KR20100130460A - A method and device for electro-chemical hydrogen production and biological carbon dioxide reduction - Google Patents

Abstract

PURPOSE: A carbon dioxide bio-reduction and hydrogen production apparatus is provided to produce hydrogen for using as an environment-friendly energy source while processing wastewater. CONSTITUTION: A carbon dioxide bio-reduction and hydrogen production apparatus comprises the following: an electrochemical wastewater treatment and hydrogen production device(10) treating pollutants inside wastewater using an electro-oxidation reaction, and producing hydrogen for using as a reductant; a gas separator(20) separating the hydrogen with other gas; a gas dissolving unit(30) dissolving carbon dioxide separated from the gas separator to insert into a carbon dioxide bio-reducer; and the carbon dioxide bio-reducer(40).

Description

A method and device for electro-chemical hydrogen production and biological carbon dioxide reduction

The present invention is a technology for stably producing and supplying hydrogen as a reducing agent, which is an essential element in the process of reducing carbon dioxide by converting carbon dioxide into methane, among various techniques for efficiently reducing carbon dioxide contained in exhaust gas. And methane conversion using the anaerobic microbial physiological activity by establishing a technology that can increase the solubility of hydrogen and carbon dioxide so that anaerobic microorganisms can easily use the carbon dioxide contained in the hydrogen and exhaust gas supplied therein. In order to increase the efficiency to reduce carbon dioxide to high efficiency, it was started to produce a new energy source methane. Specifically, hydrogen is produced as a reducing agent in the process of treating contaminants in wastewater such as electronic wastewater, and the hydrogen and carbon dioxide contained in the exhaust gas are passed through a device configured to increase the solubility of each gas. After dissolving, the present invention relates to a hydrogen production and biological carbon dioxide reduction apparatus using electrochemical wastewater treatment that can reduce carbon dioxide by converting carbon dioxide to methane using the physiological activity of anaerobic microorganisms.

In addition, the present invention discloses an electrochemical wastewater treatment technology capable of efficiently reducing ammonia nitrogen, nitrate nitrogen, and fluorine contained in wastewater such as electronic wastewater in addition to an efficient reduction technology of carbon dioxide.

Therefore, the present invention relates to a greenhouse gas reduction technology for efficiently reducing carbon dioxide 7 contained in exhaust gas, a methane conversion technology, and an environmental pollutant reduction technology capable of treating nitrogen and fluorine contained in wastewater with high efficiency.

Carbon dioxide (CO ₂ ) is one of the global warming gases that must be removed with the recent enactment of many laws, including the Kyoto Protocol. In addition, it is certain that Korea will be designated as a mandatory country to reduce greenhouse gas emissions by 2013. Therefore, it is essential to secure efficient and economical carbon dioxide reduction technology as the problem of carbon dioxide will have a lot of adverse effects on the future economic development of Korea. It is also essential to develop useful energy resources other than raw materials and to secure efficient energy resource development technology.

In addition, the wastewater generated in the semiconductor production process contains high concentrations of fluorine and a large amount of nitrogen components, and the nitrogen components present in the wastewater are not removed by the conventional fluorine removal process, but instead of nitrogen, such as a biological denitrification process, after the fluorine removal process. You must add an ingredient removal process. However, in the case of biological denitrification, the treatment cost is expensive and the nitrogen removal time is long, so the denitrification process becomes large and the operating and management conditions are difficult. Do.

Currently, as a technology for treating carbon dioxide, physicochemical separation technology, physical chemistry, and biological conversion technology are used. Among them, the reduction of carbon dioxide using biological methods can be divided into techniques using photosynthetic microorganisms and techniques using anaerobic digestion. Among them, the anaerobic digestion using the physiological activity of anaerobic microorganisms is a general reaction route that is decomposed from organics to intermediate products hydrogen and various volatile organic acids to final products methane and carbon dioxide. Of these, methane-producing bacteria that produce methane, the final product, are largely classified into two types, one is Acetotrophic methanogens, which produce methane from acetate, and the other produces methane from hydrogen and carbon dioxide. Are hydrogenotrophic methanogens. Among these, acetic acid-methane-producing methane produces methane and carbon dioxide as final products during anaerobic digestion of organic matter, while hydrogen-trophic methane-producing bacteria are methane producing only methane as final products. In addition, about 70% of the methane produced in anaerobic digestion is produced by acetic acid-producing methane-producing bacteria, and about 30% is produced by hydrogenotrophic methane-producing bacteria. The rate at which methane is produced from each substrate (acetate and carbon dioxide) is much faster for hydrogenotrophic methane-producing bacteria, but more than twice as much methane is produced by acetic-acid-producing methane-producing bacteria. This is because a large amount of produced bacteria is present. Therefore, if only hydrogen-trophic methane-producing bacteria are cultivated at high concentration and dominated, and the activity of acetic-acid-producing methane-producing bacteria is inhibited and used, it is considered that carbon dioxide can be efficiently reduced and methane, which is a useful energy source, can be produced.

Hydrotrophic methane-producing bacteria require four times more reducing agent than carbon dioxide to produce methane. That is, 1 mole of methane and 2 moles of water are produced from 4 moles of hydrogen and 1 mole of carbon dioxide as shown in the following equation.

4H ₂ + CO ₂ → CH ₄ + 2H ₂ O -130.4 ΔG ⁰ (kJ / mol CH ₄ ) (1)

For reference, acetic acid-methane-producing methane produces methane and carbon dioxide through the following reactions.

_{^{CH 3 COO - + H + →}} CH 4 + CO 2 -36 ΔG 0 (kJ / mol CH 4) (2)

Therefore, carbon dioxide is generated when acetic acid-containing methane-producing bacteria are contained as shown in the above formula. Therefore, in order to reduce carbon dioxide with high efficiency, hydrogen-trophic methane-producing bacteria should be predominantly dominated by high concentration, as shown in Equation (1). The reducing agent (especially hydrogen) must be supplied smoothly and stably. In addition to hydrogen, other reducing agents may be used as the reducing agent used for the methane conversion of carbon dioxide, but hydrogen has the highest reduction capability in converting carbon dioxide to methane.

In the electronic wastewater, the inorganic wastewater contains ammonia nitrogen and nitrate nitrogen in addition to fluorine. To date, many techniques for treating such substances have been introduced, but no technique for simultaneously removing ammonia nitrogen, nitrate nitrogen, and fluorine has been developed, and high concentrations of hydrogen production, carbon dioxide reduction, and methane simultaneously with wastewater treatment No production technology has been introduced. In other words, when electrolysis is used to produce hydrogen, pure water or an alkaline solution is used. However, when electrolysis is applied, hydrogen and oxygen are simultaneously produced. Therefore, the patent and research results, such as separating the cathode and the anode by using a suitable membrane to change the discharge path of oxygen and hydrogen have been published, but in the process of wastewater treatment as in the present invention to produce hydrogen without using the membrane The technology was not released.

In addition, the biggest problem with methane conversion of carbon dioxide using biological methods is that the solubility of hydrogen is very low. Therefore, the carbon dioxide reduction technology by converting carbon dioxide to methane can be effectively operated only when the mass production technology of hydrogen and the hydrogen solubility increasing technology have to be developed as a reducing agent of carbon dioxide as shown in Equation (1). Thus, in the present invention, by developing a technology and apparatus that can increase the solubility of hydrogen and carbon dioxide to apply to the present invention, there is a feature that can reduce the carbon dioxide and increase the methane production efficiency.

In addition, all devices that have been developed and operated to date use electricity derived from fossil fuels, and since fossil fuels emit a large amount of carbon dioxide in the process of producing electricity, the devices used in the present invention are supplied with electricity derived from fossil fuels. If used, it would potentially emit carbon dioxide, which would not serve the purpose of the present invention. Therefore, in the present invention, carbon dioxide is converted into carbon dioxide to produce electricity from the methane produced as a raw material, and the electricity produced here can be used as the electricity source of all the devices used in the present invention to reduce potential carbon dioxide generation. There is a characteristic.

As mentioned above, in Korea, where the obligation to reduce carbon dioxide is certain, the technology for efficiently and economically treating carbon dioxide must be developed, and at the same time, the technology for producing materials that can be used as useful energy resources should be developed. do.

As a result, the hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment to be disclosed by the present invention, through the improvement of environmental problems through wastewater treatment, reduction of carbon dioxide contained in the flue gas and potential carbon dioxide reduction through its own electricity production Improvements in climate change problems and the development of useful energy resource production technologies through hydrogen and methane production can be achieved.

An object of the present invention is to biologically reduce the carbon dioxide contained in the flue gas, at the same time to produce a high-efficiency hydrogen as a reducing agent at the same time as wastewater treatment, where the hydrogen and carbon dioxide contained in the flue gas is converted to methane using anaerobic microorganisms The present invention provides a device for producing hydrogen and biological carbon dioxide using an electrochemical wastewater treatment that can reduce carbon dioxide with high efficiency and produce methane that can be used as a useful energy source.

Another object of the present invention is to provide an electrochemical wastewater treatment process for stably producing and supplying hydrogen, which is a reductant essential for converting carbon dioxide to methane, and in detail, an electrochemical method is applied to an electrowaste (in particular, inorganic wastewater). The present invention provides a hydrogen production and biological carbon dioxide abatement apparatus using electrochemical wastewater treatment which simultaneously removes ammonia nitrogen, nitrate nitrogen, and fluorine and produces high concentration of hydrogen in the process.

Another object of the present invention is to provide a gas dissolving device to increase the solubility of hydrogen and carbon dioxide injected into the carbon dioxide abatement device electrochemical wastewater to make faster use of hydrogen and carbon dioxide by anaerobic microorganisms when converting carbon dioxide to methane It is to provide a hydrogen production and biological carbon dioxide reduction device using the treatment.

Another object of the present invention is to provide a methane combustion device for producing electricity by burning the methane generated in the carbon dioxide reduction device in the present invention, the electricity produced here can be used as an electricity source of all the devices disclosed in this patent It is to provide a hydrogen production and biological carbon dioxide reduction device using chemical wastewater treatment.

Hydrogen production and biological carbon dioxide reduction device using an electrochemical wastewater treatment for solving the object of the present invention, the hydrogen gas and other gases used as a reducing agent while treating the electronic wastewater using an electrooxidation reaction and an electrocoagulation reaction Electrochemical wastewater treatment and hydrogen production apparatus for generating a; A gas separation device for separating the gas generated in the electrochemical wastewater treatment and hydrogen production apparatus into a high concentration of hydrogen and other gases; A gas dissolving device for dissolving carbon dioxide separated from hydrogen separated from the gas separation device and exhaust gas; Receiving the hydrogen and carbon dioxide dissolved in the gas dissolving device is characterized in that it comprises a carbon dioxide reduction device for converting to methane using methane generating bacteria.

Preferably, the methane combustion device for producing electricity by burning the methane generated from the carbon dioxide reduction device is characterized in that it further comprises.

Preferably, the electronic wastewater is inorganic wastewater, characterized in that selected from wastewater containing any one of ammonia nitrogen, nitrate nitrogen, or fluorine.

Preferably, the electrochemical wastewater treatment and hydrogen production apparatus is characterized in that the electrode for electrooxidation and the electrode for electrocoagulation are installed in one reactor. In addition, in order to prolong the life of the electrode for electroaggregation, easy electrode replacement, efficient use of the electrode for electrocoagulation, high concentration of hydrogen production, and the characteristics of the wastewater to be treated, the electrocoagulation and electrooxidation reactions are separated and installed. It is done.

Preferably, the gas dissolving device is characterized by consisting of a pump for suctioning the culture solution in the carbon dioxide reduction device, a gas dissolving nozzle for injecting the sucked culture solution and a gas inlet for the mixed gas of hydrogen and carbon dioxide flows.

Preferably, the gas dissolving nozzle of the gas dissolving apparatus is characterized in that a spiral groove is formed on the inner surface, or a vortex induction cap is attached to the inlet of the gas dissolving nozzle.

Preferably, the methane producing bacteria is characterized in that the hydrogen-trophic methane producing bacteria.

Hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment to be disclosed by the present invention produces hydrogen as a reducing agent with high efficiency in the process of treating contaminants contained in the wastewater, such as electronic wastewater, in the hydrogen and exhaust gas produced By converting the carbon dioxide contained into methane by using the physiological activity of anaerobic microorganisms, there is an advantage that can be reduced to high efficiency and produce methane that can be used as a useful energy source.

In addition, the electrochemical wastewater treatment, there is an advantage that can be removed at the same time ammonia nitrogen, nitrate nitrogen, and fluorine from the wastewater, there is an advantage to produce hydrogen that can be used as environmentally friendly energy at the same time as wastewater treatment.

In addition, carbon dioxide, a global warming gas, can be reduced with high efficiency, and at the same time, there is an advantage of producing methane that can be used as a useful energy source.

In addition, the production of electricity from the methane produced by conversion from carbon dioxide has the advantage of having its own electricity source that can supply electricity to all the devices used in the present invention can reduce the electricity consumption from fossil fuels. Accordingly, in addition to the reduction of carbon dioxide in the exhaust gas, there is an advantage that has the potential to reduce the amount of carbon dioxide generated in the production of electricity by fossil fuel.

Therefore, according to the present invention, the improvement of environmental problems through wastewater treatment, the reduction of carbon dioxide contained in flue gas and the potential change of climate change through reduction of potential carbon dioxide generation through its own electricity production, and useful energy resource production technology through hydrogen and methane production Development and other effects can be obtained.

Hereinafter, electrochemical wastewater treatment, hydrogen production as a reducing agent, and biological carbon dioxide reduction will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram for constructing the present invention, Figure 2 is a schematic diagram of a hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment of the present invention, Figure 3 a and b is an electrochemical wastewater treatment and hydrogen production apparatus 4 is a schematic diagram of the gas dissolving apparatus of the present invention, Figure 5 is a schematic diagram of a hydrogen production and biological carbon dioxide reduction apparatus using an electrochemical wastewater treatment equipped with a methane combustion device.

The concept of the configuration for achieving the object of the present invention is to convert the carbon dioxide contained in the flue gas into methane, while reducing the carbon dioxide and at the same time to develop a technology for producing methane, a useful energy source. That is, as shown in Figure 1, hydrogen as a reducing agent necessary to convert and reduce the carbon dioxide contained in the flue gas to methane using biological conversion technology is produced and supplied through electrochemical wastewater treatment, where the hydrogen produced It is used as a reducing agent to reduce the carbon dioxide in the flue gas by converting it into methane using a carbon dioxide abatement device. It is intended to have a configuration used as a source.

Thus, as shown in Figure 2, the hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment of the present invention is an electrochemical wastewater treatment and hydrogen production apparatus 10, gas separation device 20, gas dissolving device (30) ), And carbon dioxide reduction device 40, and may further include a methane combustion device (50).

First, the electrochemical wastewater treatment and hydrogen production apparatus 10 is a device configured to produce hydrogen at the same time as wastewater treatment, the electronic wastewater flowing into the device is preferably using inorganic wastewater, Inorganic wastewater), and wastewater containing any one of ammonia nitrogen, nitrate nitrogen, or fluorine can be used.

The electrochemical wastewater treatment and hydrogen production apparatus 10 is characterized in that it can simultaneously remove ammonia nitrogen, nitrate nitrogen, and fluorine in one reactor. To this end, the electroaggregation electrode and the electrooxidation electrode are alternately configured to induce the electroaggregation reaction and the electrooxidation reaction, or the reaction tank is designed by dividing the electroaggregation reaction zone and the electrooxidation reaction zone in one reactor. , Can produce. In this case, it is preferable to configure the electrocoagulation reaction zone before the electrooxidation reaction zone. In addition, in order to prolong the life of the electrode for electrocoagulation, to efficiently use the electrode for electrocoagulation, and to produce hydrogen at a high concentration, the electrooxidation reaction and the electrocoagulation reaction may be configured in a separate process.

When the wastewater is introduced into the electrochemical wastewater treatment and hydrogen production apparatus 10, ammonia nitrogen, nitrate nitrogen, and fluorine contained in the wastewater are simultaneously removed by the electroaggregation and electrooxidation reactions configured in the wastewater treatment apparatus. At this time, in order to increase the removal efficiency of ammonia nitrogen, nitrate nitrogen, and fluorine, NaCl, H ₂ SO ₄ , or NaOH may be added.

The gas generated during the electrochemical wastewater treatment is introduced into the gas separation device 20 and separated into hydrogen and other gas used as a reducing agent, and the hydrogen separated at a high concentration flows into the gas dissolving device 30 and the like. The gas is released into the atmosphere. The treated water treated in the electrochemical wastewater treatment device flows into the sedimentation tank 13 and is discharged after removing suspended solids using a polymer.

3 shows an electrochemical wastewater treatment and hydrogen production apparatus 10 in detail.

First, Figure 3a is configured to implement the electro-oxidation reaction and electro-agglomeration reaction in one reactor for high efficiency wastewater treatment and shortening the treatment time at the same time to ammonia nitrogen, nitrate nitrogen, and fluorine contained in the electronic wastewater Figure schematically shows a device configured to be removable.

The configuration of the electrode for electrooxidation and the electrode for electroaggregation in the reactor may be configured by alternating each electrode, or may be configured by separating the electrooxidation region and the electroaggregation region. In this case, it is preferable to configure the electrooxidation region and the electroaggregation region for easy electrode replacement, efficient use of the electrode for electroaggregation, and production of high concentration of hydrogen. More preferably, the electrocoagulation region is configured first. The separation wall 14 is formed at regular intervals (adjusted according to the characteristics of the wastewater) within the reactor to separate the regions of the reaction, so that the flow of wastewater flowing into the reactor from the bottom to the top and then from the top to the bottom occurs. After the separation, the electrode for electrocoagulation is placed in the first space and the electrode for electrooxidation is placed after the second space. At this time, in consideration of wastewater characteristics, wastewater treatment efficiency, and wastewater treatment amount, the ratio of the electroaggregation zone and the electrooxidation zone and the number of separation walls can be adjusted. The treated wastewater introduced into the reactor is first treated with fluorine and nitrate nitrogen through an electrocoagulation reaction and then with ammonia nitrogen through an electrooxidation reaction. The gas generated at the same time as the wastewater treatment is introduced into the gas separation device 20 and separated into a high concentration of hydrogen and other gases, and the hydrogen separated at a high concentration is introduced into the carbon dioxide abatement device 40 through the gas dissolving device 30. do. The final treated water flows into the settling tank 13 and is discharged after removing suspended solids using a polymer.

FIG. 3b shows ammonia nitrogen, nitrate nitrogen, and separation of electrooxidation and electrocoagulation reactions for prolonging the life of the electrode for electroaggregation, easy electrode replacement, efficient use of the electrode for electroaggregation, and high concentration hydrogen production. Fig. 2 is a schematic view showing an apparatus configured to remove fluorine simultaneously in one process.

First, the wastewater to be treated is introduced into the electrocoagulation reaction tank 11, whereby fluorine and nitrate nitrogen are mainly treated by the electrocoagulation reaction, and the treated water is introduced into the precipitation tank 13 and the suspended solids are polymerized. After removal, the solution is introduced into the electrooxidation tank 12. Wastewater introduced into the electrooxidation tank 12 is discharged after removal of ammonia nitrogen through the electrooxidation reaction. The gas generated in the electrocoagulation reactor 11 is introduced into the gas separation device 20, separated into hydrogen and other gases, and the hydrogen separated at a high concentration flows into the carbon dioxide reduction device 40 through the gas dissolving device 30. In addition, the gas generated in the electrooxidation reactor 12 may be mixed with the gas generated in the electrocoagulation reactor 11 to enter the gas separation device 20 or may be discharged into the atmosphere.

In the electrochemical wastewater treatment and hydrogen production apparatus 10, an electrode for electrooxidation and an electrode for electroaggregation are used. The electrode for electrooxidation has a good electrical conductivity and a material which does not have an elution phenomenon due to application of electricity and pH (for example, , Titanium), and the electrode for electrocoagulation may be made of a material (eg, aluminum) having excellent electrical conductivity and a dissolution phenomenon due to application of electricity. In addition, the electrode for electrooxidation may be used in the form of a plate or a mesh, and the electrode for electroaggregation may use any type of electrode (plate, powder, granules, etc.) except for the mesh electrode due to the characteristics of the electrocoagulation reaction.

Next, the gas separation device 20 is a device used to separate the gas generated in the electrochemical wastewater treatment and hydrogen production device 10 into a high concentration of hydrogen and other gases. Since the gas separation device 10 mainly uses flammable gases such as hydrogen and oxygen, the gas separation device 10 may be made of a material that does not cause sparks or the like, or may have an explosion-proof device.

Next, the gas dissolving device 30 is a device configured to increase the solubility of each gas so that the hydrogen-trophic methane producing bacteria in the carbon dioxide abatement device 40 can easily use hydrogen and carbon dioxide. As shown in FIG. 4, the gas dissolving device 30 includes a pump 31, a gas dissolving nozzle 32, and a gas inlet 35.

When the gas dissolving nozzle 32 is installed in the process of circulating the culture liquid in the carbon dioxide reduction device 40 using the pump 31, and the gas inlet part 35 is connected to the gas dissolving nozzle 32, The carbon dioxide separated from the hydrogen and the exhaust gas discharged from the gas separation device 20 is introduced and mixed by the pressure reduction phenomenon generated while passing through the melting nozzle 32. It is dissolved in the form of bubbles and flows into the carbon dioxide reduction device 40. Therefore, using the gas dissolving device 30 has a feature that does not require a device for storing the carbon dioxide contained in the hydrogen or exhaust gas discharged from the gas separation device 20 at a high pressure or at a constant pressure.

In addition, a spiral groove 33 or a vortex guide cap 34 may be used on the inner wall surface of the gas dissolving nozzle 32 of the gas dissolving device. By inducing vortices to form during circulation, the stirring efficiency can be increased to uniformly distribute dissolved hydrogen and carbon dioxide, and the solubility of hydrogen and carbon dioxide can be further increased. In this case, the contact frequency and the number of times of contact between hydrogen-trophic methane producing bacteria and hydrogen and carbon dioxide are increased, and thus the carbon dioxide reduction efficiency and methane production efficiency can be increased. Here, the gas dissolving nozzle 32 is in the form of a truncated cone so that the culture solution of the carbon dioxide abatement device flows toward the bottom of the gas dissolving nozzle (bottom of the truncated cone) and flows out toward the top. That is, the gas dissolving nozzle is installed horizontally in the center of the pipe for transporting the culture medium of the carbon dioxide reduction device, and the end of the gas dissolving nozzle is installed so that the end of the gas dissolving nozzle does not exceed the hydrogen and carbon dioxide inlet (preferably the center of the hydrogen and carbon dioxide inlet). do.

Next, the carbon dioxide reduction device 40 converts hydrogen and carbon dioxide dissolved through the gas dissolving device 30 into methane using methane-generating bacteria (specifically, hydrogen-trophic methane-producing bacteria) as the only carbon source and energy source. It is a carbon dioxide reduction device using a reaction. The physiological activity of these anaerobic microorganisms can reduce carbon dioxide to low cost and high efficiency and produce methane, a useful energy source. An agitator 41 may be installed inside the carbon dioxide reduction device 40, thereby causing a uniform distribution of dissolved hydrogen and carbon dioxide introduced into the carbon dioxide reduction device, increasing the solubility of undissolved hydrogen and carbon dioxide, and hydrogenotrophic methane. By promoting the contact frequency and the number of times of contact between the production bacteria and the mixed gas, carbon dioxide reduction and methane production reaction efficiency is increased.

Next, as illustrated in FIG. 5, a methacan combustion apparatus 50 that can be additionally installed in a hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment of the present invention is installed at the rear end of the carbon dioxide reduction apparatus 40. As the carbon dioxide contained in the exhaust gas in the carbon dioxide reduction device 40 is converted to methane, it can be used to produce electricity by burning the methane produced and discharged.

The electricity produced through the methane combustion device 50 is used as an electricity source for all the devices used in the hydrogen production and biological carbon dioxide reduction device using the electrochemical wastewater treatment disclosed by the present invention. At this time, the carbon dioxide generated by the methane combustion in the methane combustion device 50 is introduced into the gas separation device 20 or the carbon dioxide reducing device 40 to be reduced through the methane conversion reaction of carbon dioxide. Therefore, the methane combustion device 50 can be operated as its own electricity source of the present invention, thereby reducing the amount of electricity derived from fossil fuels, so as to have the potential to reduce the amount of carbon dioxide generated in the production of electricity from fossil fuels. do. In addition, since the electricity produced through the methane combustion device 50, there is a feature that can reduce the power cost.

Hereinafter, the present invention will be described in more detail with reference to the experimental examples, but the present invention is not limited to these experimental examples.

Experimental Example

Experimental Example 1 Treatment of Inorganic Wastewater by Electrochemical Wastewater Treatment

In this experimental example, the two electrical reactions were applied to the electronic wastewater, particularly the inorganic wastewater, in order to remove ammonia nitrogen, nitrate nitrogen, and fluorine by using an electrooxidation reaction and an electrocoagulation reaction. First, to remove fluorine by electrocoagulation reaction, aluminum electrode was used for both anode and cathode, waste water volume 5L, electrode spacing 5 mm, residence time 5 minutes were applied. The experiments were carried out with three wastewaters: raw water, wastewater adjusted to pH 7 with raw water, and wastewater adjusted to pH 7 with naOH. The results are shown in Table 1.

Table 1. Fluoride removal and hydrogen production using electrocoagulation

Processing time
(min) pH F ^- (mg / L) H ₂ (%) A B C A B C A B C 0 2.09 7 7 336.1 336.1 336.1 0 0 0 5 3.81 8.77 9.66 260.6 11.5 231.2 100 100 100

Here, A: the inorganic wastewater raw water, B: the wastewater by adjusting the pH of the inorganic wastewater to 7, C: the wastewater by adjusting the pH of the inorganic wastewater to 7 with NaOH.

As shown in Table 1, when using the electrocoagulation reaction, maintaining the pH of the reactor to 7 is effective for the fluorine removal efficiency, it can be seen that it is more effective to use lime than NaOH when adjusting the pH. However, after the reaction, the pH rises to about 9, and when the pH of the influent wastewater is adjusted to about 3, the pH rises to about 5 ~ 7 after the reaction. Since the Al (OH) ₃ has excellent fluorine removal effect, it is effective to remove fluorine removal efficiency by adjusting the pH of the influent wastewater to 3 rather than continuously adjusting the pH of the reactor. In addition, the pH of the reaction vessel is severely changed by the electrocoagulation reaction, the pH of the influent wastewater is smaller than the pH of the reaction vessel, it can also reduce the pH adjustment reagent fee. The gas generated during the electrocoagulation process was analyzed by gas chromatography and found to be all hydrogen. Therefore, it is believed that the application of the electrocoagulation reaction can effectively perform fluorine removal and hydrogen production.

In addition, an electrooxidation reaction was applied to the chemical fluorine removal treatment water to determine the possibility of removal of the ammonia nitrogen still contained in the treated water through the electrocoagulation reaction. And the electrode coated with titanium oxide and the like was used, the electrode spacing was kept 5mm. In addition, in order to increase the removal efficiency of ammonia nitrogen, NaCl was injected 0.3%, and the results are shown in Table 2 after the experiment.

Table 2. Ammonia Nitrogen Removal by Electrooxidation.

Processing time
(min) pH NH ₃ -N
(mg / L) Conductivity
(mS / cm) 0 10.9 172.6 9.54 10 8.2 27.6 9.4 20 5.2 0 9.12

As can be seen in Table 2, it can be seen that as time passes, the pH and conductivity drop and 100% of ammonia nitrogen can be removed. Therefore, when the electrocoagulation reaction is separated and operated, the hydrogen can be produced at the same time as fluorine removal, and the treated water after the electrocoagulation process can remove ammonia nitrogen with high efficiency through the electrooxidation reaction.

The experimental results are shown in Table 3 after applying different process configurations to inorganic wastewater. This experiment was carried out to remove the fluorine and ammonia nitrogen contained in the inorganic wastewater by implementing an electroaggregation reaction and an electrooxidation reaction in one reactor for high efficiency wastewater treatment and shortening treatment time. To this end, the pH in the reaction vessel is 7, the electrode for electrocoagulation was used for the aluminum plate and the electrode for electrooxidation was coated with titanium oxide or the like on a titanium base material. Each electrode in the reactor was configured to have an electrocoagulation reaction area by arranging the electrode for electroaggregation so that the electrocoagulation reaction could be induced. . The spacing of each electrode was maintained at 5 mm, and for 60 minutes after adding NaOH, H ₂ SO ₄ , and NaCl to maximize the electrocoagulation and electrooxidation reactions.

Table 3. Inorganic wastewater treatment results applying electroaggregation and electrooxidation simultaneously

Processing time
(min) pH Conductivity
(mS / cm) NH ₃ -N
(mg / L) F (mg / L) H ₂ (%) O ₂ (%) 0 6.91 5.77 183.4 56.3 0 22 20 7.13 5.40 140.1 89.7 10.3 40 7.03 5.07 70 89.9 10.1 60 6.9 4.83 0 1.59 90.1 9.9

As a result, as shown in Table 3, 97.2% of fluorine and 100% of ammonia nitrogen were treated, and 90.1% of hydrogen and 9.9% of oxygen were generated. Therefore, the electrochemical wastewater treatment and hydrogen production apparatus disclosed in this patent can simultaneously remove contaminants contained in the inorganic wastewater among the electronic wastewater in one reactor, and can efficiently produce high concentration of hydrogen. Appeared.

Experimental Example 2: Dissolution Rate of Hydrogen and Carbon Dioxide Through Gas Dissolving Apparatus

This experimental example was conducted to examine the effects of the gas dissolving device configured to increase the solubility of each gas so that hydrogen-trophic methane producing bacteria can be easily used when hydrogen and carbon dioxide are introduced into the carbon dioxide reducing device. First, hydrogen and carbon dioxide were purchased from commercially available ones, and were mixed and used in a theoretical ratio (hydrogen: carbon dioxide = 4: 1) which was consumed by hydrogenotrophic methane producing bacteria to produce methane. All experimental conditions except the gas dissolving device were configured in the same manner, and then the dissolution rate of the mixed gas of hydrogen and carbon dioxide was measured according to the use of the gas dissolving device.

As a result of the measurement, when the gas dissolving device was used, the mixed gas was dissolved at a rate of 706.5 ml / L day, but when the gas dissolving device was not used, the gas was dissolved at the rate of 188.4 ml / L day. Therefore, if the gas dissolving device is used, the solubility of the mixed gas is about 4 times higher than that of the gas dissolving device, which is more easily used by the hydrogen-trophic methane-producing bacterium, thereby reducing the carbon dioxide reduction and the methane production efficiency.

Experimental Example 3: Carbon Dioxide Reduction and Methane Production Using Carbon Dioxide Reduction Device

This experimental example was conducted to determine the effect of using a carbon dioxide reduction device on the carbon dioxide reduction and methane production efficiency based on the experimental results in Experimental Example 2. In this experimental example, all the experimental conditions except for the gas dissolving device were configured in the same manner, and the experiment was conducted. The mixing ratio of hydrogen and carbon dioxide was used by mixing hydrogen: carbon dioxide = 5: 1. After the above experiments, the results are shown in Tables 4 and 5.

Table 4. CO2 Reduction and Methane Production Efficiency (Unit: ml / min)

Injection amount Discharge Reduction or Production H ₂ CO ₂ Total H ₂ CH ₄ CO ₂ Total H ₂ CH ₄ CO ₂ Total R1 300 60 360 60.7 49.1 3.5 113.3 239.2 49.1 56.7 246.7 R2 200 40 240 76.4 23.6 11.4 111.4 123.5 23.6 28.7 128.6

Here, R1: carbon dioxide reduction device using a gas dissolving device,

        R2: CO2 abatement device without gas dissolving device

Table 5. Carbon Dioxide Reduction and Methane Production Efficiency

A B C D E R1 59.8 49.1 56.7 1.06 0.87 R2 30.9 23.6 28.7 1.08 0.82

Where: A: 1/4 of hydrogen consumed, B: methane production, C: carbon dioxide consumed, D: (1/4 of hydrogen consumed) / CO2 consumed, E: methane produced / Amount of carbon dioxide consumed.

The theory that hydrogen-trophic methane-producing bacteria produce methane using carbon dioxide and hydrogen is shown in Equation (1). In Equation (1), hydrogen-trophic methane-producing bacteria use 4 moles of hydrogen and 1 mole of carbon dioxide. Produces one mole of methane and two moles of water. In other words, methane production reaction using hydrogen-trophic methane-producing bacteria is theoretically established when 1/4 of hydrogen consumed, carbon dioxide consumed, and methane produced are equal. Comparing the operation results of the carbon dioxide abatement device based on this theoretical formula, it can be seen that both R1 and R2 reacted similarly to the theoretical values as shown in Tables D and E. Therefore, both reactors are considered to be methane produced by the methane production reaction of hydrogenotrophic methane producing bacteria. The value of E in Table 5 should also be close to 1 in theory, but as shown in the table, 0.87 and 0.82 were determined to be calculated by adding the amount of carbon dioxide dissolved in the culture solution in addition to the carbon dioxide used for actual methane production. However, as shown in B of Table 4, the amount of methane produced can be seen that R1 produced about twice as much as R2. That is, both the R1 and R2 reactors produced methane using hydrogen and carbon dioxide similar to the theoretical formula, but the hydrogen-trophic methane cultured in the R1 reactor by dissolving more hydrogen and carbon dioxide by the gas dissolving device attached to the R1 reactor. It is judged to be used more by the production bacteria, and thus the methane production in R1 is believed to be more than R2. If the gas dissolving device is not effective, the hydrogen consumption, methane production, and carbon dioxide consumption in the R2 reactor should be similar to R1. As shown in Tables 4 and 5, an R1 reactor with a gas dissolving device is installed. As methane was produced about twice as much as in, the reduction of carbon dioxide and methane production efficiency increased due to the increased solubility of hydrogen and carbon dioxide by gas dissolving device. Therefore, dissolving a larger amount of hydrogen and carbon dioxide using a gas dissolving device will result in higher carbon dioxide reduction and methane production efficiency.

In the above, a preferred experimental example according to the present invention has been described with reference to the drawings, but this is only an example, and those skilled in the art can understand that various modifications and equivalent other embodiments are possible therefrom. There will be. Therefore, the protection scope of the present invention will be defined by the appended claims.

1 is a conceptual diagram of a configuration for achieving the object of the present invention.

Figure 2 is a schematic diagram of a hydrogen production and biological carbon dioxide reduction apparatus using the electrochemical wastewater treatment of the present invention.

3A is a process schematic diagram of an electrochemical wastewater treatment and hydrogen production apparatus in which an electrode for electrooxidation and an electrode for electroaggregation according to a first embodiment of the present invention are formed in one reactor.

3b is a process schematic diagram of an electrochemical wastewater treatment and hydrogen production apparatus in which an electrooxidation tank and an electrocoagulation tank are separated according to a second embodiment of the present invention;

4 is a schematic view of a gas dissolving device.

Figure 5 is a schematic diagram of a hydrogen production and biological carbon dioxide reduction apparatus using an electrochemical wastewater treatment equipped with a methane combustion apparatus according to a third embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: electrochemical wastewater treatment and hydrogen production apparatus 11: electrocoagulation reactor

12: electrooxidation tank 13: settling tank

14: dividing wall 20: gas separation device

30: gas dissolving device 31: pump

32: nozzle for gas melting 33: spiral groove

34: vortex induction cap 35: gas inlet

40: carbon dioxide reduction device 41: stirrer

50: methane combustion device

Claims (8)

An electrochemical wastewater treatment and hydrogen production apparatus for generating pollutants contained in the wastewater using electrooxidation and electrocoagulation reactions and generating hydrogen gas and other gases as reducing agents; A gas separation device for separating the gas generated in the electrochemical wastewater treatment and hydrogen production apparatus into a high concentration of hydrogen and other gases; A gas dissolving apparatus capable of dissolving carbon dioxide separated from hydrogen and exhaust gas separated by the gas separation apparatus and injecting the same into a carbon dioxide reducing apparatus; Hydrogen using electrochemical wastewater treatment, comprising a carbon dioxide reduction device for producing carbon dioxide while reducing carbon dioxide by converting carbon dioxide into methane using hydrogen and carbon dioxide dissolved in the gas dissolving device methane generating bacteria Production and biological carbon dioxide abatement device. According to claim 1, Hydrogen production and biological carbon dioxide reduction device using an electrochemical wastewater treatment, characterized in that it further comprises a methane combustion device for producing electricity by burning the methane produced in the carbon dioxide reduction device. The method of claim 1, wherein the electronic wastewater is inorganic wastewater, hydrogen production and biological carbon dioxide using an electrochemical wastewater treatment, characterized in that selected from wastewater containing any one of ammonia nitrogen, nitrate nitrogen, or fluorine. Abatement device. According to claim 1, Electrochemical wastewater treatment and hydrogen production apparatus hydrogen production and biological carbon dioxide reduction apparatus using an electrochemical wastewater treatment, characterized in that the electrode for electrooxidation and the electroaggregation electrode is configured in one reactor. According to claim 1, wherein the gas dissolving device is composed of a pump for sucking the culture medium in the carbon dioxide reduction device, a gas dissolving nozzle for injecting the sucked culture solution and a gas inlet to which a mixed gas of hydrogen and carbon dioxide flows in Hydrogen production and biological carbon dioxide reduction device using an electrochemical wastewater treatment. [6] The apparatus for reducing hydrogen and biological carbon dioxide of claim 5, wherein the gas dissolving nozzle of the gas dissolving device has a spiral groove formed on an inner surface thereof. 6. The apparatus of claim 5, wherein a cap for vortex induction is attached to an inlet of the gas dissolving nozzle. The apparatus of claim 1, wherein the methane-producing bacterium is a hydrogen-trophic methane-producing bacterium.

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