Method and system for electrochemically reducing hardness of wastewater

An electrochemical and wastewater technology, applied in chemical instruments and methods, water pollutants, descaling and water softening, etc., can solve the problems of increasing the burden of downstream processing, large electrode consumption, etc., to achieve a simple hard removal process, reduce the burden, cost saving effect

Pending Publication Date: 2021-08-03
SYNFUELS CHINA INNER MONGOLIA CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese patent application CN106630307A discloses a system and method for coal gasification gray water, which uses electrochemical methods to adjust pH and alkalinity to solve problems such as hardness, turbidity and suspended solids in gray water, but the iron alloy and / aluminum Alloy materials are used as active electrodes. The electrodes consume a lot during the operation of the equipment, and the elements such as Fe and / or Al generated by electrolysis are further called pollutants in water, which increases the burden of downstream treatment.

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  • Method and system for electrochemically reducing hardness of wastewater
  • Method and system for electrochemically reducing hardness of wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0084] Raw material: 100kg / h filtered gasification wastewater, total hardness 800mg / L, pH=7.9;

[0085] Such as figure 1 As shown, the above-mentioned raw materials are filtered at room temperature and then passed into an electrochemical hard removal device. In the closed electrolytic cell 1, the electrodes are plate-type inert electrodes, wherein the anode 3 is a graphite electrode, the cathode 2 is a titanium electrode; the ion exchange membrane 5 is a cationic membrane. Adjust the voltage and current so that the voltage is 30-50V, the current is 10-20A, and the temperature is 20-25°C. After electrolysis, a white precipitate is produced in the cathode chamber, and the pH value rises to 12, and the pH value of the anode chamber decreases to 3.5, and the CO 2 The gas 102 is passed into the cathode chamber, the pressure is controlled at 0.2MPa, and the released gas 103 is discharged from the top of the closed electrolytic cell 1; the wastewater 104 in the cathode chamber is f...

Embodiment 2

[0087] Raw material: 100kg / h filtered gasification wastewater, total hardness 800mg / L, pH=7.9;

[0088] Such as figure 1As shown, the above-mentioned raw materials are filtered at room temperature and then passed into an electrochemical hard removal device. In the closed electrolytic cell 1, the electrodes are plate-type inert electrodes, wherein the anode 3 is a graphite electrode, the cathode 2 is a titanium electrode; the ion exchange membrane 5 is a cationic membrane. Adjust the voltage and current so that the voltage is 30-50V, the current is 10-20A, and the temperature is 20-25°C. After electrolysis, a white precipitate is produced in the cathode chamber, and the pH value rises to 12, and the pH value of the anode chamber decreases to 3.5, and the CO 2 The gas 102 is passed into the cathode chamber, the pressure is controlled at 0.2 MPa, and the released gas 103 is discharged from the top of the closed electrolytic cell 1; the cathode chamber wastewater 104 is neutrali...

Embodiment 3

[0090] Raw materials: 100kg / h filtered gasification wastewater 101, total hardness 800mg / L, pH=7.9;

[0091] Such as figure 2 As shown, the above-mentioned raw materials are filtered at room temperature and then passed into an electrochemical hard removal device. In the closed electrolytic cell 1, the electrodes are plate-type inert electrodes placed on both sides outside the electrolytic cell; the ion exchange membrane 5 is a cationic membrane. The electrolytic cell is divided into a cathode chamber and an anode chamber, and the voltage and current are adjusted so that the voltage is 30-50V, the current is 10-20A, and the temperature is 20-25°C. While powering on, the CO 2 The gas 102 is passed into the cathode chamber, the control pressure is 0.2MPa, and the release gas 103 is discharged from the top of the electrolytic cell; the cathode chamber waste water 104 is neutralized with the alkali 108, and a large amount of white precipitates appear, which are filtered by the s...

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Abstract

The invention discloses a method and system for electrochemically reducing hardness of wastewater. The method comprises the following steps: introducing pretreated wastewater into an electrochemical hardness removal device for electrolysis, then carrying out a reaction with dispersed carbon dioxide to obtain hardness-removed wastewater, and then carrying out solid-liquid separation to obtain hardness-removed water. The electrochemical hardness removal device comprises a closed electrolytic tank, and a cathode and an anode are arranged inside or outside the electrolytic tank. According to the method for electrochemically reducing the hardness of the wastewater, provided by the invention, metal cations such as Ca<2+> and Mg<2+> in the wastewater can be effectively removed by adding nothing or adding a small amount of chemical reagents in the treatment process; and the hardness removal method has little influence on the whole sewage treatment system, the burden of the downstream sewage treatment system can be effectively reduced, and the treated water can be further treated or directly utilized according to requirements.

Description

technical field [0001] The invention relates to a method and system for electrochemically reducing the hardness of wastewater, belonging to the technical field of wastewater treatment. Background technique [0002] Water hardness (usually refers to the content of calcium and magnesium elements, and also includes metal cations such as iron, manganese, aluminum, etc., which are easy to form insoluble salts, calculated by the calcium carbonate content in water) is an important indicator to measure water quality, and regenerated water is usually used for circulating cooling The water quality requires that the sum of total alkalinity and total hardness is not higher than 700mg / L. It is generally believed in the industry that hardness + alkalinity exceeding 1200mg / L is easy to scale. Therefore, in the process of wastewater treatment, especially for the recycling of saline wastewater, whether it is concentrated by membrane technology, evaporated concentration technology, or recycle...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F5/00C02F101/10
CPCC02F5/00C02F2101/10
Inventor 耿春宇李国强刘晓娜师海峰贾梦磊王缠和董根全高琳杨勇李永旺
Owner SYNFUELS CHINA INNER MONGOLIA CO LTD
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