A denitrification liquid regeneration system and method based on ClO2 flue gas denitrification

Abstract

The present invention provides a denitration liquid regeneration system based on ClO2 flue gas denitration, comprising: a ClO2 flue gas denitration unit, a denitration liquid pretreatment unit, a denitration liquid electrolysis unit and a ClO2 generation unit. A denitration liquid regeneration method based on ClO2 flue gas denitration is also provided, comprising: a ClO2 solution is contacted with industrial waste gas to generate an oxidizing liquid, and the waste gas after denitration enters an alkaline liquid to form an alkaline absorption liquid; the alkaline absorption liquid is mixed with the oxidizing liquid and pretreated; the denitration liquid is electrolyzed to obtain a sodium chlorate electrolyte; a reducing agent is added to the sodium chlorate electrolyte to generate ClO2 gas, and the ClO2 gas is absorbed by the absorption liquid to obtain a ClO2 solution. The denitrification liquid is electrolyzed to obtain sodium chlorate electrolyte, which is then used to prepare ClO2 solution for denitrification. This realizes the recycling of ClO2 denitrification liquid resources, solves the treatment problem of denitrification liquid, and saves the treatment cost of ClO2 denitrification liquid. At the same time, the denitrification liquid is electrolyzed to regenerate sodium chlorate to prepare ClO2. Compared with purchasing sodium chlorate to prepare ClO2, the cost can be reduced by 40%.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental engineering resource utilization, and in particular relates to a denitration liquid regeneration system and method based on ClO2 flue gas denitration. Background Art

[0002] Nitrogen oxides NO x It is one of the main air pollutants produced by fuel combustion from fixed and mobile sources. For coal-fired flue gas, NO x It mainly includes NO and NO2, of which NO accounts for more than 90%. The power industry is the first industry to implement ultra-low emission transformation. Compared with the thermal power industry, the main pollutant emissions of flue gas in the non-power industry remain high and difficult to reduce, which has become the focus of air environmental protection in the new stage and the key to improving regional environmental quality.

[0003] The current mainstream SCR technology has a denitrification efficiency of more than 80-90%. The technology is mature and has no secondary pollution. x It plays a key role in the treatment of NOx, but it cannot show its superior treatment effect in the non-electric industry. There are several reasons for this: First, the suitable temperature for the catalyst of the SCR denitrification process is usually between 260 and 340 °C, while the flue gas temperature of some non-electric industries is relatively low, and its temperature window is difficult to meet the requirements of the denitrification reaction; second, the flue gas environment in the non-electric field is complex. For example, glass flue gas contains a large amount of alkali metals, such as Na salts and K salts, and cement flue gas contains a large amount of CaO. The use of SCR technology is prone to catalyst blockage and poisoning; third, the workload of some non-electric industries is unstable, the coal quality is changeable, and there are many varieties, which leads to fluctuations in the NOx concentration in the flue gas.

[0004] In the SCR process, the catalyst is produced after calculation based on various parameters of coal combustion, and there is little room for adjustment after determination, so the mature SCR technology of the power industry cannot be replicated in the non-power industry. Therefore, the nitrogen oxide control technology in my country's non-power industry is facing great pressure, and it is urgent to find an economical and efficient denitrification technology that can adapt to the characteristics of unstable flue gas volume, complex flue gas composition, and narrow temperature window in the non-power industry.

[0005] For the treatment of flue gas nitrogen oxides in the non-electric industry, the most popular denitrification technology is wet oxidation flue gas denitrification, which can be divided into O3 oxidation method, KMnO4 oxidation method, H2O2 oxidation method, NaClO2 oxidation method, and ClO2 oxidation method according to the different types of oxidants for oxidizing NO. Among them, O3 technology requires the injection of a large amount of ozone, with high investment and operating costs; H2O2 is unstable, easily decomposed by heat, and difficult to operate; NaClO2 is expensive, and its application in flue gas denitrification requires high economic costs. Overall, the ClO2 oxidation method has high efficiency and less pollution. The application of this technology in flue gas denitrification in the non-electric field is currently a hot research topic and is favored by scholars.

[0006] Although ClO2 oxidation flue gas denitrification technology has a high denitrification efficiency, it also has the following disadvantages: First, ClO2 is relatively active in nature, not easy to transport and store, and needs to be prepared on site, and the preparation of ClO2 is not economical; Second, ClO2 oxidation flue gas denitrification technology also has the denitrification liquid treatment problem that is common in wet flue gas denitrification technology. After denitrification, a large amount of waste acid and alkali absorption liquid is produced, which also brings a huge denitrification liquid treatment and disposal burden to this technology. Therefore, in order to further promote the widespread application of ClO2 oxidation flue gas denitrification technology in non-power industries, it is urgent to solve the denitrification liquid treatment and disposal problems and the preparation cost of oxidants. Summary of the invention

[0007] To solve the above technical problems, the present invention provides a denitrification liquid regeneration system and method based on ClO2 flue gas denitrification. In order to have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a general review, nor is it intended to identify key / important components or describe the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0008] The present invention adopts the following technical solution:

[0009] In some optional embodiments, a denitrification liquid regeneration system based on ClO2 flue gas denitrification is provided, comprising: a denitrification liquid electrolysis unit for electrolyzing the denitrification liquid, and a ClO2 generating unit for adding a reducing agent to the sodium chlorate electrolyte formed by electrolysis of the denitrification liquid electrolysis unit and absorbing the ClO2 gas with an absorbing liquid to obtain a ClO2 solution.

[0010] In some optional embodiments, the denitrification liquid electrolysis unit includes: a peristaltic pump, a diaphragmless electrolytic cell and a sodium chloride solution storage tank for conveying sodium chloride solution to the diaphragmless electrolytic cell, and the peristaltic pump pumps the denitrification liquid into the diaphragmless electrolytic cell.

[0011] In some optional embodiments, the anode of the membraneless electrolytic cell is a ruthenium-iridium coated titanium plate, the cathode is a titanium plate, the electrode spacing of the electrode plate is 3 mm, and the current density is 2800 mA / m 2 , the temperature of the electrolyte is 82°C and the pH of the electrolyte is 6.0-6.8.

[0012] In some optional embodiments, the denitrification liquid electrolysis unit further includes: a feeding device and an acidic solution storage tank for conveying the acidic solution into the diaphragmless electrolytic cell, and the feeding device is provided with a discharge port for feeding sodium dichromate into the diaphragmless electrolytic cell.

[0013] In some optional embodiments, the ClO2 generating unit includes: a ClO2 generator, a ClO2 absorption device and a feeder for adding a reducing agent to the ClO2 generator; the liquid inlet of the ClO2 generator is connected to the sodium chlorate electrolyte outlet of the denitrification liquid electrolysis unit, and the ClO2 gas generated by the ClO2 generator is introduced into the absorption liquid contained in the ClO2 absorption device.

[0014] In some optional embodiments, the denitrification liquid regeneration system based on ClO2 flue gas denitrification further includes: a ClO2 flue gas denitrification unit for denitrifying industrial waste gas; the ClO2 flue gas denitrification unit includes: a ClO2 solution storage tank, a spray tower, an alkali absorption device, and an oxidizing liquid storage tank for containing the oxidizing liquid generated by the contact between the ClO2 solution and the industrial waste gas, the liquid outlet of the ClO2 solution storage tank is connected to the spray port at the top of the spray tower, and the waste gas after denitrification by the spray tower enters the alkali absorption device through the upper part of the denitrification tower for absorption to form an alkali absorption liquid.

[0015] In some optional embodiments, the denitrification liquid regeneration system based on ClO2 flue gas denitrification further includes: a denitrification liquid pretreatment unit for pretreating the denitrification liquid; the denitrification liquid pretreatment unit includes: a mixing tank, an ion exchange resin device for removing impurity ions and a concentration separation tank for separating and concentrating sodium chloride, the alkali absorption liquid in the alkali absorption device and the oxidizing liquid in the oxidizing liquid storage tank are transported to the mixing tank for mixing, the mixed denitrification liquid is transported to the ion exchange resin device, the denitrification liquid with impurity ions removed is transported to the concentration separation tank, and the denitrification liquid treated in the concentration separation tank is transported to the diaphragmless electrolytic cell for electrolysis.

[0016] The present invention also provides a denitration liquid regeneration method based on ClO2 flue gas denitration, comprising: electrolyzing the denitration liquid to obtain a sodium chlorate electrolyte; adding an acid and a reducing agent into the sodium chlorate electrolyte to cause an oxidation-reduction reaction to generate ClO2 gas, and absorbing the ClO2 gas with an absorption liquid to obtain a ClO2 solution.

[0017] In some optional embodiments, the denitrification liquid regeneration method based on ClO2 flue gas denitrification further includes: adding sodium chloride solution, sodium dichromate and acid into the denitrification liquid during the electrolysis of the denitrification liquid.

[0018] In some optional embodiments, the denitrification liquid regeneration method based on ClO2 flue gas denitrification further includes: the ClO2 solution contacts the industrial waste gas through a spray tower to produce an oxidizing liquid, and the waste gas after denitrification enters the alkaline liquid to form an alkaline absorption liquid; the alkaline absorption liquid is mixed with the oxidizing liquid, and the mixed denitrification liquid is pretreated, and the pretreatment process is first to remove impurity ions in the denitrification liquid through an ion exchange resin device, and then separate and concentrate the sodium chloride.

[0019] The beneficial effects brought by the present invention are:

[0020] 1. Solve the problem of denitrification liquid treatment, which not only saves the treatment cost of ClO2 denitrification liquid, but also provides a new way for the preparation of ClO2 solution in ClO2 oxidation flue gas denitrification technology, so that ClO2 denitrification technology can realize the recycling of denitrification liquid resources;

[0021] 2. The present invention is based on the fact that ClO2 denitration liquid is mainly sodium salt, and utilizes the denitration liquid to electrolyze and regenerate sodium chlorate to prepare ClO2. That is, the denitration liquid subjected to ClO2 oxidation denitration is electrolyzed to regenerate sodium chlorate, and the regenerated sodium chlorate is then used to prepare the denitration oxidant ClO2. Compared with purchasing sodium chlorate to prepare ClO2, the cost can be reduced by 40%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a denitration liquid regeneration system based on ClO2 flue gas denitration of the present invention. DETAILED DESCRIPTION

[0023] The following description and accompanying drawings fully demonstrate specific embodiments of the present invention so that those skilled in the art can practice them. Other embodiments may include structural, logical, electrical, process and other changes. The embodiments represent possible variations only. Unless clearly required, separate components and functions are optional, and the order of operation may vary. The parts and features of some embodiments may be included in or replace the parts and features of other embodiments.

[0024] like Figure 1 As shown, in some illustrative embodiments, a denitrification liquid regeneration system based on ClO2 flue gas denitrification is provided, comprising: a ClO2 flue gas denitrification unit 1, a denitrification liquid pretreatment unit 2, a denitrification liquid electrolysis unit 3 and a ClO2 generation unit 4.

[0025] The ClO2 flue gas denitrification unit 1 is used for denitrifying industrial waste gas. Specifically, the ClO2 flue gas denitrification unit 1 comprises: a ClO2 solution storage tank 11, a spray tower 12, an alkali absorption device 13 and an oxidizing liquid storage tank 14.

[0026] The ClO2 solution storage tank 11 is filled with a ClO2 solution for denitration treatment. The liquid outlet 11a of the ClO2 solution storage tank is connected to the spray port at the top of the spray tower 12. The ClO2 solution enters the spray tower 12 through the spray port at the top of the spray tower 12 for spraying. The industrial waste gas enters the spray tower 12 from the bottom of the spray tower 12. The industrial waste gas contains NO and NO2, wherein the NO content is more than 90%. The ClO2 solution and the NO-containing x The industrial waste gas is contacted and reacted, and the oxidizing liquid formed after the reaction is introduced into the oxidizing liquid storage tank 14.

[0027] The oxidizing liquid storage tank 14 is used to hold the oxidizing liquid produced by the contact between the ClO2 solution and the industrial waste gas. The main components of the oxidizing liquid are hydrochloric acid, nitric acid, and chlorine dioxide solution. The waste gas after ClO2 denitration mainly contains ClO2, NO2, NO, etc., which are discharged from the upper part of the spray tower 12 and enter the alkali absorption device 13 for absorption. The alkali is selected as NaOH to form an alkali absorption liquid. The main component of the alkali absorption liquid is sodium salt. NO is oxidized to NO2 and enters the alkali absorption liquid to become salts such as sodium nitrate, which are stored in the alkali absorption device.

[0028] The denitration liquid pretreatment unit 2 is used to pretreat the denitration liquid. In the actual spray denitration process, some metal ions, such as Fe 3+ , Cu 2+ and other foreign ions; and the flue gas environment of some non-electric industries is complex, such as glass flue gas contains a large amount of alkali metals, such as Na salts and K salts, and cement flue gas contains a large amount of CaO. If you want to regenerate the denitrification liquid by electrolysis, in order to prevent the impurity ions from corroding or clogging the electrolytic cell and affecting the service life and electrolysis efficiency of the electrolytic cell, the denitrification liquid needs to be pretreated. Specifically, the denitrification liquid pretreatment unit 2 includes: a mixing tank 21, an ion exchange resin device 22 and a concentration separation tank 23.

[0029] The alkaline absorption liquid in the alkaline absorption device 13 and the oxidizing liquid in the oxidizing liquid storage tank 14 are transported to the mixing tank 21 for mixing. The mixed denitrification liquid is transported to the ion exchange resin device 22. The ion exchange resin device 22 is used to remove impurity ions. The denitrification liquid with impurity ions removed is transported to the concentration separation tank 23. The denitrification liquid treated by the concentration separation tank 23 is transported to the membraneless electrolytic cell 31 for electrolysis. A peristaltic pump is used for liquid transportation between the mixing tank 21, the ion exchange resin device 22 and the concentration separation tank 23. The denitrification liquid pretreatment unit 2 realizes the denitrification liquid after the oxidizing liquid and the alkaline absorption liquid are mixed, and the impurity ions are removed by the ion exchange resin. Then, the denitrification liquid enters the concentration separation tank 23 to separate and concentrate the sodium chloride to obtain a sodium chloride solution. The concentrated denitrification liquid enters the denitrification liquid electrolysis unit 3 as an electrolyte.

[0030] The denitrification liquid electrolysis unit 3 is used to electrolyze the denitrification liquid. Specifically, the denitrification liquid electrolysis unit 3 includes: a peristaltic pump, a membraneless electrolytic cell 31, a sodium chloride solution storage tank 32, a feeding device 33 and an acidic solution storage tank 34. The peristaltic pump pumps the denitrification liquid in the concentration separation tank 23 into the membraneless electrolytic cell 31. The sodium chloride solution storage tank 32 is used to transport the sodium chloride solution to the membraneless electrolytic cell 31 and replenish sodium chloride to ensure the supply of chloride ions. The acidic solution storage tank 34 is used to transport the acidic solution into the membraneless electrolytic cell 31. Acid is added during the electrolysis process to maintain the acidic environment of the electrolyte. The feeding device 33 is provided with a discharge port 33a for feeding sodium dichromate into the membraneless electrolytic cell 31. Adding a small amount of Na2Cr2O7 to the electrolyte can promote the electrolysis efficiency. On the other hand, a special film can be formed at the cathode to prevent chlorate and hypochlorite from undergoing reduction reaction at the cathode.

[0031] The anode of the non-diaphragm electrolyzer is a ruthenium-iridium coated titanium plate, the cathode is a titanium plate, the electrode spacing of the electrode plate is 3mm, and the current density is 2800mA / m 2 , the temperature of the electrolyte is 82°C, the pH of the electrolyte is 6.0-6.8, and the amount of sodium dichromate added is 1-4 g / L.

[0032] The ClO2 generating unit 4 is used to use the sodium chlorate electrolyte formed by electrolysis of the denitrification liquid electrolysis unit 3, add a reducing agent, and absorb the ClO2 gas with an absorbing liquid to obtain a ClO2 solution. Specifically, the ClO2 generating unit 4 includes: a ClO2 generator 41, a ClO2 absorbing device 42, and a feeder 43. The liquid inlet of the ClO2 generating unit is connected to the sodium chlorate electrolyte outlet 31a of the denitrification liquid electrolysis unit.

[0033] The liquid inlet of the ClO2 generating unit, i.e., the liquid inlet 41a of the ClO2 generator, is connected to the sodium chlorate electrolyte liquid outlet 31a of the denitrification liquid electrolysis unit. The ClO2 gas generated by the ClO2 generator 41 is introduced into the absorption liquid contained in the ClO2 absorption device 42. The feeder is used to add a reducing agent to the ClO2 generator. The regenerated sodium chlorate electrolyte obtained by the denitrification liquid electrolysis unit 3 is used, and a reducing agent is added and acidic conditions are provided to cause a redox reaction to generate ClO2 gas. The ClO2 gas is then absorbed by a low-temperature absorption liquid to obtain a ClO2 solution, so as to prepare for chlorine dioxide spray oxidation denitrification, thereby realizing the cycle of the process. The acid solution storage tank 34 is also used to transport the acid solution into the ClO2 generator 41.

[0034] The principle of the oxidative flue gas denitrification of the present invention is: ClO2 first oxidizes NO to NO2, and then further oxidizes NO2 to nitric acid, and then sodium hydroxide is used to absorb the waste gas. The components of the waste gas are excess ClO2 and NO2. The reaction equation is as follows:

[0035] 5NO+2ClO2+H2O=5NO2+2HCl

[0036] 5NO2+ClO2+3H2O=5HNO3+3HCl

[0037] The overall reaction is:

[0038] 5NO+3ClO2+4H2O=5HNO3+3HCl

[0039] The reaction equation of the alkali absorption process is as follows:

[0040] 2ClO2+2NaOH=NaClO2+NaClO3+H2O

[0041] 2NO2+2NaOH=NaNO3+NaNO2+H2O

[0042] The mixed reaction equation of the oxidizing liquid and the alkaline absorption liquid is as follows:

[0043] HCl+NaOH=NaCl+H2O

[0044] HNO3+NaOH=NaNO3+H2O

[0045] In summary, it can be seen that after the chlorine dioxide denitrification oxidation liquid and the alkaline absorption liquid are mixed, the main components of the mixed liquid are NaCl, NaNO3, NaNO2, NaClO2, NaClO3, etc., which can be separated and concentrated. According to the principle of preparing sodium chlorate by electrolysis of sodium chloride, the chlorine dioxide denitrification liquid can be electrolyzed to regenerate sodium chlorate.

[0046] The principle of electrolysis is as follows:

[0047] In the electrolytic cell 31 without a diaphragm, NaCl containing a small amount of Na2CrO7 is electrolyzed. First, Cl2 precipitated at the anode reacts with OH produced at the cathode. - The disproportionation reaction occurs as follows:

[0048] Cl2+2OH - →ClO - +Cl - +H2O

[0049] The resulting hypochlorite can then be further oxidized to chlorate as follows:

[0050]

[0051] The following reactions are carried out simultaneously in the solution:

[0052] 2ClO - +H2O→2HClO+2OH -

[0053]

[0054] As important intermediates for the synthesis of NaClO3, hypochlorous acid and hypochlorite ions are essential in the NaClO3 electrolyte. The addition of Na2Cr2O7 inhibits the reduction reaction of the active ingredients at the cathode, improves the efficiency of the hydrogen evolution reaction at the cathode, and ultimately leads to a significant increase in the NaClO3 yield.

[0055] Preparation principle of ClO2: It is generally prepared by the reaction of sodium chlorate with a reducing agent under acidic conditions. For example, the most common method is the reaction of sodium chlorate with hydrochloric acid to prepare ClO2, as follows:

[0056] 2NaC1O3+4HC1=2C1O2+C12+2NaC1+2H2O

[0057] According to a large number of experiments, the concentrations of NO3- and ClO2 in the denitrification liquid have little effect on the electrolytic regeneration of NaClO3, so the electrolysis of the denitrification liquid can be achieved.

[0058] The present invention also provides a denitrification liquid regeneration method based on ClO2 flue gas denitrification, comprising:

[0059] The ClO2 solution contacts the industrial waste gas through the spray tower to produce an oxidizing solution, and the denitrified waste gas enters the alkaline solution to form an alkaline absorption solution;

[0060] The alkaline absorption liquid is mixed with the oxidation liquid, and the mixed denitration liquid is pretreated, wherein the pretreatment process is to first remove the impurity ions in the denitration liquid, and then separate and concentrate the sodium chloride;

[0061] Electrolyzing the denitrification liquid to obtain a sodium chlorate electrolyte;

[0062] A reducing agent is added to the sodium chlorate electrolyte to cause a redox reaction to generate ClO2 gas, and the ClO2 gas is absorbed by an absorbing liquid to obtain a ClO2 solution.

[0063] In the process of electrolyzing the denitrification liquid, sodium chloride solution, sodium dichromate and acid are added into the denitrification liquid.

[0064] After the ClO2 solution is sprayed in the spray tower for oxidation and denitrification, the reaction products such as nitric acid and hydrochloric acid enter the oxidation liquid storage tank, NO is oxidized to NO2 and enters the alkaline absorption liquid to become salts such as sodium nitrate. The oxidation liquid and the alkaline absorption liquid enter the denitrification liquid pretreatment neutralization tank together for mixing, and then the impurity ions are removed by ion exchange resin, and then enter the concentration tank to pre-treat the components therein roughly to concentrate and separate, and obtain sodium chloride solution; the sodium chloride solution obtained by pretreatment enters the diaphragmless electrolytic cell for electrolysis, and sodium chloride can be supplemented during the electrolysis process to ensure the supply of chloride ions. At the same time, acid is also added to maintain the acidic environment of the electrolyte, and sodium dichromate is added to improve the electrolysis efficiency; the electrolytic solution after electrolysis enters the ClO2 generator, and acid and reducing agent are added to react with the sodium chlorate solution to prepare ClO2. The prepared ClO2 gas is absorbed by the absorption device to obtain ClO2 solution, which is ready for ClO2 spray oxidation flue gas denitrification to realize the cycle of the process.

[0065] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments herein can all be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on specific applications and the design constraints imposed on the entire system. A skilled person can implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of the present disclosure.

Claims

1. A denitrification liquid regeneration system based on ClO2 flue gas denitrification, characterized in that: Applied in non-electrical industries; The invention comprises: a denitration liquid electrolysis unit for electrolyzing a denitration liquid, and a ClO2 generating unit for electrolyzing a sodium chlorate electrolyte formed by the denitration liquid electrolysis unit, adding an acid and a reducing agent into the sodium chlorate electrolyte to generate ClO2 gas by an oxidation-reduction reaction to obtain a ClO2 solution; It also includes: a ClO2 flue gas denitration unit for denitrifying industrial waste gas; the ClO2 flue gas denitration unit includes: a ClO2 solution storage tank, a spray tower, an alkali absorption device, and an oxidizing liquid storage tank for containing an oxidizing liquid generated by contact between the ClO2 solution and the industrial waste gas, the liquid outlet of the ClO2 solution storage tank is connected to the spray port at the top of the spray tower, and the waste gas after denitration in the spray tower enters the alkali absorption device through the upper part of the spray tower for absorption to form an alkali absorption liquid; It also includes: a denitration liquid pretreatment unit for pretreating the denitration liquid; the denitration liquid pretreatment unit includes: a mixing tank, an ion exchange resin device for removing impurity ions, and a concentration separation tank for separating and concentrating sodium chloride, the alkali absorption liquid in the alkali absorption device and the oxidizing liquid in the oxidizing liquid storage tank are transported to the mixing tank for mixing, the mixed denitration liquid is transported to the ion exchange resin device, the denitration liquid with impurity ions removed is transported to the concentration separation tank, and the denitration liquid treated in the concentration separation tank is transported to a diaphragm-free electrolytic cell for electrolysis; Based on the fact that ClO2 denitrification liquid is mainly sodium salt, sodium chlorate is regenerated by electrolysis of the denitrification liquid to prepare ClO2, that is, the denitrification liquid subjected to ClO2 oxidation denitrification is electrolyzed to regenerate sodium chlorate, and the regenerated sodium chlorate is then used to prepare the denitrification oxidant ClO2.

2. A denitration liquid regeneration system based on ClO2 flue gas denitration according to claim 1, characterized in that: The denitration liquid electrolysis unit comprises: a peristaltic pump, a diaphragmless electrolytic cell and a sodium chloride solution storage tank for conveying sodium chloride solution to the diaphragmless electrolytic cell. The peristaltic pump pumps the denitration liquid into the diaphragmless electrolytic cell.

3. A denitration liquid regeneration system based on ClO2 flue gas denitration according to claim 2, characterized in that: The anode of the diaphragmless electrolytic cell is a ruthenium-iridium coated titanium plate, the cathode is a titanium plate, the electrode spacing of the electrode plate is 3 mm, and the current density is 2800 mA / m 2 , the temperature of the electrolyte is 82°C and the pH of the electrolyte is 6.0-6.

8.

4. A denitration liquid regeneration system based on ClO2 flue gas denitration according to claim 3, characterized in that: The denitration liquid electrolysis unit further comprises: a feeding device and an acid solution storage tank for conveying an acid solution into the diaphragmless electrolytic cell. The feeding device is provided with a discharge port for feeding sodium dichromate into the diaphragmless electrolytic cell.

5. A denitration liquid regeneration system based on ClO2 flue gas denitration according to claim 4, characterized in that: The ClO2 generating unit comprises: a ClO2 generator, a ClO2 absorption device and a feeder for adding a reducing agent to the ClO2 generator; the liquid inlet of the ClO2 generator is connected to the sodium chlorate electrolyte outlet of the denitrification liquid electrolysis unit, and the ClO2 gas generated by the ClO2 generator is introduced into the absorption liquid contained in the ClO2 absorption device.

6. A denitrification liquid regeneration method based on ClO2 flue gas denitrification, characterized in that: include: Electrolyzing the denitrification liquid to obtain a sodium chlorate electrolyte; adding an acid and a reducing agent to the sodium chlorate electrolyte to cause an oxidation-reduction reaction to generate ClO2 gas, and absorbing the ClO2 gas with an absorbing liquid to obtain a ClO2 solution; Also includes: during the electrolysis of the denitrification liquid, adding sodium chloride solution, sodium dichromate and acid to the denitrification liquid; The method also includes: a ClO2 solution contacts industrial waste gas through a spray tower to generate an oxidizing liquid, and the waste gas after denitration enters an alkaline liquid to form an alkaline absorption liquid; the alkaline absorption liquid is mixed with the oxidizing liquid, and the mixed denitration liquid is pretreated, and the pretreatment process is first to remove impurity ions in the denitration liquid through an ion exchange resin device, and then separate and concentrate the sodium chloride.

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