CN206318819U - A kind of electrolysis handles the device of desulfurization wastewater - Google Patents

Abstract

The utility model discloses a device for treating desulfurization wastewater by electrolysis, which belongs to the field of chemical equipment. The device is composed of a desulfurization wastewater pretreatment device, an electrolysis device and a chlorine condenser; the desulfurization wastewater pretreatment device is composed of a wet scrubber, a neutralization tank, a mixing tank, a flocculation tank, and an inclined plate clarifier; the electrolysis device is composed of Composed of an electrolytic cell, a bubbling reactor and a blower, the electrolytic cell is divided into an anode chamber and a cathode chamber, the anode chamber is provided with an anode plate, the cathode chamber is provided with a cathode plate, and the anode chamber and the cathode chamber are separated by an ion exchange membrane. The device adopts oxygen-consuming cathode technology, the cathode does not produce hydrogen, the discharge potential of the cathode is reduced, the power consumption is significantly reduced, and there are significant economic benefits; the principle of the electrolysis system is simple, and can be modified on the original basis, and the modification cost is low. The requirements are low.

Description

A device for treating desulfurization wastewater by electrolysis

technical field

The utility model belongs to the field of chemical equipment, in particular to a device for treating desulfurization wastewater by electrolysis.

Background technique

Wet limestone gypsum flue gas desulfurization is the mainstream process for flue gas desulfurization of coal-fired power plant boilers in my country. In order to maintain the safe and stable operation of the desulfurization system, ensure the quality of gypsum products and ensure the desulfurization efficiency, it is necessary to control the concentration of C1- in the slurry. The general requirement is less than 20g/L, so a large amount of wastewater needs to be discharged regularly. The wastewater discharged from the desulfurization system is weakly acidic and contains a large amount of suspended solids, trace heavy metal ions and chlorine, fluorine, sulfate ions, etc. In particular, chloride ions can form soluble salts with most metal ions. Common treatment technologies are difficult to remove chloride ions from water, which has a great impact on the maintenance and operation of the WFGD system.

At present, power plants at home and abroad generally carry out the following treatment methods for desulfurization wastewater: 1) mix the desulfurization wastewater with the by-product gypsum formed by concentration and then discharge it to the ash yard; 3) Discharge or reuse after treatment by a separate wastewater treatment system; 4) Electrodialysis or reverse osmosis; 5) Multi-effect evaporation, membrane distillation and molecular distillation technologies; 6) In addition, there are fluidized bed methods , membrane separation method, ion exchange method and electrocoagulation method, etc.

Through evaporation crystallization, membrane distillation and molecular distillation, the water in desulfurization wastewater can be separated from chloride salt and calcium salt, and the processed product is mixed salt of sodium chloride and calcium sulfate, which has low economic value and equipment investment Large, complex production process, high operating costs. Therefore, it is necessary to develop a low-cost device that can be modified on the basis of existing equipment.

Utility model content

Aiming at the deficiency of the existing desulfurization wastewater treatment equipment, the utility model provides a device for treating desulfurization wastewater by electrolysis, which is characterized in that the device is composed of a desulfurization wastewater pretreatment device, an electrolysis device and a chlorine condenser; the desulfurization wastewater The pretreatment device is composed of a wet scrubber, a neutralization tank, a mixing tank, a flocculation tank, and an inclined plate clarifier; the electrolysis device is composed of an electrolytic cell, a bubbling reactor, and a blower; the electrolytic cell is divided into an anode chamber and a cathode chamber. The anode chamber is equipped with an anode plate, the cathode chamber is equipped with a cathode plate, the bubbling reactor is located near the cathode plate of the cathode chamber, the blower is located outside the electrolytic cell and connected to the bubbling reactor through the blower gas inlet, the anode chamber and the cathode chamber separated by ion exchange membranes; the water outlet of the wet scrubber is connected to the neutralization tank, the neutralization tank is connected to the mixing tank and the flocculation tank in turn, the water outlet of the flocculation tank is connected to the inclined plate clarifier, and the overflow of the inclined plate clarifier The liquid outlet is connected with the water inlet of the anode chamber of the electrolytic cell; the gas outlet of the anode chamber of the electrolytic cell is connected with the chlorine condenser.

The neutralization box, the mixing box and the flocculation box are three independent equipment or a triple box of neutralization, mixing, and flocculation.

The anode chamber of the electrolyzer has one or more desulfurization waste water inlets, one or more desalination waste water outlets, and one or more gas outlets; the cathode chamber of the electrolyzer is provided with one or more lye inlets, one or more An outlet for lye, an inlet for blower gas, and an outlet for waste gas.

The anode plate is a ruthenium-based coated titanium electrode, and the cathode plate is an ODC microporous oxygen catalytic electrode.

The electrolytic cell adopts the method of parallel connection of multiple pairs of anode plates and multiple pairs of cathode plates, and the distance between the anode plates and the cathode plates is adjustable.

The ion exchange membrane is a cation exchange membrane.

After the electrolytic cell is energized, the separation is realized through the oxidation reaction of chloride ions in the solution to form molecular chlorine, which escapes as a gas at the anode plate of the electrolytic cell. The process of oxidation reaction is as follows:

2Cl ^- (aq) -2e ^- =Cl ₂ (g) E ₀ =1.36V (1)

The process of cathodic reduction reaction is as follows:

O ₂ (g)+4H ⁺ (aq)+4e ^- ＝2H ₂ OE ₀ ＝1.23V (2)

The utility model has the advantages that: the device adopts oxygen-consuming cathode technology, the cathode does not generate hydrogen gas, the discharge potential of the cathode is reduced, the power consumption is significantly reduced, and there are significant economic benefits; the principle of the electrolysis system is simple, and can be modified on the original basis, Moreover, the transformation cost is low, and the requirements for the operating conditions of the device are low.

Description of drawings

Figure 1 is a schematic diagram of a device for electrolytic treatment of desulfurization wastewater.

detailed description

The utility model provides a device for treating desulfurization wastewater by electrolysis. The invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, a device for electrolytically treating desulfurization wastewater is composed of a desulfurization wastewater pretreatment device, an electrolysis device and a chlorine condenser; the desulfurization wastewater pretreatment device consists of a wet scrubber 9, a neutralization tank 10, The mixing box 11, the flocculation box 12, and the inclined plate clarifier 13 are composed; the electrolysis device is composed of an electrolysis cell 1, a bubbling reactor 7, and a blower 8; the electrolysis cell is divided into an anode chamber 2 and a cathode chamber 3, and the anode chamber 2 is provided with an anode plate 5, the cathode chamber 3 is provided with a cathode plate 6, the bubbling reactor 7 is located near the cathode plate 6 in the cathode chamber, and the blower 8 is located outside the electrolytic cell 1 and connected to the bubbling reactor 7 through the gas inlet of the blower , the anode chamber 2 is separated from the cathode chamber 3 by the ion exchange membrane 4; the water outlet of the wet scrubber 9 is connected to the neutralization tank 10, and the neutralization tank 10 is connected to the mixing tank 11 and the flocculation tank 12 successively, and the flocculation tank 12 The water outlet is connected with the inclined plate clarifier 13, and the overflow liquid outlet of the inclined plate clarifier 13 is connected with the water inlet of the anode chamber 2 of the electrolytic cell; the gas outlet of the anode chamber 2 of the electrolytic cell is connected with the chlorine condenser 14.

Pump the desulfurization wastewater in the wet scrubber 9 into the neutralization tank 10, add NaOH solution in the neutralization tank 10, and adjust the pH value to 8-9.

The neutralized desulfurization wastewater enters the mixing tank 11, and trimercapto trisulfide sodium salt is added in the mixing tank 11 at a dosage of 7-8 mg/L to remove Cr ³⁺ , Hg ²⁺ , and Cd in the desulfurization wastewater. ²⁺ and other heavy metal ions.

The desulfurization waste water that removes part of the heavy metal ions enters the flocculation box 12, and ferric chloride sulfate (trade name PFS) and polyacrylamide (trade name PAM) are added in the flocculation box 12, and the dosage is PFS 20-30mg/L respectively , PAM 2-3mg/L, the combined use of PFS and PAM can make the crystallized inorganic salts, heavy metal complexes and SS fine flocs accumulate into larger particles, and flocculate and settle after the wastewater enters the clarifier.

The flocculated desulfurization wastewater overflows into the inclined plate clarifier 13 for clarification, wherein the supernatant is pumped into the anode chamber 2 of the electrolytic cell 1 as the effluent of the pretreatment process for electrolytic treatment.

The pretreated desulfurization wastewater is pumped into the anode chamber 2 of the electrolytic cell 1, and at the same time, a sodium hydroxide solution with a concentration of 0.5 mol/L is pumped into the cathode chamber 3 of the electrolytic cell 1, wherein the desulfurization wastewater Fill the anode chamber 2 and the cathode chamber 3 with the sodium hydroxide solution respectively. Afterwards, direct current is passed into the electrolytic cell 1 and the current is controlled to be 3A, and desalted water is obtained in the anode chamber 2 of the electrolytic cell 1 through electrolysis.

During the electrolysis process, the air from the blower 8 is passed into the vicinity of the cathode plate 5 in the cathode chamber 3 through the bubbling reactor 7, so as to increase the dissolved oxygen content near the cathode plate, and a reduction reaction occurs to generate water.

Chlorine gas produced at the anode plate 3 of the anode chamber during electrolysis of desulfurization wastewater enters the chlorine gas liquefier 14 through the gas outlet for liquefied storage.

Finally, the desalted water obtained in the anode chamber 2 is returned to the wet scrubber 9 as recycled water to be used as water for wet scrubbing.

Claims (6)

1. a kind of electrolysis handles the device of desulfurization wastewater, it is characterised in that the device is by desulfurization wastewater pretreatment unit, electrolysis Device and chlorine condenser composition；The desulfurization wastewater pretreatment unit by wet scrubber, neutralize case, blending bin, flocculation tanks, Cantboard clarifier is constituted；The electrolysis unit by electrolytic cell, bubbling reactor, blower unit into；The electrolytic cell is divided into anode It is provided with room and cathode chamber, anode chamber in positive plate, cathode chamber and is provided with minus plate, bubbling reactor is located at the minus plate of cathode chamber Near, air blower is located at outside electrolytic cell and is connected by blower gas import with bubbling reactor, and anode chamber passes through with cathode chamber Amberplex is separated；The delivery port of the wet scrubber is connected with neutralizing case, neutralizes case and blending bin, flocculation tanks successively phase Even, the delivery port of flocculation tanks is connected with cantboard clarifier, and the overflow box outlet of cantboard clarifier and the anode chamber of electrolytic cell are entered The mouth of a river is connected；The gas vent of the anode chamber of electrolytic cell is connected with chlorine condenser.

2. a kind of electrolysis according to claim 1 handles the device of desulfurization wastewater, it is characterised in that the neutralization case, Blending bin, flocculation tanks are three autonomous devices or neutralization, mixing, three headers of flocculation.

3. a kind of electrolysis according to claim 1 handles the device of desulfurization wastewater, it is characterised in that the electrolytic cell There are one or more desulfurization wastewater imports, one or more desalinization wastewater outlets, one or more gas vents in anode chamber；Electrolysis The cathode chamber of groove be provided with one or more lye imports, one or more lye exports, a blower gas import, one give up Gas is exported.

4. a kind of electrolysis according to claim 1 handles the device of desulfurization wastewater, it is characterised in that the positive plate is Ruthenium system coated titanium electrode, the minus plate is ODC micropore oxygen catalysis electrodes.

5. a kind of electrolysis according to claim 1 handles the device of desulfurization wastewater, it is characterised in that electrolytic cell is using more The mode in parallel with multipair minus plate to positive plate, spacing is adjustable between positive plate and minus plate.

6. a kind of electrolysis according to claim 1 handles the device of desulfurization wastewater, it is characterised in that the ion exchange Film is cation-exchange membrane.