Process for the production of water-free molten urea
AssigneesMitsui Toatsu Chemicals, Inc., Toyo Engineering Corporation of Japan
InventorsKazumichi Kanai, Tetsuo Kimura, Akito Fukui
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Abstract
An aqueous urea solution is concentrated to a substantially water-free molten urea by conducting successively a first step of concentrating said aqueous urea solution under the conditions forming a urea slurry and a second step of concentrating said urea slurry under conditions forming a substantially water-free molten urea free from crystalline urea.
Claims6
A process for concentrating an aqueous urea solution to a substantially water-free molten urea which comprises subjecting said aqueous urea solution to a first evaporation in a first evaporation zone at a temperature of from 40.degree. C to 120.degree. C to form a urea slurry, said slurry comprising urea crystals suspended in a saturated solution of urea, said crystals being from 10 to 60 percent by weight of the weight of said urea slurry, and subjecting said urea slurry to a second evaporation in a second evaporation zone at a temperature above 132.7.degree. C to dissolve the urea crystals and form a substantially water-free molten urea.
Dependencies are inferred from the claim text.