TWI352616B - Method for treating gas containing fluorine compou - Google Patents

Description

1352616 IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to a method for treating a fluorine-containing compound gas, and more particularly to an adsorption displacement reaction of a fluorine-containing compound gas. [Prior Art]

In recent years, environmental awareness has increased. In order to reduce the greenhouse effect, fluorine-containing compounds used in semiconductor processes must be processed before they can be discharged to the atmosphere. Generally, fluorine-containing compounds used are, for example, perfluorocarbons (PFCs). It is a general term for hydrocarbons containing a plurality of fluorine atoms, such as CF4, C2F4, C2HF3, C2F6, C3F6, etc., and has extremely high chemical stability. The current fluorine-containing compound treatment technologies mainly include high-temperature direct decomposition method, high-energy ion decomposition method and catalytic decomposition method. Among them, the high-temperature direct decomposition method and the catalytic decomposition method are the most mature, and the catalyst decomposition method has lower operating temperature and decomposition. High efficiency and high security. Catalytic decomposition method mainly has two methods: cyclic hydrolysis reaction and adsorption displacement reaction. The hydrolysis reaction must be carried out under the condition of containing water gas. PFC will be converted into hydrofluoric acid and carbon dioxide after the catalyst reaction, so it is necessary to add one. The wet scrubber removes hydrofluoric acid; and the adsorption displacement reaction uses a chemical adsorbent to remove the PFC compound at a high temperature (400 to 700 ° C), and then removes the PFC compound to remove the PFC. After the reaction, carbon monoxide or carbon dioxide is produced, and no acid gas is generated. Cyclic hydrolysis has higher treatment 0954-A22114TWCIPF(N2); P54960008TWC1; kelly 6 1352616, and 2 life' but the equipment is more complicated and difficult to maintain; the treatment of adsorption displacement is related to the adsorption dose, but the relative life is shorter, if it is treated High; Chen PFC requires frequent replacement of chemical adsorbents. ""

Guild ASSOciates, described in the US Patent Early Disclosure, Cong Qin No. 7, describes the use of A as a carrier and the hydrolysis of the active constituents Zr〇2 and c〇2〇3 to decompose pFCs with a catalytic activity of 90〇. /〇 above. Sh〇wa Denk〇, US Patent No. US63096! No. 8, describes a hydrolyzable catalyst-decomposing PFCs using Al2〇3 and Aip〇4 as carriers and having active components of Ce〇2, La2〇3 and Cr〇3. Its catalyst activity is close! 〇〇% conversion rate. It is worth noting that water vapor is required in the above reaction conditions. If there is no water vapor in the intake composition, the removal effect will be greatly reduced, and the conversion rate is only 7.5 %.

Showa Denko KK, in U.S. Patent No. 6,63,421 B1, describes an adsorptive displacement reaction type adsorbent which is an alkaline earth metal compound containing a carbonate of alumina and magnesium, calcium, strontium or barium, which is water-free. Fluoride is converted into an oxide under steam conditions to remove it. The advantage is that the equipment is simple and does not produce hydrofluoric acid after the reaction, but the disadvantage is that the service life is short and the frequency of adsorbent replacement is high. Therefore, there is a need in the industry for an adsorption-replacement type adsorbent for removing a fluorine-containing compound, which can be converted into a stable compound without water vapor and removed, and has a long catalyst life. [4] The content of the fluorochemical gas is fluorochemical It is adsorbed by the active adsorbent and reacts with the active adsorbent. The composition of the active adsorbent comprises a zeolite and a soil metal compound, and the weight ratio of the vermiculite to the soil metal compound is 1:20 to 4:6. In order to make the above objects, features, and advantages of the present invention more comprehensible, the following detailed description is made in conjunction with the accompanying drawings.

[Embodiment] The object of the present invention is to develop a chemical adsorbent capable of treating pFC, and the method for treating a fluorine-containing compound gas of the present invention is to carry out an adsorption displacement reaction using the following adsorption reaction type catalyst as an active adsorbent. Since the specific surface area of the raw sorbent is greater than 1 in DH, the initial conversion rate is more than 99%, and the initial conversion rate is not more than 1% by weight. Life expectancy. The active adsorbent and the treatment method for removing the fluorine-containing compound in the gas provided by the present invention pass a gas containing a fluorine-containing compound at 3 〇〇 8 8 ° C through an active adsorbent formed by a zeolite and an alkaline earth metal compound. Fluoride in the gas will be adsorbed by and reacted with the active adsorbent to convert the fluoride into a stable compound, for example, CF4 is converted to CO or C〇2, and the fluorine will be adsorbed by the active adsorbent or reacted with the active adsorbent after the reaction. The agent reacts to form a stable compound. The composition of the active adsorbent of the present invention comprises: a zeolite and an alkaline earth metal compound, and the weight ratio of the zeolite to the alkaline earth metal compound is about 120 to 4:6', wherein the alkaline earth metal compound is, for example, a carbonate of magnesium, calcium, barium or strontium. 0954-A22114TWCIPF(N2); P54960008TWC1; kel|y 8 1352616 The specific surface area of zeolite is more than 400m2/g, the composition of zeolite can be Si〇2 and Al2〇3' and the molar ratio of SiO2 and Al2〇3 is 丨0: 1 to 1〇〇: 1. The ratio of the zeolite to the soil metal compound in the active adsorbent of the present invention needs to be within a certain range. When the zeolite component is too low, the effect of rapidly decomposing the fluorine-containing compound cannot be achieved; when the soil metal compound is too low, the ratio is lowered. Adsorption amount. Generally, in the composition of the above active adsorbent, the zeolite is about 4 to 40 by weight of 3: a percentage, and the soil-measuring metal compound is about 96 to 60% by weight. In addition to the zeolite and the soil metal compound, the particulate active adsorbent of the present invention may additionally optionally include a binder to aid in shaping the weight of the appropriate binder in the active adsorbent. The ratio of the adhesive used herein is not limited to 0.5% to 9%. Those skilled in the art will be able to select an appropriate adhesive. The binder may be an organic or inorganic compound 'and wherein the organic compound is, for example, a mercapto cellulose, a polyvinyl alcohol, a polycarbonate resin, or a polyacrylic acid 'inorganic compound, for example It is a commonly used binder for sputum sol and ginseng melamine or its smelting melamine, boehmite, pseudo boehmite or aluminum trichloride, including but not limited to: citric acid Sodium, alumina, sodium formate, sodium hydroxide, methyl cellulose, polyvinyl alcohol, and the like. The binder generally comprises from about 4% to about 1% by weight of the adsorbent, preferably from about 0.5% to about 3% by weight. The fluorine-containing compound which can be removed by the treatment method of the present invention includes perfluorocarbons, hydrofluorocarbons, NF3 or SF6, and the concentration of the fluorine-containing compound in the intake gas can be 〇.01~5. Molar% (mol%), and the concentration of oxygen in the intake gas may be 2 to 20 0954-A22114TWCIPF {N2); P54960008TWC1 ikelly 9 1352616 Molar% (mol%). The treatment method of the present invention can use a conventional fixed bed reaction system to take about 72 ml of the above-mentioned active adsorbent having a particle size of 0.3 to 0.8 cm into a stainless steel tube having an inner diameter of 2 cm, and heating and controlling the feed by an electric heating furnace. The inlet temperature of the gas entering the stainless steel tube is between 300 and 800 ° C, the space flow rate of the inlet gas is about 437 hours, and the total flow rate of the feed gas is about 525 ml / minute for the adsorption capacity evaluation test.

The treatment method of the present invention and the active adsorbent are particularly suitable for treating a dry etching process of a semiconductor or photovoltaic industry and a fluorine compound-containing gas discharged from a chemical vapor deposition (CVD) apparatus, and further, the treatment method of the present invention and the active adsorbent It is not limited to the semiconductor or optoelectronics industry. On the contrary, any industrial waste gas containing a fluorine-containing compound component can be treated by the active adsorbent of the present invention and the treatment method. At the same time, since the treatment method of the present invention employs an adsorption displacement reaction, unlike the hydrolysis reaction, hydrofluoric acid is produced, so that it is not necessary to add a wet scrubber to remove hydrofluoric acid. The following are examples of the preparation and treatment of a fluorine-containing compound gas of the active adsorbent of the present invention, and a comparative example of a conventional adsorption reaction type catalyst production method and a fluorine-containing compound gas. [Example 1] The preparation of the active adsorbent CaC03/Y-Ze〇me (weight ratio: 70/30) was obtained by taking 140 g of calcium carbonate (purity: 98.6%) and 60 g of Y-type zeolite, wherein the composition of the Y-type zeolite includes SiO 2 . And A1203, and the molar ratio of SiO2 and Al2〇3 is 30: 1, after mixing thoroughly, add 54 grams of lwt% thiol cellulose and 42 grams of water, and thoroughly stir and mix the mixture for about 20 minutes in a kneading machine until The kneaded material was in the form of a dough, and then extruded into a strip shape (diameter 4·4 cm) by an extracting machine of 0954-A22114TWCIPF (N2); P54960008TWC1 .kelly 1*352616, and then dried at n〇°C for 4 hours. Then move to a high temperature furnace and simmer for 5 hours. The sintered white product was pulverized and sieved to a cent column for use. [Example 2] Active adsorbent CaCXV ZSM-5-Zeome (preparation by weight ratio of 7〇/3)

Take calcium carbonate (purity 98.6%) 157.5 grams plus ZSM-5 type Buddha stone 67,5 grams 'where the composition of ZSM-5 type zeolite includes Si〇2 and Al2〇3, and the molar ratio of SiO2 and A1203 is 5〇 : 1, after thorough mixing, add 54 grams of lwt% mercapto cellulose and 4 grams of water, mix the mixture thoroughly and mix for about 20 minutes with a kneading machine until the kneaded material is in the form of dough, and then use an extrusion molding machine to After extruding into a strip shape (0.4 cm in diameter), it was dried at ll 〇 ° C for 4 hours, and then transferred to a high temperature furnace and calcined at 550 ° C for 4 hours. The sintered white product was pulverized and sieved to a column of 0.3 to 0.8 cm for use. [Example 3] Active adsorbent CaCCVY-Zeolite (prepared by a ratio of 76/2 sentences, 130 grams of anti-acid mother (purity 98.6%) was added to γ-type Fossil 4 gram, wherein the composition of the Y-type zeolite included Si 〇 2 and Al2〇3, and the molar ratio of SiO2 and Al2〇3 is 30:1', and the binder is added after mixing (54 g of lwt% thiol cellulose and pseudo-alumina (pseud〇boehmite) 15 g) And 35 g of water, the mixture was thoroughly stirred and kneaded in a kneading machine for about 20 minutes until the kneaded material was in the form of dough, 0954-A22114TWCIPF (N2); P549600〇8TWC1; kelly 1352616 and then extruded into an extruder. After strip (diameter: 4 cm), it is dried at 11 ° C for 4 hours, then transferred to a high temperature furnace and calcined at 55 ° C for 4 hours. The white product after sintering is pulverized and sieved to 0.3 to 0.8 cm. The column was reserved. [Example 4] Preparation of active adsorbent CaC03/ZSM-5-Zeolite (weight ratio: 93/7) * Take calcium carbonate (purity 98.6%) 170 g Add ZSM-5 type zeolite 9 12克, wherein the composition of the ZSM_5 type zeolite comprises SiO 2 and Al 2 〇 3, and the molar ratio of Si 〇 2 and AhO 3 is 50 : 1 ' Adhesive (54 g of 1 wt% thiol cellulose and pseudo Q boehmite (24 g) and 18.5 g of water 'mixed and kneaded the mixture thoroughly for about 20 minutes with a blender' until the kneaded material appeared The dough was shaped and then spread out in a strip shape (diameter: 4 cm) by an extrusion molding machine, and then dried at 110 ° C for 4 hours, and then transferred to a high temperature furnace and calcined at φ 550 ° C for 4 hours. The sintered white product was pulverized and sieved to a column of #3 to 0.8 cm. [Comparative Example 1] Preparation of active adsorbent CaC03/Kaolin (70/30) was taken from calcium carbonate 14 g plus kaolin (kaolin) (Showa Chemicals Inc., 72.10% Si02 content, 19.57% Al2〇3 content) 60 g, fully mixed, add 54 g of lwt% mercapto cellulose and 40 g of water, stir the mixture thoroughly and mix with a mixer For about 20 minutes, until the kneaded material is in the form of dough, and then extruded into a strip shape (0.4 cm in diameter) by an extruder to form 0954-A22114TWCIPF (N2); P54960008TWC1; kelly 12 1-352616, at 110 °c Dry for 4 hours, then move to a high temperature furnace and calcine for 4 hours at 550 ° C. After sintering The white product was pulverized and sieved to take alternate 0.3~0.8 cm of the column. Capability testing of PFC for catalyst decomposition of the examples and comparative examples

The decomposition ability of the catalyst decomposition perfluorocarbon (PFC) of the above examples and comparative examples was tested using a conventional fixed bed reaction system. 72 ml of the particulate catalyst synthesized in Comparative Example 1 and Examples 1, 2, 3 and 4 were respectively placed in a stainless steel tube having an inner diameter of 2 cm, and then heated by an electric heating furnace to control the inlet of the feed gas into the stainless steel tube. The temperature and feed gas conditions are: l. The concentration of SF6 is 3000 ppm, the oxygen concentration is 5 mol%, and the others are nitrogen. 2. The reaction temperature is 650 °C. 3. The feed gas space flow rate is 437 hours -1 and the total feed gas flow rate is approximately 525 ml/min. Among them, there is no water in the feed gas. The graph of the removal rate of the perfluorocarbon (PFC) and the reaction time of the particulate catalyst synthesized in Comparative Example 1 and Examples 1, 2, 3 and 4 is shown in Fig. 1. The above-mentioned catalyst decomposition perfluorocarbon (PFC) decomposition ability is listed in Table 1 below: 0954-A22114TWCIPF (N2); P54960008TWCl; kelly 13 1-352616 Table 1 Active adsorbent decomposition PFC effect Catalyst initial removal rate ( °/〇) Time (hours) at which the removal rate reached 86% Comparative Example 1 > 99 0.1 Example 1 > 99 18 Example 2 > 99 19 Example 3 > 99 24 Example 4 > 99 29

As is apparent from the results of Table 1, the use of the active adsorbent composed of kaolin and calcium carbonate in Comparative Example 1 has a short treatment life for PFCs, and it is almost impossible to effectively treat PFCs gas. Since kaolin is a mixture of different ratios of SiO 2 and ai 2 o 3 , unlike zeolites, which have a special structure, PFCs can be adsorbed and decomposed. In the present invention, Examples 1, 2, 3 and 4 are active adsorbents containing different kinds of zeolites, and the initial removal rate is equivalent to that of Comparative Example 1, and the removal rate is further extended to 86%, which shows the present invention. The active adsorbent containing the zeolite component has a relatively high initial removal rate and treatment life, thereby reducing the frequency of replacement of the adsorbent. Although the present invention has been disclosed in its preferred embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application attached. 0954-A22114TWCIPF(N2); P54960008TWC1; Kelly 14 1352616 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph showing the removal rates and reaction times of Examples 1, 2, 3 and 4 and Comparative Example 1. [Main component symbol description] None.

0954-A22114TWCIPF(N2); P54960008TWC1 ;kelly 15

Claims (1)

β 年〆月日日 Revision 96137233 Revision date: 100.8.31 X. Patent application scope: 1 · A gas-containing compound gas treatment method, including · contacting a gas containing a fluorine-containing compound with an active adsorbent And causing the fluorine-containing compound to be adsorbed by the active adsorbent and performing an adsorption displacement reaction with the active adsorbent, wherein the fluorine-containing compound comprises perfluorocarbons, hydrofluorocarbons (hydr〇fluorocarb〇ns), Nf3 or SF6, and 3 wherein the composition of the active adsorbent comprises: zeolite and a soil-measuring metal compound, and the weight ratio of the zeolite to the alkaline earth metal compound is 1:20 to 4:6. Wherein the gas-containing compound gas is as described in the method, wherein the alkaline earth metal compound comprises magnesium m (tetra) carbonate _ T phase 利 。 θ Α fluorochemical gasification method, wherein the specific surface area of the zeolite is greater than the meter m2 / g. The gas treatment compound gas range and the Af〇β include Si〇2 and Al2〇3, and the molar ratio of 2 3 is 1 〇: 1 to 1 〇〇: 1. Rational 5 method as in the case of the fluorochemical gas according to the item (4), wherein the composition of the active adsorbent further comprises a weight ratio of 点人如合剂 in the active adsorbent of 〇.5%~9% / 5 十And the adhesion level =?:=; the compound containing the compound gas includes the compound 'and the organic part% (p〇lyvlnyi alc〇h〇I), poly 96137233 revision date: 100.8.31 The carbonic acid or polyacryHc acid is modified, and the inorganic compound comprises cerium sol and aluminum oxide or its precursor aluminum nitrate, boehmite, pseudo boehmite or three 7. The method for treating a fluorine-containing compound gas according to claim 1, wherein the water content in the gas does not exceed 1% by weight. 8. The fluorine content as described in claim 1 The method for treating a compound gas, wherein the specific surface area of the active adsorbent is greater than 10 μm 2 /g. 9. The method for treating a fluorine-containing compound gas according to claim 1, wherein the proportion of oxygen in the gas It is 2~20 mol%. 10. The method for treating a fluorine-containing compound gas according to the first aspect of the invention, wherein the ratio of the fluorine-containing compound in the gas is 0.01 to 5 mol%. 11. The fluorine-containing compound gas according to claim 1 The treatment method, wherein the initial conversion rate of the adsorption displacement reaction is higher than 99%. 12. The method for treating a fluorine-containing compound gas according to claim 1, wherein the adsorption displacement reaction has a reaction temperature of 300 to 800 °C.