Abstract: The present invention relates to a method of reduction of nitrogen oxides in gas mixtures, especially the removal/decomposition of nitrogen oxide in hot combustion gases. The hot gas mixture which contains N.sub.2 O is given a retention time of 0.1-3 seconds before being cooled down. About 90% of N.sub.2 O is thereby decomposed to N.sub.2 and O.sub.2. A hot gas mixture formed by catalytic combustion of ammonia is given a retention time of 0.5-2 seconds before it is cooled in a heat recovery unit. The combustion gases can also be brought in contact with a metal or metal oxide catalyst for selective decomposition of the N.sub.2 O.

Abstract: Method for the removal of and prevention of formation of salt deposits in critical sections of a plant. The salt deposits, especially ammonium nitrate deposits, are treated with steam, supplied in such amounts that a water vapor pressure is established which is higher than the existing saturated vapor pressure above the salt deposits at the existing temperatures. The physical requirements for salt removal are hereby immediately established with resulting instantaneous cleaning of all surfaces coated by deposits, independent of where these deposits are located.The invention also relates to process equipment means for performing the method.

Abstract: A method is provided for the removal of and the prevention of formation of salt deposits in critical sections of a plant. The salt deposits, especially ammonium nitrate deposits, are treated with steam, supplied in such amounts that a water vapor pressure is established which is higher than the existing saturated vapor pressure above the salt deposits at the existing temperatures. The physical requirements for salt removal are hereby immediately established with resulting instantaneous cleaning of all surfaces coated by deposits, independent of where these deposits are located.