Patent ID: 11912649
Assignee: STAMICARBON B.V.
Field: Chemical engineering (Chemistry)
Classification: CPC C  B  Y | IPC B  C

Claim 0:
1. A method for the removal of ammonia from an off-gas of a finishing section of a urea production plant, wherein the finishing section operates a conversion of a urea melt into solid urea products, thereby generating an ammonia-containing off-gas, the method comprising: obtaining said urea melt by evaporating water from an aqueous urea solution in a first stage evaporation section, so as to form a first water vapour and a concentrated urea solution; further evaporating water from said concentrated urea solution in at least one second stage evaporation section so as to form a second water vapour and the urea melt; subjecting the off-gas to contact with an acidic scrubbing liquid in a scrubbing system so as to provide a scrubbed off-gas and a utilized scrubbing liquid comprising one or more ammonium salts and water; and sending the utilized scrubbing liquid to the second stage evaporation section, thereby subjecting it to evaporation of water together with the concentrated urea solution; and sending said urea melt to the finishing section for conversion of the urea melt into the solid urea products and the ammonia-containing off-gas, wherein all of the urea melt sent to the finishing section comprises the one or more ammonium salts.