Sewage reuse treatment method for power plant circulating water

A treatment method and technology for circulating water, applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., which can solve problems such as pressure difference rise, influence of operation stability, and decrease of desalination rate. , to achieve the effect of reducing the frequency of chemical cleaning, extending the operating cycle and improving the utilization rate

Active Publication Date: 2011-12-14
STATE GRID HEBEI ENERGY TECH SERVICE CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Circulating water and sewage water quality components are complex, the salt content in water, COD, SiO 2 , hardness, alkalinity and other indicators are doubled compared with natural water bodies. When it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis fouling, resulting in a decrease in reverse osmosis output, shortened operating cycle, and frequent chemical cleaning. , the water supply of the power plant is insufficient, which will shorten the life of the reverse osmosis membrane element in severe cases, which greatly affects the stability of the reverse osmosis operation of the power plant
[0003] At present, most of the power plants using circulating water and sewage reuse adopt ultrafiltration as the reverse osmosis pretreatment process. Ultrafiltration occupies a large area and has high investment costs. The SDI value of the reverse osmosis influent drops to the required range, but the removal effect of ultrafiltration on the organic matter and microorganisms in the water is poor. increase, the desalination rate decreases, etc., the operation stability is affected
Usually power plants have to reduce the recovery rate of reverse osmosis to operate. At present, the recovery rate of conventional reverse osmosis is 75%, and the recovery rate of reverse osmosis in some circulating water reuse systems even drops to 60%, that is, more than a quarter of the influent water is used as concentrated water emissions, which is a large waste for the system

Method used

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  • Sewage reuse treatment method for power plant circulating water

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Experimental program
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Embodiment 1

[0021] (1) Set the water volume to 200m 3 / h circulating water sewage is injected into the mechanical agitation acceleration clarification tank, and its hardness value and alkalinity value are measured to be 10mmol / L and 6mmol / L respectively, and the difference between the hardness value and alkalinity value is greater than 3mmol / L, so add carbonic acid first Sodium makes the difference between the hardness value and the alkalinity value less than 1mmol / L, and then add quicklime to the above-mentioned circulating water to soften, so that the concentration of hydroxide in the circulating water is 0.1-0.3mmol / L, and then add it to the softened circulating water Add polyferric sulfate and polyacrylamide for coagulation and clarification treatment, the addition amount of polyferric sulfate and polyacrylamide is 40mg / L and 1.0mg / L respectively; the mechanical agitation acceleration clarification tank adopts Ф14300 mechanical agitation acceleration clarification tank 1 Taiwan, the d...

Embodiment 2

[0034] In this embodiment, the hardness value and alkalinity value of circulating water sewage are 7mmol / L and 6mmol / L respectively, and the difference between hardness value and alkalinity value is less than 3mmol / L. The concentration is 0.1-0.3mmol / L; The addition amount of polyferric sulfate and polyacrylamide is 20mg / L and 0.6mg / L respectively; Other steps are with embodiment 1. The water quality of the reverse osmosis produced water in this embodiment also meets the reuse standard.

Embodiment 3

[0036] In this embodiment, the hardness value and alkalinity value of circulating water sewage are 9mmol / L and 6mmol / L respectively, and the difference between hardness value and alkalinity value is not more than 3mmol / L. The root concentration is 0.1-0.3mmol / L; the addition amount of polyferric sulfate and polyacrylamide is 10mg / L and 2mg / L respectively; other steps are the same as in Example 1. The water quality of the reverse osmosis produced water in this embodiment also meets the reuse standard.

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Abstract

The invention relates to a reliable reverse osmosis high-recovery treatment method for recycling circulating water from a power plant. The method comprises the following steps: coagulating and clarifying the discharge water of the circulating water, adding an acid to adjust the pH value to 9.0-9.5, filtering with a variable-aperture filtering pool and a multi-medium filter, treating the filtered water with a two-stage sodium ion exchanger, adjusting the effluent to be alkaline, conveying to a reverse osmosis process, carrying out ultrafiltration on the reverse osmosis concentrated water part,and recycling as a solvent for regenerating the sodium ion exchanger. The treatment method provided by the invention has the beneficial effects of effectively reducing the reverse osmosis fouling risk caused by circulating water, prolonging the reverse osmosis operation period, reducing the chemical cleaning frequency, improving reverse osmosis operation stability, effectively improving the utilization rate of the circulating water, so that the maximum recovery of reverse osmosis can reach 95%, reasonably recycling part of the reverse osmosis concentrated water and saving a lot of water resources; and the reverse osmosis produced water can be directly used for heat network water replenishing and circulating water replenishing of the power plant. The method plays a good promotion role in solving the short water supply of the power plant, improving recycling utilization rate of the circulating water and the like, and is also suitable for chemical industry, petroleum, steel and other fields utilizing the discharge water of the circulating water as production water.

Description

technical field [0001] The invention relates to a treatment method for recycling sewage of power plant circulating water. technical background [0002] Sewage reuse of circulating water is an effective way to solve the shortage of water resources in power plants and realize the reduction of sewage discharge and the utilization of sewage resources. Circulating water and sewage water quality components are complex, the salt content in water, COD, SiO 2 , hardness, alkalinity and other indicators are doubled compared with natural water bodies. When it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis fouling, resulting in a decrease in reverse osmosis output, shortened operating cycle, and frequent chemical cleaning. , Insufficient water supply of the power plant will shorten the life of the reverse osmosis membrane element in severe cases, which greatly affects the stability of the reverse osmosis operation of the power plant. [0003] At pres...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04
Inventor 刘克成龙潇王平马东伟高燕宁张建华
Owner STATE GRID HEBEI ENERGY TECH SERVICE CO LTD
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