CONTINUOUS PROCESS FOR THE MANUFACTURE OF CYANURIC ACID

摘要

A highly pure cyanuric acid is manufactured in a continuous process in which urea and/or buiret is/are dissolved in an inert solvent and circulated at a high velocity and a temperature in the range 180 DEG C to 250 DEG C through a loop between a heat exchanger (6) and a forced-circulation evaporative crystallizer body (5). Cyanuric acid crystallizes from the reaction mixture as it circulates to form a slurry. Ammonia formed during the reaction is removed at reduced pressure at (7) as the reaction mixture enters the evaporative crystallizer body (5). A portion of the slurry of cyanuric acid is continuously removed at (9) as it circulates through the loop and may be filtered to recover the cyanuric acid. The filtrate is returned to a feed tank (4) and additional solvent, urea or biuret added to meet concentration desired in the reaction mixture. The solution from the feed tank is added to the reaction mixture circulating through the loop at a rate to replace the volume of cynanuric acid slurry that is removed.