KR20060035679A - Method and apparatus to treat process-waste-air containing vocs and malodor safely and efficiently using the process of hybrid system composed of photo-catalytic reactor, mixing chamber and biofilter - Google Patents

Abstract

According to the present invention, although the pollutant load of volatile organic compounds or odor pollutants generated at industrial sites is largely varied according to process conditions, and the flow rate of process waste gas is also largely varied according to process conditions, waste gas is continuously and safely saved. The present invention relates to a selective treatment method utilizing the synergistic effects of a hybrid system combined with a photocatalytic reactor, a mixing tank, and a biofilter for efficient and efficient purification and discharge, and a process and apparatus of the hybrid system. Synergy of hybrid system consisting of UV / photocatalytic reactor and (mixture tank) and biofilter based on pollutant load which is measured by concentration of pollutant and pollutant, not pollutant concentration. Reasonably distinguishing between the economical hybrid process and the biofilter process alone, the photochemical treatment of high concentrations of volatile organic compounds, which cannot be biologically treated, depends on the process conditions. By minimizing the use of UV / photocatalytic processes that cause serious problems, such as the production of many kinds of intermediate derivatives that are harmful to the human body, including substances, by selectively introducing and mixing waste gases and atmospheres before the biofilter process Incoming pollutant concentration and pipe It provides a method and apparatus that can treat waste gas including pollutant generated in industrial sites without any problem, and also minimizes the design scale of biofilter or UV / photocatalytic reactor by utilizing synergy effect of hybrid system to reduce investment cost and operation cost. Waste gas containing volatile organic compounds and odor pollutants generated at industrial sites can be treated safely and economically.

Photocatalytic reactor, mixing tank, biofilter, hybrid system, process waste gas

Description

Method and apparatus for safe and efficient treatment of process waste gas containing volatile organic compounds or odor using hybrid system process combined with photocatalytic oxidation, mixing tank and biofilter VOCs and malodor safely and efficiently using the process of hybrid system composed of photo-catalytic reactor, mixing chamber and biofilter}

1 is a view showing a process and apparatus of a hybrid system combined with a photocatalytic reactor, a mixing tank, and a biofilter to efficiently remove volatile organic compounds or odors contained in the process waste gas when the flow rate of the process waste gas is relatively low.

FIG. 2 illustrates a process and apparatus of a hybrid system combined with a photocatalytic reactor, a mixing tank, and a biofilter to efficiently remove volatile organic compounds or odors contained in the process waste gas when the flow rate of the process waste gas is relatively high.

* Explanation of symbols on the main parts of the drawings

1. Process waste gas

2. Blower

3. Gas flow meter

4. Electrochemical Real-Time Concentration Analyzer

5. UV-light source

6. Photocatalyst coated glass beads

7. Photocatalytic Reactor

8. glass tube

9. Electrochemical Real-Time Concentration Analyzer

10. Blowers

11. Gas flow meter

12. Mixing tank

13. Bio Filter

14. Liquid medium tank

15. Water Tank

16. Spray

17. Microbial carriers (compost, waste tire carriers and activated carbon)

18. Medium pump

19. Water Pump

20. Tubular Photocatalytic Reactor

21. Perforated Partition

22. Process waste gas transfer pipe

23. Humidifier

According to the present invention, although the pollutant load of volatile organic compounds or odor pollutants generated at industrial sites is largely varied according to the change of process conditions, the flow rate of process waste gas is also largely varied according to the change of process conditions. A selective treatment method of a hybrid system such as FIGS. 1 and 2 combined with a photocatalytic reactor, a mixing tank, and a biofilter for discharge, and a process and apparatus of the hybrid system.

Volatile organic compounds and odors generated at existing industrial sites are mainly treated by adsorption, absorption or biological treatment. However, the adsorption and absorption methods require secondary treatment of adsorbents and absorbents, and biological treatments that preferentially decompose contaminants into stable substances such as water and carbon dioxide are preferred.

In industrial sites, there is a large variation in the pollutant load of volatile organic compounds or odor pollutants and the flow rate of waste gas generated according to changes in process conditions of the industrial site. Therefore, the concentration of volatile organic compounds or odor pollutants in the waste gas generated at industrial sites can also change frequently depending on the pollutant load and the waste gas flow rate.

On the other hand, biological treatment of waste gas containing volatile organic compounds or odor pollutants has advantages such as no need for secondary treatment as compared to adsorption and absorption methods as described above. However, when the concentration of pollutants toxic to the microorganisms present in the exhaust gas to be treated is above a certain concentration that negatively affects the growth or survival of the microorganisms, the microorganisms are deactivated and the use of microbial treatment methods such as biofilters is limited. . In addition, if the pollution load of volatile organic compounds or odor pollutants caused by the change of process conditions in the industrial site increases rapidly and exceeds the designed maximum elimination capacity of biological treatment facilities such as biofilters, It is not possible to meet the treatment concentration standards of the exhaust gas, so additional processes need to be installed before or after the biofilter process.

Patent Publication No. 10-2004-0073637 is a problem in that it is impossible to treat a biological treatment system in a high concentration range of volatile organic compounds. Therefore, when the concentration of the treatment source in exhaust gas is higher than the concentration of biological treatment, the above-described hybrid process is used. And when the concentration is low, a method and apparatus for selectively using a biological treatment and a photochemical treatment using only a biofilter have been disclosed. However, Patent Publication No. 10-2004-0073637 has a problem that it is impossible to treat the biological treatment system in the high concentration range of volatile organic compounds. Although the waste gas treatment method can be selected as a pretreatment process, the motivation and purpose of presenting the photochemical method and the synergy effect of the hybrid system consisting of the photocatalytic reactor and the biofilter are not mentioned. Similarly, Korean Patent Publication No. 10-2004- In Examples and Comparative Examples of 0073637, only the performance results when operating only the biofilter and the biofilter and the photocatalytic reactor and the biofilter were simply compared, and examples of the synergy characteristics of the hybrid process itself were not presented. Therefore, rather than claiming the hybrid system itself consisting of photocatalytic reactor and biofilter, it focuses only on the fact that biological treatment is impossible in the high concentration range of volatile organic compounds. Patents and methods of selectively using biological and photochemical treatments are claimed. However, biological treatment generally completely decomposes volatile organic compounds mainly into carbon dioxide and water, but when photochemically treating high concentrations of volatile organic compounds that are not biologically treated, many kinds of harmful substances to humans, including suspected carcinogens, are subject to process conditions. It is possible to produce intermediate derivatives of, which can cause more serious problems in the photochemical treatment of high concentrations of volatile organic compounds, which are not possible in the industrial biological treatment. In addition, since photochemical treatment uses UV-B or UV-C having a short wavelength harmful to the human body in general, access is limited and difficult to handle.

An object of the present invention is to measure the concentration and load of pollutant generated in the industrial field, and to simultaneously use the UV / photocatalytic reactor and biofilter process based on the pollutant load expressed as the product of the concentration and the flow rate, not the pollutant concentration. And the case where it is possible only by biofilter process, by reducing the use of UV / photocatalytic reaction process, it can reduce the use of suspicion of carcinogenic substances produced according to process conditions when photochemical treatment of high concentration of volatile organic compounds that cannot be biologically treated. Minimize serious problems such as many kinds of intermediate derivatives that are harmful to the human body, and minimize the design scale of the biofilter or UV / photocatalytic reactor by utilizing the synergy effect of the hybrid system as in Example 1. Reduce and also mix waste gas and atmosphere Is a way to handle a waste gas containing contaminants generated in the industrial field, regardless of the concentration of contaminants flowing by selectively used to introduce a mixing step before biofilter process and apparatus to provide.

The technical method of the present invention is described as the following reasonable divisions.

1) when the pollutant load is less than the designed maximum elimination capacity of the biofilter by measuring the waste gas flow rate to be treated and the concentration of pollutant in the waste gas in real time;

 A) If the concentration of pollutant in the waste gas is not high for biological treatment, supply air from the atmosphere before mixing the biofilter and mix it with the waste gas from the mixing chamber, dilute it to the biotreatable concentration, and treat it with biofilter.

B) If the concentration of pollutant in waste gas is lower than that, treat it with biofilter without dilution.

2) If the pollutant load exceeds the designed maximum elimination capacity of the biofilter by measuring the waste gas flow rate and the pollutant concentration in the waste gas in real time, the incoming waste gas is passed through the UV / photocatalytic reactor to remain in the treated waste gas. The biocatalytic waste gas treated with the photocatalyst was designed by designing a UV / photocatalytic reactor such that the pollutant load was less than the combined total removal capacity of the hybrid system and the designed maximum elimination capacity of the biofilter as in Example 1. The filter is supplied in the same manner as in 1) above.

The configuration of the present invention is the introduction of the gas flow meter (3) and the electrochemical real-time concentration analyzer (4) capable of calculating the pollutant load of volatile organic compounds and odor pollutants as shown in Figs. photocatalytic reactor (7 or 20) for the removal of volatile organic compounds and odor pollutants when the generated pollutant load is greater than the designed maximum elimination capacity, and the concentration of the pollutant is too high due to the reduced flow of waste gas into the biofilter. When biological treatment is impossible, it consists of a mixing tank 12 which dilutes waste gas with the atmosphere and a biofilter 13 in which oxidative decomposition of a pollutant is caused by microorganisms.

As a process of the present invention, the process waste gas (1) containing a volatile organic compound or odor pollutant is blown by a blower (2) to determine the flow rate in the gas flow meter (3) and the concentration in the electrochemical real-time concentration analyzer (4). The measurement calculates the contamination load of volatile organic compounds or odor sources. When the pollutant load is less than the designed maximum elimination capacity of the biofilter A) If the pollutant concentration in the waste gas is not high for biological treatment, air is supplied from the atmosphere before the biofilter 13 process. And dilute to a concentration capable of biological treatment by mixing with waste gas flowing from the) and passing through the humidifier 23 and then treating it with the biofilter 13, and b) if the concentration of pollutant in the waste gas is lower than that, without dilution. Process as (13). On the other hand, the waste gas flow rate to be treated and the concentration of pollutant in the waste gas are measured in real time with a gas flow meter (3) and an electrochemical real-time concentration meter (4) so that when the pollution load is more than the designed maximum elimination capacity of the biofilter, The waste gas is passed through a UV / photocatalytic reactor (7). The residual pollutant concentration of the waste gas treated with the UV / photocatalytic reactor (7 or 20) was measured by the electrochemical real-time concentration meter (9), and the residual pollutant load was transferred to the UV / photocatalytic reactor (7 or 20) and the biofilter (13). The UV / photocatalytic reactor 7 is designed and photocatalytically treated so that the synergy effect of the hybrid system as in Example 1 and the combined total removal capacity of the designed maximum elimination capacity of the biofilter 13 is less than or equal to the total removal capacity. The waste gas is supplied to the biofilter 13 through the humidifier 23, and the method is the same as the above-mentioned pollution load is less than or equal to the designed maximum elimination capacity of the biofilter 13.

First, when the flow rate of the process waste gas (1) generated in the industrial site is relatively small as shown in FIG. 1, the photocatalytic reactor (7 or 20) is made of a transparent glass tube (8) and the outer diameter is A circular double tube made of shielded glass or corrosion-resistant plastic or metal was fabricated and filled with glass beads (6) coated with a photocatalyst containing TiO ₂ between the inner diameter and the outer diameter. 5) was inserted into the glass beads coated with photocatalyst (6) to induce photodegradation reaction by photocatalyst for volatile organic compound or odor component contained in waste gas. In addition, the photodegradation reaction was improved by coating a photocatalyst on the outside of the inner diameter and the inner diameter of the process waste gas. Second, when the flow rate of the process waste gas (1) generated in the industrial site is relatively large, as shown in Figure 2, the photocatalytic reactor 20 contains a volatile organic compound or odor emitted to the blower (2) in the industrial site A photocatalyst containing TiO ₂ is coated between the perforated partitions 21 inside the round or square or other shaped plastic or metal tube 22 having corrosion resistance connecting the atmosphere or waste gas to the gas mixing tank 12. Filled with glass beads 6 and holes at regular intervals in the longitudinal direction of the filled tube, the transparent glass tubes 8 with the end to which the ultraviolet lamp 5 is to be inserted are placed in the vertical or diagonal direction of the filled tube length. A plurality of ultraviolet lamps 5 are inserted into each of the glass tubes 8 arranged. In addition, the photocatalytic reaction effect was improved by coating the photocatalyst on the inner surface of the tube, which is the photocatalytic reactor 20, in contact with the atmosphere or waste gas.

Waste gas introduced through the humidifier 23 to the upper portion of the biofilter 13 passes between the microbial carriers 17 filled in the biofilter, and the volatile organic compound or odor generating source included in the biofilter inlet gas is microorganisms. It is removed through absorption and biodegradation by the membrane, and the waste gas treated by the hybrid system is discharged to the atmosphere. On the other hand, the biofilter 13 mainly uses organic carriers including compost, bark, and peat as a microbial carrier 17, and granular activated carbon or internal pores are greatly extruded as a support. Waste tire carriers (see Chemical Engineering Journal, 39 (5), 600-606) were filled in the biofilter 13. In order to maintain proper humidity of the microbial carrier 12 inside the biofilter 13 and proper environment for adherent microorganisms, the liquid medium 14 and the water 15 containing nutrients are periodically pumped by the spray 16. To (18 and 19).

Example 1

The following is the result of treating waste gas containing ethanol and toluene using a hybrid system process, which is a combination of a photocatalytic reactor and a biofilter as a pre-process such as the present invention. As a photocatalyst, a circular pyrex tube of 4 cm (inner diameter) x 8 cm (outer diameter) x 47 cm (length) was used, and a 15 W UV-A lamp was used as a light source. On the other hand, the biofilter, which is a post process, filled the microbial carrier composed of compost and granular activated carbon of 18 cm and 20 cm, respectively, with 5 cm (diameter) x 25 cm (length) tubes at the upper and lower ends.

Table 1. Contribution to Hybrid System Performance of Photocatalytic Reaction Process

Elimination capacity Toluene (g / m ³ / h) Ethanol (g / m ³ / h)  Maximum value of hybrid system 130 230  Maximum value of biofilter 90 100 Increase due to addition of photocatalytic reaction process as a whole process 40 (100%) 130 (100%) Direct contribution of the photocatalytic reaction process 7 (17.5%) 28 (21.5%) Indirect contribution of the photocatalytic reaction process 33 (82.5%) 102 (78.5%)

As shown in Table 1, in the case of the simultaneous removal of ethanol and toluene, the hybrid catalyst in which the photocatalytic decomposition process is added to the existing biofilter process in the case of the simultaneous removal of ethanol and toluene, the photocatalyst at 100% increase in the ethanol elimination capacity The direct contribution of the decomposition process was 21.5% and the indirect contribution generated as a synergy effect of the hybrid system process was 78.5%. On the other hand, when the increase in toluene elimination capacity was 100%, the direct contribution of the photocatalytic decomposition process was 17.5% and the indirect contribution generated as a synergy effect of the hybrid system process was 82.5%. In this way, the efficiency of the waste gas treatment system was maximized economically by effectively utilizing the process characteristics that create the synergy effect of the hybrid system consisting of the photocatalytic decomposition process, which is a pre-process, and the biofilter process, which is a post-process.

In the present invention, first, the concentration of the pollutant and the pollutant load generated at an industrial site are measured, and the UV / photocatalytic reactor and the biofilter process are simultaneously used based on the pollutant load expressed as the product of the pollutant concentration and the flow rate, not the pollutant concentration. Cases that could only be achieved by the biofilter process were reasonably classified. Therefore, by using UV / photocatalytic process as much as possible, it is possible to generate high concentrations of volatile organic compounds contained in process waste gas by UV / photocatalytic process. Serious problems such as many kinds of intermediate derivatives harmful to the human body, including suspected carcinogens, can be minimized. Second, if the concentration of pollutant in the waste gas is too high for biological treatment, but the pollutant load is below the designed maximum elimination capacity of the biofilter, the biofilter is a mixed process of mixing the waste gas and the atmosphere instead of using the UV / photocatalytic reaction process. Introduced and optionally used before the process, it is possible to treat waste gases including pollutants generated at industrial sites regardless of the concentration of pollutant introduced. Third, the increase in elimination capacity of volatile organic compounds in the hybrid system that adds the photocatalytic decomposition process to the existing biofilter process was created as a synergy effect of the hybrid system process rather than the direct contribution of the photocatalytic decomposition process. By making the indirect contribution more than doubled, it is not only the high elimination capacity for volatile organic compounds of the hybrid system, but also the high economic efficiency of the hybrid system. Therefore, by utilizing the synergy effect of the hybrid system consisting of UV / photocatalytic reactor and biofilter, it is possible to minimize the design scale of the biofilter or UV / photocatalytic reactor to reduce the investment cost and operating cost.

Claims (7)

As a process of the present invention, the process waste gas (1) containing a volatile organic compound or odor pollutant is blown by a blower (2) to determine the flow rate in the gas flow meter (3) and the concentration in the electrochemical real-time concentration analyzer (4). If the pollutant load is less than the designed maximum elimination capacity of the biofilter, a) If the pollutant concentration in the waste gas is high, which is impossible for biological treatment, supply air from the atmosphere prior to the biofilter 13 process. In (12), the biogas is mixed with the waste gas introduced through the humidifier 23 and diluted to a concentration capable of biological treatment, and treated with the biofilter 13, and b) If the concentration of the pollutant in the waste gas is lower than that, the biomass is not diluted. The filter 13, while the waste gas flow rate to be treated and the concentration of pollutant in the waste gas are measured by the gas flow meter 3 and the electrochemical If the pollutant load is greater than the designed maximum elimination capacity of the biofilter by measuring in real time with a real-time concentration meter (4), the incoming waste gas is passed through the UV / photocatalytic reactor (7 or 20) and then UV / photocatalytic reactor ( 7 or 20), the residual pollutant concentration of the waste gas treated by the electrochemical real-time concentration meter (9) is used to measure the synergy of the hybrid system consisting of the UV / photocatalytic reactor (7 or 20) and the biofilter (13). Design the UV / photocatalytic reactor 7 or 20 so that the effect and the total designed removal capacity of the biofilter 13 are equal to or less than the sum of the designed maximum elimination capacities. To the biofilter 13, the method being used when the above-mentioned pollution load is equal to or less than the designed maximum elimination capacity of the biofilter 13 The process waste gas is treated through the selective use of the hybrid system and the biofilter 13 based on the pollutant load, not the concentration of the process waste gas 1 containing the same volatile organic compound or odor source, and the biofilter 13 All methods and apparatus for dilution to biologically treatable concentrations when the concentration of process waste gas entering the process is high where biological treatment is not possible The inner diameter is made of transparent glass tube (8) and the outer diameter is made of shielded glass or annular double tube (7) made of plastic or metal with corrosion resistance and coated with photocatalyst including TiO ₂ between inner and outer diameters. Design and Apparatus for Photocatalytic Reactor 7 Filled with Glass Beads 6 and Inserting Light Source 5 Inside the Inner Diameter The inner diameter is made of transparent glass tube (8), and the outer diameter is made of shielded glass or annular double tube (7) made of plastic or metal with corrosion resistance. Design and apparatus of photocatalytic reactor (7) to improve photolysis reaction by coating with photocatalyst on outside of inner diameter and inside of outer diameter Photocatalytic reaction process and apparatus using as a photocatalytic reactor 20 a pipe 22 for transporting waste gas containing volatile organic compounds or odors When the tube 22 for transporting process waste gas containing volatile organic compounds or odors is used as the photocatalytic reactor 20, the end to which the light source 5 is inserted is made by making holes at regular intervals in the longitudinal direction of the tube 22. Design and apparatus of photocatalytic reactor 20 for arranging transparent glass tube 8 vertically or obliquely in length of tube 22 Photocatalyst which coats the inner surface of the glass, plastic tube or metal tube 22 with the photocatalyst containing TiO ₂ which is in contact with the waste gas of corrosion-resistant round or square or other forms of corrosion-resistant transporting process waste gas containing volatile organic compounds or odors. Design and Apparatus of Reactor 20 Filled glass, plastic tubes or metal tubes 22 with corrosion resistance to transport process waste gases containing volatile organic compounds or odors as glass beads 6 coated with a photocatalyst containing TiO ₂ . Design and apparatus of the photocatalytic reactor 20

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