Device and method for recycling calcium magnesium in desulfurization waste water by using carbonization method

A technology of desulfurization wastewater and carbonization method, which is applied in the direction of chemical instruments and methods, magnesium hydroxide, calcium carbonate/strontium/barium, etc., can solve the problems of non-recyclable sludge, increased sludge volume, large consumption of chemicals, etc., and achieves increased Effects of waste water reuse rate, reduction of drainage, and mitigation of adverse effects

Inactive Publication Date: 2018-01-23
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Traditional wastewater softening is mainly to remove calcium and magnesium by adding alkali to precipitate, which consumes a lot of chemicals and produces a lot of sludge
Chinese invention patent CN 105621742 A softens desulfurization wastewater by sequentially adding calcium hydroxide, organic sulfur, sulfate, and carbonate, whi...

Method used

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  • Device and method for recycling calcium magnesium in desulfurization waste water by using carbonization method
  • Device and method for recycling calcium magnesium in desulfurization waste water by using carbonization method
  • Device and method for recycling calcium magnesium in desulfurization waste water by using carbonization method

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Experimental program
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Effect test

Embodiment 1

[0057] Preliminary test of carbonization method to recover calcium and magnesium in desulfurization wastewater: During the experiment, the calcium ion concentration in the simulated desulfurization wastewater was 5313mg / L, the magnesium ion concentration was 3247mg / L, the CO2 flow was controlled at 0.6L / min, and the temperature was controlled by The constant temperature magnetic stirrer is controlled at 20°C.

[0058] CO2 was continuously fed into the simulated desulfurization wastewater, and samples were taken for measurement when the pH was 9.0, 8.5, 8.0, 7.5, 7.0, and 6.0. The result is as figure 2 shown. It can be seen that when the pH is high, more Mg precipitates and less Ca precipitates. As the pH decreases, Mg precipitates gradually decrease, while Ca precipitates gradually increase, and finally stabilize at 80-90%. This is because, when the pH is high in the first stage, hydroxide precipitation is first generated, and Ca(OH) 2 Ksp is 5.5 x 10 -6 , Mg(OH) 2 The K...

Embodiment 2

[0061] The limestone pulping system 11 sends the prepared limestone slurry into the desulfurization tower 1, and the flue gas passes into the desulfurization tower 1, and the desulfurized flue gas is introduced into the aeration tank 5 by the fan 4, and the desulfurization wastewater generated by the desulfurization tower 1 is Pass into neutralization pool 2, add Ca(OH) 2 Adjust the pH to 9 to precipitate heavy metals and other impurities in the desulfurization wastewater. The sediment in the neutralization tank 2 is sent to the plate and frame filter press 3 for pressure filtration and treated as sludge. The upper water in the neutralization tank 2 is passed into the aeration tank 5. The flue gas sent to the aeration tank by fan 4 contains 15% CO 2 , can be used to adjust the pH of the wastewater in the aeration tank, and the aeration can be stopped after the pH is adjusted to 7. At this time, most of the Ca in the wastewater 2+ CaCO 3 form precipitated. After the solutio...

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Abstract

The invention discloses a device and a method for recycling calcium magnesium in desulfurization waste water by using a carbonization method. By adopting the device and the method, desulfurization waste water is simply pretreated to remove heavy metals, CO2 is introduced to reduce the pH value of wastewater, CaCO3 in the wastewater is separated and fed back to a desulfurization tower for continuous utilization, alkali is put into a clear liquid to sediment most Mg, and Mg(OH)2 in sediment is recycled. The device has the advantages that most hardness of wastewater is removed, calcium and magnesium are recycled, and certain economic benefits are made for power plants.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a device and method for recovering calcium and magnesium in desulfurization wastewater by carbonization. Background technique [0002] With the increasingly stringent environmental protection standards, zero discharge of desulfurization wastewater has become a trend. The mainstream zero discharge technology is based on evaporation, and the high content of calcium and magnesium in wastewater can easily cause scaling of equipment and affect the normal operation of subsequent water treatment units. [0003] At present, the main technical means of common desulfurization wastewater zero discharge technologies include membrane concentration treatment and evaporation crystallization, etc. Evaporation technologies mainly include flue spray evaporation, bypass flue evaporation, mechanical atomization evaporation, etc., through liquid phase evaporation, pollutants are removed f...

Claims

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Application Information

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IPC IPC(8): C02F9/08C01F11/18C01F5/14
Inventor 马双忱朱思洁刘亚争向亚军陈嘉宁
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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