Formaldehyde-adding-free urea granulation process

A urea granulation technology that does not need to be added. It is applied in the direction of urea compound fertilizer, separation of dispersed particles, liquid into beads and granulation, etc. It can solve the problems of secondary pollution hazards and loss, and achieve environmental protection and safety in the production process. Production cost The effect of low, high particle strength

Active Publication Date: 2017-07-28
CASALE SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The urea products produced by the above two processes contain formaldehyde and its compounds in addition to urea single nitrogen fertilizer, which is unacceptable for urea products for industrial use
For urea products for agricultural use, if formaldehyde is not added accurately, it will be lost to the atmosphere, soil, water system and other environments, causing secondary pollution hazards

Method used

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  • Formaldehyde-adding-free urea granulation process
  • Formaldehyde-adding-free urea granulation process
  • Formaldehyde-adding-free urea granulation process

Examples

Experimental program
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Embodiment 1

[0040] This embodiment relates to the technological process of the method of the present invention (its flow chart sees figure 1 ),details as follows:

[0041] The urea solution is sent to the granulator 102 through the granulation feed pump 101 for granulation. The granulator is a fluidized bed granulation equipment, including a fluidizing air fan 103 and an atomizing air fan 104 . After the large-grain urea produced by the granulator passes through the drying and cooling process of the fluidized bed dryer 105, the particle size is sieved through the urea sieve 106. or The large granular urea product becomes a qualified formaldehyde-free large granular urea product after being cooled by the final product cooler 107.

[0042] In addition, the air containing urea dust discharged from the granulator enters the dust scrubber 109, and after being wet-washed with water, the tail gas is discharged into the atmosphere. General exhaust gas contains urea dust 20mg / m 3 . The ai...

Embodiment 2

[0044] This embodiment relates to a preparation process of urea granules, comprising the following steps:

[0045] 1) urea solution with a mass concentration of 75% is used as a raw material, and is fed into a granulator at a pressure of 0.6 MPa and a temperature of 135° C., and is granulated by an atomized fluidized bed granulation process;

[0046] Control the temperature of the fluidized bed in the granulator to 100°C, and the outlet product temperature to 100°C;

[0047] 2) After the granulation is completed, the urea granules are dried at 60°C;

[0048] 3) After the drying is completed, the urea granules are sieved, and the sieved particle size is or The product is finally cooled to below 50°C to obtain formaldehyde-free large particle urea.

Embodiment 3

[0050] This embodiment relates to a preparation process of urea granules, comprising the following steps:

[0051] 1) urea solution with a mass concentration of 99% is used as a raw material, and is fed into a granulator at a pressure of 0.2 MPa and a temperature of 135° C., and is granulated by an atomized fluidized bed granulation process;

[0052] Control the temperature of the fluidized bed in the granulator to 115°C, and the outlet product temperature to 110°C;

[0053] 2) After the granulation is completed, the urea granules are dried at 100°C;

[0054] 3) After the drying is completed, the urea granules are sieved, and the sieved particle size is or The product is finally cooled to below 50°C to obtain formaldehyde-free large particle urea.

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Abstract

The present invention relates to a formaldehyde-adding-free urea granulation process. According to the formaldehyde-adding-free urea granulation process, when large formaldehyde-free urea particles are produced, a 75-99% (wt) urea solution is conveyed into a granulator without the addition of a formaldehyde solution, granulation is performed through a atomized fluidized bed granulation process, and drying and cooling are performed to prepare the large particle urea, wherein the urea-dust-containing air discharged during the production process is respectively subjected to standard dry dust removing treatment and standard wet dust removing treatment at a normal temperature under a normal pressure. According to the present invention, the nitrogen content of the obtained large-particle formaldehyde-free urea can be up to 46.5% and is superior to the national standard of urea (GB2440-2001) (excellent grade), and the obtained large-particle formaldehyde-free urea can completely and simultaneously meet industrial uses and agricultural uses, can be directly used for vehicle urea, and has characteristics of large particle, uniform particle, low Biuret content, high particle strength, good fluidity, breaking resistance, caking resistance, easy storage, and easy use.

Description

technical field [0001] The invention relates to the field of urea granulation production, in particular to a urea granulation process without adding formaldehyde. Background technique [0002] At present, solid urea, which is synthesized from ammonia and carbon dioxide, is the most important type of nitrogen fertilizer, and it is widely used in agricultural production as fertilizer. [0003] The process methods for producing large particle urea mainly include: Hydro company (HYDRO) and Toyo Engineering Company (TEC) fluidized bed granulation process. The former is an atomized fluidized bed, and the latter is a jet fluidized bed. During the granulation process, formaldehyde solution or urea aldehyde compound formed by the reaction of formaldehyde and urea solution is added. [0004] The production process of large granular urea in Hydro company see figure 2 : The raw material urea solution with a concentration of 95% (wt) is sent to the granulator 202 through the granulatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J2/04C05C9/00B01D47/06
CPCB01D47/06B01J2/04C05C9/005
Inventor 王威
Owner CASALE SA
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