SYSTEM FOR GRANULATION OF UREA IN FLUIDISED BED WITH LOW POWER CONSUMPTION AND LOW EMISSIONS Russian patent published in 2025 - IPC C05C9/00 C05C3/00 

FIELD: agriculture.

SUBSTANCE: system for granulating urea in a fluidised bed includes: an ammonia extraction column, a fluidised bed granulator, a first screen, a second screen, a cooler, a first bucket elevator, a second bucket elevator, a combined dust collector and a smelting tank; wherein the ammonia extraction column is located upstream of the fluidised bed granulator and the molten urea of the feedstock is granulated in the fluidised bed granulator after removal of free ammonia in the ammonia extraction column; system is arranged so that granulated ureas produced by fluidised bed granulator are sorted on the first screen according to three characteristics: lumpy urea, powdered urea and intermediate granulated urea; sifted lump urea is processed; and after the intermediate granulated urea is cooled in the cooler, it is raised by means of the first bucket elevator and then enters the second screen for sorting, the materials are sorted according to three characteristics: finished urea, powdered urea and coarse granulated urea, the finished urea is cooled to temperature below 50 °C and sent beyond border as urea end product, after the coarse granulated urea is ground into a powder, it is combined with urea powder, as well as with the urea powder leaving the first screen, directed to the fluidised bed granulator via a pipe, used as a seed crystal for granulation; wherein the combined dust arrester and melting tank are successively connected to a fluidised bed granulator, the dust-containing exhaust gases produced by the fluidised bed granulator are first fed into a combined dust arrester and more than 80 % of dust larger than 10 mcm are removed, dust in exhaust gases is emitted into atmosphere after cleaning to level of less than 10 mg/Nm³, and dust removed by combined dust collector is fed into melting tank, wherein said dust is fused into fluid and directed to fluidised bed granulator urea solution inlet pipe to be mixed with initial urea solution upstream of granulator. Mixed urea solution is fed to fluidised bed granulator for granulation.

EFFECT: invention provides ultralow concentration of ammonia and urea dust in exhaust gases.

10 cl, 2 dwg