KR20200017232A - Processing system for industrial gases comprising fluorine gas and method for treating fluorine gas using thereof - Google Patents

Abstract

The present invention relates to a fluorine-based industrial gas treatment system, which comprises: a burner unit mounted with a toxic gas inlet, a fuel inlet, an air inlet for combustion, a pilot burner, a burning chamber, a UV sensor, a pressure sensor, a temperature sensor, and an LNG pipe; a filter dust collector (bag-filter); an adsorption tower mounted with an absorbent solution supply nozzle including a filling material which is an absorbent in a tower and spraying an adsorbent solution, and including an absorbent which is a filling material in the tower to increase the contact efficiency of gas and liquid in a horizontal type; a water film type wet electrostatic precipitator for removing acidic mist by condensation generated when supersaturated moisture and high-concentration toxic gas are removed from the inside of the adsorption tower; and a plate type heat exchanger having a white smoke reducing function.

Description

Processing system for industrial gases comprising fluorine gas and method for treating fluorine gas using

The present invention relates to a fluorine-based industrial gas treatment system and a method for treating fluorine-based industrial gas using the same.

The distribution and production of special gases used in the development of the semiconductor and advanced display industries is increasing, and the purchase and use of special gases is being made at small scales in research institutes, universities, or companies.

Due to the industrial development of such semiconductors and advanced displays, treatment of residual gas remaining after use is emerging as a new problem.

In particular, special gases used in these industries are very toxic such as high pressure, explosion, flammability, strong acid or alkali, so special care and handling are necessary. Among these toxic gases, the fluorinated toxic gases are very unstable and dangerous, so they are first stabilized by thermal oxidation reaction through combustion, and then discharged through dust collection and gas absorption processes, but the high concentration of HF acid gases generated during gas absorption processes. The micro mist is generated through the condensation of acid gas (Acid Dew) by the contact of gas and liquid in the absorption tower. The particle size of generated fine mist is in the range of 0.3 ~ 3㎛ and is discharged at the rear of the duct, and it is possible to remove harmful substances such as generation of odorous substance OF2, white smoke, fluorine compound's efficiency and ultra fine particle discharge and environmental degradation. Generate.

Accordingly, the present inventors have applied fluorine-based industrial gas using a water film type wet electrostatic precipitator and special activated carbon at the rear of the absorption tower in order to efficiently remove hydrogen fluoride (HF) and fine mist particles, which are a problem in the semiconductor and advanced display industries. The present invention has been completed by developing a treatment system.

Republic of Korea Patent Publication No. 10-2005-0040176

Accordingly, an object of the present invention is to provide a fluorine-based industrial gas treatment system in which a water film type wet electrostatic precipitator and special activated carbon are applied to the rear end of an absorption tower.

In order to achieve the above object, the present invention, a toxic gas inlet, fuel inlet, combustion air inlet, pilot burner, burning chamber, UV sensor, pressure sensor, temperature sensor and burner unit is installed LNG; Bag filters; bag filters; An adsorption tower including a filler as an adsorbent in the tower and having an absorbent liquid supply nozzle for spraying the absorbent liquid, and including an adsorbent as a filler in the tower so as to improve the contact efficiency between the gas and the liquid in a horizontal type; Water film type wet electrostatic precipitator for removing acid mist due to condensation generated when supersaturated water and high concentration of toxic gas are removed in the adsorption tower; And a plate heat exchanger having a white smoke reduction function.

In one embodiment of the present invention, the fluorine-based industrial gas may be a fluorine-based compound fluorine, boron trifluoride, silicon tetrafluoride or tungsten hexafluoride.

In one embodiment of the present invention, the bag filter (bag filter) is a combustion gas discharged through the burner is introduced into the lower end of the filter dust collector and the combustion gas passes through the filter cloth, the dust of the filter dust collector It may be to remove dust and harmful gas adhering to the filter dust collector by back pressure so that the air purified in the dust collecting process flows in the opposite direction by pulsed compressed air at the upper end.

In one embodiment of the present invention, the absorbent liquid sprayed by the absorbent liquid supply nozzle located at the top of the adsorption tower may be KOH.

In one embodiment of the present invention, the water film type wet electrostatic precipitator forms a water film by continuously flowing water to the dust collecting electrode, and applies a negative charge high voltage of direct current (DC) to a discharge electrode containing a plurality of discharge pins. The negative charge is applied to the acid mist passing between the dust collector and the discharge electrode to induce and attach the acid mist toward the dust collector having the positive electrode property to continuously remove the dust attached to the dust collector. Can be.

In one embodiment of the present invention, the upper part of the water film type wet electrostatic precipitator contains a special activated carbon to process the residual low concentration of residual gas to be discharged to the F2 gas and OF2, the special activated carbon is hollow cylindrical shape And the specific surface area (BET) may be more than 900m ² / g.

In one embodiment of the present invention, the plate heat exchanger is composed of a heat transfer panel having a honeycomb cross-sectional area, the heat transfer panel has two outer wall and two ends of the outer wall and the plate-shaped spaced so as to form a through hole therein along the longitudinal direction It may be formed of an end wall for forgetting, the interior of the through-hole may be formed in a plurality of gaps for forgetting the outer wall in the honeycomb cross-sectional shape so as to widen the heat transfer area of the external air passing through.

The fluorine-based industrial gas treatment system provided by the present invention has an effect of safely and efficiently removing fluorine-based compounds generated in industrial gas by applying a water film type wet electrostatic precipitator and special activated carbon to the rear end of the absorption tower.

Figure 1 shows a schematic diagram of a burner of one configuration in the fluorine-based industrial gas treatment system of the present invention.
Figure 2 shows a schematic diagram of a bag-filter of one configuration in the fluorine-based industrial gas treatment system of the present invention.
Figure 3 shows a schematic diagram of the adsorption tower of one configuration in the fluorine-based industrial gas treatment system of the present invention.
Figure 4 shows a schematic diagram of a water film type wet precipitator of one configuration in the fluorine-based industrial gas treatment system of the present invention.
Figure 5a shows the principle of the conventional white smoke reduction device, Figure 5b shows the principle of white smoke reduction using the De-plumer of the present invention.
Figure 6 shows a schematic diagram of the de-Plumer for reducing white smoke as one configuration in the fluorine-based industrial gas treatment system of the present invention.
7 is a schematic diagram showing the entire system process of the fluorine-based industrial gas treatment according to the present invention.
8 is a schematic view showing the process from the entire process of the fluorine-based industrial gas treatment of the present invention to the adsorption tower treatment.
9 is a schematic view showing the process from the water film type wet scrubber to the last process after the adsorption tower in the entire process of the fluorine-based industrial gas treatment of the present invention.

The present invention relates to a fluorine-based industrial gas processing system that can safely and efficiently process fluorine-based industrial gas generated in the semiconductor and advanced display industry, specifically, the fluorine-based industrial gas processing system of the present invention is a toxic gas inlet, A burner unit equipped with a fuel inlet, a combustion air inlet, a pilot burner, a burning chamber, a UV sensor, a pressure sensor, a temperature sensor, and an LNG pipe; Bag filters; bag filters; An adsorption tower including a filler as an adsorbent in the tower and having an absorbent liquid supply nozzle for spraying the absorbent liquid, and including an adsorbent as a filler in the tower so as to improve the contact efficiency between the gas and the liquid in a horizontal type; Water film type wet electrostatic precipitator for removing acid mist due to condensation generated when supersaturated water and high concentration of toxic gas are removed in the adsorption tower; And a plate heat exchanger having a white smoke reduction function.

Detailed description of each component constituting the system of the present invention is as follows.

First, a burner is provided with a pilot burner at an inlet of fluorine gas, and the burner is fueled by LNG containing methane as a main component. In the vicinity of the pilot burner, the upper part of the combustion furnace and the upper side of the upper part of the furnace, a toxic gas inlet is installed to inject toxic gas at an appropriate angle so that the process gas is introduced into the combustion furnace so that the pilot burner and the flame can be mixed.

The burner may be provided with a combustion gas inlet through which combustion gas is supplied, and the supplied combustion gas is used as a fuel to form a flame in the burning chamber. The combustion gas inlet may be provided at the top of the burner, and supplies the combustion gas to the burner at a constant pressure and flow rate. Also, the supplied combustion gas may flow in the downward burning chamber direction, and is ignited in the burner to generate a flame for combustion of the process gas in the burning chamber.

The burning chamber is located under the burner, and the chamber is provided with a space for combustion of the processing gas. The process gas is burned in the burning chamber by the flame generated in the burner, and powder may be produced in the process. Hazardous substances contained in the process gas are pyrolyzed in powder form, and the resulting powder may be collected by flowing to the bottom of the burning chamber, and a separate processing unit may be connected to the bottom of the burning chamber to collect the powder.

In addition, a space formed inside the burning chamber has a reducing combustion section for reducing the processing gas using methane, and an oxidation combustion section for converting a large amount of gas by air injection into carbon dioxide is positioned below the reducing combustion section.

In addition, in combustion, the refractory material is heated while injecting the theoretical air amount necessary for fuel and complete combustion to stabilize the combustion chamber temperature at 650 ° C or higher, and the refractory used is high purity to withstand high temperature, corrosion and corrosion resistance. A refractory of 80% of alumina was applied.

A schematic diagram of the burner as one component in the system of the present invention is shown in FIG. 1.

In the description for the operation of the burner according to the present invention of Figure 1, the processing gas is a fluorine gas, a vertical type of heat storage direct burning type, a safety device UV sensor (detecting the flame state of the flame to detect Not Flame ), Pressure sensor (detection of static pressure abnormality by detecting dust accumulation at the bottom of chamber), temperature sensor (temperature sensor to detect fire in case of fire due to abnormal operation), LNG pipe (pressure gauge installed Is detected).

In addition, in the case of the toxic gas inlet, gas such as F2, SiF4, BF4 or WF6 is injected and N2 is applied to the double pipe to prevent clogging.

The LNG supply allows fuel to be supplied at a pressure of about 300mmAq and is operated in ignition mode, heating mode, operation mode and fire mode. N2 is supplied to the Purge N2 pipe at the LNG supply port and the toxic gas inlet, and the double pipe structure prevents clogging.

The primary combustion air inlet (Combustion Air) injects the primary combustion air to supply the air necessary for complete combustion. The other secondary combustion air inlet located at the bottom of the primary combustion air inlet injects secondary combustion air, and can receive oxygen insufficient in the injection of toxic gas through the secondary combustion air, and in the operation mode, TE-401 Depending on the temperature of the supply may vary. Cooling Air is interlocked according to TE-402's temperature and is always operated to keep the temperature of exhaust gas after burner below 120 ℃.

In addition, the combustion reaction for each gas type is as shown in Table 1 below, HF as the gas phase, oxide of the fluorine compound is generated in the particulate phase.

Type of gas Combustion reaction F2 2F ₂ (g) + CH 4 (g) + O ₂ (g) = 4HF (g) + CO ₂ (g) BF3 4BF ₃ (g) + 3CH ₄ (g) + 6O ₂ (g) = 2B2O ₃ (s) + 12HF (g) + 3CO ₂ (g) SiF4 SiF ₄ (g) + 2O ₂ (g) + CH ₄ (g) = SiO ₂ (s) + 4HF (g) + CO ₂ (g) WF6 2WF ₆ (g) + 6O ₂ (g) + 3CH ₄ (g) = 2WO ₃ (s) + 12HF (g) + 3CO ₂ (g)

In addition, in treating the fluorine gas in the gas chamber, the gas chamber is partitioned and ventilated to the fluorine gas treatment system so that no damage occurs in case of gas leakage from the fluorine gas cylinder discharge cabinet and the gas chamber, and is divided into high concentration and low concentration according to the gas concentration. Thus, a high concentration of gas discharged from the cylinder is to be supplied to the combustion furnace, and the ventilation gas discharged from the cabinet and the gas room hood is divided into low concentrations to be treated with a scrubber.

In addition, the high concentration pipe supplied from the fluorine gas cabinet to the combustion furnace was supplied safely when leaking by using a double pipe. Among the double pipes, STS316 was used for the inner pipe and STS304 pipe was used for the external pipe. The double pipe was filled with nitrogen so that the gas could be shut off automatically due to the pressure change when the gas leaked in the pipe.

In addition, in order to safely treat the fluorine gas cylinder, N2 purge was carried out at least five times to replace the remaining bottle inside the cylinder.In this case, the initial exhaust concentration was 100% and the cylinder was supplied and replaced by n times N2 purge (P2 / P1) ⁿ to reduce the exhaust concentration to be able to safely handle the cylinder, the concentration reduction effect according to the number of N2 purge is as shown in Table 2 (pressure is maintained absolute pressure).

Count density Remarks First exhaust One 100% concentration 1 substitution (P2 / P1) 1 2 substitutions (P2 / P1) 2 3 substitutions (P2 / P1) 3 4 substitutions (P2 / P1) 4 5 substitutions (P2 / P1) 5

Next, the incident field material discharged through the burner is introduced into a bag filter and removed.

The role of the filter dust collector is to remove dust from the combustion gas and to remove dust and harmful gas on the surface of the filter bag while passing the combustion gas through the filter cloth. The collected branches are dust of fluorine oxide and exist as dry powder.

The material of the filter used for the dust collector may be a surface coated with PTFE in the fiber class, it can be used up to a temperature of 160 ℃. In addition, the dust is pulsed by using the compressed air at the upper end of the filter bag, and by inflating by back pressure so that the air flows in the opposite direction of the purified air flow during the dust collection process, the dust attached to the filter outer wall falls to the lower hopper. The schematic diagram of the said filter dust collector used by this invention is shown in FIG.

Thereafter, the gas from which the particulate contaminants are removed by the above process is introduced into the adsorption tower to remove toxic gases from the adsorption tower. The adsorption tower according to the present invention is filled in the tower so as to improve the contact efficiency between the gas and the liquid in a horizontal type. (Adsorbent) and spray absorbent (KOH) to absorb toxic gases. The neutralization reaction of the toxic gas by KOH as an absorption liquid is shown in Table 3 below.

Type of gas Neutralization (absorption) F2 4HF (g) + 4KOH (aq) = 4KF (s) + H20 (l) BF3 B 2 O 3 (s) + 6H 2 O (l) = 2H 3 BO 3 (s) +.
2H3 BO3 (s) + 6KOH (aq) = 2K3 BO3 (l) +. SiF4 4HF (g) + 4KOH (aq) = 4KF (s) +. WF6 12HF (g) + 12KOH (aq) = 12KF (s) +.

The body of the adsorption tower is made of FRP (unsaturated polyester resin and glass fiber) with excellent acid resistance, and the internal filler used Tri Pack 2 as polypropylene (PP) material. Moreover, the nozzle which supplies an absorption liquid is attached to the upper part. In the packed layer containing the absorbent liquid, the harmful gas and the absorbent liquid are in contact with the gas-liquid to increase the absorption efficiency of the harmful gas, and the clogging caused by the particles can be reduced due to the continuously supplied absorbent liquid.

On the other hand, the condensation generated when the supersaturated water in the adsorption tower and the high concentration of fluorinated gas (HF) is removed generates an acid mist, and the generated acid mist is removed by a water film type wet electrostatic precipitator.

Water film type wet electrostatic precipitator according to the present invention to form a water film (Water Film) by continuously flowing water to the dust collector to remove the acid mist, by applying a negative charge high voltage of direct current (DC) to the discharge electrode having a plurality of edges The negative charge is applied to the acid mist passing between the dust collecting electrode and the discharge electrode, and has the principle of inductively attaching it to the dust collecting electrode having a relatively positive electrode property. It has a feature that can be removed by using.

Specifically, a schematic view of the water film type wet electrostatic precipitator according to the present invention is shown in FIG. 4, and as shown in FIG. 4, harmful gas containing dust flows into the lower side of the electrostatic precipitator and undergoes a purification process from the inside to the upper side. It is discharged wet electrostatic precipitator. At the lower end of the wet electrostatic precipitator, a gas inlet through which noxious gas flows is formed, a water tank is formed at the inner bottom part, and a gas outlet at which the purified gas is discharged is formed at the upper end part. Inner upper and lower parts of the water film type wet electrostatic precipitator of the present invention are provided with an upper injection part and a lower injection part for transferring water of a water tank through a pump and spraying downward and upward through a plurality of nozzles, respectively, with an automatic valve.

In addition, a plurality of upper supports are horizontally coupled to the lower side of the upper injection unit at intervals back and forth, and the upper supports are connected to a high voltage supply device. A plurality of discharge electrodes are vertically coupled to the upper support at intervals left and right, and a plurality of discharge pins are coupled to the outer peripheral surface of the discharge electrode at intervals vertically.

The body and internal dust collecting plate of the water film type wet electrostatic precipitator are made of FRP (unsaturated polyester resin and glass fiber), and the applied water film nozzle is a viton. SUS316L is made up of a number of discharge pins attached to the round bar.

Furthermore, special activated carbon (Charcoal), which is the last stage of gas treatment, processes the final low concentration of residual gas, and its components are discharged to F2 gas and OF2. OF2 gas is a odor-causing substance at a very low ppm concentration and is removed by the final special activated carbon. The reaction scheme is as follows.

2F ₂ + C → CF ₄

2OF ₂ + 2C → CF ₄ + CO ₂

The special activated carbon used at this time can be operated at low differential pressure by increasing the porosity in the hollow cylindrical shape, and the specific surface area (BET) is used with more than 900m ² / g.

On the other hand, the hot exhaust gas passing through the burner is cooled while passing through the wet absorption tower and the humidity becomes high. In general, the exhaust gases emitted from the combustion process such as incinerators or boilers are introduced with a wet scrubber system in order to prevent pollution at the final stage, and the temperature reduction in the wet system of exhaust gases discharged at a high temperature (150 to 300 ° C.) In the absence of heat exchange with, it is merely an adiabatic cooling process in which sensible heat is converted to latent heat. As a result, the exhaust gas is cooled to 40 to 80 ° C but is discharged at a very high absolute humidity. At this time, the hot and humid exhaust gas discharged to the relatively cold outside condenses into fine droplets in the atmosphere, scatters visible light, and white smoke occurs as if white smoke is emitted from the chimney.

According to the Figure 5a of the present invention, in the exit state of the wet absorption tower reaches the saturation line and when discharged to the cold outside air is cooled along the process line (2 → 3), if the upper portion of the saturation line of the process line, that is, past the supersaturation region Condensation and condensation may occur and fine water droplets may form, causing white smoke.

Therefore, when using the De-plumer in the state of the rear end of the wet absorption tower reaching the saturation point to remove and reduce the white smoke phenomenon, as shown in Figure 5b by heat exchange with the outside air to reach the two points along the shot line and heated exhaust Is mixed to lower the temperature and humidity to reach three points. The process line, which reaches outside conditions, passes below the saturation line from point 3 to point 4, eliminating and reducing white smoke.

Here, De-Plumer for reducing white smoke can use a plate heat exchanger, and is composed of a heat-transfer panel having a honeycomb cross-sectional area made of polyethylene (PE) with excellent corrosion resistance. The white smoke phenomenon can be suppressed by cooling the wet and hot exhaust gas by exchanging heat with the outside air. A schematic diagram of the De-Plumer for reducing white smoke is shown in FIG. 6.

De-Plumer for reducing white smoke according to the present invention is connected to the chimney end of the incinerator or boiler, and the exhaust gas is ventilated through the first vent formed through the upper and lower respectively, and the outside air is vented through the blowing fan. Two air holes are provided in the housing formed on the left and right of the enclosure, respectively. Therefore, first and second air holes through which exhaust gas passes are formed on the upper and lower sides of the housing, respectively, and second air holes through which external air passes. A plurality of coupling holes are arranged in which both ends of the plurality of heat transfer panels provided inside the enclosure are separated from each other so that the external air vented through the second vent hole is not diluted with the exhaust gas vented through the first vent hole. The separators are formed in the left and right sides of the enclosure adjacent to the second vent hole. Both ends are coupled to the separator and provided inside the enclosure, and the exhaust gas vented through the first vent hole and the outside air vented through the second vent hole are insulated from each other. A plurality of heat transfer panels having a through hole through which the outside air sucked through the second vent hole to the heat exchange is provided in the is provided.

The heat transfer panel is composed of two outer wall spaced plate-shaped so as to form a through hole therein along the longitudinal direction and an end wall that forgets both ends of the outer wall, and the heat transfer area of the outside air passing through the inside of the through hole is wide. In the honeycomb cross-sectional shape, a plurality of partition walls forgetting the outer wall are formed at intervals.

In addition, the structure of the honeycomb cross-sectional shape having a through hole in the cross section is structurally strengthened by the partition wall installed on the air side even if the heat transfer thickness of the heat transfer panel is thin, and even when the heat transfer panel is welded to the separator, Structural safety can be secured.

The fluorine-based industrial gas treatment system of the present invention comprising the above configuration is a gaseous pollutant (HF) that can be discharged from the duct when treating toxic fluorine gas, ultrafine PM2.5 or less, hydrofluoric acid mist, OF2 odor gas Or you can safely remove white lead.

As described above, the overall process diagram of the fluorine-based industrial gas treatment system according to the present invention is shown in Figure 7, the process from the entire process diagram to the adsorption tower is shown in Figure 8, from the water film type wet scrubber to the final process after the adsorption tower The process of is shown in FIG.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the appended claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims (5)

A burner unit equipped with a toxic gas inlet, a fuel inlet, a combustion air inlet, a pilot burner, a burning chamber, a UV sensor, a pressure sensor, a temperature sensor, and an LNG pipe;
Bag filters; bag filters;
An adsorption tower including a filler as an adsorbent in the tower and having an absorbent liquid supply nozzle for spraying the absorbent liquid, and including an adsorbent as a filler in the tower to improve the contact efficiency between the gas and the liquid in a horizontal type;
Water film type wet electrostatic precipitator for removing acid mist due to condensation generated when supersaturated water and high concentration of toxic gas are removed in the adsorption tower; And
Includes; plate-type heat exchanger having a smoke reduction function
Fluorine-based industrial gas treatment system. The method of claim 1,
The filter bag (bag-filter) is a combustion gas discharged through the burner flows into the lower end of the filter dust collector and passes the combustion gas through the filter cloth, when the dust is pulsed with the compressed air at the upper end of the filter dust collector to clean in the dust collection process And back pressure so that the compressed air flows in the opposite direction to remove dust and harmful gases adhering to the filter dust collector. The method of claim 1,
The water film type wet electrostatic precipitator forms a water film by continuously flowing water to the collecting electrode, and applies a negative charge high voltage of direct current (DC) to a discharge electrode containing a plurality of discharge pins, and passes between the collecting electrode and the discharge electrode. A fluorine-based industrial gas treatment, characterized in that a negative charge is applied to an acid mist to induce and attach an acid mist toward a dust collecting electrode having a positive electrode property to continuously remove dust attached to the dust collecting electrode. system. The method of claim 1,
The upper part of the water film type wet electrostatic precipitator contains special activated carbon to process the final low concentration residual gas to be discharged to F2 gas and OF2. The special activated carbon has a hollow cylindrical shape and a specific surface area (BET) of 900 m2 / The fluorine-based industrial gas treatment system, characterized in that more than g. The method of claim 1,
The plate heat exchanger is composed of a heat transfer panel having a honeycomb cross-sectional area, the heat transfer panel is composed of two plate-shaped spaced outer walls and end walls forgetting both ends of the outer wall so as to form a through hole therein along the longitudinal direction. A fluorine-based industrial gas processing system, characterized in that a plurality of partition walls forgetting the outer wall are formed in the honeycomb cross-sectional shape so as to widen the heat transfer area of the outside air passing through the ball.

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