Title:
尿素の造粒方法
Document Type and Number:
Japanese Patent JP6851869
Kind Code:
B2
Abstract:
When recovering and utilizing the urea and NH3contained in a gas that contains urea dust and NH3and has been discharged from a urea granulation step, an aqueous urea solution to be fed to the urea granulation step is prevented from suffering the precipitation of an ammonium salt while inhibiting the solution from increasing in water content. The method for granulating urea comprises: a granulation step in which granular solid urea is produced from a feed aqueous urea solution using air, a recovery step in which urea dust and NH3are recovered, using an acid-containing aqueous solution, from the air discharged from the granulation step, thereby obtaining a recovery liquid containing urea and an ammonium salt, a salt concentration regulation step in which an aqueous urea solution having a lower ammonium salt concentration than the recovery liquid is mixed with the recovery liquid to regulate the ammonium salt concentration in the recovery liquid, a concentration step in which water contained in the liquid obtained in the salt concentration regulation step is vaporized to concentrate the liquid obtained in the salt concentration regulation step, thereby obtaining a concentrated recovery liquid, and a mixing step in which the concentrated recovery liquid is mixed with the feed aqueous urea solution, the concentrated recovery liquid being regulated so as to have an ammonium salt concentration of 7 mass% or less.
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| WO/2020/235999 | TREATMENT OF OFFGAS FROM UREA FINISHING |
| WO/1994/013630 | PROCESS FOR OBTAINING CARBAMIDE |
Inventors:
Shuhei Nakamura
Akiko Ushifusa
Kei Sasaki
Akiko Ushifusa
Kei Sasaki
Application Number:
JP2017052199A
Publication Date:
March 31, 2021
Filing Date:
March 17, 2017
Export Citation:
Assignee:
Toyo Engineering Corporation
International Classes:
C07C273/16; C07C275/00
Domestic Patent References:
| JP2000001466A | ||||
| JP9227493A | ||||
| JP2012509833A | ||||
| JP2015520741A |
Foreign References:
| WO2016159336A1 | ||||
| US20110229394 |
Attorney, Agent or Firm:
Akio Miyazaki
Masaaki Ogata
Masaaki Ogata