Zero-emission process and system for desulfurization wastewater

A desulfurization wastewater and zero-discharge technology, applied in multi-stage water treatment, water/sewage treatment, heating water/sewage treatment, etc., can solve problems such as pollution, large environmental pollution, and no economic value of calcium salts and magnesium salts. The effect of reducing the amount of production, increasing the variety, and increasing the value of recycling

Pending Publication Date: 2017-05-31
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 discharge of desulfurization wastewater in thermal power plant wastewater is not large, but its pollution is serious. The water quality is characterized by high content of suspended solids, pH value, and COD value. Exceeding standards include suspended solids, pH value, mercury, copper, lead, zinc, arsenic, Calcium, magnesium, aluminum, iron, fluoride, sulfate, carbonate, etc., are very polluting to the environment and belong to the first category of pollutants
Therefore, great attention is paid to the treatment of desulfurization wastewa

Method used

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  • Zero-emission process and system for desulfurization wastewater
  • Zero-emission process and system for desulfurization wastewater
  • Zero-emission process and system for desulfurization wastewater

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0071] Example 1: Evaporation at 50°C

[0072] Solubility components of sodium chloride-sodium sulfate-water, as shown in Table 3:

[0073] Table 3 Solubility of sodium chloride-sodium sulfate-water at 50℃

[0074]

[0075]

[0076] According to the mutual solubility relationship of sodium chloride-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 is greater than 24.2%, so that sodium chloride crystals can be precipitated, and Sodium sulfate did not precipitate out. That is, the primary evaporation is:

[0077] M(Na 2 SO 4 ) / (M total-M evaporation)*100%<5.3%;

[0078] M evaporation 2 SO 4 )*100% / 5.3%;

[0079] M evaporation <15943.2-317.3*100% / 5.3% Kg / h;

[0080] That is, M evaporation <9956.4Kg / h;

[0081] Now, the sodium chloride component content is: M (NaCl) / (M total-M evaporation)*100%=2900 / (15943.2-9956.4)*100%=48.44%;

[0082] The solubility of sodium ch...

Example Embodiment

[0089] Example 2: Evaporation at 75°C

[0090] Solubility components of sodium chloride-sodium sulfate-water, as shown in Table 4:

[0091] Table 4 Solubility of sodium chloride-sodium sulfate-water at 75°C

[0092]

[0093] According to the mutual solubility relationship of sodium chloride-sodium sulfate at 75°C, the first-stage evaporation must control the sodium sulfate component to be less than 4.95%, while the sodium chloride component is greater than 25.25%, so that pure sodium chloride crystals can be precipitated. And sodium sulfate did not separate out. That is, the primary evaporation is:

[0094] M(Na 2 SO 4 ) / (M total-M evaporation)*100%<4.95%;

[0095] M evaporation 2 SO 4 )*100% / 4.95%;

[0096] M evaporation <15943.2-317.3*100% / 4.95% Kg / h;

[0097] That is, M evaporation <9533.1Kg / h;

[0098] Now, sodium chloride component content is:

[0099] M(NaCl) / (M total-M evaporation)*100%=2900 / (15943.2-9533.1)*100%=45.24%;

[0100] The solubility of sodium c...

Example Embodiment

[0107] Example 3: Evaporation at 100°C

[0108] Solubility components of sodium chloride-sodium sulfate-water, as shown in Table 5:

[0109] Table 5 Solubility of sodium chloride-sodium sulfate-water at 100°C

[0110]

[0111]

[0112] According to the mutual solubility relationship of sodium chloride-sodium sulfate at 100°C, the first-stage evaporation must control the sodium sulfate component to be less than 4.51%, and the sodium chloride component is greater than 25.9%, so that sodium chloride crystals can be precipitated, and Sodium sulfate did not precipitate out. That is, the primary evaporation is:

[0113] M(Na 2 SO 4 ) / (M total-M evaporation)*100%<4.51%;

[0114] M evaporation 2 SO 4 )*100% / 4.51%;

[0115] M evaporation <15943.2-317.3*100% / 4.51% Kg / h;

[0116] That is, M evaporation <8907.7Kg / h;

[0117] At this moment, the sodium chloride component content is:

[0118] M(NaCl) / (M total-M evaporation)*100%=2900 / (15943.2-8907.7)*100%=41.23%;

[0119] The...

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Abstract

The invention discloses a zero-emission process and system for desulfurization wastewater. The zero-emission process comprises the following steps: 1) feeding the desulfurization wastewater into a primary reactor-clarifier, adding lime for adjusting a pH value, collecting sludge containing Mg(OH)2 and CaSO4 precipitate, and removing flocculate in the clarifier by means of a floatation tank; 2) feeding wastewater in the floatation tank into a secondary reactor-clarifier, and adding Na2SO4 for generating CaSO4 precipitate; and 3) feeding wastewater in the secondary reactor-clarifier into a third-stage reactor-clarifier, adding Na2CO3 or feeding flue gas containing CO2 to the third-stage reactor-clarifier to generate CaCO3 precipitate. The process employs a separate and fractional purification process to separately dispose reactant substances mixed together previously into valuable substances, thereby reducing output of the sludge and increasing types of recovered products. As a result, the zero-emission comprehensive resource recovery use value of the desulfurization wastewater is increased.

Description

technical field [0001] The invention relates to the field of power plant desulfurization wastewater, in particular to a zero-discharge process and system for desulfurization wastewater. Background technique [0002] SO in the flue gas of thermal power plants in my country 2 The emissions 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 discharged from the absorption slurry after hydraulic separation is called desulfurization wastewater. The discharge of desulfurization wastewater in thermal power plant wastewater is not large, but its pollution is serious. The water quality is characterized by high content of suspended solids, pH value, and COD value. Exceeding standards include suspended solids, pH value, mercury, copp...

Claims

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Application Information

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IPC IPC(8): C02F9/10C01D3/04C01F11/46C01F11/18
CPCC01D3/04C01F11/18C01F11/46C02F9/00C02F2301/08C02F1/5236C01P2006/80C02F1/24C02F1/04C02F1/001
Inventor 黄莹莹张广林莫新来谭子斌莫明光
Owner 广州新普利节能环保科技有限公司
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