As told this produces ammonia without water (dry/dried urea is understood - dry it just below the docomposition temperature... ).
As told the ammonia will be pretty hot though free from water. A iron or SS tube-spiral through icewater will suffice as precooler - a standard spriral glasscooler fed with icewater will suffice if the amount of ammonia is not to large. No copper, no brass but plain old iron/mild steel is perfectly ok here.
Your question is not to answer universally as cooling depends on the amounts processed, heat transfer capability, temperature difference...and, and, and...
hope this helps nevertheless.