KR20120097974A - Process and apparatus for treating organic matters using complex electrolysis - Google Patents

Abstract

PURPOSE: A method and an apparatus for treating organic materials based on complex electrolysis are provided to effectively eliminate organic materials by maximizing the efficiency of electrolysis. CONSTITUTION: A method for treating organic materials includes the following: a catalytic agent is introduced into wastewater in order to accelerate the generation of hydroxyl groups; and the wastewater is electrolyzed. The electric current density of the electrolysis is adjusted according to the concentration of organic materials in the wastewater. The catalytic agent is a material containing nascent oxygen such as hydrogen peroxide or ozone.

Description

Processing and Apparatus for Treating Organic Matters Using Complex Electrolysis

The present invention relates to a method and apparatus for treating organic material including a hardly decomposable substance, and in particular, to maximize the generation of hydroxyl groups by the electrolysis method of injecting a catalyst using a complex electrolysis method that can improve the efficiency of organic matter treatment compared to the energy consumption. It relates to an organic material treatment method and apparatus.

In the case of nuclear power plants, ethanolamine (ETA) wastewater containing high-concentration organic matter and sulfuric acid generated during regeneration of multiple desalination plants is mixed with other system water and transferred to the wastewater treatment facility. After precipitation, it is processed through filtration process. However, COD (Chemical Oxygen Demand) and TN (Total Nitrogen) caused by ethanolamine compounds generated from regeneration of multiple desalination facilities have not been prepared effectively so far, and can actively cope with the enforcing environmental regulations. There is a need for technical development of the existing treatment methods.

Chemicals currently used as pH regulators in secondary plant water systems include ammonia, morpholine, and ethanolamine (ETA). However, ethanolamine rather than ammonia is used as a pH regulator in most nuclear power plants in Korea as well as abroad. Since ethanolamine can maintain high pH even at low temperature under high temperature and high pressure conditions, it can reduce the load of Condensate Polishing Plant, and cation exchange resin has high sodium selectivity in amine mode, so it is a steam generator. The use of ethanolamine as a pH regulator to replace ammonia is continuously increasing because it can minimize corrosion of steam generators along with the advantage of minimizing the inflow of sodium.

However, the use of ethanolamine has been a factor in increasing the COD and T-N of the effluent from the wastewater generated during the regeneration of the multiple desalination plant. Plant water circulating in the secondary system is regenerated to remove impurities periodically using ion exchange resin of a multiple desalination plant, and at this time, compounds such as ethanolamine, hydrazine, and ionic substances in the plant water are discharged together. Hundreds to thousands of compounds contain large amounts of nitrogen and organic compounds and are expressed in COD.

CODs expressed in this way exceed the discharge limit and discharge water quality standards under the "Act on Water and Water Ecosystem Conservation", so it is not possible to discharge them to the ocean without proper treatment. It is known to exist in the form of compounds (3 to 5 ppm when used with ammonia, 20 to 65 ppm when using ethanolamine). Ethanolamine is a hardly degradable organic compound, which meets COD effluent water quality standards under the "Act on Water and Aquatic Conservation". Various treatment technologies are being developed to satisfy.

At present, the treatment of regeneration wastewater of multiple desalination facilities of power generation facilities is a general physicochemical treatment method. Although it is composed of filtration process after precipitation, the removal efficiency is relatively low, and the multiple desalination plant regeneration wastewater and other system water are introduced into the wastewater treatment facility together. Ethanolamine is difficult to remove through precipitation due to inadequate flocculation reaction, and is not effectively removed even in a filtration process such as activated carbon, so there is a limitation in processing by physicochemical treatment method. Currently, the treatment method is able to proactively cope with the "Water Quality and Aquatic Ecosystem Conservation Act" which is strengthened due to low treatment efficiency and large fluctuations in treatment efficiency according to changes in pollutants (throughput, concentration, etc.). A situation is needed.

Recently, electrodialysis and electrolysis were added to the existing physicochemical treatment method to treat regeneration wastewater of plural desalination facilities, and organic matter and TN of regeneration wastewater of plural desalination facilities were treated. It is applied to some power plants and new nuclear power plants.

However, the above-mentioned electrolysis method has an excellent effect on the COD and TN treatment efficiency of the multi-desalination plant regeneration wastewater, but it is necessary to achieve the task of maximizing the treatment efficiency of organic matter and TN while minimizing the amount of power and maintenance cost. There is a need.

Therefore, an object of the present invention is to improve the amount of power of the electrolysis facility applied to the regeneration wastewater treatment of the multiple desalination plant of the existing nuclear power plant and to activate the generation of hydroxyl groups through the catalyst injection to maximize the COD and TN removal efficiency through the electrolysis plant The present invention provides an organic material processing method and apparatus including a hardly decomposable material using a complex electrolysis method for effectively treating organic materials.

In addition, the present invention is to provide an organic material processing method and apparatus using a complex electrolysis method that can maximize the treatment effect of the organic material while using a minimum power by elastically adjusting the amount of power used for electrolysis according to the concentration of the organic material.

According to the present invention, in order to achieve the above object, in the organic material treatment method for sterilizing and treating the organic matter, the step of introducing a catalyst for promoting the generation of hydroxyl groups in the waste water to be treated; And electrolytically treating the wastewater to which the catalyst is added, and providing an organic material treatment method using a complex electrolysis method, wherein the current density is selectively controlled according to the concentration of organic material during the electrolysis.

The catalyst is characterized in that the material having a generator oxygen.

The catalyst is characterized in that hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ).

The electrolysis step is characterized by operating at a high current density when the concentration of the organic material is high, and operates at a low current density when the concentration of the organic material is low.

According to the present invention, it is advantageous to use an electrolysis method that is convenient for process control according to loads of organic matter and T-N in wastewater, and in addition, it is possible to effectively remove organic matter by maximizing electrolysis efficiency using a catalyst.

In addition, according to the present invention, there is an advantage that the amount of power used for electrolysis can be selectively adjusted according to the concentration of the organic material to minimize the amount of power and the organic treatment effect can be maximized.

In addition, the present invention is to reduce the residual chlorine concentration generated during the electrolysis has the advantage of reducing the maintenance cost by simplifying the after-treatment process.

1 is a schematic diagram schematically showing an organic material processing apparatus using a complex electrolytic method applied to the present invention,
Figure 2 is a graph showing the treatment tendency of TN and COD according to the electrolysis time in the electrolysis method of the present invention,
Figure 3 is a graph comparing the treatment efficiency of the hardly decomposable organics according to an embodiment of the present invention.

In the present invention, by introducing a catalyst for the purpose of maximizing the generation of hydroxyl radicals (OH radical) by electrolysis of wastewater containing organic matters, such as regeneration wastewater of multiple desalination plant, heavy water and sewerage to promote the generation of hydroxyl groups to improve the efficiency of electrolysis It was intended to improve.

In addition, the current density applied to the electrolysis bath according to the present invention is also linked to the concentration of the organic matter. In other words, in the initial state in which organic matter is present in the waste water at high concentration, it operates at high current density to dissociate high concentration organic matter quickly, and then adopts a method of operating at low current density when organic matter is changed to low concentration. Compared to the method of continuously operating the current density, the organic material removal and sterilization process is performed to significantly increase the processing efficiency compared to the input energy by reducing the amount of power consumed as a whole.

Here, for example, hydrogen peroxide (H ₂ O ₂ ), ozone (O ₃ ), or the like may be used as the catalyst, and there is no particular limitation as long as the material has generator oxygen.

The hydroxyl group (OH radical) is generated when the electrolysis of water, is involved in the sterilization and disinfection of almost all contaminants, and is a natural substance harmless to the human body while exhibiting a strong sterilization effect.

Of the existing substances, the oxidative power of hydroxy groups (the ability to sterilize, disinfect and disintegrate) is stronger than ozone (O ₃ ) or chlorine (Cl ₂ ), but it is toxic or harmful to humans like chlorine (Cl ₂ ) or ozone (O ₃ ). Therefore, the production of hydroxyl groups should be maximized during electrolysis. To this end, in the present invention, hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ) having generator oxygen is added as a catalyst.

In the present invention, the organic matter treatment apparatus including the electrolysis tank shown in FIG. 1 is used in order to perform electrolysis by adding the above catalyst.

The organic material treatment apparatus of the present invention includes a catalyst input device capable of promoting the generation of hydroxyl groups in the electrolysis tank, and the catalyst supplied through the catalyst input device at the inlet side when the wastewater to be treated by the electrolysis device is introduced. Ensure uniform mixing with influent.

When using such an electrolysis device, the treatment of organic matter by direct oxidation by electric current and magnetic field during electrolysis, sterilization by electric field, indirect oxidation by treatment and sterilization of organic material by hypochlorous acid during electrolysis and In addition, it is possible to simultaneously proceed with organic matter treatment and sterilization by hydroxyl group.

1 is a schematic diagram schematically showing an organic material processing apparatus using a complex electrolysis method applied to the present invention.

Referring to FIG. 1, electrolysis tank 10 for discharging and disinfecting organic matter by electrolyzing the incoming wastewater and discharging the treated water is applied with a current of the electrolysis tank 10 to secure operating safety. Rectifier 20, a catalyst input device 40 for supplying a catalyst to the wastewater flowing into the electrolysis tank, a control panel 30 for controlling the catalyst input device 40 and the rectifier 20, respectively, And a mixer 50 for mixing the catalyst supplied from the catalyst input device 40 to the wastewater to be supplied to the electrolysis tank 10.

As the electrode (not shown) used in the electrolytic bath 10, for example, a plate-type electrode may be used, and the electrode may be combined with a bipolar and a monopolar method. can do. As the electrode used herein, it is also possible to use the electrode disclosed in Korean Patent No. 553364, developed and registered by the applicant of the present invention.

In addition, the rectifier 20 detects the voltage or current of the current flowing between the electrodes in the electrolysis tank 10 in order to ensure the operational stability of the electrolysis tank, and sets the upper and lower limits of the detected voltage or current. A rectifier disclosed in Korean Patent No. 918424 developed and registered by the applicant of the present invention may be used, which has a function of blocking a voltage or current according to a set value and a function of automatically changing a current according to an organic substance concentration.

The catalyst introduced into the catalyst dosing device 40 is, for example, hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ) and the like, wherein the dosage of ozone (O ₃ ) is 10 ppm to maintain the control panel 30 Controlled by The dose of ozone (O ₃ ) is determined in consideration of the solubility of ozone in water and the initial concentration of hardly decomposable substances. The solubility of ozone in water is inversely proportional to temperature and proportional to pressure according to Henry's law. Because it is determined.

The mixer 50 serves to mix the catalyst introduced from the catalyst input device 40 to the incoming wastewater and supply it to the electrolysis tank 10. The electrolysis tank 10 promotes the generation of hydroxyl groups generated during electrolysis by the catalyst to maximize the electrolysis efficiency, so as to sterilize and treat the organic matter and discharge it to the treated water.

At this time, in order to improve the efficiency of the electrolysis tank 10, the current density supplied to the electrolysis tank 10 is selectively adjusted according to the concentration of the organic material. In other words, in the initial high concentration state, the current density is increased to operate, and when the low concentration state is reached, the current density is reduced and operated to reduce the total power amount, and the results are shown in Tables 1 and 2.

Note 1) Power required = Output power / (Power factor x Efficiency): Power required (KVA), Power factor (0.9), Efficiency (0.9)

Note 2) The amount of electricity used for electrolyzer in electrolysis facility.

Note 3) The amount of electricity used for other equipment for the operation of electrolysis facilities.

Table 1 is a comparison of the power consumption of the electrolysis facility, Table 2 is a comparison of the influent and treated water quality conditions and efficiency by the electrolysis operation conditions.

Table 1 compares the power requirements for the method of continuously applying a constant current density to reduce the amount of power of the electrolysis facility and the process of changing the current density to a high current density and a low current density according to organic matter concentration. The above power reduction reduces the equipment designed to keep all the 15 sets of electrolysis tanks at a constant high current density (120 mA / cm 2) for 5 days to drop the TN and COD _Mn values to the target level. When decomposing, 7 sets of high current density (130mA / ㎠) are operated to dissociate hardly decomposable organic matter, and when the concentration of dissociated organic matter decreases, all 15 sets of electrolysis tanks are operated at low current density (80mA / ㎠). To achieve the same performance.

In this case, the removal rate satisfies the effluent water quality criteria in almost the same manner as shown in Table 2, but as shown in Table 1, in terms of power consumption, 2,125 kVA-5 days versus 1195.4 kVA-5 days (1171 kVA-1.87 days / 1210 kVA). -3.13 days), the power consumption is reduced. Since this corresponds to 56.3% of the initial design power, it can be seen that there is about 43.7% of power savings.

The reason why the power can be reduced as described above will be described with reference to the graph of FIG. 2. Referring to FIG. 2, when a high current density is applied at the initial stage of electrolysis, a phenomenon in which an ethanolamine (ETA) compound, which is a hardly decomposable substance, is rapidly dissociated appears. The ethanolamine compound which causes COD and TN in the regeneration wastewater mixed with the multiple desalination plant shows the phenomenon of decomposition after dissociation. It can be seen that the method of dividing into two stages proceeding at a low current density (70 to 80 mA / cm 2) exhibits an effect of reducing power as compared to the conventional method of continuously electrolyzing at a high current density (120 mA / cm 2).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to these examples, and may be appropriately changed by those skilled in the art within the scope of the present invention.

Comparative Examples 1 and 2 and Example 1

Non-degradable wastewater, for example, was used for wastewater diluted with multiple desalination plant wastewater (CPP regeneration wastewater) of Yeonggwang 1-4 nuclear power plant. Batch performance was evaluated for 100 liters of water, and an electrolysis device was connected to a storage tank (not shown) to test the waste water. At this time, the amount of ozone was 10 ppm and the current density of the electrolysis device was 60 mA / cm ² .

Comparative Example 1 is a condition to be treated only with ozone, Comparative Example 2 is a condition to be treated only by electrolysis, Example 1 was subjected to electrolysis using the organic matter treatment apparatus of FIG. The experiment was carried out as.

After the experiment proceeds for 30 minutes, the concentration of the treated water is measured and the treatment efficiency according to the experimental conditions as the treatment concentration value compared to the concentration of the raw waste water is shown in Table 3 and FIG.

Experimental conditions COD _Cr Treatment Concentration Power Consumption Per 1ppm treatment
Power Consumption Efficiency comparison
(Relative) Comparative Example 1;
Ozone (10 ppm injection) ΔC = 20ppm 600w 30.0w 28.5% Comparative Example 2;
Electrolysis (60mA / cm ² ) ΔC = 70ppm 1,600w 22.8w 100.0% Example 1;
Electrolysis + ozone;
Complex electrolysis ΔC = 138ppm 2,200w 15.9w 197.1%

Table 3 compares the removal efficiency of the hardly decomposable substance, which is shown in FIG. 3 as a graph.

As shown in Table 3 and Figure 3, it was evaluated that the organic matter treatment efficiency appears in the order of electrolysis + ozone (complex electrolysis) of Example 1, electrolysis of Comparative Example 2, ozone of Comparative Example 1.

In Table 3, the throughput of the electrolysis + ozone (complex electrolysis) CODcr of Example 1 is ΔC = 138 ppm, arithmetically the ΔC = 20ppm of ozone of Comparative Example 1 and ΔC = 70ppm of electrolysis of Comparative Example 2 It can be seen that the throughput is ΔC = 48 ppm higher than the sum of ΔC = 90 ppm.

3 shows the CODcr throughput according to time, and the organic matter treatment efficiency is improved in the order of Comparative Example 1 (only, O ₃ ), Comparative Example 2 (only, Electrolysis), and Example 1 (Electrolysis + O ₃ ). Able to know.

Here, the chemical oxygen demand (COD) is measured according to the degree of oxidation by potassium dichromate and shows the result measured by CODcr by the water pollution process test method.

The reason why the throughput is increased is determined by the hydroxyl group, and in the case of Example 1 in which two processes of ozone and electrolysis are combined, it can be confirmed that a synergistic effect occurs to achieve a high efficiency treatment process at low power.

Thus, Example 1 combining the two processes can be treated to less than the water quality standards that efficiently require a hardly decomposable organic matter while reducing the power consumption significantly compared to Comparative Examples 1 and 2 by promoting the formation of hydroxyl groups.

The present invention can be applied to an electrolysis device for treating various kinds of wastewater including organic matter.

10: electrolysis tank 20: rectifier
30: control panel 40: catalyst input device
50: mixer

Claims (9)

In the wastewater treatment method for removing or sterilizing organic matter,
Adding a catalyst for promoting hydroxyl group production to the wastewater to be treated; And
Electrolytically treating the wastewater to which the catalyst is added,
The organic material treatment method using a complex electrolysis method characterized in that the current density is selectively adjusted according to the concentration of the organic material during the electrolysis. The method of claim 1, wherein the catalyst is a material having generator oxygen. The method of claim 1, wherein the catalyst is hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ). The organic material of claim 1, wherein the electrolysis is performed at a high current density when the concentration of the organic material is high, and at a low current density when the concentration of the organic material is low. Treatment method. The method of claim 1, wherein when the organic material is an ethanolamine compound, the dissociation process of the ethanolamine compound is operated under a high current density (130-150 mA / cm 2) condition, and the low current density (70) after the ethanolamine compound is dissociated. The organic material processing method using the compound electrolysis method, characterized in that operating under ~ 80mA / ㎠) conditions. In the wastewater treatment apparatus for treating or sterilizing organic matter,
An electrolysis tank (10) for discharging the wastewater by electrolyzing the incoming wastewater to remove and sterilize the organic matter,
Rectifier 20 to ensure the operation safety of the electrolysis tank 10,
Catalyst input device 40 for supplying a catalyst to the wastewater flowing into the electrolysis tank,
The control panel 30 for controlling the catalyst input device 40 and the rectifier 20, respectively, and the catalyst supplied from the catalyst input device 40 to the incoming waste water are mixed and supplied to the electrolysis tank 10. Organic material processing apparatus using a compound electrolysis method comprising a mixer (50) for. The organic material processing apparatus of claim 6, wherein the catalyst is a material having generator oxygen. The organic material processing apparatus of claim 6, wherein the catalyst is hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ). The organic material of claim 6, wherein the electrolysis is performed at a high current density when the concentration of the organic material is high, and at a low current density when the concentration of the organic material is low. Processing unit.

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