| 摘要 |
<p>Liquid NH3 is preheated, pref. to 80 degrees C-160 degrees C, and part is passed to a heat exchanger where CO2 is added to form (NH1)2CO3. The mole ratio of NH3:CO2 is below 4 and the pref. temp. of formation is 175 degrees C-190 degrees C. The material from the heat exchanger plus the rest of the NH3 passes to a urea formation zone. The NH3 distribution is used to control the temp. of the urea formation, pref. between 150 degrees C-225 degrees C. The product passes through the heat exchanger to heat the (NH4)2CO3 formation. Unreacted cpds. are separated and they may be recirculated.</p> |
