Patent attributes
A method for the removal of ammonia from the off-gas of a finishing section of a urea production plant, a corresponding urea plant, and a method of accordingly modifying a pre-existing urea plant. In a scrubbing section, off-gas is brought into contact with acidic scrubbing liquid to provide a scrubbed off-gas and a utilized scrubbing liquid comprising ammonium salt. The method specifies an evaporation section, which is part of the urea plant that produces urea melt, that is divided into first and second stages. The first stage is part of the urea melt production plant. The second stage is decoupled, as regards recirculation of liquids other than the urea product stream, from the urea melt production plant. This is accomplished by sending utilized scrubbing liquid containing ammonium salts to the second stage evaporation section, and condensed vapours from said second stage evaporation section to said scrubbing section.
