Pretreatment method for high-salinity desulfurized wastewater of coal-fired power plant and system

A technology for desulfurization wastewater and coal-fired power plants. It is applied in the direction of gaseous effluent wastewater treatment, multi-stage water treatment, water/sewage treatment, etc. It can solve the problems of reducing operating costs, removing impure products, and high process operating costs. Improve value-added effects and reduce operating costs

Inactive Publication Date: 2019-07-02
CHNA ENERGY INVESTMENT CORP LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a pretreatment method and system for high-salt desulfurization wastewater in coal-fired power plants in order to overcome the problems of impure removal products and high process operating costs in the prior art. The application of the method and system can effectively Highly separate monovalent ions and divalent ions in desulfurization wastewater, and can recover calcium sulfate with higher purity, and can reduce the operating cost of purification and pretreatment of high-salt desulfurization wastewater in coal-fired power plants

Method used

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  • Pretreatment method for high-salinity desulfurized wastewater of coal-fired power plant and system
  • Pretreatment method for high-salinity desulfurized wastewater of coal-fired power plant and system
  • Pretreatment method for high-salinity desulfurized wastewater of coal-fired power plant and system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0093] The high-salt desulfurization wastewater (flow rate 20t / h) of the coal-fired power plant whose composition is shown in Table 1 is passed into figure 1 In the first acidity adjustment unit of the high-salt desulfurization wastewater system of the coal-fired power plant shown, a hydrochloric acid solution with a concentration of 20% by weight is added to the first acidity adjustment unit to obtain a stock solution with a pH value of 7;

[0094] The secondary clear water returned by the stock solution and the downstream is passed into the filter unit, and the sodium hypochlorite of 5 mass ppm of the total amount of the stock solution and the secondary clear water is added, and ultrafiltration (ultrafiltration equipment provided by GE company) is carried out to obtain the filtered product water, The SDI value is 0.5; the weight ratio of stock solution and secondary clear water is 1.5:1;

[0095] Add hydrogen peroxide in an amount of 20 mass ppm of filtered product water to ...

Embodiment 2

[0102] The high-salt desulfurization wastewater (flow rate 20t / h) of the coal-fired power plant whose composition is shown in Table 1 is passed into figure 1 In the first acidity adjustment unit of the high-salt desulfurization wastewater system of the coal-fired power plant shown, a hydrochloric acid solution with a concentration of 20% by weight is added to the first acidity adjustment unit to obtain a stock solution with a pH value of 8;

[0103] The secondary clear water returned by the stock solution and the downstream is passed into the filter unit, and the sodium hypochlorite of 10 mass ppm of the total amount of the stock solution and the secondary clear water is added, and ultrafiltration (ultrafiltration equipment provided by GE company) is carried out to obtain the filtered product water, The SDI value is 0.8; the weight ratio of stock solution and secondary clear water is 3.5:1;

[0104] Add ferric chloride with an amount of 5 mass ppm of filtered product water to ...

Embodiment 3

[0111] The high-salt desulfurization wastewater (flow rate 20t / h) of the coal-fired power plant whose composition is shown in Table 1 is passed into figure 1 In the first acidity adjustment unit of the high-salt desulfurization wastewater system of the coal-fired power plant shown, a hydrochloric acid solution with a concentration of 15% by weight is added to the first acidity adjustment unit to obtain a stock solution with a pH value of 6;

[0112] The secondary clear water returned by the stock solution and the downstream is passed into the filter unit, and the hydrogen peroxide of 5 mass ppm of the total amount of the stock solution and the secondary clear water is added, and ultrafiltration (ultrafiltration equipment provided by GE company) is carried out to obtain the filtration product Water, the SDI value is 0.6; the weight ratio of stock solution and secondary clear water is 2:1;

[0113] Add ferric chloride that is 10 mass ppm of filtered product water to the filtered...

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Abstract

The invention relates to the field of purification of high-salinity desulfurized wastewater of coal-fired power plants and discloses a pretreatment method for the high-salinity desulfurized wastewaterof a coal-fired power plant and a system. The method comprises the steps: (1) subjecting the desulfurized wastewater to pH adjusting, so as to obtain raw liquor; (2) adding a microbicide into the rawliquor, and carrying out filtering treatment, so as to obtain filtering produced water; (3) adding a scale inhibitor and a scale inhibitor deactivator into the filtering produced water, and carryingout ion separation, so as to obtain high-concentration brine and pretreatment produced water; (4) adding lime into the high-concentration brine, carrying out a primary reaction, and subjecting an obtained primary reaction product to primary solid-liquid separation, so as to obtain primary clear water and primary sludge; (5) subjecting the primary clear water to acidity adjusting, so as to obtain acidity adjusted produced water; and (6) adding sodium sulfate into the acidity adjusted produced water, and carrying out a secondary reaction and normal-temperature calcium sulfate separation by crystallization sequentially, thereby obtaining secondary clear water and secondary sludge, wherein the secondary clear water returns to the step (2) for filtering treatment. By the method and the system,the pretreatment cost of the desulfurized wastewater of the coal-fired power plant can be effectively reduced.

Description

technical field [0001] The invention relates to the field of purification of high-salt desulfurization wastewater in coal-fired power plants, in particular to a pretreatment method and system for high-salt desulfurization wastewater in coal-fired power plants. Background technique [0002] Most power plants and coal chemical plants in my country use limestone wet desulfurization technology to remove SO from flue gas. 2 , the resulting desulfurization wastewater has become one of the most difficult wastewater for coal-fired power plants due to its complex composition and many types of pollutants. At present, the chemical precipitation method (commonly known as triple box precipitation) is mainly used in China to treat desulfurization wastewater. The treated water has a high salt content, and it is easy to cause secondary pollution after direct discharge. At the same time, due to the small amount of desulfurization wastewater and high salt content, the process system for furt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01F11/46C02F103/18
CPCC01F11/46C02F1/001C02F1/442C02F1/444C02F1/50C02F1/58C02F1/66C02F1/722C02F1/76C02F5/00C02F5/02C02F9/00C02F2101/101C02F2103/18C02F2209/02C02F2209/03C02F2209/055C02F2209/06C02F2301/08
Inventor 李国涛钟振成熊日华程子洪李小端张微尘佟振伟霍卫东李永龙卫昶
Owner CHNA ENERGY INVESTMENT CORP LTD
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