Ion exchange desalting method and device

A technology of ion exchange and ions, applied in the direction of ion exchange water/sewage treatment, etc., can solve the problems of inability to reduce the amount of alkali, silicic acid precipitation, etc., achieve the effect of reducing the amount of alkali, reducing the amount of alkali, and simplifying the process flow

Inactive Publication Date: 2011-02-23
CHONGQING MAYHEAT TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to regeneration efficiency and free CO 2 The stripping efficiency problem, the actual consumption of acid and alkali is higher than the theoretical value, especially the anion exchange resin, because the strongly basic ion exchange resin adsorbs silicate, it needs to use an excessive amount of alkali during regeneration, otherwise it will cause silicic acid precipitation, The method of combining strong and weak resins cannot reduce the amount of alkali

Method used

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  • Ion exchange desalting method and device
  • Ion exchange desalting method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Example 1: The total number of influent cations is 5mmol / l, where Ca 2+ , Mg 2+ The content is 4mmol / l, the total number of anions is 5mmol / l, of which the strong acid anion (SO 4 2- , Cl - , NO 3 - etc.) with a content of 3mmol / l, bicarbonate HCO 3 - The content is 1.8mmol / l, and the silicate is 0.2mmol / l (the units are based on the monovalent ions commonly used in water treatment, the same below). The outlet water requires a conductivity of 1??s / cm.

[0040] After the feed water is exchanged by a weakly alkaline anion exchanger, the OH produced - The ion concentration is equal to the strong acidic anion concentration, that is, 3mmol / l, and bicarbonate HCO3 - combine to form carbonate CO 3 2- 3.6mmol / l, the formation of precipitate is also 3.6mmol / l, after filtering the precipitate through the filter, the content of cation entering the cation exchanger is 1.4mmol / l.

[0041] Ion exchange is an equivalent exchange. It can be known that the amount of acid r...

Embodiment 2

[0044] Example 2: The total number of influent cations is 6mmol / l, where Ca 2+ , Mg 2+ The content is 3mmol / l, the total number of anions is 6mmol / l, of which the strong acid anion (SO 4 2- , Cl - , NO 3 - etc.) with a content of 4mmol / l, bicarbonate HCO 3 - The content is 1.9mmol / l, and the silicate is 0.1mmol / l. The outlet water requires a conductivity of 10??s / cm.

[0045] After the feed water is exchanged by a weakly alkaline anion exchanger, the OH produced - The ion concentration is equal to the strong acidic anion concentration, that is, 4mmol / l, and bicarbonate HCO 3 - combine to form carbonate CO 3 2- 3.8mmol / l, the precipitate formed is 3mmol / l, after filtering the precipitate through the filter, the cation content entering the cation exchanger is 3mmol / l.

[0046] Ion exchange is an equivalent exchange. It can be seen that the amount of acid required in theory is 3 mmol for every 1 liter of water treated. While the traditional desalination system req...

Embodiment 3

[0049] Example 3: The total number of influent cations is 3.4mmol / l, where Ca 2+ , Mg 2+ The content is 2.8mmol / l, and the total number of anions is 3.4mmol / l, among which the strong acid anion (SO 4 2- , Cl - , NO 3 - etc.) with a content of 2mmol / l, bicarbonate HCO 3 - The content is 1.3mmol / l, and the silicate is 0.1mmol / l. The conductivity of the outlet water is required to be 0.1??s / cm.

[0050] After the feed water passes through the weakly basic anion exchanger, the OH produced - The ion concentration is equal to the strong acidic anion concentration, that is, 2mmol / l, and bicarbonate HCO 3 - combine to form carbonate CO 3 2- 2.6mmol / l, the precipitate was 2.6mmol / l.

[0051] The heavy carbonic acid is completely precipitated, no carbon remover is installed, and a mixed ion exchanger is required for high production water requirements. In order to reduce equipment investment, a strong alkaline anion exchanger may not be installed, and the water from the ca...

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Abstract

The invention discloses an ion exchange desalting method and an ion exchange desalting device. The method comprises the following steps of: 1) absorbing highly-acid anions in water by adopting weakly-alkaline anion exchange resin; 2) performing precipitation or filtration on the water; and 3) absorbing cations in the water by adopting cation exchange resin. The method and the device have the advantages that: OH<-> ions released by the weakly-alkaline anion exchange resin are bonded with bicarbonate ions HCO3<-> in the water to form carbonate CO3<2->, and the carbonate CO3<2-> forms insoluble electrolyte with calcium and magnesium ions in the water to partially remove dissolved electrolyte from the water and reduce the using amount of acids in a regeneration process; simultaneously, the weakly-alkaline anion exchange resin does not absorb silicate, so the use of excessive alkaline is avoided in the regeneration process and the using amount of the alkaline is reduced in the regeneration process; and a carbon-removal process can be selectively adopted, so a process flow is simplified.

Description

technical field [0001] The invention relates to a method for preparing desalinated water, in particular to an ion exchange desalination method and device. Background technique [0002] Natural water contains dissolved electrolytes in the form of ions such as calcium ions Ca 2+ , Magnesium ion Mg 2+ , Chloride ion Cl - , bicarbonate HCO 3 - Wait. [0003] When using heat treatment equipment such as boilers and heat exchangers, in order to prevent adverse effects on the heating surface due to the precipitation of electrolytes in water or corrosion of metal materials by electrolytes, it is usually required to completely or partially remove electrolytes from feed water and circulating cooling water. This process is called desalination or Desalination, correspondingly water is called desalted water or desalinated water, pure water. In some production processes such as pharmaceuticals and sulfuric acid production, in order to ensure product quality, demineralized water is al...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/42
Inventor 麻克栋
Owner CHONGQING MAYHEAT TECH
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