KR20190085358A - An apparatus and a method for removing harmful fluoride by using aqueous methanol solution - Google Patents

Abstract

The present invention relates to a method which effectively removes harmful fluorine compounds such as perfluorocarbons, sulfur hexafluoride (SF_6), and nitrogen trifluoride (NF_3), discharged from semiconductor, solar cells, light emitting diodes and display manufacturing industries. The method for removing harmful fluorine compounds with a series of continuous processes comprises the steps of: efficiently recovering heat energy inside a continuous process to generate promotion gases containing hydrogen and steam in order to effectively remove the harmful fluorine compounds at a lower temperature; and promoting hydrogenation or hydrolysis of the harmful fluorine compounds by the promotion gases, and decomposing and converting the same into a simple fluorine compound capable of being easily removed in a follow-up step. According to the present invention, the present invention has a very high energy efficiency, does not need any external facilities for supplying fuels or promotion gases, and is implemented as an integrated small device which minimizes heat exchange capacities and the use of insulation members, thereby reducing investing costs and operating costs in terms of economic aspects, and expanding an application range in terms of industrial aspects.

Description

[0001] The present invention relates to an apparatus and a method for removing harmful fluorine compounds using an aqueous methanol solution,

The present invention relates to the use of harmful fluoride compounds such as perfluorocarbons, SF ₆ , and nitrogen trifluoride (NF ₃ ), which are emitted after being used in semiconductors, solar cells, light emitting diodes, ) Effectively.

Fluorine compounds such as nitrogen trifluoride (NF ₃ ), perfluorocarbons and sulfur hexafluoride (SF ₆ ) are used in semiconductors, solar cells, light emitting diodes (LED) dry etching process or as a cleaning gas to remove residues in a chamber after chemical vapor deposition (CVD).

Since the above-mentioned fluorine compounds are harmful in themselves or are a greenhouse gas having a very high global warming index, if they are not sufficiently removed in the above process but are included in the process exhaust gas, they may cause safety, health and environmental problems .

Since the harmful fluorine compound has a very stable structure, it is not easily decomposed per se. However, simple fluorine compounds such as hydrofluoric acid (HF), fluorine gas (F ₂ ) and fluorine oxides It can be relatively easily removed.

Conventional known methods for decomposing and converting harmful fluorine compounds include a combustion method, a plasma decomposition method, a catalytic thermal decomposition method, a catalytic conversion method, and the like. However, some of these prior art technologies have a very low energy efficiency, Decomposition and conversion proceeds at a very high temperature, so that a large amount of heat recovery part is required to overcome low energy efficiency and it is necessary to use an excessive heat insulating material. Another problem is that installation is restricted because a separate device for supplying fuel or promoting gas is required.

For example, the combustion method is a method in which the combustion exhaust gas obtained by burning fuel of hydrocarbons first heats the process exhaust gas at a temperature of 800 ° C. or more, and then converts decomposition and conversion of harmful fluorine compounds into simple fluorine compounds And the following exhaust gas may contain carbon monoxide and nitrogen oxides such as NO, N ₂ O, and NO _{2 in} addition to a simple fluorine compound. (Korean Patent No. 10-0527284) discloses a burner designed for combustion decomposition of a fluorine compound, and another prior art (Korean Patent Laid-Open No. 10-2011-0095305) The method comprising:

In terms of chemical reactions, each stage of the combustion process can be explained as follows. First, water vapor (H ₂ O), carbon monoxide (CO), and carbon dioxide (CO ₂ ) are produced by combustion of hydrocarbons, and the product can participate in decomposition and conversion of harmful fluorine compounds. Next, the oxidation reaction and the addition reaction, which are the main reaction at the high temperature, proceed together, and the following reaction schemes 1 to 3 are the main reactions.

[Reaction 1] 2NF ₃ + O ₂ ? 2NO + 3F ₂

[Reaction 2] 2NF ₃ + 3H ₂ O → NO + NO ₂ + 6HF

[Reaction Scheme 3] 2F ₂ + 2H ₂ O → 4HF + O ₂

The simple fluorine compound contained in the exhaust gas after the reaction, that is, HF or F _2, can be neutralized by passing the above-mentioned exhaust gas through a basic aqueous solution or adsorbed, absorbed or fixed to a solid material, which is one kind of adsorbent. As a result of this reaction, fluorine oxides containing a small amount of oxygen may be produced together, but these can also be removed by the application of the method described above. Carbon monoxide generated by the combustion of hydrocarbons must be converted to carbon dioxide through a separate oxidation catalyst and NO ₂ and N ₂ O generated by the additional oxidation-reduction process of NO and NO produced by the reaction formulas 1 and _{2 3} N ₂ of nitrogen oxide (NOx) such as O are to be reduced to N ₂ by selective catalytic reduction catalyst in a separate reactor.

Perfluorocarbons and sulfur hexafluoride can also be decomposed and converted in a similar manner to the above Reaction Schemes 1 to 3. In the exhaust gas after the decomposition and conversion of the perfluorocarbon gas, the exhaust gas contains a considerable amount of carbon monoxide and carbon dioxide And in the case of sulfur hexafluoride, an oxide of sulfur such as sulfur dioxide (SO ₂ ) or sulfur trioxide (SO ₃ ) or sulfuric acid may be included.

As another example of the combustion method, an electric heater may be used to supply heat energy necessary for the decomposition and conversion of harmful fluorine compounds. This method is known as an electric heating combustion method. At this time, It is necessary to provide water vapor separately with oxygen or air.

As another example, the plasma decomposition method is a method in which a process exhaust gas containing a harmful fluorine compound and an accelerated gas composed of hydrogen, ammonia, hydrocarbon, oxygen, or a mixed gas containing at least one of them are introduced into a reactor equipped with a plasma electrode And passing the mixed gas through a plasma field formed by applying a high voltage to the electrode to decompose and convert harmful fluorine compounds. Such a method is described in various prior arts (Korean Patent No. 10-0783793, Korean Patent No. 10-1527507). The result of the decomposition and conversion of the harmful fluorine compound may be different depending on the type and composition of the promoted gas. However, when oxygen is used as the accelerating gas, the result of the decomposition and conversion of the harmful fluorine compound is as follows: There is no difference. Since a plasma device requires a large amount of power and a large portion of the input power is used for heating the electrode itself rather than the gas flow, the energy required for the entire processing capacity is increased, resulting in a very low energy efficiency. And there is a disadvantage that the lifetime is reduced due to electrode erosion. In addition, there is also a problem that nitrogen (N ₂ ) introduced together with the process exhaust gas is used as a dilution gas and is simultaneously decomposed to generate a large amount of nitrogen compounds (NOx) such as N ₂ O and NO.

As another example, catalytic pyrolysis is a method in which a harmful fluorine compound and an adsorbent composed of a specific component are brought into contact with each other at a relatively low temperature to chemically fix the same at the time of decomposition and conversion. During the above process, the adsorbent is converted into a solid containing fluorine, and the fixing performance deteriorates, and the adsorbent is periodically replaced. The prior art (Korean Patent No. 10-1178918) discloses a low-temperature adsorption treatment agent containing iron oxide or iron (Fe), an alkali metal compound and an alkaline earth metal compound as an adsorption treatment agent at a temperature of 200 ° C to 600 ° C, And contacting the fluorine compound gas with the fluorine compound gas.

As another example, the catalytic conversion method can decompose and convert harmful fluorine compounds contained in the process exhaust gas at a lower temperature by using a catalyst, so that a comparable effect can be obtained while using less energy than the combustion method . Specifically, the harmful fluorine compound is decomposed and converted by oxygen at a high temperature of 800 ° C to 1,200 ° C, but when a catalyst is used, oxygen or air may be blown together to decompose and convert at 500 ° C to 900 ° C. A prior art document (Korean Patent Publication No. 1999-045278) discloses a method of decomposing an exhaust gas containing perfluorocarbon and SiF ₄ under an alumina catalyst after heating. Specifically, a nonporous alumina having a specific surface area of 150 m ² / g or less Is used. Another prior art (Korean Patent No. 10-0536479) discloses a composite catalyst for decomposing perfluorocarbons in which a transition metal is supported on porous alumina.

HF, F ₂ , or fluorine oxide produced by the decomposition and conversion of harmful fluorine compounds through the above method is a strong acidic or highly corrosive gas and may lead to a rapid catalytic activity loss. Therefore, it has excellent oxidation activity and corrosion resistance and corrosion resistance It is necessary to construct the catalyst with this very strong component. However, in spite of a lot of efforts, the problem of deterioration of the catalyst performance is not sufficiently improved, and in this industry, an expensive catalyst is periodically replaced and used, and the subsequent exhaust gas contains carbon monoxide or a large amount of nitrogen oxides Problems are also not easily improved.

Recently, studies on the effect of another accelerating gas have been carried out in an attempt to effectively remove harmful fluorine compounds at a lower temperature, and active research is underway to develop a catalyst with higher performance. Commercially available catalysts such as Ti, Si, Sn, and powders have been used to reduce the decomposition temperature of NF _{3 in} the prior literature (Chem. Mater. 1995, 7, 683-687) 2009, 7 (3), 147-150) reports the results of a study that significantly reduced the hydrolysis temperature of NF ₃ using various metal phosphates as catalysts. However, these examples are laboratory-scale studies and there are many challenges to be overcome in order to successfully apply them to actual industrial sites as well as the cases of the methods described above.

Korean Patent No. 10-0527284 Korean Patent Publication No. 10-2011-0095305 Korea Patent No. 10-0783793 Korean Patent No. 10-1527507 Korean Patent No. 10-1178918 Korean Patent Publication No. 1999-0045278 Korean Patent No. 10-0536479

Elizabeth Vileno et al., Chemistry of Materials, 1995, 7, 683-687 Takeshi Takubo et al., Catalysis Communications, 2009, 7 (3), 147-150

The above-described conventional technology can realize decomposition and conversion of harmful fluorine compounds at a lower temperature, can recover heat energy by a more effective method, and is realized as a compact, integrated device with high energy efficiency and easy installation It is difficult to provide a series of continuous processes that can be performed.

Accordingly, the present inventor has proposed a method of effectively and economically removing harmful fluorine compounds such as perfluorocarbons, nitrogen trifluoride and sulfur hexafluoride which are emitted in the course of manufacturing semiconductors, solar cells, light emitting diodes and displays We have tried to develop our example. As a result, it is possible to effectively recover heat energy in the continuous process, so that the energy efficiency is very high and it is not necessary to supply the accelerated gas from the outside, so that the present invention can be realized as a simple and compact integrated device.

An apparatus for removing harmful fluorine compounds using an aqueous methanol solution according to the present invention comprises:

(a) a second reaction unit for generating a promoted gas from an aqueous methanol solution;

(b) a mixing section for mixing the accelerated gas and the process exhaust gas from which the impurities have been removed;

(c) a first reaction part for decomposing and converting the harmful fluorine compound contained in the mixed gas obtained through the mixing part into a simple fluorine compound; And

(d) a second purifier for removing a simple fluorine compound from the gas flow discharged from the first reaction part.

The second reaction unit may include a third heat exchange unit for recovering thermal energy in the continuous process.

The second reaction unit includes a catalytic reaction unit for generating an accelerated gas by steam reforming reaction of methanol.

The mixing unit may further include a first purifying unit for pre-purifying impurities contained in the process exhaust gas.

The third purifier may further include a third purifier for removing residual ammonia, carbon monoxide, and nitrogen oxides (NOx) contained in the exhaust gas at a downstream end of the second purifier. Preferably, the third purifier includes a catalyst or an adsorbent for selectively removing the residual components. More preferably, the third purifier includes activated carbon and zeolite.

The first reaction unit includes a hydrogenation catalyst, a hydrolysis catalyst, or a catalytic reaction unit including both of them.

The hydrogenation catalyst may include metals, alloys, oxides, salts, or combinations thereof, including Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir or combinations of one or more thereof.

Wherein the hydrolysis catalyst is selected from the group consisting of a metal, an alloy, a salt, an oxide, a metal, a metal, a metal, a metal, , Hydroxides, or combinations thereof.

The first reaction unit may further include a preheating unit for preheating the mixed gas to a reaction temperature.

It is more preferable that the catalytic reacting portion includes a hydrolysis catalyst for the hydrogenation catalyst in a weight ratio of 0.1 to 10.

A method for removing harmful fluorine compounds using an aqueous methanol solution according to the present invention includes:

(a) a second reaction step of producing a promoted gas from an aqueous methanol solution;

(b) a mixing step of mixing the promoted gas with the process exhaust gas from which the impurities have been removed;

(c) a first reaction step of decomposing and converting a harmful fluorine compound contained in the mixed gas obtained through the step (b) into a simple fluorine compound; And

(d) a second purifying step of removing a simple fluorine compound from the first reaction gas discharged from the first reaction step (c).

Before the first reaction step (c), a first purifying step (cc) for pre-purifying the impurities contained in the process exhaust gas may be further included.

The second purging step (d) or the first purging step ( cc ) may be carried out using a dry method or a wet method.

(E) for removing residual ammonia, carbon monoxide, and nitrogen oxides (NOx) contained in the second purifying gas discharged in the second purifying step (d).

The third purge step (e) may be carried out in a catalytic or adsorption manner. Preferably, the third purification step (e) may be carried out using activated carbon and zeolite.

The promoting gas of the second reaction step (a) is produced through the steam reforming reaction of methanol. The steam reforming reaction of the methanol is preferably carried out by recovering thermal energy in the continuous process.

The first reaction step may be performed by a hydrogenation catalyst, a hydrolysis catalyst, or a catalytic reaction of both.

The hydrogenation catalyst may include metals, alloys, oxides, salts, or combinations thereof, including Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir or combinations of one or more thereof.

Wherein the hydrolysis catalyst is selected from the group consisting of a metal, an alloy, a salt, an oxide, a metal, a metal, a metal, a metal, , Hydroxides, or combinations thereof. If the space velocity is excessively high, the conversion rate is low, and if the space velocity is too low, the amount of catalyst used increases and the heat transfer area becomes large The space velocity (GHSV) of the first reaction part is preferably 100 to 5000 ^hr < ^-1 >.

In the meantime, it is more preferable that the first reaction step includes a hydrolysis catalyst for the hydrogenation catalyst at a weight ratio of 0.1 to 10.

The present invention relates to a method for effectively removing harmful fluorine compounds such as perfluorocarbons, sulfur hexafluoride (SF ₆ ) and nitrogen trifluoride (NF ₃ ) emitted from semiconductors, solar cells, light emitting diodes, The method comprising the steps of efficiently recovering thermal energy in a continuous process so as to effectively remove the harmful fluorine compound at a lower temperature to generate a promoted gas containing hydrogen and water vapor, To a simple fluorine compound which is easy to remove in a subsequent step by promoting the hydrogenation or hydrolysis of the fluorine compound in the subsequent step .

According to the present invention, it is possible to realize an integrated type small-sized apparatus in which energy efficiency is very high, no separate external facility for supplying fuel or promoted gas is required, use of the heat exchange capacity and the heat insulating member is minimized, The investment and operation costs can be reduced and the scope of application can be expanded in the industry.

1 schematically shows an example of a continuous process for removing harmful fluorine compounds according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

In describing the embodiments, the same designations and the same names are used, and thus overlapping additional descriptions are omitted below. In the drawings referred to below, the accumulation ratio is not applied.

The amount of thermal energy and the efficiency of thermal energy shown in the comparative examples and the examples are determined by the electrical energy required for driving various measuring instruments, compressors, pumps, controllers and the like required for the operation of the process, This is a numerical value considering only the heat energy supplied into the continuous process and the heat energy recovered in the continuous process in steady-state operation except energy.

In the following, device elements will be added in more detail, focusing on the method according to the invention.

The first purification step ( cc ): Step of pre-purifying impurities from the process exhaust gas

Step ( cc ) of the present invention can be carried out by previously removing impurities such as acidic gases such as HCl or HF, corrosive gases such as F ₂ or Cl ₂ and compounds containing silicon such as SiF ₄ contained in the process exhaust gas The purpose of which is to prevent deactivation of the catalyst, corrosion of the apparatus or piping, surface contamination of the heat exchanging part, which may be caused in the subsequent step. Specifically, process exhaust gas is introduced into the continuous process according to the present invention through process exhaust gas supply 101 of FIG. Thereafter, it is heated by the first heat exchanger 131 of FIG. 1 and introduced into the first purifier 111 of FIG. In the first purifying part, the impurities can be removed by a dry method or a wet method.

The dry method is a method for adsorbing or chemically sticking impurities contained in a process exhaust gas to a solid adsorbent such as activated carbon, metal powder, metal hydroxide or metal oxide to remove the impurities. The dry adsorption method includes a step of adsorbing the adsorbent, Lt; / RTI > tower. The adsorbent may be in the form of a powder, a molded product of a specific type, a specific support, and may be a solid composed of activated carbon, a metal powder, a metal hydroxide, a metal oxide or a combination thereof. In some cases, Or an alkaline earth metal salt or an impregnated solid. The metal hydroxide and the metal oxide may be composed of Al, Fe, Si, Ti or a combination of at least one of them, and the alkali metal and the alkaline earth metal may include Group 1 and Group 2 in the periodic table. In a special case, it may include a metal salt of an ionic organic substance or an organic metal complex.

The wet method is a method of neutralizing and removing by using an absorption liquid which is an aqueous solution in which a neutralizing agent is dissolved, by removing the solubility of the gas or passing the process exhaust gas through the absorption liquid or by spraying the absorption liquid onto the process exhaust gas Method. The absorbing solution may be an aqueous alkaline solution in which pure water, an alkali metal salt or an alkaline earth metal salt is dissolved, or an aqueous solution containing a hydrophilic organic compound. The wet scrubbing apparatus embodying the wet method may be in the form of a water tank or a tower, and may include a nozzle for spraying a filler or an absorbing liquid therein.

The purifying efficiency of the first purifying unit 111 is improved as the temperature is higher. However, if the temperature is too high, there may be problems such as deterioration of the performance of the adsorbent, evaporation of the absorbent solution, necessity of excessive heat insulating material, and so, it is preferable to maintain the temperature in the range of room temperature to 80 ° C. In this case, the heat energy necessary to maintain the above temperature is supplied through the first heat exchanging unit 131 of FIG.

The gas flow through the first purifier 111 may be top-down or bottom-up. The concentration of each impurity after being purified in the first purification section 111 is maintained at 0 to 20 ppm or less, more preferably 0 to 5 ppm or less, to prevent poisoning of the catalyst used in the first reaction section . The method of step (aa) has the economic effect of reducing the amount of absorption solution or adsorbent used, contributing to miniaturization of the apparatus and reducing operating costs.

Second reaction step (a): a step of producing an accelerated gas containing water vapor and hydrogen from an aqueous methanol solution

The second reaction step (a) of the present invention is a step of steam-reforming a mixed gas composed of water vapor and gaseous methanol to generate accelerated gas. The promoted gas includes unconverted water vapor, the reaction products hydrogen and carbon dioxide. The principle of the steam reforming reaction is shown in the following reaction formula (4).

???????? CH ₃ OH (g) + H ₂ O (g)? 3H ₂ (g) + CO ₂ (g) ? H _{2 O} = + 49.5 KJ / mol

1, the metering pump 141 of FIG. 1 continuously and quantitatively supplies an aqueous solution containing methanol and water at a specific ratio through an aqueous methanol solution supply unit 102. The methanol aqueous solution is vaporized in the fourth heat exchanger 134 of FIG. 1 to be a mixed gas composed of water vapor and gaseous methanol, and then further heated to the inlet temperature of the second reaction unit 122 of FIG. 1 . At this time, a heat exchange unit may be added between the second reaction unit 122 and the fourth heat exchange unit 134, or a separate heating device may be provided to enhance the thermal efficiency.

The mixed gas of water vapor and methanol introduced into the reactor is converted into hydrogen and carbon dioxide through steam reforming reaction as shown in Scheme 4. The conversion of methanol and the yield of hydrogen may vary depending on reaction variables such as reaction temperature, reaction pressure, and the ratio of steam to methanol. The higher the reaction temperature is, the better the range of 180 to 400 is suitable from the viewpoint of economic selection of the material of the reactor and the volume of use of the heat insulating material. The reaction pressure is preferably as low as possible, but a separate vacuum generating device is required to maintain the pressure below atmospheric pressure, and therefore, from a practical point of view, it is preferable that the pressure range is from atmospheric pressure to 10 atm or less.

The space velocity (GHSV) of the steam reforming reaction may be 100 to 20,000 hr ^-1 on the basis of standard conditions (STP). However, if the space velocity is excessively high, the conversion rate is low. If the space velocity is too low, It is practically preferable to be 500 to 5000 hr < ^-1 >.

As the catalyst for the steam reforming reaction, a catalyst composed of CuO, ZnO, and Al ₂ O ₃ may be used. However, it is preferable to use the Ce and / or La based rare earth metals, Pt, Pd and Ru It is more effective to use a catalyst containing a noble metal in the system.

Since the steam reforming reaction is an endothermic reaction, it is preferable to rapidly supply the heat required for the reaction. The heat energy required for the reaction may be supplied using a separate heating device, but in the present invention, the heat is successively recovered from the process exhaust gas discharged from the outlet of the first reaction unit 121 of FIG. 1 and the third heat exchange unit 133 ) To the second reaction part 122 composed of the preheating part and the catalytic reaction part. The second reaction unit 122 and the third heat exchange unit 133 may be designed in a specific form in order to rapidly supply the heat required for the steam reforming reaction. For example, the preheating unit and the catalyst reaction unit integrated with the heat exchange unit You may.

Mixing step (b): mixing the promoted gas with the process exhaust gas from which the impurities have been removed

The mixing step (b) of the present invention is a step of mixing the process exhaust gas from which the impurities have been removed through the first purifying step (aa) and the promoted gas generated in the second reaction step (a).

1, the outlet gas of the first purifying section 111, which has passed through the first purifying section 111 of FIG. 1 and has been purified to a range of 0 to 20 ppm of each impurity, 2 heat exchanging part 132 to be introduced into the mixing part 142. And then mixed with the promoted gas of the second reaction step (a) introduced through another inlet of the mixing part 142 to produce a mixed gas and then discharged through the outlet. In the exemplary method of the present invention, an in-line mixer is used to uniformly mix the outlet gas of the first purifier 111 and the promoted gas. However, in order to achieve the same object, May be used.

A first reaction step (c): decomposing and converting a harmful fluorine compound contained in the mixed gas produced in the mixing step (b) into a simple fluorine compound through a hydrogenation reaction and / or a hydrolysis reaction

The first reaction step (c) of the present invention promotes the hydrogenation reaction and / or the hydrolysis reaction to decompose and convert harmful fluorine compounds contained in the process exhaust gas. For example, one of the perfluorocarbons, CF ₄ , can be decomposed and converted into the simpler fluorine compounds through the following reaction pathway.

[Chemical formula 5] CF ₄ + 4H _{2 -} > CH ₄ + 4HF

???????? CF ₄ + 2H ₂ ? CH ₄ + 2F ₂ ?????

[Chemical formula 7] CF ₄ + 2H ₂ O? CO ₂ + 4HF

[Chemical Formula 8] CF ₄ + H ₂ O? CO + 2HF + F ₂

In addition to HF and F ₂ produced by decomposition and conversion according to the above Reaction Schemes 5 to 8, fluorine oxides containing carbon such as COF ₂ may be generated as another reaction pathway.

In addition, NF ₃ , a harmful fluorine compound, can be decomposed and converted through the following reaction pathway.

[Reaction Scheme 9] NF ₃ + 3H ₂ → NH ₃ + 3HF

[Formula 10] NF ₃ + 2H _{2 -} > NH ₃ + HF + F ₂

[Reaction Scheme 11] 2NF ₃ + 3H ₂ O → NO + NO ₂ + 6HF

2NF ₃ + 2H ₂ O? 2NO + F ₂ + 2HF

Similar to the case of decomposition and conversion of CF ₄ , a fluorine oxide containing nitrogen may be further generated.

On the other hand, the harmful fluorine compound SF ₆ can be converted to SO ₂ , SO ₃ , or sulfuric acid and a simple fluorine compound via a reaction path similar to the above.

1, the mixed gas discharged from the mixing portion 142 of FIG. The mixed gas is heated to a temperature of 0 to 100 or less of the reaction temperature in the preheating part so that the hydrogenation reaction and the hydrolysis reaction can proceed smoothly.

The decomposition and conversion of harmful fluorine compounds proceeds rapidly as the temperature is higher, but it is preferable to keep the reaction temperature at 250 to 600 in terms of practical use. Specifically, the reaction temperature of NF ₃ is preferably 250 to 600, the reaction temperature of the perfluorocarbon gas containing CF ₄ is preferably 300 to 600, and the reaction temperature of SF ₆ is preferably maintained at 350 to 600. If the reaction temperature is too low and the heat insulating material and the heat cost excessively increased if it exceeds 600 ^o C is difficult and degradation and conversion of the fluorine compounds.

The thermal energy required to maintain the reaction temperature of the first reaction part 121 can be supplied by burning hydrocarbons fuel, but more conveniently by electric heating.

The influence of the reaction pressure on the decomposition rate or conversion rate of the harmful fluorine compound is not great, but it is preferable to maintain the reaction pressure at 0.5 to 10 atm in order to increase the residence time in the catalyst layer and to cope with the pressure loss. If necessary, a pressurizing device, such as a compressor, may be provided at a proper position of the downstream end of the process exhaust gas inlet 101 of FIG. 1, and a suitable pressure device may be provided between the downstream end of the first reaction unit 121 and the discharge unit 103 A vacuum device, such as a vacuum pump, may be located at the location.

In order to sufficiently decompose and convert the harmful fluorine compound, it is preferable to generate an excessive promoted gas in the second reaction part 122 and supply it to the first reaction part 121. For example, when the harmful fluorine compound is NF ₃ , the sum of the flow rate of hydrogen and the flow rate of water vapor is preferably 0.5 to 20 times the flow rate of NF _3. However, in order to generate a large amount of promoted gas, , It is more preferable that the thermal energy is 0.5 to 10 times in terms of practical use. On the other hand, when the harmful fluorine compound is SF ₆ , it is preferably 1.0 to 20 times, and when the harmful fluorine compound is perfluorocarbon, it is preferably 0.5 to 30 times, although it is variable depending on the number of carbon atoms constituting the perfluorocarbon.

The mixed gas introduced into the first reaction unit 121 is passed through a preheating unit, a catalyst layer filled with a catalyst for hydrogenation reaction and a catalyst for hydrolysis reaction at a space velocity (GHSV) of 100 to 5000 hr ^{-1 on} a standard condition (STP) Contact.

The catalyst for hydrogenation reaction (hereinafter, referred to as a hydrogenation catalyst) comprises 1) an active component in a metal, alloy or oxide state selected from Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir, A porous carbon material including carbon nanotubes, activated carbon, activated carbon fibers or the like, or a metal, alloy or oxide state selected from Fe, Al, Si, Ti, Sn, Zn and a combination of at least one of them, 3) (S), Group 2 elements of the periodic table, Group 2 elements of the periodic table, rare earth metals, phosphorus, nitrogen, chlorine, sulfur and combinations of one or more of these. However, hydrogenation catalysts It is also acceptable.

The catalyst for hydrolysis reaction (hereinafter referred to as " hydrolysis catalyst ") is a catalyst for hydrolysis reaction (hereinafter referred to as " hydrolysis catalyst " An active ingredient which is a metal salt or metal oxide or hydroxide selected from the group consisting of metal, alloy, phosphoric acid, nitric acid, sulfuric acid or carbonic acid; 2) a porous carbon material including carbon nanotubes, activated carbon, A metal salt selected from the group consisting of Si, Ti, Sn, Zn or a combination of at least one of them, an alloy, a metal salt containing phosphoric acid, nitric acid, sulfuric acid or carbonic acid or a metal oxide or a hydroxide; 3) a Group 1 element of the periodic table; Group elements, rare earth elements, and combinations of one or more of these, although commonly known acid catalysts may be used.

The hydrogenation catalyst and the hydrolysis catalyst may be separately prepared and packed in the reactor. In this case, the respective catalysts may be separately packed in the reactor or may be mixed in a predetermined ratio to be charged evenly in the reactor. In addition, the components of the two catalysts may be appropriately combined to produce one kind of catalyst effective for both the hydrogenation reaction and the hydrolysis reaction, and the catalyst may be uniformly packed. If the weight ratio of the hydrolysis catalyst to the hydrogenation catalyst is too low, it is difficult to accelerate the hydrolysis and conversion reaction. On the other hand, when the weight ratio of the hydrolysis catalyst to the hydrogenation catalyst is excessively low, Promoting the conversion reaction may be difficult, and the weight ratio of the hydrolysis catalyst to the hydrogenation catalyst is preferably in the range of 0.1 to 10.

The hydrogenation catalyst and the hydrolysis catalyst may accelerate the reduction reaction of some nitrogen oxides and the decomposition reaction of some ammonia (NH ₃ ) in addition to the decomposition and conversion of harmful fluorine compounds.

In the first reaction part according to the method of the present invention, 90 to 100% of the harmful fluorine compounds were decomposed and converted by the hydrogenation reaction and the hydrolysis reaction.

A second purification step (d): a purification step of removing a simple fluorine compound contained in the exhaust gas from the first reaction step (c)

In one embodiment of the invention, the second purging step (d) is a step of removing a simple fluorine compound, for example a fluorine compound such as HF, F ₂ or COF ₂ , which is the product of decomposition and conversion of the harmful fluorine compound.

1, the exhaust gas discharged from the first reaction unit 121 of FIG. 1 transfers heat energy required by the second reaction unit 122 through the third heat exchange unit 133 Lt; / RTI > Thereafter, the thermal energy required for vaporization and heating of the methanol aqueous solution is transferred through the continuously installed fourth heat exchanging unit 134, and the cooled heat is transferred to the second purifying unit 112. In the second purifying part 112, simple fluorine compounds can be removed by a dry method or a wet method. The apparatus including the adsorbent or the absorbing solution of the second purifying unit 112 can be configured in the same manner as the first purifying unit 111 described above. However, the metal, metal hydroxide and / or metal oxide constituting the adsorbent may be selected from Al, Co, Fe, Mn, Ni, Si, Sn, Ti or a combination of at least one thereof.

The removal efficiency of the second purifier 112 is improved as the temperature is higher. However, when the temperature is excessively high, there is a problem that the absorbing liquid must evaporate or excessively use the heat insulating material. Therefore, it is preferable to maintain the temperature in the range of room temperature to 200 캜. It is more preferable to keep the temperature at 50 to 180 DEG C for the dry process and 50 to 80 DEG C for the wet process. As a side effect of the second purifying section 112, it is possible to adsorb or absorb ammonia, carbon monoxide, sulfur oxides, sulfuric acid, and nitrogen oxides (NOx).

The gas flow passing through the second purifying part 112 may be either a top-down type or a bottom-up type. The outlet concentration of the simple fluorine compound may minimize the influence of the outlet of the third purifying part 113 on the catalyst and the adsorbent Preferably in the range of 0 to 10 ppm, more preferably in the range of 0 to 1 ppm.

A third purifying step (e): a final purifying step of removing the residual ammonia, carbon monoxide, and nitrogen oxides (NOx) contained in the exhaust gas of the second purifying step (d)

The third purifying step (e) of the present invention is a step of purifying the harmful fluorine compound through the step of decomposing and converting the harmful fluorine compound. After completion of the removal of the simple fluorine compound, the residual purifying step (e) As the step of selectively removing the sulfuric acid products or the sulfuric acid, a catalytic system or an adsorption system may be used.

The catalyst system may be a combination of a reactor comprising a generally well-known three-way catalyst, a device comprising a low temperature oxidation catalyst and a device comprising a subsequently selectively arranged selective reduction catalyst.

The adsorption method is a method of adsorbing or chemically sticking to a solid adsorbent such as activated carbon, metal powder, metal hydroxide or metal oxide to remove the adsorbent, and may be in the form of an adsorbent and a vessel, a tank or a tower containing the adsorbent. The adsorbent may be in the form of a powder, a molded product having a specific shape, a specific support, or a solid material composed of a combination of activated carbon, metal powder, metal hydroxide, metal oxide, zeolite or the adsorbent. In some cases, the above solid matter may be added by a method of mixing or impregnating an alkali metal salt or an alkaline earth metal salt. The metal hydroxide and the metal oxide may be selected from Al, Co, Fe, Mn, Ni, Si, Sn, Ti or a combination of at least one of them. The alkali metal and the alkaline earth metal include Group 1 and Group 2 of the periodic table . On the other hand, it is also possible to use a metal salt of an ionic organic material or an organic metal complex in accordance with the purpose. When the concentration of each residual component is equal to or lower than the discharge reference value of each component, the third purification step (e) may be omitted.

The effects of the present invention can be further specified by the following Comparative Examples and Examples. The principles of the present invention and the techniques to be implemented through the present invention are not limited to the specific embodiments of the present invention, as they may be used for the removal of other harmful components through minor modifications apparent to those skilled in the art.

Comparative Example  1: How to remove harmful fluorine compounds

In order to remove the NF ₃ contained in the process exhaust gas after the chemical vapor deposition (CVD) chamber cleaning, a series of continuous processes consisting of 1) a combustion decomposition and conversion section, 2) a cooling section, 3) a heat exchange section, and 4) Respectively. The process effluent gas was introduced into the continuous process configured as described above at a flow rate of 41.24 liters per minute (standard conditions, STP). The contents of each component constituting the process exhaust gas are shown in Table 1.

ingredient content (%) NF ₃ (nitrogen trifluoride) 1.0 HCl (hydrochloric acid) 0.5 HF (hydrofluoric acid) 0.5 F ₂ (fluorine) 0.5 SiF ₄ (silicon tetrafluoride) 0.5 N ₂ (nitrogen) 97 Sum 100

The process exhaust (S1-1) having the composition of Table 1 above is introduced into the inlet of the in-line mixer and at the other inlet the air (S1-2) is introduced at a flow rate of 20.6 liters per minute under standard conditions (STP) And mixed with the process exhaust gas (S1-1) in the mixer.

The mixed gas S1-3 is introduced into the low temperature portion of the shell and tube type heat exchanger, heated to 350, and then introduced into the inlet of the combustion type decomposition and conversion portion composed of the preheater and the combustion chamber. Preheated and then introduced into the combustion chamber. The internal temperature of the combustion chamber filled with granular SiC was maintained at 800. Thermal energy required for heating the preheater and the combustion chamber was supplied to the electric heater. In the combustion chamber, NF ₃ was mainly decomposed and converted to N ₂ , nitrogen oxides (NO x) and F ₂ , and SiF ₄ was converted to SiO ₂ and F ₂ . The concentration of NF ₃ at the combustion chamber outlet was about 0.1% by volume, and the sum of the decomposition rate and the conversion rate of NF ₃ was about 85%, considering that the outlet flow rate based on the standard conditions (STP) was 62.41 liters per minute.

The combustion gas S1-4 discharged from the outlet of the combustion chamber is cooled to 500 and then introduced into the high temperature section of the shell and tube type heat exchange section to generate heat energy necessary for heating the mixture gas S1-3 And cooled to 167 to be introduced into the introduction port located at the lower end of the wet purification section. The humidified purging section includes a filling layer composed of a spherical alumina ball inside a cylindrical column, and an injection nozzle for continuously spraying a 1 wt% NaOH aqueous solution is provided at an upper end. The NaOH aqueous solution injected through the injection nozzle flows down along the filling layer of the alumina balls and is contacted with the combustion gas (S1-4) in the upwardly flowing wet purification unit, and then stored in the storage tank provided below. The concentration of HCl, HF, F ₂ , fluorine oxide, and SiO ₂ contained in the combustion gas (S1-4) after the decomposition and conversion is removed to 1 ppm or less.

The purge gas (S1-5) discharged to the upper outlet of the wet purifier is discharged to the outside of the workplace. No nitrogen oxide (NOx) of about 80 ppm concentration contained in the purge gas (S1-5) is removed separately. The amount of externally supplied heat energy to remove NF ₃ in this manner was 304.3 watts per hour (Wh), and the amount of heat energy that was not recovered and discarded was 299.5 watts per hour (Wh), with a thermal efficiency of about 1.5% .

Comparative Example  2: Of harmful fluorine compounds Catalytic  How to uninstall

In order to remove NF ₃ contained in the process exhaust gas, a series of continuous processes consisting of 1) a pre-purification unit, 2) a catalytic decomposition and conversion unit, 3) a cooling unit, 4) a heat exchange unit, and 5) a purification unit. The process effluent gas was introduced into the continuous process configured as described above at a flow rate of 41.24 liters per minute (standard conditions, STP). The contents of the components constituting the process exhaust gas were the same as those in Table 1 of Comparative Example 1.

The process exhaust gas S2-1 was introduced into the inlet of the pre-purification section. The pre-purification section was composed of a cylindrical container (canister) containing 40 liters of an adsorbent prepared by impregnating 5 wt% potassium hydroxide (KOH) into a cylindrically shaped iron oxide having an average diameter of 3 mm and an average length of 5 mm, The replacement period of the adsorbent was estimated to be 3 months. The flow of the process exhaust gas is a bottom-up type, and an empty space is provided between the introduction port of the process exhaust gas and the filler layer of the adsorbent so that the process exhaust gas can pass through the filler layer evenly contacting with the adsorbent after staying for a predetermined time. The inlet pressure of the gas was maintained at 1.2 to 1.5 atm in consideration of the pressure drop caused in the adsorbent-packed bed. HCl, HF, F ₂ , and SiF ₄ contained in the process exhaust gas (S2-1) are removed while passing through the packed bed of the adsorbent to remove HCl, HF, F2, and SiF4 from the purge gas (S2-2) The outlet concentrations of HF, F ₂ , and SiF ₄ remained at 0 to 1 ppm, respectively.

The purge gas S2-2 discharged from the outlet of the pre-purifier is introduced into the inlet of the in-line mixer and the air S2-3 having a flow rate of 10.3 liters per minute on the standard conditions (STP) And is uniformly mixed with the purge gas S2-2 in the in-line mixer.

The mixed gas S2-4 is introduced into the low temperature portion of the shell and tube type heat exchanger, heated to 350, and then introduced into the inlet of the catalytic converter composed of the preheater and the catalytic reactor. The pre-preheated mixed gas (S2-4) in the preheater is composed of 20 wt% NiO and 80 wt% Al ₂ O ₃ at a space velocity of 2,500 hr ^{-1 on} a standard condition (STP) basis A cylindrical catalyst having an average diameter of 1.8 mm and an average length of 4 mm was introduced into the reactor filled with about 1.1 Kg. The heat energy required for the preheating was supplied by an electric heater, and the catalytic reactor was maintained at a reaction temperature of 650 and a reaction pressure of 1.2 to 1.5 atm. In the catalytic reactor, a portion of the NF ₃ was decomposed and converted to N ₂ , nitrogen oxides (NO x) and F ₂ . The concentration of NF ₃ at the outlet of the catalytic reactor was about 0.1% by volume, and the conversion rate of NF ₃ was about 90% considering that the outlet flow rate was 50.72 liters per minute on the basis of standard conditions (STP).

The converted gas S2-5 discharged from the outlet of the catalytic reactor is cooled to 500 and then introduced into the high temperature section of the shell and tube type heat exchange section to heat the mixed gas S2-4 described above And cooled to 170, and then introduced into the inlet located at the bottom of the wet cleaning section.

The structure of the wet purifying portion was the same as that of Comparative Example 1, and HF, F _2, and fluorine oxides included in the conversion gas (S2-5) after decomposition and conversion were removed to a concentration of 1 ppm or less. The purge gas S2-6 discharged to the upper outlet of the wet purifier is discharged to the outside of the workplace, but the nitrogen oxide (NOx) contained in the purge gas S2-6 at a concentration of about 70 ppm has not been removed separately. The amount of heat energy supplied from the outside for the removal of NF ₃ by the above method was 164.8 W (Wh), and since there is no substantial heat recovery, the thermal efficiency is 0%.

Example  1: NF in process exhaust gas according to the present invention ₃ How to remove

Through the process exhaust gas inlet 101 of FIG. 1, process exhaust gas was introduced into the continuous process of the present invention at a flow rate of 41.24 liters per minute (standard conditions). The content of each component constituting the process exhaust gas is shown in Table 1 of Comparative Example 1.

The process exhaust gas introduced through the inlet 101 of FIG. 1 passes through the first heat exchanger 131, is heated to 61.7 ° C., and then introduced into the first purifier 111.

The first purifying part 111 is configured to be adsorbed. Cylindrically formed adsorbent having an average diameter of 3 mm and an average length of 5 mm was filled with 40 liters of an adsorbent composed of iron oxide impregnated with 5 wt% potassium hydroxide (KOH), and the replacement period of the adsorbent was estimated to be 6 months. The first purifier 111 was made of a cylindrical container (canister) containing the adsorbent, and the flow of the process exhaust gas was bottom-up. The first purifying part 111 has an empty space between the introduction port of the process exhaust gas and the adsorbent filling layer so that the gas flow is maintained in contact with the adsorbent for a predetermined time and passes through the filling layer. The pressure of the gas introduction part was maintained at 1.2 to 1.5 atm in consideration of the pressure drop caused in the adsorbent packing layer. Through the packed bed of the adsorbent and of the HCl, HF, F _2, SiF of ₄ is removed first purge gas discharged from the first purification unit (111) HCl, HF, F 2 and SiF ₄ involved in the process off-gas The outlet concentrations remained at 0 to 1 ppm levels, respectively.

The process exhaust gas that has passed through the first purification unit 111 is introduced into the second heat exchange unit 132, heated to 150.6 based on the outlet temperature, and then introduced into the mixing unit 142.

On the other hand, an aqueous solution in which the methanol and water in FIG. 1 were mixed at a weight ratio of 1: 2.25 was supplied from the methanol aqueous solution supply unit 102 to the fourth heat exchanging unit 134 at a flow rate of 1.277 g per minute by the metering pump 141. The methanol aqueous solution is vaporized into a mixed gas of water vapor and methanol in the fourth heat exchanging unit 134, and further heated to a temperature of 180 ° C and introduced into the second reaction unit 122 at 1.5 atm.

The mixed gas of methanol and water vapor introduced into the second reaction part 122 is further heated up to the reaction temperature 220 in the preheating part included in the second reaction part 122 so that the steam reforming of the second reaction part 122 Was introduced into the catalytic reaction part for reaction. The space velocity (GHSV) of 2,000 hr the mixture is based on standard conditions (STP) ^{- 1.} As the catalyst for the steam reforming reaction of methanol, 0.1 wt% of platinum (Pt) was added to a Cu / Zn / alumina catalyst composed of 42 wt% of CuO, 42 wt% of ZnO and 10 wt% of Al ₂ O ₃ A spherical catalyst having a diameter of 1 to 2 mm was used. The catalyst had a density of 1.2 Kg / l and filled the reactor with 49.5 g. As a result of the steam reforming reaction, the methanol was converted to 100%, and the composition of the promoted gas discharged from the second reaction part 122 is shown in Table 2 below.

ingredient Flow rate (liter / minute) Steam (H ₂ O) 0.825 Hydrogen (H ₂ ) 0.825 Carbon dioxide (CO ₂ ) 0.275 Sum 1.925

The thermal energy required by the second reaction unit 122 is recovered by supplying heat energy contained in the first reaction gas at a high temperature discharged from the first reaction unit 121. In the present invention, The third heat exchanging unit 133 may be constructed such that the second reaction unit 122 is integrated into the inside or outside of the pipe connecting the first reaction unit 121 and the second purification unit 112 without using a separate heat exchanger, And a special device was designed and used. Likewise, the fourth heat exchanging unit 134 also achieves the improvement of the thermal efficiency and the simplification of the apparatus by using a special integrated device designed similar to the third heat exchanging unit 133.

The promoted gas is introduced into another inlet of the mixing section 142. The mixing portion 142 of the present embodiment is constituted by an in-line mixer having two inlets and one outlet, and the process exhaust gas and the promoted gas introduced into the respective inlets are uniformly mixed and discharged, As shown in FIG.

The first reaction part 121 is composed of a preheating part and a catalyst reaction part. The mixed gas is heated to 300 through the preheating part, and then the catalyst is charged at a space velocity of 2,500 hr ^{-1 on} the basis of standard conditions (STP) Lt; / RTI > The heat energy necessary for the preheating was supplied to the electric heater. The reactor of the first reactor maintained a reaction pressure of 1.2 to 1.5 atm at a reaction temperature of 300 and absolute pressure. A hydrogenation catalyst of the same volume and a hydrolysis catalyst were mixed well and filled evenly in the reactor. The sum of the weights of the two catalysts was 0.86 Kg.

The hydrogenation catalyst comprises 20 wt% of NiO, 5 wt% of MoO ₃ , 5 wt% of V ₂ O ₅ , 3 wt% of CeO 2, 2 wt% of K ₂ CO ₃ , 65 wt% of Al ₂ O ₃ And a cylindrical solid having an average diameter of 1.8 mm and an average length of 4 mm. The catalyst was subjected to reduction treatment by flowing a reducing gas composed of 10% of hydrogen and 90% of nitrogen at 450 ° C. in a separate pretreatment apparatus, and then purified air was flowed at room temperature to form an oxygen protective film on the surface. The specific gravity of the finished catalyst was 0.8 Kg / L.

The hydrolysis catalyst is composed of 20 wt% nickel phosphate, 10 wt% vanadium phosphate, 5 wt% SnO, 40 wt% SiO ₂ , 25 wt% Al ₂ O ₃ A cylindrical solid having an average diameter of 1.8 mm and an average length of 4 mm, and the specific gravity of the finished catalyst was 0.9 kg / L.

Considering that the concentration of NF ₃ at the outlet of the first reaction unit 121 was about 0.048 vol% and the discharge flow rate at the outlet was about 43.05 liters per minute on the basis of standard conditions (STP), the first reaction unit 121, And about 95% of the NF ₃ contained in the mixed gas was decomposed and converted.

In addition, the exit concentration of ammonia is 0.045% by volume and the exit concentration of nitrogen oxides (NOx) is about 0.034% by volume. These values are lower than theoretically calculated values, and some of them are decomposed or reduced inside the reactor.

The first reaction gas discharged from the first reaction unit 121 is introduced into the third heat exchange unit 133 at a flow rate of about 43 liters per minute and is supplied to the second reaction unit 122 through the preheating of the promoted gas and the steam reforming reaction And is then introduced into the fourth heat exchanging unit 134. The heat exchanging unit 134 is provided with a heat exchanger (not shown). Subsequently, the fourth heat exchanging unit 134 supplies the thermal energy required for vaporizing the methanol-water mixed solution and heating the vaporized mixed gas, and is cooled to a temperature of about 169 to be introduced into the second purifying unit 112 of FIG. 1 do.

The second purifying part 112 is configured to be adsorbed, and is configured to include two different adsorbing layers having a total volume of 20L. The first adsorption layer first contacting with the first reaction gas was constituted by filling a cylindrical iron oxide having an average diameter of 3 mm and an average length of 5 mm into a 15 L volume of an adsorbent composed of 5 wt% of potassium hydroxide (KOH) impregnated. The second adsorption layer was prepared by mixing activated carbon having an average particle size of 3 mm and impregnated with 5 wt% of KOH and zeolite 5A containing 3 wt% of NiO having an average diameter of 3 mm in a volume of 1: 1, The total volume was 5L. The second purging portion 112 was made of a cylindrical container (canister) including the first and second adsorption layers, and the flow of the first reaction gas was top down.

In addition, an empty space is provided between the inlet of the first reaction gas and the first adsorption layer so that the gas can stay in the adsorbent after passing through the adsorption layer for a predetermined period of time. The pressure of the gas inlet portion was maintained at 1.2 to 1.5 atm in consideration of the pressure drop caused in the adsorbent packing layer.

The first reactive gas passes through the filler layer of the adsorbent and the simple fluorine compounds such as HF, F ₂ , and fluorine oxides are effectively removed, and the second reactive gas, which is discharged from the second purifier 112, The outlet concentrations remained at 0 to 1 ppm levels, respectively. Also, the adsorption, decomposition or reduction reaction of ammonia and nitrogen oxide (NOx) proceeded at the same time, and the outlet concentration of ammonia was about 47 ppm and the sum of the outlet concentrations of nitrogen oxides was about 35 ppm.

The second purifying gas discharged from the second purifying unit 112 is introduced into the second heat exchanging unit 132 at a flow rate of about 42.1 liters per minute under standard conditions (STP) to transfer thermal energy, Then, the heat is transferred to the first heat exchanger 131, transferred to the third heat exchanger 131, cooled to 40, and introduced into the third purifier 113.

The third purging section 113 is constructed by filling 5 liters of activated carbon and 5 liters of zeolite 5A into upper and lower layers in a cylindrical container, and the second purifying gas flows downward. The concentration of ammonia and nitrogen oxides (NOx) at the outlet of the third purifying unit 113 is detected to be 10 ppm or less and the third purifying gas discharged from the third purifying unit 113 is discharged to the outside through the discharging unit 103 .

As a result, according to Example 1 of the present invention, 95% of NF ₃ in the process exhaust gas was removed. In order to achieve the NF ₃ removal rate, thermal energy of about 67 watts per hour (Wh) was supplied, and thermal energy of about 9 watts (Wh) was discharged to the outside, resulting in a thermal efficiency of about 86.4%.

The experimental results of Comparative Example 1, Comparative Example 2 and Example 3 are summarized in Table 3 below.

NF ₃ Removal Rate (%) Decomposition and conversion temperature ( ^o C) Thermal energy supply per hour (Watts, Wh) Thermal efficiency (%) Comparative Example 1 85 800 304 1.5 Comparative Example 2 90 600 165 0 Example 1 95 300 67 86.4

101: Process exhaust gas supply unit 102: Methanol aqueous solution supply unit
103: discharge part 141: metering pump
111: first purifier 112: second purifier
113: third purifying section 142: mixing section
121: first reaction part 122: second reaction part
131: first heat exchanger 132: second heat exchanger
133: third heat exchanger 134: fourth heat exchanger

Claims (25)

(a) a second reaction unit for generating a promoted gas from an aqueous methanol solution;
(b) a mixing section for mixing the accelerated gas and the process exhaust gas from which the impurities have been removed;
(c) a first reaction part for decomposing and converting the harmful fluorine compound contained in the mixed gas obtained through the mixing part into a simple fluorine compound; And
(d) a second purifier for removing a simple fluorine compound from the gas flow discharged from the first reaction unit. The apparatus for removing harmful fluorine compounds according to claim 1, wherein the second reaction unit includes a third heat exchange unit for recovering thermal energy in a continuous process. The apparatus for removing harmful fluorine compounds according to claim 1, wherein the second reaction unit includes a catalytic reaction unit for generating an accelerated gas by steam reforming reaction of methanol. The apparatus of claim 1, further comprising a first purifier for pre-purifying impurities contained in the process exhaust gas prior to the mixing unit. The method according to claim 1, further comprising a third purifying unit for removing residual ammonia, carbon monoxide, and nitrogen oxides (NOx) contained in the exhaust gas at a rear end of the second purifying unit, using a methanol aqueous solution to remove harmful fluorine compounds Device to remove. The apparatus according to claim 5, wherein the third purifier includes a catalyst or an adsorbent for selectively removing the residual components, using an aqueous methanol solution to remove harmful fluorine compounds. The apparatus according to claim 6, wherein the third purification section comprises activated carbon and zeolite, using an aqueous methanol solution to remove harmful fluorine compounds. The apparatus of claim 1, wherein the first reaction unit includes a hydrogenation catalyst, a hydrolysis catalyst, or a catalytic reaction unit including both of the hydrogenation catalyst and the hydrolysis catalyst. The process of claim 8, wherein the hydrogenation catalyst is selected from the group consisting of metals, alloys, oxides, salts, or combinations thereof comprising Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir, An apparatus for removing harmful fluorine compounds using an aqueous solution. The method of claim 8, wherein the hydrolysis catalyst is selected from the group consisting of Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir, Fe, Al, Si, Ti, Sn, Zn, An apparatus for removing harmful fluorine compounds using an aqueous methanol solution, comprising an alloy, a salt, an oxide, a hydroxide or a combination thereof. The apparatus for removing harmful fluorine compounds according to claim 8, further comprising an aqueous methanol solution, wherein the first reaction section further comprises a preheating section. The apparatus for removing harmful fluorine compounds according to claim 8, wherein the catalytic reaction portion comprises a hydrolysis catalyst for the hydrogenation catalyst in a ratio of 0.1 to 10 by weight. (a) a second reaction step of producing a promoted gas from an aqueous methanol solution;
(b) a mixing step of mixing the promoted gas with the process exhaust gas from which the impurities have been removed;
(c) a first reaction step of decomposing and converting a harmful fluorine compound contained in the mixed gas obtained through the step (b) into a simple fluorine compound; And
(d) removing a simple fluorine compound from the first reaction gas discharged from the first reaction step (c). 14. The method of claim 13, further comprising, prior to the first reaction step (c), removing a harmful fluorine compound using an aqueous methanol solution, further comprising a first purge step (cc) How to. 15. The method according to claim 13 or 14, wherein the second purification step (d) or the first purification step (cc) uses a dry or wet method to remove harmful fluorine compounds using an aqueous methanol solution. 14. The method of claim 13, further comprising a third purge step (e) for removing residual ammonia, carbon monoxide, nitrogen oxides (NOx) contained in the second purge gas discharged in the second purge step (d) A method for removing harmful fluorine compounds using an aqueous methanol solution. 17. The method of claim 16, wherein the third purge step (e) is carried out in a catalytic or adsorption manner using a methanol aqueous solution. 18. The method of claim 17, wherein the third purge step (e) is carried out using activated carbon and zeolite, using a methanol aqueous solution to remove harmful fluorine compounds. 14. The method of claim 13, wherein the accelerated gas in the second reaction step (a) is produced through the steam reforming reaction of methanol, using a methanol aqueous solution to remove harmful fluorine compounds. 20. The method of claim 19, wherein the steam reforming reaction of methanol is carried out by recovering thermal energy in a continuous process, wherein the harmful fluorine compound is removed using an aqueous methanol solution. 14. The method according to claim 13, wherein the first reaction part has a space velocity (GHSV) of 100 to 5000 ^hr < ^-1 > using an aqueous methanol solution to remove harmful fluorine compounds. 14. The method of claim 13, wherein the first reaction step is carried out with a hydrogenation catalyst, a hydrolysis catalyst, or a catalytic reaction of both, using a methanol aqueous solution to remove harmful fluorine compounds. 23. The method of claim 22, wherein the hydrogenation catalyst comprises a metal, an alloy, an oxide, a salt, or a combination thereof comprising Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir, A method for removing harmful fluorine compounds using an aqueous methanol solution. The method of claim 22, wherein the hydrolysis catalyst is selected from the group consisting of Ni, Co, V, Mo, W, Pt, Pd, Ru, Ir, Fe, Al, Si, Ti, Sn, Zn, , An alloy, a salt, an oxide, a hydroxide, or a combination thereof, is used to remove the harmful fluorine compound. 23. The method of claim 22, wherein the first reaction step comprises a hydrolysis catalyst to a hydrogenation catalyst in a ratio of from 0.1 to 10 by weight, wherein the harmful fluorine compound is removed using an aqueous methanol solution.

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