Process and installation for the recovery of ammonia during the separation of nitrogen oxide from waste gases

摘要

Process and apparatus wherein nitrogen oxides NO.sub.x contained in waste gases produced by combustion of fossil fuels in a firing plant are removed by reacting the waste gases with ammonia NH.sub. 3 to reduce the nitrogen oxides to elementary nitrogen N.sub.2 ; subjecting the waste gases after being so reacted to wet waste gas cleaning whereby the washing water removes the unreacted ammonia (slip) from the waste gas to produce slip enriched washing water; raising the pH value of the slip enriched washing water to a value of more than 10, introducing air into the pH raised slip enriched washing water to remove the slip from the water and produce an air-slip mixture and recycling the slip into the furnace to react with waste gases to lower the amount of ammonia discharged into the atmosphere.