Abstract: A urea granulation process and the apparatus suitable for operating that process integrates a method for reducing ammonia emissions from a urea granulation plant which is emitted by a urea production process by scrubbing the off-gas and recovering the scrubber bleed and integrating it into the granulation process so that ammonium salts are completely contained by the process.

Abstract: The invention relates to a process for the granulation of a concentrated urea solution whereas the granulation produces a urea granulate and a dust laden air, which is then fed into a dust scrubber which removes the coarser dust with a less concentrated urea solution and which releases a residual air comprising air with ammonia, carbon dioxide water and an aerosol comprising mainly ammonium isocyanate and a part of very fine urea sublimate, whereas the aerosol is then separated off and fed into a isomerisation unit which comprises a stripping where the ammonium isocyanate reacts with steam to form urea which is then redirected into the dust scrubber as a less concentrated urea solution, and the residual air is directed into an acidic scrubber which releases clean air into the atmosphere which finally leads to a recycling of the aerosol of ammonium isocyanate into urea. The invention also relates to a device for carrying out the related process.

Abstract: A process for the granulation of urea with a scrubbing system includes several waste streams for removal of dust and ammonia from the off-gas of a urea granulation unit. A urea granulator, a granulator scrubber dust stage, a granulator scrubber acid stage, product coolers, a product cooler scrubber dust stage, an evaporation unit, and a condenser unit are included in the system. A first stream of fresh air is sent into the urea granulator, whereby dust- and ammonia-laden air is drawn off from the granulator and conveyed into a granulator scrubber dust stage, followed by a granulator scrubber acid stage and ammonia is scrubbed from that air by the generation of an ammonium salt. A second stream of fresh air is used for cooling the product drawn off from the urea granulator in product coolers. The cooling air is thus heated up and conveyed to a product cooler scrubber dust stage.

Abstract: The invention relates to a process for the granulation of a concentrated urea solution whereas the granulation produces a urea granulate and a dust laden air, which is then fed into a dust scrubber which removes the coarser dust with a less concentrated urea solution and which releases a residual air comprising air with ammonia, carbon dioxide water and an aerosol comprising mainly ammonium isocyanate and a part of very fine urea sublimate, whereas the aerosol is then separated off and fed into a isomerisation unit which comprises a stripping where the ammonium isocyanate reacts with steam to form urea which is then redirected into the dust scrubber as a less concentrated urea solution, and the residual air is directed into an acidic scrubber which releases clean air into the atmosphere which finally leads to a recycling of the aerosol of ammonium isocyanate into urea. The invention also relates to a device for carrying out the related process.