| 摘要 |
<p>PURPOSE:To separate an inert gas with little amounts of accompanying NH3 and CO2, by subjecting a synthetic solution in which urea is synthesized at a urea synthesizing pressure near the equilibrium of the urea and the maximal temperature is reached to the heat exchange indirectly with NH3 at the urea synthesizing pressure, and reducing the temperature of the urea synthetic solution to a specific temperature. CONSTITUTION:A mixed gas of an uncondensed NH3 with CO2 and water containing an inert gas and a condensed ammonium carbamate solution are fed from a carbamate condenser 3 to the bottom of a urea synthesizing tube 1 and reacted with NH3 fed from a tube 5 to form ammonium carbamate, which is then converted into urea while being lifted in the tube 1. NH3, pressurized to a urea synthesizing pressure, and preheated to ordinary temperature -150 deg.C is fed from a line 11 to a cooler 4 dipped in the liquid phase in contact with the gaseous phase at the top of the tube 1 to reduce the temperature of the urea synthetic solution by 5-30 deg.C. The inert gas is taken out of a line 19, and the synthetic solution is lowered in the tube 6, heated to the temperature before the cooling and fed into the top of a stripper 2.</p> |
