PROCESS DESCRIPTION

In the Ostwald process, ammonia and oxygen are converted to nitrogen monoxide and water vapour in a reactor on a noble metal net catalyst. Subsequently, the reactor discharge is cooled in a condenser to a temperature at which the water condenses. Here, a part of the nitrogen monoxide reacts with water and oxygen to form an aqueous solution containing nitric acid, it also contains nitrogen oxides, in particular nitrogen monoxide, in dissolved form. The remaining gas mixture which does not dissolve is fed to an absorption tower, where part of the gaseous nitrogen oxide is reacted with oxygen and water to form nitric acid.