Distillation: processes – separatory – Convective distillation with normally gaseous medium – e.g. – air
Patent
1995-04-06
1997-01-28
Warden, Robert J.
Distillation: processes, separatory
Convective distillation with normally gaseous medium, e.g., air
159 472, 203 27, 203 29, 203 95, 564 66, 564 71, 564 72, 564 73, B01D 300, B01D 338, C07C27316
Patent
active
055974546
ABSTRACT:
A urea production process combining lower pressure urea concentration and carbamate recovery steps into a single non-vacuum operation. Following high pressure stripping wherein a bulk of unreacted carbamate is recovered from the reaction effluent, remaining carbamate is stripped by heated air at atmospheric pressure wherein urea is concurrently concentrated without the use of vacuum evaporators. Weak carbamate solution subsequently formed is stripped of water (and residual urea is hydrolyzed) using air and steam at a medium pressure single tower hydrolyzer/stripper to obtain a concentrated carbamate stream suitable for recycle to the reactor. The process employs heat integration for enhanced energy efficiency and produces a good quality aqueous condensate suitable for direct use as boiler feed water. Thus the aqueous condensate produced requires no additional cooling and ammonia treatment. The process employs simplified and reduced process unit operation to eliminate equipment for cost reduction.
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Hydrocarbon Processing, Nov. 1977, pp. 232-233.
Carpenter Robert
Warden Robert J.
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