Recycling system and recycling process for recycling salt from desulfurization waste water

A desulfurization wastewater and recycling system technology, applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, alkali metal chloride, etc., can solve problems such as affecting salt purity, and achieve the effect of avoiding corrosion

Active Publication Date: 2015-07-29
广州新普利节能环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The desulfurization wastewater contains more NaCl, and the NaCl product in the wastewater can be recovered while the desulfurization wastewater is being treated, but the wastewater also contains more other components

Method used

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  • Recycling system and recycling process for recycling salt from desulfurization waste water
  • Recycling system and recycling process for recycling salt from desulfurization waste water

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment

[0033] refer to Figure 1-2 , a recovery system for recovering salt from desulfurization wastewater described in this embodiment includes a purification treatment device 1, a pre-heat exchange device 2, a primary evaporative crystallization device 3, a primary transfer pump 4, and a secondary evaporative crystallization device 5. The first-stage centrifuge 6, the drying bed 7, the second-stage centrifuge 8 and the salt-dissolving barrel 9; the purification treatment device 1 is a demineralized water device.

[0034] One of the water inlets of the purification treatment device 1 is connected to the desulfurization waste water conveying pipe 10, and the water outlet of the purification treatment device 1 is connected to the preheat exchange device 2 and the primary evaporative crystallization device 3 through pipes in turn; the primary evaporative crystallization The primary concentrated brine output port of the device 3 is connected to the secondary evaporative crystallization ...

Embodiment 1

[0060] Example 1: Evaporation at 50°C

[0061] The solubility components of sodium chloride-sodium sulfate-water are shown in Table 3:

[0062] Table 3 Solubility of sodium chloride-sodium sulfate-water at 50℃

[0063]

[0064]

[0065] According to the mutual solubility relationship between sodium chloride and sodium sulfate at 50 °C, the first-stage evaporation should control the sodium sulfate component to be less than 5.3%, and the sodium chloride component to be greater than 24.2%, so that sodium chloride crystals can be precipitated, while Sodium sulfate did not precipitate. That is, the primary evaporation is:

[0066] M (Na2SO4) / (M 总 -M 蒸发 )*100%<5.3%;

[0067] M 蒸发 总 -M (Na2SO4) *100% / 5.3%;

[0068] M 蒸发 <15943.2-317.3*100% / 5.3%Kg / h;

[0069] i.e. M 蒸发 <9956.4Kg / h;

[0070] At this moment, the sodium chloride component content is: M(NaCl) / (M total-M evaporation)*100%=2900 / (15943.2-9956.4)*100%=48.44%;

[0071] When the solubility of sodium chlorid...

Embodiment 2

[0078] Example 2: Evaporation at 75°C

[0079] The solubility components of sodium chloride-sodium sulfate-water are shown in Table 4:

[0080] Table 4 Solubility of sodium chloride-sodium sulfate-water at 75℃

[0081]

[0082] According to the mutual solubility relationship between sodium chloride and sodium sulfate at 75 °C, the first-stage evaporation should control the sodium sulfate component to be less than 4.95%, and the sodium chloride component to be greater than 25.25%, so that pure sodium chloride crystals can be precipitated. The sodium sulfate did not precipitate. That is, the primary evaporation is:

[0083] M (Na2SO4) / (M 总 -M 蒸发 )*100%<4.95%;

[0084] M 蒸发 总 -M (Na2SO4) *100% / 4.95%;

[0085] M 蒸发 <15943.2-317.3*100% / 4.95%Kg / h;

[0086] i.e. M 蒸发 <9533.1Kg / h;

[0087] At this time, the sodium chloride component content is:

[0088] M (NaCl) / (M 总 -M 蒸发 )*100%=2900 / (15943.2-9533.1)*100%=45.24%;

[0089] When the solubility of sodium chloride ...

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Abstract

The invention discloses a recycling system and a recycling process for recycling salt from desulfurization waste water. The system comprises a purifying device, a heat pre-exchange device, a first-stage evaporative crystallizing device, a first-stage material transferring pump, a second-stage evaporative crystallizing device, a first-stage centrifuge, a drying bed, a second-stage centrifuge and a salt dissolving bucket. According to the system and the method disclosed by the invention, purified desulfurization waste water is subjected to two-stage evaporation; by controlling the evaporation amount and the evaporation temperature of a first-stage evaporator, the waste water is concentrated and crystallized to generate NaCl, and Na2SO3 is not crystallized, so that the content of NaCl is enabled to be above 99%. Afterwards, a material of the first-stage evaporator is transferred to a second-stage evaporator to be evaporated and concentrated again to generate NaCl crystal and Na2SO4 crystal. The system and the method disclosed by the invention can be used for continuously producing high-purity NaCl of which the purity is larger than 99%.

Description

technical field [0001] The invention relates to the field of desulfurization wastewater from power plants, in particular to a recovery system and a recovery process for recovering salt from desulfurization wastewater. Background technique [0002] SO in the flue gas of thermal power plants in my country 2 Emissions from the flue gas are strictly controlled, so most thermal power plants use limestone wet flue gas desulfurization (FGD) to desulfurize the flue gas. But at the same time, in order to balance the concentration of chloride ions in the absorption liquid, a part of the absorption slurry must be discharged, and the clear liquid after the hydraulic separation of the absorption slurry is discharged as desulfurization wastewater. The discharge of desulfurization wastewater in thermal power plant wastewater is not large, but its pollution is serious, and the water quality is characterized by high content of suspended solids, pH value, and COD value. Calcium, magnesium, ...

Claims

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Application Information

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IPC IPC(8): C02F9/10C01D3/06
Inventor 张广林莫新来黄莹莹谭子斌
Owner 广州新普利节能环保科技有限公司
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