Urea

Abstract

Ammoni a and carbon d iox i de are compressed to a pressure in the range of 150-220 bar and a temperature of l80-220oC, an exothermic reaction occurs to form carbonate which is then dehydrated to urea. The unconverted carbonate and excess reactants are removed in the solution purification stages and returned to the reaction system. The urea solution is evaporated to achieve required concentration for fertiliser or technical grade urea. If a low biuret content is required, the product is concentrated by crystallisation. The final shaping of the product is almost always done by prilling.