CN1227053C - Treatment equipment and method for organic waste gas containing VOC - Google Patents

Abstract

The present invention discloses a treatment device and method for VOC-containing organic waste gas, the main feature of which is the integration of _O3 oxidation technology and traditional wet scrubbing technology, which can improve the treatment efficiency, economy, scope of application and system control method of the current traditional technology for treating odor and organic waste gas. According to the treatment technology of the present invention, the waste gas to be treated is absorbed by the circulating scrubbing liquid when passing through the wet scrubber, and the dissolved pollutants can be decomposed by the oxidant in the high-efficiency oxidation reaction tank by chemical oxidation, and the pH value control method is used to improve the VOC waste gas removal efficiency and the oxidant utilization rate. In addition to providing the above-mentioned chemical reaction, the high-efficiency oxidation reaction tank also provides the function of monitoring and adjusting the water quality entering the high-efficiency oxidation reaction tank.

Description

Treatment equipment and method for organic waste gas containing VOC

technical field

The invention relates to waste gas treatment technology, in particular to a treatment device and method for VOC-containing organic waste gas.

Background technique

Semiconductor process waste gas contains a large amount of volatile organic compounds (volatile organic compounds; VOCs), such as isopropyl alcohol (IPA), acetone (acetone), methyl ethyl ketone (MEK) and some high boiling point substances (such as dimethylacetamide, DMSO, NMP, etc.).

At present, the commercialized technologies for treating VOC-containing waste gas from semiconductors mainly include rotary wheel concentration incineration technology, activated carbon adsorption technology and wet scrubbing technology. The rotary enrichment incineration technology consumes a large amount of fuel, and the activated carbon adsorption technology requires frequent replacement of activated carbon, both of which have high operating costs. Moreover, based on the current experience of using the rotary wheel concentration incineration technology in the semiconductor industry, it is found that this technology has poor removal effect on high boiling point substances (such as the main component of photoresist), and will destroy the adsorption capacity of the adsorption material used in the concentration wheel , leading to a continuous decrease in the treatment efficiency of pollutants.

The high-boiling-point substances used in the semiconductor industry are almost completely soluble in water, so wet scrubbing technology can transfer the high-boiling-point substances in the gas phase to the liquid phase for oxidation and removal. However, wet scrubbing technology requires a large amount of clean water and discharges a large amount of wastewater in order to maintain a high treatment efficiency. It is unwise to do so when the water shortage and water pollution problems in the semiconductor industry are not resolved. In addition, the traditional oxidation scrubbing technology of adding oxidant combines the oxidant and the washing tower together. When the oxidant is too much, the oxidant will remain in the exhaust gas. If the operation is improper, there will be a problem of re-dissipation, resulting in secondary pollution; and when the oxidant When the reaction rate with pollutants is slow, the treatment efficiency is reduced; the types of oxidants available for traditional oxidation washing are limited, except for O ₃ , which has low oxidizing power and low treatment efficiency.

O ₃ is the best oxidizing agent among the currently commercialized oxidizing agents, but because of its high manufacturing cost, it is mostly used in tap water treatment and chemical processes. Most of the air pollution treatment is academic research, and there are few practical engineering applications (O ₃ For water and wastewater treatment, refer to European patents EP0859746, EP0791101, EP0495707, US patents US53645377, US5851407, US 5637231, etc.), O ₃ is mainly used for disinfection or removal of some organic matter in water and wastewater treatment as follow-up It is treated before the treatment equipment, so its organic matter treatment efficiency does not need to be very high. Most of the traditional O ₃ reaction tanks use a single reaction tank and a single aeration method design, and there is no control on water quality, such as pH and carbonate. The organic matter removal efficiency and O ₃ utilization rate are low, and O ₃ waste gas is generated, so an O ₃ destroyer needs to be installed at the waste gas discharge port. In order to increase the efficiency of gas phase O ₃ transfer to liquid phase, U.S. Patents US5851407, US5637231, and US5989439 use high pressure or venturiinjector to quickly dissolve gas phase O ₃ , but for slow reaction rate and organic matter, it will cause a lot of ozone and waste, and equipment operation and maintenance not easy.

Therefore, in order to perfect the treatment technology of organic waste gas, it is necessary to improve the above problems.

Contents of the invention

The technical problem to be solved by the present invention is to provide a treatment equipment and method for organic waste gas containing VOC.

One of the objectives of the present invention is to provide an organic waste gas treatment device and method that can reduce operating costs.

The second object of the present invention is to provide an organic waste gas treatment device and method that will not be affected by high boiling point substances.

The third object of the present invention is to provide an organic waste gas treatment device and method that can greatly reduce water consumption and discharge wastewater.

The fourth object of the present invention is to provide an organic waste gas treatment equipment and method with high VOC removal efficiency and high O ₃ utilization rate.

In order to achieve the above object, the present invention provides a treatment equipment for organic waste gas containing VOC, including:

(a) A scrubber, used to receive the above-mentioned organic waste gas, so that the organic pollutants in the waste gas can be transferred to the scrubbing liquid;

(b) an oxidation treatment unit comprising an ozone aeration device, used to receive the washing liquid from the washing tower, and introduce an oxidant containing ozone generated by the ozone aeration device into the washing liquid and organic pollutants in the washing liquid carry out an oxidation reaction; and

(c) A reflux device, which is used to circulate the cleaning solution of the above-mentioned oxidation treatment unit to the above-mentioned washing tower for the purpose of absorbing pollutants in the exhaust gas.

The present invention also provides a treatment method for VOC-containing organic waste gas, the main steps of which include:

(a) Leading the organic waste gas into a scrubber, absorbing the organic pollutants in the waste gas with the scrubbing liquid, and performing preliminary oxidation by the ozone-containing oxidant;

(b) introducing the above-mentioned cleaning solution containing pollutants into at least one oxidation tank, and mixing it with an oxidant containing ozone to carry out an oxidation reaction; and

(c) re-introduce the above-mentioned washed liquid after the reaction into the above-mentioned washing tower, and repeat steps (a) and (b).

The main feature of the present invention is the integration of O ₃ oxidation technology and traditional wet scrubbing technology, through the design of high-efficiency multi-stage oxidation reaction tank and the control of operating conditions to treat organic waste gas, which can improve the utilization rate of oxidant and the treatment efficiency of organic pollutants. Therefore, there is no problem of secondary pollution of oxidants, and the adverse effect of slowing down the reaction rate of oxidants and pollutants due to the increase of carbonate. The technology of the present invention is especially suitable for the organic waste gas of the semiconductor industry containing VOC with high water solubility.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the accompanying drawings further illustrate the organic waste gas treatment equipment and method of the present invention in detail.

Description of drawings

Figure 1 is an advanced oxidation scrubbing system useful in the practice of the present invention.

Fig. 2 is one of the specific embodiments of pollutant oxidation unit of the present invention

Fig. 3 is the second embodiment of the pollutant oxidation unit of the present invention

Fig. 4 is the third embodiment of the pollutant oxidation unit of the present invention

Fig. 5 is the fourth embodiment of the pollutant oxidation unit of the present invention

Detailed ways

In Fig. 1, the advanced oxidation washing system shown in the present invention consists of oxygen or air inlet 1, ozone generator 2, ozone outlet 3, ozone aeration device 4,5, advanced oxidation reaction tank 6,7, washing liquid circulation help Pu 8, flow indicator device 9, washing tower body 10, washing liquid circulation pump 11, exhaust gas windmill 12, inlet 13 before exhaust gas treatment, exhaust gas concentration monitoring point before treatment 14, low concentration ozone inlet 14, exhaust gas concentration monitoring point after treatment 15. It is composed of exhaust gas outlet 17 after treatment, water quality monitoring points 18 and 22 of washing liquid, monitoring system 19, medicine tank 20 and medicine dosing machine 21.

The invention integrates traditional wet scrubbing technology with high-efficiency _O3 oxidation technology as a procedure for treating water-soluble organic and/or odorous waste gas. In the exhaust gas treated by the present invention, water-soluble VOC refers to organic compounds that are easily soluble in water at normal temperature and pressure, such as lipids, ethers, aldehydes, alcohols, ketones and organic acids. The above-mentioned odor-containing waste gas refers to the nitrogen and sulfur elements in the molecular structure, which cause the generally known odor components, such as hydrogen sulfide, methyl mercaptan, ethanethiol, dimethyl sulfide and similar sulfur-containing compounds. Nitrogen such as ammonia, dimethylamine, methylamine and similar nitrogen-containing compounds.

Waste gas treatment equipment and method of the present invention will be described in detail as follows in conjunction with Fig. 1:

The scrubber includes a scrubber body 10, a sprinkler head, an inlet 13 before exhaust gas treatment, an outlet 17 after exhaust gas treatment, and the like. Firstly, the influent exhaust gas is introduced into the scrubber, so that the organic pollutants in the exhaust gas are transferred to the washing liquid, and then react with the dissolved ozone and hydroxyl radicals in the washing liquid for oxidative decomposition. The aforementioned washing tower can be a vertical or horizontal packed tower, a Venturi tower, a sieve tray tower, and the like. The windmill 12 for collecting exhaust gas can be installed at the front end of the inlet before the exhaust gas treatment, or at the rear end of the outlet after the exhaust gas treatment, depending on the situation.

The oxidation treatment unit is used to receive the washing liquid from the washing tower, and introduce an oxidant containing ozone into the washing liquid for oxidation reaction. The oxidation treatment unit of the present invention includes at least one oxidation tank 6, 7, and at least one oxidizing agent inlet 4, 5 is arranged in the oxidation tank for introducing ozone into the oxidation tank to carry out oxidation reaction with the organic pollutants in the washing liquid. The washing liquid is introduced into the advanced oxidation reaction tanks 6 and 7 through the circulating pump 11 to mix with the oxidizing agent to carry out the oxidation reaction and monitor the water quality of the washing liquid to maintain the pH value between 8 and 11. The oxidant is introduced at the front end of the reaction tank, and the contact mode between the washing liquid and the oxidant can be co-current or counter-current. The aforementioned oxidant is ozone or ozone plus hydrogen peroxide. The aforementioned reaction tank can be vertical or horizontal. There is at least one reaction tank or two or more in series. And each reaction tank should be equipped with more than one oxidant inlet, and then through the fine bubble aeration device 4, 5 to dissolve the ozone in the washing liquid, or design the reaction tank as a packed tower to increase the utilization of ozone gas Rate.

The reflux device 8 is used to re-introduce the reacted washing liquid into the washing tower body 10 for absorbing pollutants in the exhaust gas. .

The exhaust gas treatment equipment of the present invention may further include an outflow pipeline (not shown), which is used to partially introduce the reacted washing liquid into the waste water pool, avoid the accumulation of carbonate produced by the reaction, and reduce the hydrogen and oxygen free radicals produced by ozone efficiency.

In addition, the present invention also includes the monitoring of the water quality of the washing liquid and the waste gas treatment monitoring system 19. The positions for monitoring the concentration and treatment efficiency of the waste gas inflow are the waste gas inlet 14 and the waste gas outlet 16 of the scrubber; the position for monitoring the water quality of the washing liquid is the oxidation tank The washing liquid inlet 18 and outlet 22. Control the water quality and quantity of the circulating washing liquid entering the advanced oxidation tank, monitor and control the concentration of exhaust gas, treatment efficiency, ozone supply, etc. Dosing (including hydrogen peroxide and sodium hydroxide) systems 20 and 21 provide the above solutions to adjust the water quality of the washing liquid. The oxidizing agent supply system 2 supplies the oxidizing agent of the above-mentioned solution. According to the monitoring value of the exhaust gas inflow and outflow concentration and the set value of the treatment efficiency, it can be used as a reference for the increase or decrease of the oxidant supply in the washing liquid. When the inflow concentration increases or the efficiency decreases, the oxidant supply is increased; when the inflow concentration decreases or When efficiency increases, reduce oxidizer supply.

The above-mentioned advanced oxidation reaction tank is designed according to the composition of the waste gas, the number of tanks of the advanced oxidation reaction tank or the way of oxidant introduction. When the removal rate of pollutants and oxidants in the waste gas does not need to be too high, such as less than 80%, the reaction tank can be designed One tank or one section of oxidant inlet; when the removal rate is required to be higher, the reaction tank can be designed as multiple tanks, the combination method is series connection, or multiple sections of oxidant inlet are set in a single oxidation tank. As shown in Figure 2, it is a single-stage oxidant distribution/single-tank oxidation tank design. As shown in Figure 3, it is a single-stage oxidant distribution/multi-tank oxidation tank design method. As shown in Figure 4, it is a multi-stage oxidant distribution/single-tank oxidation tank design. As shown in Figure 5, it is a multi-stage oxidant distribution/multi-tank oxidation tank design method. According to the present invention, the residence time of each tank or each section of the above-mentioned advanced oxidation reaction tank is preferably about 2-10 minutes.

Compared with the currently existing organic waste gas treatment technology, the treatment method of the present invention has the following advantages:

1. The present invention can completely overcome the high-boiling-point substance clogging problem and the risk of fire in the concentrated incineration technology (the mainstream technology of the semiconductor industry at present).

2. The present invention uses oxidation technology to recycle the washing liquid, overcomes the problem of a large amount of waste water discharge in traditional wet washing, and improves the treatment efficiency, economy, scope of application and system control mode of the traditional wet washing absorption technology for treating odor and organic waste gas at present .

3. The present invention uses _O3 as the oxidizing agent to enhance the oxidation power, and utilizes the design of oxidation and washing tank separation to make effective use of the oxidizing agent, increase the efficiency of VOC waste gas treatment, and improve the treatment of organic matter by traditional oxidation washing.

4. The present invention utilizes the multi-stage _O3 oxidation reaction tank design to control the amount of gas phase _O3 transported to the liquid phase according to the reaction rate of organic matter, so as to increase the _O3 utilization rate of traditional _O3 oxidation technology. And it operates under normal pressure, no pressurization device is needed, and the design and maintenance of the reaction tank are easy.

5. The present invention can increase the generation of OH free radicals by controlling the operating conditions (pH value), thus increasing the oxidation power and treatment efficiency of the prior art.

6. The present invention uses the control of the frequency of changing the washing liquid to reduce the interference of carbonates and increase the efficiency of hydrogen and oxygen free radicals produced by ozone, thus increasing the treatment efficiency of the prior art.

7. The present invention integrates the traditional wet washing tower, multi-stage O ₃ oxidation reaction tank design and operating condition control to improve oxidation efficiency and save floor space. The waste gas to be treated is absorbed by the circulating washing liquid when it passes through the washing tower, and the dissolved pollutants can be decomposed by chemical oxidation by the oxidant in the high-efficiency oxidation reaction tank, and the pH value control is used to improve the removal efficiency of VOC and the oxidant utilization rate. In addition to providing the above chemical reactions, the high-efficiency oxidation reaction tank also provides the function of monitoring and adjusting the water quality entering the high-efficiency oxidation reaction tank. And use the system control method to improve the utilization rate of oxidant and the treatment efficiency of organic pollutants.

The embodiment of the present invention is to test the waste gas containing VOC in the semiconductor industry. The main components of the waste gas from the semiconductor factory A are MEK and IPA, and the total hydrocarbon concentration is about 100-200ppmv asmethane. The main source of waste gas from semiconductor factory B is the photoresist stripper ACT690, the composition is DMSO (dimethyl sulfoxide), and the total hydrocarbon concentration is about 35 ppmv as methane. The oxidant is O ₃ , and the design and aeration method of the oxidation reaction tank used in the test of the semiconductor factory A is one-stage. The design and aeration method of the oxidation reaction tank used in the test of the semiconductor factory B is a two-stage type. The test conditions and test results are shown in the table below. exhaust gas source Oxidation tank design method Ozone supply (g/hr) H ₂ O ₂ supply (g/hr) Handling air volume (CMM) Average concentration after treatment (ppmv) Average concentration before treatment (ppmv) average processing efficiency Semiconductor factory A section 30 0 0.7 31 115 73% Semiconductor factory A section 7 1.4 1.4 74 187 60% Semiconductor factory B second stage 3 0.3 1.7 4.3 28.8 85%

Compared with the traditional wet scrubbing technology, the efficiency of organic waste gas treatment under long-term operation is compared in the following table: exhaust gas source The treatment technology of the present invention*traditional wet washing technology average processing efficiency average processing efficiency Semiconductor factory A 73% 30% Semiconductor factory B 85% 10%

*Purely use water as absorbent without adding any additives

In the present invention, the comparison of the organic waste gas treatment efficiency of the waste gas of the semiconductor factory A under the conditions of different pH values of the washing liquid is as follows: pH value 7 10 Processing efficiency 30% 73%

According to the present invention, the water carbonate content and organic waste gas treatment efficiency of the waste gas of semiconductor factory A are compared as follows under different washing liquid water exchange frequencies: Washing liquid water change frequency 60 liters/day 180 liters/day Carbonate treatment efficiency 600ppm52% 100ppm73%

The present invention compares with the traditional _O3 oxidation technology, the _O3 gas concentration and the _O3 utilization rate at the waste gas treatment discharge outlet are compared in the following table under long-term operation: Processing technology of the present invention Traditional O ₃ Oxidation Technology Concentration O ₃ utilization rate of exhaust gas outlet O ₃ 0.03ppmv>99.9% 3000ppmv90%

Note: The inflow O ₃ gas concentration is 30000ppmv

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in this art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, The scope of protection of the present invention should be defined by the scope of the appended patent application.

Claims (18)

1. a waste gas treatment equipment is applicable to and handles the organic exhaust gas that contains VOC, it is characterized in that comprising:

(a) scrubbing tower in order to receive described organic exhaust gas, transfers in the cleaning solution organic pollution in this waste gas;

(b) an oxidation processes unit that comprises ozonation aerated device, in order to receiving cleaning solution from scrubbing tower, and the oxidant that will contain the ozone that produces by this ozonation aerated device import in this cleaning solution with cleaning solution in organic pollution carry out oxidation reaction; And

(c) reflux is circulated to above-mentioned scrubbing tower in order to the cleaning solution with above-mentioned oxidation processes unit, as the usefulness that absorbs the pollutant in the waste gas.

2. waste gas treatment equipment as claimed in claim 1 is characterized in that described scrubbing tower is vertical or horizontal.

3. waste gas treatment equipment as claimed in claim 1 is characterized in that more comprising a medicine system, and to make the pH value of cleaning solution be to maintain between the 8-11 in order to medicament is imported this oxidation trough.

4. waste gas treatment equipment as claimed in claim 1 it is characterized in that described oxidation processes unit comprises at least one oxidation trough, and this oxidation trough has at least one oxidant introducing port.

5. waste gas treatment equipment as claimed in claim 1 is characterized in that described oxidation processes unit is two or two above oxidation trough series connection.

6. waste gas treatment equipment as claimed in claim 1 is characterized in that more comprising an outflow tube road, in order to the part cleaning solution is derived this system.

7. waste gas treatment equipment as claimed in claim 1 is characterized in that more comprising an exhaust-gas treatment monitoring system.

8. a processing method that contains the VOC organic exhaust gas is characterized in that comprising the following steps:

(a) organic exhaust gas is imported a scrubbing tower, absorb organic pollution in this waste gas with cleaning solution;

(b) the described cleaning solution that contains pollutant is imported at least one oxidation trough, mix with the oxidant that comprises ozone and carry out oxidation reaction; And

(c) above-mentioned reacted cleaning solution is imported in the above-mentioned scrubbing tower again, and the repeating step (a) and (b).

9. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that the organic contamination system of described organic exhaust gas is selected the group that forms from following: ester class, ethers, aldehydes, alcohols, ketone and organic acid.

10. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that more comprising in the described organic exhaust gas stink composition nitrogenous in the molecular structure, element sulphur.

11. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that described oxidant more comprises hydrogen peroxide.

12. the processing method that contains the VOC organic exhaust gas as claimed in claim 8, the way of contact that it is characterized in that described oxidant and cleaning solution are concurrent or incorgruous stream.

13. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that describedly at step (b), the pH value of this cleaning solution maintains between the 8-11.

14. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that described oxidation trough has at least one oxidant introducing port.

15. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that described oxidation trough is series connection more than two or two.

16. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that described cleaning solution is 2-10 minute at the hydraulic detention time of each oxidation trough.

17. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that more comprising in step (c) the part cleaning solution is derived this system.

18. the processing method that contains the VOC organic exhaust gas as claimed in claim 8 is characterized in that described organic exhaust gas is the waste gas that manufacture of semiconductor produced.