. As the figures indicate the reactive surface area of the solid film is very high. The effective area calculated for a mono-molecular layer of reactants is about 10 4 times the area of the metal carrier plates.