Urea production apparatus, method for modifying urea production apparatus, and method for producing urea

Abstract

A urea production apparatus (10) includes a first evaporator (EV1) obtaining a first off-gas and a concentrated urea solution from a urea solution, a condenser (C1) cooling the first off-gas to obtain condensate water, a second evaporator (EV2) obtaining a second off-gas and a highly concentrated urea solution from the concentrated urea solution, a granulator (F) obtaining the solid urea product from the highly concentrated urea solution, a scrubber (SCR) contacting the second off-gas and a third off-gas discharged from the granulator (F) with the cleaning solution to obtain a cleaning-processed recovered solution containing a clean gas, ammonium salt, and urea, and a recovery pipe configured to supply the cleaning-processed recovered solution to a second evaporator (EV2). The second evaporator (EV2) obtains the highly concentrated urea solution and the second off-gas from a mixture of the concentrated urea solution and the cleaning-processed recovered solution.