| 摘要 |
<p>1,268,430. Process for the production of urea. SNAM PROGETTI S.p.A. 14 Nov., 1969 [16 Dec., 1968], No. 56005/69. Heading C2C. A process for the continuous production of an aqueous solution of urea comprises reacting CO 2 and NH 3 in the presence of water in a first reactor so as to form an aqueous solution of ammonium carbamate, converting in a second reactor at least part of the ammonium carbamate in the aqueous solution to urea, decomposing any unconverted ammonium carbamate into CO 2 and NH 3 , stripping in the presence of a gas which is inert to the initial reactants or to ammonium carbamate, the last-mentioned CO 2 and NH 3 from the urea, causing or allowing the purified urea to be withdrawn as an aqueous solution, and recycling to the first reactor the inert gas and the stripped CO 2 and NH 3 , said inert gas leaving the first reactor as a gaseous effluent and at least a part of said effluent inert gas being re-employed in a subsequent stripping operation.</p> |
