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Comprehensive treatment method for formaldehyde-containing acid wastewater

A technology for comprehensive treatment of acidic wastewater, applied in the direction of water/sewage multi-stage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., to achieve the effect of purifying industrial wastewater, high income, and low energy consumption

Active Publication Date: 2014-09-03
SHANDONG TAIHE WATER TREATMENT TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is only suitable for the treatment of a small amount of formaldehyde-containing wastewater

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1 (best embodiment)

[0022] A comprehensive treatment method for formaldehyde-containing acidic waste water, providing the following specific implementation steps

[0023] (1) At normal temperature, pump liquid ammonia into the treatment tank of acidic waste water containing formaldehyde, and add it while stirring. The formaldehyde-containing acidic wastewater in this example comes from the wastewater produced by aminotrimethylene phosphonic acid, wherein the mass percent concentration of formaldehyde in the wastewater is 3.5%, and the mass percent concentration of hydrogen chloride is 17%.

[0024] (2) Detect the pH value of the waste liquid to 5, stop adding liquid ammonia, and obtain a dilute ammonium chloride solution.

[0025] (3) Concentrate the dilute ammonium chloride solution at -0.08MPa vacuum distillation, control the tower top temperature at 35°C to collect formaldehyde, and obtain a formaldehyde solution with a mass percentage concentration of ...

Embodiment 2

[0030] A comprehensive treatment method for formaldehyde-containing acidic waste water, providing the following specific implementation steps

[0031] (1) Under normal temperature conditions, pump liquid ammonia into the treatment tank of formaldehyde-containing acidic wastewater and add it while stirring. In this case, the formaldehyde-containing acidic wastewater comes from the production wastewater of aminotrimethylene phosphonic acid, wherein the mass percent concentration of formaldehyde in the wastewater is 2.7%, and the mass percent concentration of hydrogen chloride is 14%.

[0032] (2) Detect the pH value of the waste liquid to 6, stop adding liquid ammonia, and obtain a dilute ammonium chloride solution.

[0033] (3) Concentrate the dilute ammonium chloride solution at -0.08MPa vacuum distillation, control the tower top temperature at 35°C to collect formaldehyde, and obtain a formaldehyde solution with a mass percentage concentration of 37.6%.

[0034] (4) When the...

Embodiment 3

[0038] A comprehensive treatment method for formaldehyde-containing acidic waste water, providing the following specific implementation steps

[0039] (1) Under normal temperature conditions, pump liquid ammonia into the treatment tank of formaldehyde-containing acidic wastewater and add it while stirring. The formaldehyde-containing acidic wastewater in this example comes from the wastewater produced by ethylenediamine tetramethylene phosphonic acid, wherein the mass percent concentration of formaldehyde in the wastewater is 3.5%, and the mass percent concentration of hydrogen chloride is 17%.

[0040] (2) Detect the pH value of the waste liquid to 7, stop adding liquid ammonia, and obtain a dilute ammonium chloride solution.

[0041] (3) Concentrate the dilute ammonium chloride solution at -0.08MPa vacuum distillation, control the tower top temperature at 35°C to collect formaldehyde, and obtain a formaldehyde solution with a mass percent concentration of 36.8%.

[0042] (4...

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PUM

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Abstract

The invention provides a comprehensive treatment method for formaldehyde-containing acid wastewater, which is specifically designed for large amounts of formaldehyde-containing hydrochloric acid waste liquid produced in the process of producing organic phosphorus-water treatment reagents such as nitrilotrimethylene triphosphonic acid, ethylenediamine tetramethylenephosphonic acid and the like. The comprehensive treatment method provided by the invention comprises the following steps: adding liquid ammonia into formaldehyde-containing acid wastewater, and adjusting the PH value of the obtained mixture to be 5-7 so as to produce an ammonium chloride dilute solution; carrying out decompressed rectification, concentration, crystallization and dehydration on the ammonium chloride dilute solution so as to obtain ammonium chloride crystals which can be used as a raw material of nitrilotrimethylene triphosphonic acid and also can be used as a crop nitrogen fertilizer; carrying out rectification and purification on formaldehyde in the wastewater so as to obtain a formaldehyde solution with a mass percent concentration of greater than or equal to 20%, wherein the formaldehyde solution can be recycled as an organic phosphorus production raw material; and removing the formaldehyde in the wastewater by steaming until the formaldehyde concentration is less than 2 mg / L, the chlorine ion content is less than or equal to 3 ppm and the PH value is 5-7, so that the wastewater reaches the second-class discharge standard of industrial wastewater.

Description

technical field [0001] The invention belongs to the field of chemical production and provides a comprehensive treatment method for formaldehyde-containing acidic waste water. Solve the discharge problem of formaldehyde-containing acidic wastewater in the production process of organic phosphine water treatment chemicals, protect the environment, and realize the comprehensive utilization of resources. Background technique [0002] Organic phosphine water treatment agents such as aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, etc. are the most widely used scale and corrosion inhibitors. Calcium and magnesium ions form complexes and disperse in water, destroying the normal crystallization of calcium sulfate, calcium carbonate, magnesium sulfate, and magnesium carbonate to form scales. Due to the unique anti-scaling and anti-scaling properties of organic phosphine, it is widely used in mining, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10
Inventor 程终发刘全华宋盟盟任泽旭万振涛张秀华
Owner SHANDONG TAIHE WATER TREATMENT TECH CO LTD