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Method for comprehensively utilizing waste gas and waste liquid in production of biurea

A biurea and waste liquid technology, which is applied in the preparation of urea derivatives, organic compounds, alkali metal chlorides, etc., can solve the problems of high economic value of by-products, difficult recovery and purification processes, and environmental pollution, achieving significant economic benefits Benefits and environmental protection significance, wide application, high value effect

Inactive Publication Date: 2012-06-13
福建省邵武市榕丰化工有限公司
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Problems solved by technology

[0014] The purpose of the present invention is to overcome the defects of low added value of by-products and difficult recovery and purification process in the traditional biurea process technology, the discharge of filtrate causes environmental pollution and other defects, and provides a method for comprehensive utilization of waste gas and waste liquid in the production of biurea, which prevents from the source Generation of pollutants, high economic value of by-products

Method used

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  • Method for comprehensively utilizing waste gas and waste liquid in production of biurea
  • Method for comprehensively utilizing waste gas and waste liquid in production of biurea

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Embodiment 1

[0027] Technical Features:

[0028] (1) According to the traditional process, urea and sodium hypochlorite are used to react to generate hydrazine hydrate stock solution, and the hydrazine hydrate stock solution is passed into SO 2 Gas, NaHSO 3 or Na 2 S 2 o 5 One of them, the pH value of the hydrazine hydrate solution is 6.0-7.0, the hydrazine hydrate solution is cooled and crystallized, and the solid-liquid separation is obtained to obtain Na 2 SO3 ·7H 2 O product and the 1st filtrate containing hydrazine hydrate;

[0029] NaOH, NaCO in hydrazine hydrate 3 with SO 2 Gas absorption reaction to form Na 2 SO 3 , The pH of the reaction end point is 6.0~7.0, and the reaction temperature is maintained at 30~55°C during the absorption process.

[0030] 2NaOH+SO 2 →Na 2 SO 3 +H 2 O ----------------(5)

[0031] Na 2 CO 3 +SO 2 →Na 2 SO 3 +CO 2 ↑-----------(6)

[0032] or hydrazine hydrate with NaHSO under stirring conditions 3 Neutralization reaction produces N...

Embodiment 2

[0059] Hydrazine hydrate and the third filtrate carry out neutralization reaction to generate Na 2 SO 3 Feed liquid, Na 2 SO 3 The feed liquid is cooled and crystallized, and Na is obtained after solid-liquid separation. 2 SO 3 7H 2 O product and 1st filtrate.

[0060] Add urea according to the amount of hydrazine hydrate in the first filtrate for condensation reaction, and the condensation reaction process produces NH 3 Pumped together with water vapor for gas-liquid separation, NH 3 Perform absorption reaction with the second filtrate, and remove a small amount of condensed water for the primary product of biurea, NH 4 Except for the washing water of Cl products, the rest are all recycled and comprehensively utilized.

[0061] A small amount of biurea primary product, NH 4 After the neutralization reaction of the Cl product washing solution and the hydrazine hydrate stock solution, it is used as a supplementary solution in the condensation reaction process.

[0062...

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Abstract

The invention provides a method for comprehensively utilizing a waste gas and waste liquid in the production of biurea, which belongs to the technical field of comprehensive utilization of the waste gas and waste liquid in the production of the biurea (ADC product midbody). Hydrazine hydrate, urea and a SO2 gas used as reaction raw materials and an intermediate product NaHSO3 used as circulating mother liquor carry out neutralization reaction, condensation reaction, SO2 gas absorption and NH3 gas absorption to generate products of Na2SO3.7H2O, biurea and NH4Cl, and biurea washing liquid is evaporated and crystallized to obtain a NaCl product. The invention obtains the products of Na2SO3 and NH4Cl with high additional values by the comprehensive utilization of the waste gas and the waste liquid in the production of the biurea and solves the problem of environmental pollution caused by the abundant discharge of secondary products which are (NH4)SO4, Na2SO4 and NaCl in the production process of a traditional process.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of waste gas and waste liquid in the production of biurea (ADC product intermediate), and more specifically relates to a method for comprehensive utilization of waste gas and waste liquid in the production of biurea. Background technique [0002] Biurea is used as an intermediate in the production process of foaming agent ADC products, and its traditional process is divided into two steps: [0003] (1) Synthesis of hydrazine: use urea and sodium hypochlorite to react to generate hydrazine hydrate [0004] h 2 NCONH 2 +NaClO+2NaOH→H 2 NNH 2 h 2 O+NaCl+Na 2 CO 3 ---------(1) [0005] (2) Condensation system of biurea [0006] With the hydrazine hydrate of the previous process under acidic conditions (with H 2 SO 4 ) condensation to generate biurea, the whole production process is controlled at PH=4~5, and the temperature is controlled at 105°C. [0007] N 2 h 4 h 2 O...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C281/06C07C273/18C01D5/14C01D3/04C01C1/16
Inventor 黄绳炀陈世豪夏霆邹福旺张明坤黄兵陈鼎东吴元金
Owner 福建省邵武市榕丰化工有限公司
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