PRODUCTION OF GRANULAR UREA

Japanese Patent JP3667418

B2

PROBLEM TO BE SOLVED: To obtain granular urea capable of solving problems of water removal in a granulating column method and problems of concentration of diluted formaldehyde in a fluidized bed/spouted bed method by using a specific means in granulating urea in the presence of formaldehyde.
SOLUTION: A urea solution is divided into a urea solution A and a urea solution B, the urea solution A is sent from a line 12 to a blender 1 and formaldehyde is transported from a line 13 to the blender 1. Urea is reacted with formaldehyde in the blender 1 and a mixed solution is sent to an evaporator 2 and concentrated. The prepared mixed solution of urea/formaldehyde is mixed through a line 16 with the urea solution B and sent to a granulating facility 5 to give granulated urea. Since the urea solution A is reacted with formaldehyde under a condition of ≥16.5, the concentrating operation can be carried out while preventing a polymerization reaction of urea and formaldehyde. Since the amount of urea exposed to heating is extremely small, formation of biuret as a by-product in a product can be neglected. The molecular ratio of urea/formaldehyde is ≥0.5.

Eiji Fujii
Haruyuki Morikawa

JP1654196A

July 06, 2005

February 01, 1996

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Toyo Engineering Corporation

B01J2/02; B01J2/04; B01J2/16; C05C9/00; C05C9/02; C07C273/02; C07C273/14; C07C275/00; (IPC1-7): C07C275/00; B01J2/04; B01J2/16; C05C9/02; C07C273/02

JP1286985A
JP6305869A
JP56109882A
JP5416427A
JP61216725A

Kaoru Furuya
Takahiko Mizobe
Satoshi Furuya
Shinji Mochida

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