METHOD AND UNIT FOR THE PRODUCTION OF GRANULATED CARBAMIDE

摘要

The invention relates to methods and apparatus for the production of granulated carbamide. The technical result is in efficient utilization of the heat of crystallization of the carbamide, which is liberated in the process of producing granulated carbamide. Granulated carbamide is produced by dispersing a melt (solution) thereof in a granulation zone, where it solidifies with the formation of granules, and the granules are cooled. The melt (solution) is first cooled in a recuperator by heat-exchange with a heat-transfer agent until partial formation of crystals in the melt or solution. The heat-transfer agent (preferably water) is passed from the recuperator into the boiler of an absorption refrigeration plant for heating the working liquid with subsequent return of the heat-transfer agent to the recuperator. Cooling of the carbamide melt (solution) may be carried out at the boiling point of the heat-transfer agent, with condensation of the resultant vapour in the boiler of the absorption refrigeration plant. Water is cooled in the refrigeration plant and is passed to cooling of the carbamide production working media, preferably to the cooling of granules in or outside of the granulation zone and/or to the cooling of air which is fed into the granule cooling zone, with subsequent return thereof to the refrigeration plant.