Technique for recycling waste fluid containing urea

A waste liquid recovery and urea technology, applied in heating water/sewage treatment, degassed water/sewage treatment, chilled water/sewage treatment, etc., can solve the problems of high energy consumption, excessive discharge, high operating costs, etc., and achieve equipment investment The effect of reducing, eliminating pollution and saving resources

Inactive Publication Date: 2004-10-27
河北阳煤正元化工集团有限公司
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  • Summary
  • Abstract
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AI Technical Summary

Problems solved by technology

[0010] In view of the above problems existing in the existing urea process urea-containing waste liquid treatment process, combined with the characteristics of the use of low-pressure steam in urea production plants that use coal as raw material, and the low-pressure steam is most...

Method used

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  • Technique for recycling waste fluid containing urea
  • Technique for recycling waste fluid containing urea
  • Technique for recycling waste fluid containing urea

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Embodiment 1

[0029] Embodiment 1: as Figure 4 As shown, first the urea process contains urea, NH 3 and CO 2 The waste liquid from the condensate tank 1 is preheated by the heat exchanger 2, and then sent to the desorption tower 4, and the NH in the urea-containing waste liquid is indirectly heated by steam 3 and CO 2 Desorption; then containing NH 3 and CO 2 The desorbed gas is condensed through the reflux condenser 5, and the condensate is divided into two paths, one path is used as tower top reflux, and the other path returns to the urea production system; the urea waste liquid discharged from the desorption tower 4 is divided into two paths, and one path passes through the reboiler 9 Heating is returned to the bottom of the desorption tower 4, and the other way is sent to the evaporator 10, and the medium-pressure steam of 2000Kpa is used to control the evaporation and concentration under the pressure of 300Kpa. When the concentration of urea is 40%, the obtained urea concentrate i...

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Abstract

A process for reclaiming the sewage containing urea includes desorbing said sewage by desorption tower, condensing the desorbed gas by condenser, refluxing part of condensed liquid to tower top, returning rest back to production system of urea, concentrating the urea solution discharged from absorption tower by medium-pressure steam, returning the concentrated solution back to urea evaporating system, and delivering the generated secondary steam to low-pressure steam system. Its advantages are less investment in equipment and no environmental pollution.

Description

technical field [0001] The invention relates to the treatment of waste water solution in the field of chemical production, in particular to a process for concentrating and recovering urea-containing waste liquid in the urea production process. Background technique [0002] The urea-containing waste liquid obtained during the urea evaporation and concentration process of the urea production plant generally contains NH 3 , CO 2 And 1 to 3% urea, due to its serious pollution, this waste liquid cannot be directly discharged into the environment. where NH 3 , CO 2 Usually, it can be concentrated and recovered by desorption, but urea is difficult to recover because it is not volatile. The current treatment method generally adopts the hydrolysis-desorption process, that is, at a certain temperature to ensure that the urea-containing waste liquid has enough residence time in the hydrolysis tower to hydrolyze it into NH 3 and CO 2 , and then recovered by stripping or rectificat...

Claims

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Application Information

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IPC IPC(8): C02FC02F1/04C02F1/20C02F1/22
Inventor 刘金成郭彦书
Owner 河北阳煤正元化工集团有限公司
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