FIELD: chemistry. SUBSTANCE: essence of this method resides in producing carbamide from carbon dioxide with excess of ammonia at temperature of 175 to 200 C and pressure of 13 to 22 MPa and feeding reaction products to several stages of decomposition of ammonium carbamate admixture with gradually lowering pressure at each stage. At first stage, prescribed pressure is maintained at level equal to that of pressure existing in synthesis zone and decomposition process is conducted with heating and at the same time allowing self-desorption of ammonia excess contained in reaction products. This method prescribes maintaining temperature of 175 to 190 C in the first condensation zone and temperature of 155 to 170 C in the second one, using part of fresh carbon dioxide in the second decomposition stage at average pressure, admitting carbon dioxide into synthesis reactor, returning ammonium carbamate solution resulted from process of condensation of gases at high pressure to synthesis reactor by means of ejector, fresh ammonia to be introduced into synthesis zone serving as injection medium, and then allowing partial condensation of gaseous products delivered from decomposition stage at average pressure in tubular falling-film heat exchanger. This method further prescribes using condensation heat for heating urea solution for its preliminary concentration. EFFECT: advanced technique. 5 cl, 1 dwg
