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Process for recovering urea microparticles

A particle and urea technology, which is applied in the field of droplet and dusty urea recovery, can solve the problems of huge equipment, complex operation and low recovery efficiency, and achieve the effect of small investment, low operation cost and simple equipment

Inactive Publication Date: 2004-02-04
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] The technical problem to be solved in the present invention is to provide a method for recovering urea particles in plate trays, so as to overcome the shortcomings of the prior art, such as huge equipment, high investment, complicated operation, and low recovery efficiency, and can be used in the design of new factories. Adopted, it is more suitable for on-site transformation of existing urea plants to increase production and reduce expenditure

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  • Process for recovering urea microparticles
  • Process for recovering urea microparticles
  • Process for recovering urea microparticles

Examples

Experimental program
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Effect test

Embodiment 1

[0038] A large-scale plant with a daily production capacity of 1,740 tons of urea is equipped with a plate-type washing tray of the present invention on the upper part of the first-stage evaporative separator and the second-stage separator to recover the urea solution particles entrained in the negative-pressure superheated steam to improve economic benefits. A series recovery process of one-stage evaporation and two-stage evaporation is adopted, and it is required to obtain a urea solution with a concentration of 30% (wt) after a series of washings.

[0039] unit

Embodiment 2

[0041] A urea production plant increased the air flux of the prilling tower to 150,000m due to the expansion of production 3 / h, adopt mechanical ventilation, intend to recover the urea dust particles entrained in the air, and prepare a urea solution with a concentration of 30% (wt) for recovery. Adopt the sieve wash tray that the present invention arranges liquid flow evenly distributed plate, implementation data is as follows:

[0042] Urea output 170000t / y

[0043] Air flow 150000m 3 / h

[0044] Entrainment of urea 2kg / t urea

[0045] Adding washing water (inlet) 3t / h

[0046] Concentration of urea solution 30% (wt)

[0047] Gas-liquid ratio 50000

[0048] Tray Type and Quantity Sieve Tray with Distributed Plates for Liquid Flow, 3pcs

[0049] Tower body size 3000×4000 rectangular, plate spacing = 0.5m

[0050] Liquid flow intensity Γ 3 / m.h

[0051] Urea recovery >90%

[0052] Because the liquid flow intensity Γ3 / m.h, the outer weir and the liquid flow uniform di...

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Abstract

A process for recovering the urea microparticles from the liquid drops and dust containing urea in urea production system features that the overheat vapour or gas containing urea particles passes through the washing tower tray from bottom to top of tower and washing water passes through the tower from top to bottom, obtaining the urea solution with 20-30 % of wt concentration. Its advantages are high recovery yield (90-99%), simple equipment and low cost.

Description

technical field [0001] The invention relates to a recovery method of drop and dust urea in the urea production process. Background technique [0002] In the urea production process, the evaporation process of urea solution and the granulation process of urea produce a certain amount of droplets and dust containing urea. [0003] The evaporation process of the urea solution is usually equipped with a secondary evaporator for evaporating the water in the urea solution. If the urea solution droplets entrained in the superheated steam escaping from the top of the evaporator (including the pre-flash tank) are not recovered, they will dissolve into the condensate during the steam condensation process and become a dilute urea solution. It not only causes losses, but also pollutes the environment. The recovery process of urea in this dilute liquid is quite complicated. The current industrial method is to hydrolyze urea into NH under pressure and high temperature. 3 and CO 2 , an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D47/06C07C273/16
Inventor 张成芳刘时贤郑治胜
Owner EAST CHINA UNIV OF SCI & TECH