method for reducing aerosol emissions from a urea granulation plant with treatment of the resulting purifier drainage, and device for producing urea granulates

摘要

Method for Reducing Aerosol Emissions from a Urea Granulation Plant with Treatment of Drains Resulting from the Purifier, and Device for Producing Urea Granules The invention relates to a process for granulating a concentrated urea solution by considering that the granulation produces a urea granulate and a dust-laden air, which is then fed into a dust purifier which removes the rougher powder with a less concentrated solution of urea and which releases residual air comprising ammonia, dioxide air carbon, water and an aerosol comprising mainly ammonium isocyanate and a very fine sublimate part of urea, whereas the aerosol is then separated and fed into an isomerization unit comprising extraction where the ammonium isocyanate reacts with steam. to form the urea which is then redirected into the powder purifier as a less concentrated solution. and the waste air is directed into an acidic purifier that releases clean air into the atmosphere which ultimately leads to a recycling of the ammonium isocyanate aerosol in the urea. The invention also relates to a device for performing the related process.