Abstract: A method for producing urea granules having low moisture absorption capacity, with a urea granulator, having a granule flow inlet side and oppositely a granule flow outlet side, forming an axis alongside which granules from a urea solution and a urea/ammonium salt-stream are formed, whereby the solution and the salt-stream are sprayed as a mixture or separately via a feed system unit via various nozzles into the granulator onto a seed material. In this process the highest amount of the salt-stream is sprayed into the granulator at the granule flow inlet side and the amount of the salt-stream is decreased alongside the axis of the granulator from the granule flow inlet side to the granule flow outlet side.

Abstract: A method for producing urea granules having low moisture absorption capacity, with a urea granulator, having a granule flow inlet side and oppositely a granule flow outlet side, forming an axis alongside which granules from a urea solution and a urea/ammonium salt-stream are formed, whereby the solution and the salt-stream are sprayed as a mixture or separately via a feed system unit via various nozzles into the granulator onto a seed material. In this process the highest amount of the salt-stream is sprayed into the granulator at the granule flow inlet side and the amount of the salt-stream is decreased alongside the axis of the granulator from the granule flow inlet side to the granule flow outlet side.

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.

Abstract: The invention relates to a method for removing ammonia and dust from a waste gas that occurs during the production of fertilizers, preferably urea, in which method the waste gas is introduced into a first washer, and a cooling gas is introduced into the one washer and an aqueous solution is introduced into the other washer, whereby both the waste gas and the cooling gas pass through at least one mist collector before exiting from the washer, in each instance, is supposed to be developed further in such a manner that the waste gas pollution can be clearly reduced. This is accomplished in that the additional water is first introduced into a fine-washing area of the first washer, delimited by the mist collector on the top and by a liquid-impermeable partition bottom at the bottom, and sprayed onto the at least one mist collector, and the aqueous solution that forms in the fine-washing area is subsequently passed into the second washer.

Abstract: The invention relates to a method for removing ammonia and dust from a waste gas that occurs during the production of fertilizers, preferably urea, in which method the waste gas is introduced into a first washer, and a cooling gas is introduced into the one washer and an aqueous solution is introduced into the other washer, whereby both the waste gas and the cooling gas pass through at least one mist collector before exiting from the washer, in each instance, is supposed to be developed further in such a manner that the waste gas pollution can be clearly reduced. This is accomplished in that the additional water is first introduced into a fine-washing area of the first washer, delimited by the mist collector on the top and by a liquid-impermeable partition bottom at the bottom, and sprayed onto the at least one mist collector, and the aqueous solution that forms in the fine-washing area is subsequently passed into the second washer.