Patent ID: 6200540
Filing Date: 2001-03-13
Classification: B01D,B01J,C07C

Abstract:
A urea synthesis apparatus comprising (a) a vertical urea synthesis column, (b) a vertical condenser with a cooler integrated with and above said vertical urea synthesis column, a partition wall provided between a lower urea synthesis zone functioning as a urea synthesis column and an upper condensation zone functioning as a condenser to divide them from each other, (c) a stripper for stripping unreacted ammonia and unreacted carbon dioxide, contained in a urea synthesis solution from said urea synthesis column, by means of feed carbon dioxide to separate them from the solution as a mixed gas of ammonia, carbon dioxide and water, (d) a first down pipe passing through said partition wall and located within said synthesis column and said condenser that has an opening in each of the top part of said condenser and the bottom part of said urea synthesis column and is for making said condenser communicate with said urea synthesis column to allow the condensate to flow down from the top part of said condenser to the bottom part of said urea synthesis column by gravity, (e) a piping for introducing feed ammonia or feed carbon dioxide into the bottom part of said urea synthesis column, (f) a second down pipe that has an opening in the top part of said urea synthesis column and is for introducing the urea synthesis solution into the top part of said stripper by gravity, (g) a piping for introducing said mixed gas from said stripper into the bottom part of said condenser, (h) a piping for introducing an absorption medium or an absorption medium and feed ammonia into the bottom part of said condenser, (i) a piping for discharging inert gas, joined to the top part of said condenser, (j) a piping for introducing at least a part of feed carbon dioxide, joined to the bottom part of said stripper, and (k) a piping for discharging an aqueous urea solution containing unseparated unreacted ammonia and unreacted carbon dioxide from the bottom part of said stripper for further treatments.