Single crystal furnace tail gas purification method and device

Abstract

The present invention relates to a method and device for purifying the tail gas of a single crystal furnace. The method for purifying the tail gas of a single crystal furnace is as follows: removing particulate impurities from the tail gas of the auxiliary pump; removing carbon dioxide and water; performing rectification to obtain crude argon gas as a product, using the first path of the crude argon gas as a heat source for rectification to obtain crude argon liquid, using the crude argon liquid as the reflux liquid for rectification, and using the second path of the crude argon gas after reheating to merge with the tail gas of the main pump to obtain the feed gas; removing particulate impurities from the feed gas; removing hydrocarbons, oxygen, and part of carbon monoxide; removing carbon dioxide and water; and performing rectification to obtain high-purity argon gas as a product. The device for purifying the tail gas of a single crystal furnace includes an auxiliary pump filter compression system, an auxiliary pump purification system, a first rectification tower, an auxiliary pump compressor, a first rectification tower evaporator, a main pump filter compression system, a primary purification system, a secondary purification system, a second rectification tower, a heat exchanger group, and a nitrogen circulation system. The present invention has a high extraction rate and can reduce resource waste and environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of tail gas treatment of single crystal furnaces, and particularly relates to a method and device for purifying the tail gas of a single crystal furnace. Background Art

[0002] In the prior art, for the tail gas generated by a single crystal furnace in a single crystal silicon production equipment, usually only simple dust removal and other treatments are carried out and then it is discharged directly, which not only causes waste of resources such as argon, but also causes environmental pollution. Therefore, it is necessary to purify the tail gas of the single crystal furnace. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for purifying the tail gas of a single crystal furnace with a high extraction rate, so as to reduce resource waste and environmental pollution.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A method for purifying the tail gas of a single crystal furnace, which is used to purify the tail gas of the auxiliary pump and the main pump of the single crystal furnace. The method for purifying the tail gas of the single crystal furnace includes the following steps:

[0006] Step 1: Remove the particulate impurities in the tail gas of the auxiliary pump to obtain the filtered tail gas of the auxiliary pump;

[0007] Step 2: Remove carbon dioxide and water in the filtered tail gas of the auxiliary pump to obtain the purified tail gas of the auxiliary pump;

[0008] Step 3: Cool and rectify the purified tail gas of the auxiliary pump to obtain the crude product argon gas, and divide the crude product argon gas into two paths;

[0009] Step 4: Reheat, compress and cool the first path of the crude product argon gas to obtain the heat source crude argon gas, use the heat source crude argon gas as the heat source for rectification to obtain the crude argon liquid, use the crude argon liquid as the reflux liquid for rectification, and reheat the second path of the crude product argon gas and mix it with the tail gas of the main pump to obtain the raw material gas;

[0010] Step 5: Remove the particulate impurities in the raw material gas to obtain the filtered raw material gas;

[0011] Step 6: Remove hydrocarbons, oxygen and part of carbon monoxide in the filtered raw material gas to obtain the preliminarily purified raw material gas;

[0012] Step 7: Remove carbon dioxide and water in the preliminarily purified raw material gas to obtain the thoroughly purified raw material gas;

[0013] Step 8: Cool and rectify the thoroughly purified raw material gas to obtain the product high-purity argon gas, and reheat the product high-purity argon gas and send it to the user.

[0014] In step 6, hydrocarbons, oxygen and part of carbon monoxide in the filtered feed gas are removed by a catalytic method.

[0015] In step 7, carbon dioxide and water in the preliminarily purified feed gas are removed by an adsorption method.

[0016] The nitrogen cycle is used to provide heat source and cold source for the rectification of the thoroughly purified feed gas in step 8 and to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in step 7.

[0017] The nitrogen cycle is as follows: Supplementary nitrogen and recycled nitrogen are mixed, compressed and cooled to provide a heat source for the rectification of the thoroughly purified feed gas in step 8 to obtain liquid nitrogen. The liquid nitrogen is used to provide a cold source for the rectification of the thoroughly purified feed gas in step 8 to obtain nitrogen. The nitrogen is divided into two paths. The first path of nitrogen is reheated to become the recycled nitrogen. The second path of nitrogen is reheated, pressurized, cooled, expanded and reheated to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in step 7.

[0018] The present invention also provides a single crystal furnace tail gas purification device for high extraction rate purification of single crystal furnace tail gas, thereby reducing resource waste and environmental pollution. The solution is as follows:

[0019] A single crystal furnace tail gas purification device is used to purify the tail gas of the auxiliary pump and the main pump of the single crystal furnace by implementing the aforementioned single crystal furnace tail gas purification method. The single crystal furnace tail gas purification device includes:

[0020] An auxiliary pump filter compression system, which is used to remove particulate impurities in the auxiliary pump tail gas to obtain the filtered auxiliary pump tail gas;

[0021] An auxiliary pump purification system, which is used to remove carbon dioxide and water in the filtered auxiliary pump tail gas to obtain the purified auxiliary pump tail gas;

[0022] A first rectification tower, which is used to rectify the purified auxiliary pump tail gas to obtain the crude argon gas of the product;

[0023] An auxiliary pump compressor, which is used to compress the first path of the crude argon gas of the product;

[0024] A first rectification tower evaporator, which is used to use the hot source crude argon gas to provide a heat source for rectification to obtain the crude argon liquid;

[0025] Main pump filter compression system, which is used to remove particulate impurities in the raw gas to obtain the filtered raw gas;

[0026] Primary purification system, which is used to remove hydrocarbons, oxygen and part of carbon monoxide in the filtered raw gas to obtain the preliminarily purified raw gas;

[0027] Secondary purification system, which is used to remove carbon dioxide and water in the preliminarily purified raw gas to obtain the thoroughly purified raw gas;

[0028] Second distillation column, which is used to distill the thoroughly purified raw gas to obtain the product high-purity argon gas respectively;

[0029] Heat exchanger group, which is used to cool the purified tail gas of the auxiliary pump, reheating and cooling the first path of the product crude argon gas, reheating the second path of the product crude argon gas, cooling the thoroughly purified raw gas, and reheating the product high-purity argon gas;

[0030] The auxiliary pump filter compression system has a gas inlet and a gas outlet, the auxiliary pump purification system has a gas inlet and a gas outlet, the first distillation column has a gas inlet, a gas outlet and a reflux liquid inlet, the auxiliary pump compressor has a gas inlet and a gas outlet, the first distillation column evaporator has a gas inlet and a liquid outlet, the main pump filter compression system has a gas inlet and a gas outlet, the primary purification system has a gas inlet and a gas outlet, the secondary purification system has a gas inlet and a gas outlet, and the second distillation column has a gas inlet and a gas outlet;

[0031] The tail gas of the auxiliary pump is connected to the gas inlet of the auxiliary pump filter compression system. The gas outlet of the auxiliary pump filter compression system is connected to the gas inlet of the auxiliary pump purification system. The gas outlet of the auxiliary pump purification system is connected to the gas inlet of the first rectification column through the heat exchanger group. The gas outlet of the first rectification column is respectively connected to the gas inlet of the auxiliary pump compressor through the heat exchanger group and to the gas inlet of the main pump filter compression system through the heat exchanger group. The gas outlet of the auxiliary pump compressor is connected to the gas inlet of the first rectification column evaporator through the heat exchanger group. The liquid outlet of the first rectification column evaporator is connected to the reflux liquid inlet of the first rectification column. The raw material gas is connected to the gas inlet of the main pump filter compression system. The gas outlet of the main pump filter compression system is connected to the gas inlet of the primary purification system. The gas outlet of the primary purification system is connected to the gas inlet of the secondary purification system. The gas outlet of the secondary purification system is connected to the gas inlet of the second rectification column through the heat exchanger group. The gas outlet of the second rectification column is connected to the user through the heat exchanger group.

[0032] The primary purification system is a catalytic carbon monoxide and hydrocarbon system that uses a catalytic method to remove hydrocarbons, oxygen, and part of carbon monoxide in the filtered raw material gas. The secondary purification system is an adsorption dehydration and decarbonization system that uses an adsorption method to remove carbon dioxide and water in the preliminarily purified raw material gas.

[0033] The heat exchanger group includes:

[0034] The first main heat exchanger, which is used to cool the purified tail gas of the auxiliary pump, reheating and cooling the first path of the crude argon product gas, and reheating the second path of the crude argon product gas;

[0035] The second main heat exchanger, which is used to cool the thoroughly purified raw material gas and reheating the high-purity argon product gas;

[0036] The gas outlet of the auxiliary pump purification system is connected to the gas inlet of the first rectification column through the first main heat exchanger. The gas outlet of the first rectification column is connected to the gas inlet of the auxiliary pump compressor through the first main heat exchanger. The gas outlet of the auxiliary pump compressor is connected to the gas inlet of the first rectification column evaporator through the first main heat exchanger. The gas outlet of the first rectification column is connected to the gas inlet of the main pump filter compression system through the first main heat exchanger;

[0037] The gas outlet of the secondary purification system is connected to the gas inlet of the second rectification column through the second main heat exchanger. The gas outlet of the second rectification column is connected to the user through the second main heat exchanger.

[0038] The single crystal furnace tail gas purification device further includes a nitrogen circulation system, which is used to provide heat source and cold source for the second rectification tower and provide regeneration gas for the secondary purification system.

[0039] The nitrogen circulation system includes a circulating nitrogen compressor, a second rectification tower evaporator, a second rectification tower condenser, an expander, and a cooler; the circulating nitrogen compressor has a gas inlet and a gas outlet, the second rectification tower evaporator has a gas inlet and a liquid outlet, the second rectification tower condenser has a liquid inlet and a gas outlet, the expander has a compression end and an expansion end, the compression end has a gas inlet and a gas outlet, the expansion end has a gas inlet and a gas outlet, and the cooler has a gas inlet and a gas outlet; the secondary purification system has a regeneration gas inlet;

[0040] The heat exchanger group further includes a secondary heat exchanger and a liquid nitrogen subcooler;

[0041] Make-up nitrogen and circulating nitrogen are connected to the gas inlet of the circulating nitrogen compressor. The gas outlet of the circulating nitrogen compressor is connected to the gas inlet of the second rectification tower evaporator through the secondary heat exchanger. The liquid outlet of the second rectification tower evaporator is connected to the liquid inlet of the second rectification tower condenser through the liquid nitrogen subcooler. The gas outlet of the second rectification tower condenser is connected to the gas inlet of the circulating nitrogen compressor through the liquid nitrogen subcooler and then through the secondary heat exchanger, and is connected to the gas inlet of the compression end through the second main heat exchanger. The gas outlet of the compression end is connected to the gas inlet of the cooler. The gas outlet of the cooler is connected to the gas inlet of the expansion end through the second main heat exchanger. The gas outlet of the expansion end is connected to the regeneration gas inlet of the secondary purification system through the second main heat exchanger.

[0042] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The present invention purifies the tail gas of the single crystal furnace, has a high extraction rate, can reduce resource waste and environmental pollution. Brief Description of the Drawings

[0043] Attached Figure 1 It is a schematic diagram of the single crystal furnace tail gas purification device of the present invention.

[0044] In the above drawings: 1. First main heat exchanger; 2. First rectification tower; 3. Auxiliary pump compressor; 4. First rectification tower evaporator; 5. Second main heat exchanger; 6. Second rectification tower; 7. Secondary heat exchanger; 8. Circulating nitrogen compressor; 9. Second rectification tower evaporator; 10. Second rectification tower condenser; 11. Liquid nitrogen subcooler; 12. Expander; 13. Cooler. Detailed Embodiments

[0045] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0046] Embodiment 1: The tail gas of the single crystal furnace includes two parts, namely the tail gas of the auxiliary pump (the tail gas discharged from the auxiliary pump of the single crystal furnace) and the tail gas of the main pump (the tail gas discharged from the main pump of the single crystal furnace). Among them, the components and volume contents of the tail gas of the auxiliary pump are approximately: Ar: >34%, N2: ~52%, O2: ~13%, CO: ~1200 ppmV and other trace impurities.

[0047] For the tail gas of the single crystal furnace, the following purification method for the tail gas of the single crystal furnace is adopted. This purification method for the tail gas of the single crystal furnace includes the following steps:

[0048] Step 1: Remove the particulate impurities in the tail gas of the auxiliary pump to obtain the filtered tail gas of the auxiliary pump. While removing the particulate impurities, the tail gas of the auxiliary pump can be compressed to 0.3 - 0.5 MpaG.

[0049] Step 2: Remove carbon dioxide and water in the filtered tail gas of the auxiliary pump to obtain the purified tail gas of the auxiliary pump. After this Step 2, the dew point of H2O in the purified tail gas of the auxiliary pump ≤ -73°C, CO2 ≤ 0.5 ppmV.

[0050] Step 3: Cool and rectify the purified tail gas of the auxiliary pump to obtain crude argon gas of the product (O2: ≤600 ppmV), and divide the crude argon gas of the product into two paths. Waste gas is also obtained through rectification, and the waste gas is reheated and then discharged.

[0051] Step 4: Reheat, compress, and cool the first path of the crude argon gas of the product to obtain heat source crude argon gas. Use the heat source crude argon gas to provide heat source for rectification to obtain crude argon liquid, use the throttled crude argon liquid as the reflux liquid for rectification, and reheat the second path of the crude argon gas of the product and then merge it with the tail gas of the main pump to obtain the raw material gas. The components and volume contents of the raw material gas are approximately: Ar: >99%, N2: 4000 ppmV, O2: 500 ppmV, CO <2000 ppmV and other trace hydrocarbons.

[0052] Step 5: Remove the particulate impurities in the raw material gas to obtain the filtered raw material gas. While removing the particulate impurities, the raw material gas can be compressed to 0.8 MpaG. After compression, the raw material gas passes through the raw material gas buffer oxygen balance system to maintain the oxygen content not exceeding 500 ppmV.

[0053] Step 6: Use a catalytic method to remove hydrocarbons, oxygen, and part of carbon monoxide in the filtered raw material gas to obtain the preliminarily purified raw material gas. After preliminary purification, the impurities CH4 + hydrocarbons <0.5 ppmV, O2 <0.5 ppmV.

[0054] Step 7: Remove carbon dioxide and water in the preliminarily purified feed gas by adsorption to obtain the thoroughly purified feed gas. After thorough purification, the H2O dew point ≤ -73 °C, and CO2 ≤ 0.5 PPmV.

[0055] Step 8: Cool and rectify the thoroughly purified feed gas to obtain the product high-purity argon gas (0.5 MpaG), and send the reheated product high-purity argon gas to the user. Waste gas is also obtained through rectification, and the waste gas is reheated and then vented.

[0056] In the above solution, the nitrogen cycle is used to provide heat source and cold source for the rectification of the thoroughly purified feed gas in Step 8 and to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in Step 7. Specifically, the nitrogen cycle is as follows: Mix the supplementary nitrogen and the recycled nitrogen, compress (increase the pressure to 1.2 - 1.5 MpaG), and cool to provide heat source for the rectification of the thoroughly purified feed gas in Step 8 to obtain liquid nitrogen. Use the throttled liquid nitrogen to provide cold source for the rectification of the thoroughly purified feed gas in Step 8 to obtain nitrogen. Divide the nitrogen into two paths. Reheat the first path of nitrogen to become the aforementioned recycled nitrogen. Reheat, pressurize, cool, expand, and reheat the second path of nitrogen to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in Step 7.

[0057] As shown in the Figure 1 accompanying figure, a single crystal furnace tail gas purification device for purifying the tail gas of the auxiliary pump and the main pump of the single crystal furnace to implement the aforementioned single crystal furnace tail gas purification method includes an auxiliary pump filter compression system, an auxiliary pump purification system, a first rectification tower 2 (auxiliary pump rectification tower), an auxiliary pump compressor 3, a first rectification tower evaporator 4, a main pump filter compression system, a primary purification system, a secondary purification system, a second rectification tower 6 (lower tower), and a heat exchanger group. The first rectification tower evaporator 4 is arranged at the bottom of the first rectification tower 2.

[0058] The sub-pump filter compression system is used to remove particulate impurities in the sub-pump tail gas to obtain filtered sub-pump tail gas. The sub-pump purification system is used to remove carbon dioxide and water in the filtered sub-pump tail gas to obtain purified sub-pump tail gas. The first rectification tower 2 is used to rectify the purified sub-pump tail gas to obtain crude argon gas as a product. The sub-pump compressor 3 is used to compress the first path of crude argon gas as a product. The first rectification tower evaporator 4 is used to utilize the heat source of crude argon gas to provide heat for rectification to obtain crude argon liquid. The main-pump filter compression system is used to remove particulate impurities in the raw gas to obtain filtered raw gas. The primary purification system is used to remove hydrocarbons, oxygen, and part of carbon monoxide in the filtered raw gas to obtain preliminarily purified raw gas. The secondary purification system is used to remove carbon dioxide and water in the preliminarily purified raw gas to obtain thoroughly purified raw gas. The second rectification tower 6 is used to rectify the thoroughly purified raw gas to separately obtain high-purity argon gas as a product. The heat exchanger group is used to cool the purified sub-pump tail gas, reheating and cooling the first path of crude argon gas as a product, reheating the second path of crude argon gas as a product, cooling the thoroughly purified raw gas, and reheating the high-purity argon gas as a product.

[0059] The sub-pump filter compression system has a gas inlet and a gas outlet; the sub-pump purification system has a gas inlet and a gas outlet; the first rectification tower 2 has a gas inlet in the middle, a gas outlet at the top, and a reflux liquid inlet in the upper part; the sub-pump compressor 3 has a gas inlet and a gas outlet; the first rectification tower evaporator 4 has a gas inlet and a liquid outlet; the main-pump filter compression system has a gas inlet and a gas outlet; the primary purification system has a gas inlet and a gas outlet; the secondary purification system has a gas inlet and a gas outlet; the second rectification tower 6 has a gas inlet in the middle and a gas outlet in the upper part. The sub-pump tail gas is connected to the gas inlet of the sub-pump filter compression system, the gas outlet of the sub-pump filter compression system is connected to the gas inlet of the sub-pump purification system, the gas outlet of the sub-pump purification system is connected to the gas inlet of the first rectification tower 2 through the heat exchanger group, the gas outlet of the first rectification tower 2 is respectively connected to the gas inlet of the sub-pump compressor 3 through the heat exchanger group and the gas inlet of the main-pump filter compression system through the heat exchanger group, the gas outlet of the sub-pump compressor 3 is connected to the gas inlet of the first rectification tower evaporator 4 through the heat exchanger group, the liquid outlet of the first rectification tower evaporator 4 is connected to the reflux liquid inlet of the first rectification tower 2, the main-pump tail gas is also connected to the gas inlet of the main-pump filter compression system so as to converge with the second path of crude argon gas as a product to form raw gas, the gas outlet of the main-pump filter compression system is connected to the gas inlet of the primary purification system, the gas outlet of the primary purification system is connected to the gas inlet of the secondary purification system, the gas outlet of the secondary purification system is connected to the gas inlet of the second rectification tower 6 through the heat exchanger group, and the gas outlet of the second rectification tower 6 is connected to the user through the heat exchanger group.

[0060] In addition, the first rectification column 2 further has an exhaust gas outlet located in its middle and lower part, and the second rectification column 6 further has an exhaust gas outlet located in its middle and upper part. The exhaust gas outlet of the first rectification column 2 is connected to the atmosphere via a heat exchanger group, and the exhaust gas outlet of the second rectification column 6 is connected to the atmosphere via a heat exchanger group.

[0061] In the above solution, the primary purification system is a catalytic carbon monoxide and hydrocarbon system that uses a catalytic method to remove hydrocarbons, oxygen, and part of carbon monoxide in the filtered raw material gas, and the secondary purification system is an adsorption dehydration and decarbonization system that uses an adsorption method to remove carbon dioxide and water in the preliminarily purified raw material gas.

[0062] The heat exchanger group mainly includes a first main heat exchanger 1 and a second main heat exchanger 5. The first main heat exchanger 1 is used to cool the purified tail gas of the auxiliary pump, reheating and cooling the first stream of crude argon product, and reheating the second stream of crude argon product. The second main heat exchanger 5 is used to cool the thoroughly purified raw material gas and reheating the high-purity argon product. Then, the gas outlet of the auxiliary pump purification system is connected to the gas inlet of the first rectification column 2 via the first main heat exchanger 1, the gas outlet of the first rectification column 2 is connected to the gas inlet of the auxiliary pump compressor 3 via the first main heat exchanger 1, the gas outlet of the auxiliary pump compressor 3 is connected to the gas inlet of the first rectification column evaporator 4 via the first main heat exchanger 1, and the gas outlet of the first rectification column 2 is connected to the gas inlet of the main pump filter compression system via the first main heat exchanger 1. The gas outlet of the secondary purification system is connected to the gas inlet of the second rectification column 6 via the second main heat exchanger 5, and the gas outlet of the second rectification column 6 is connected to the user via the second main heat exchanger 5. The exhaust gas outlet of the first rectification column 2 is connected to the atmosphere after passing through the first main heat exchanger 1, and the exhaust gas outlet of the second rectification column 6 is connected to the atmosphere after passing through the second main heat exchanger 5.

[0063] The single crystal furnace tail gas purification device further includes a nitrogen circulation system, which is used to provide heat source and cold source for the second rectification column 6 and regeneration gas for the secondary purification system.

[0064] Specifically, the nitrogen cycle system includes a circulating nitrogen compressor 8, a second rectification tower evaporator 9, a second rectification tower condenser 10, an expander 12, and a cooler 13. The second rectification tower evaporator 9 is arranged at the bottom of the second rectification tower 6, and the second rectification tower condenser 10 is arranged at the top of the second rectification tower 6. The circulating nitrogen compressor 8 has a gas inlet and a gas outlet; the second rectification tower evaporator 9 has a gas inlet and a liquid outlet; the second rectification tower condenser 10 has a liquid inlet and a gas outlet; the expander 12 has a compression end and an expansion end, the compression end has a gas inlet and a gas outlet, and the expansion end has a gas inlet and a gas outlet; the cooler 13 has a gas inlet and a gas outlet; the secondary purification system has a regeneration gas inlet. The heat exchanger group further includes a sub-heat exchanger 7 and a liquid nitrogen sub-cooler 11. The supplementary nitrogen and the circulating nitrogen are connected to the gas inlet of the circulating nitrogen compressor 8. The gas outlet of the circulating nitrogen compressor 8 is connected to the gas inlet of the second rectification tower evaporator 9 through the sub-heat exchanger 7. The liquid outlet of the second rectification tower evaporator 9 is connected to the liquid inlet of the second rectification tower condenser 10 through the liquid nitrogen sub-cooler 11. The gas outlet of the second rectification tower condenser 10 is connected to the gas inlet of the circulating nitrogen compressor 8 through the liquid nitrogen sub-cooler 11 and then through the sub-heat exchanger 7, and is also connected to the gas inlet of the compression end through the second main heat exchanger 5. The gas outlet of the compression end is connected to the gas inlet of the cooler 13. The gas outlet of the cooler 13 is connected to the gas inlet of the expansion end through the second main heat exchanger 5. The gas outlet of the expansion end is connected to the regeneration gas inlet of the secondary purification system through the second main heat exchanger 5.

[0065] The gas outlet of the second rectification tower 6 can also branch out a branch to be connected to a user through the sub-heat exchanger 7. The second rectification tower condenser 10 further has a gas inlet and a liquid outlet, and the second rectification tower 6 further has a reflux liquid inlet at its upper part. Then, the waste gas outlet of the second rectification tower 6 also branches out a branch to be connected to the gas inlet of the second rectification tower condenser 10, and the liquid outlet of the second rectification tower condenser 10 is connected to the reflux liquid inlet of the second rectification tower 6.

[0066] The process flow of the above-mentioned single crystal furnace tail gas purification device is as follows: The oil-free raw material sub-pump's rough argon gas, that is, the sub-pump tail gas (Ar: > 34%, N2: 52%, O2: 13%, CO ≤ 1200 ppmV and other trace impurities), after passing through the sub-pump filter compression system, removes solid particles and is compressed to 0.3 - 0.5 MpaG, becoming the filtered (compressed) sub-pump tail gas. The compressed sub-pump rough argon gas passes through the sub-pump purification system to remove CO2 and water. After purifying the impurities: H2O dew point ≤ -73 °C, CO2 ≤ 0.5 ppmV, becoming the purified sub-pump tail gas. The thoroughly purified sub-pump tail gas enters the first rectification tower 2 (sub-pump rectification tower) after being cooled by the first main heat exchanger 1 to participate in rectification. The waste gas obtained at the bottom of the first rectification tower 2 (sub-pump rectification tower) is reheated by the first main heat exchanger 1 and then discharged. The product rough argon gas (O2: ≤ 600 ppmV) obtained at the top of the first rectification tower 2 (sub-pump rectification tower) is divided into two paths. The first path is reheated by the first main heat exchanger 1 and then enters the sub-pump compressor 3 for compression. Then, after being cooled by the first main heat exchanger 1 again, it enters the first rectification tower evaporator 4. The gas is liquefied into a liquid in the first rectification tower evaporator 4 and then throttled by a throttle valve and sent to the top of the first rectification tower 2 as reflux liquid to participate in rectification. The second path is reheated by the first main heat exchanger 1 and then sent to the main pump tail gas collection pipe to converge with the main pump tail gas (main pump rough argon gas). The second path of the product rough argon gas generated by the sub-pump converges with the oil-free raw material main pump tail gas (Ar: > 99%, N2: 4000 ppmV, O2: 500 ppmV, CO < 1000 ppmV and other trace hydrocarbons), and after passing through the main pump filter compression system, removes solid particles and is compressed to 0.8 MpaG, becoming the filtered (compressed) raw material gas. The filtered raw material gas passes through the raw material gas buffer oxygen balance system to maintain the oxygen content not exceeding 500 ppmV, and then passes through the primary purification system (catalytic CO and hydrocarbon system) for primary purification. After primary purification, the impurities CH4 + hydrocarbons < 0.5 ppmV, O2 < 0.5 ppmV, and part of the CO is removed. The CO2 and water generated by the catalytic CO and hydrocarbons are removed by the secondary purification system (adsorption dehydration and decarburization system). After purifying the impurities: H2O dew point ≤ -73 °C, CO2 ≤ 0.5 ppmV, becoming the thoroughly purified raw material gas. The thoroughly purified raw material gas enters the second rectification tower 6 (lower tower) after being cooled by the second main heat exchanger 5 to participate in rectification. The product high-purity argon gas (0.5 MpaG) obtained at the bottom of the second rectification tower (lower tower) is reheated by the second main heat exchanger 5 and / or the auxiliary heat exchanger 7 and then sent to the customer as a product. The waste gas obtained at the top of the second rectification tower 6 (lower tower), that is, rough argon gas (where the CO content is ~2 - 5%), is reheated by the second main heat exchanger 5 and then discharged. A part of this waste gas can also be extracted, condensed into liquid nitrogen by entering the second rectification tower condenser 10, and used as the reflux liquid of the second rectification tower 6.The recycled nitrogen and the makeup nitrogen from the cold box are compressed by the recycled nitrogen compressor 8, and the pressure is increased to 1.2~1.5 MPaG. After being cooled by the sub-heat exchanger 7, it enters the second rectification tower evaporator 9 to provide heat source. The nitrogen is liquefied into liquid nitrogen, and after throttling through the valve, it enters the second rectification tower condenser 10 to provide the cold source required by the rectification tower. The nitrogen at the top of the second rectification tower condenser 10 is preliminarily reheated by the liquid nitrogen sub-cooler 11 and then divided into two parts. One part of the nitrogen enters the recycled nitrogen compressor 8 after being reheated by the sub-heat exchanger 7; the other part of the nitrogen enters the second main heat exchanger 5, is reheated, enters the boosting end of the expander 12 to be boosted, is cooled to about 40 °C by the cooler 13, and the cooled nitrogen enters the second main heat exchanger 5 to be further cooled and then sent to the expansion end of the expander 12 for expansion. The expanded nitrogen enters the adsorption dehydration and decarbonization system after being reheated by the second main heat exchanger 5 to provide the regenerated nitrogen.

[0067] The comprehensive argon extraction rate of the product of the above solution: ≥96%.

[0068] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for purifying the tail gas of a single crystal furnace, which is used to purify the tail gas of the auxiliary pump and the main pump of the single crystal furnace, and is characterized in that: The method for purifying the tail gas of the single crystal furnace comprises the following steps: Step 1: Removing particulate impurities in the tail gas of the auxiliary pump to obtain filtered tail gas of the auxiliary pump; Step 2: Removing carbon dioxide and water in the filtered tail gas of the auxiliary pump to obtain purified tail gas of the auxiliary pump; Step 3: Cooling and rectifying the purified tail gas of the auxiliary pump to obtain crude product argon gas, and dividing the crude product argon gas into two paths; Step 4: Reheating, compressing and cooling the first path of the crude product argon gas to obtain heat source crude argon gas, using the heat source crude argon gas to provide heat source for rectification to obtain crude argon liquid, using the crude argon liquid as the reflux liquid for rectification, reheating the second path of the crude product argon gas and mixing it with the tail gas of the main pump to obtain feed gas; Step 5: Removing particulate impurities in the feed gas to obtain filtered feed gas; Step 6: Removing hydrocarbons, oxygen and part of carbon monoxide in the filtered feed gas to obtain preliminarily purified feed gas; Step 7: Removing carbon dioxide and water in the preliminarily purified feed gas to obtain thoroughly purified feed gas; Step 8: Cooling and rectifying the thoroughly purified feed gas to obtain product high-purity argon gas, and reheating the product high-purity argon gas and sending it to users.

2. The single crystal furnace tail gas purification method according to claim 1, wherein: In the said Step 6, hydrocarbons, oxygen and part of carbon monoxide in the filtered feed gas are removed by a catalytic method.

3. The single crystal furnace tail gas purification method according to claim 1, characterized in that: In the said Step 7, carbon dioxide and water in the preliminarily purified feed gas are removed by an adsorption method.

4. The single crystal furnace tail gas purification method according to claim 1, wherein: The nitrogen cycle is used to provide heat source and cold source for the rectification of the thoroughly purified feed gas in Step 8 and to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in Step 7.

5. The single crystal furnace tail gas purification method according to claim 4, characterized in that: The said nitrogen cycle is: mixing the supplementary nitrogen and the recycled nitrogen, compressing and cooling them to provide heat source for the rectification of the thoroughly purified feed gas in Step 8 to obtain liquid nitrogen, using the liquid nitrogen to provide cold source for the rectification of the thoroughly purified feed gas in Step 8 to obtain nitrogen, dividing the nitrogen into two paths, reheating the first path of the nitrogen to become the recycled nitrogen, reheating, boosting, cooling, expanding and reheating the second path of the nitrogen to provide regeneration gas for the removal of carbon dioxide and water in the preliminarily purified feed gas in Step 7.

6. A tail gas purification device for a single crystal furnace, which is used to purify the tail gas of the auxiliary pump and the main pump of the single crystal furnace when implementing the single crystal furnace tail gas purification method as described in claim 1, and is characterized in that: The device for purifying the tail gas of the single crystal furnace comprises: An auxiliary pump filter compression system, which is used to remove particulate impurities in the tail gas of the auxiliary pump to obtain the filtered tail gas of the auxiliary pump; An auxiliary pump purification system, which is used to remove carbon dioxide and water in the filtered tail gas of the auxiliary pump to obtain the purified tail gas of the auxiliary pump; A first rectification tower, which is used to rectify the purified tail gas of the auxiliary pump to obtain the crude product argon gas; An auxiliary pump compressor, which is used to compress the first path of the crude product argon gas; A first rectification tower evaporator, which is used to use the heat source crude argon gas to provide heat source for rectification to obtain the crude argon liquid; Main pump filter compression system, which is used to remove particulate impurities in the raw gas to obtain the filtered raw gas; Primary purification system, which is used to remove hydrocarbons, oxygen and part of carbon monoxide in the filtered raw gas to obtain the preliminarily purified raw gas; Secondary purification system, which is used to remove carbon dioxide and water in the preliminarily purified raw gas to obtain the thoroughly purified raw gas; Second rectification column, which is used to rectify the thoroughly purified raw gas to respectively obtain the product high-purity argon gas; Heat exchanger group, which is used to cool the purified tail gas of the auxiliary pump, reheating and cooling the first path of the product crude argon gas, reheating the second path of the product crude argon gas, cooling the thoroughly purified raw gas, and reheating the product high-purity argon gas; The auxiliary pump filter compression system has a gas inlet and a gas outlet, the auxiliary pump purification system has a gas inlet and a gas outlet, the first rectification column has a gas inlet, a gas outlet and a reflux liquid inlet, the auxiliary pump compressor has a gas inlet and a gas outlet, the first rectification column evaporator has a gas inlet and a liquid outlet, the main pump filter compression system has a gas inlet and a gas outlet, the primary purification system has a gas inlet and a gas outlet, the secondary purification system has a gas inlet and a gas outlet, and the second rectification column has a gas inlet and a gas outlet; The tail gas of the auxiliary pump is connected to the gas inlet of the auxiliary pump filter compression system, the gas outlet of the auxiliary pump filter compression system is connected to the gas inlet of the auxiliary pump purification system, the gas outlet of the auxiliary pump purification system is connected to the gas inlet of the first rectification column through the heat exchanger group, the gas outlet of the first rectification column is respectively connected to the gas inlet of the auxiliary pump compressor through the heat exchanger group and the gas inlet of the main pump filter compression system through the heat exchanger group, the gas outlet of the auxiliary pump compressor is connected to the gas inlet of the first rectification column evaporator through the heat exchanger group, the liquid outlet of the first rectification column evaporator is connected to the reflux liquid inlet of the first rectification column, the raw gas is connected to the gas inlet of the main pump filter compression system, the gas outlet of the main pump filter compression system is connected to the gas inlet of the primary purification system, the gas outlet of the primary purification system is connected to the gas inlet of the secondary purification system, the gas outlet of the secondary purification system is connected to the gas inlet of the second rectification column through the heat exchanger group, and the gas outlet of the second rectification column is connected to the user through the heat exchanger group.

7. The single crystal furnace tail gas purification device according to claim 6, characterized in that: The primary purification system is a catalytic carbon monoxide and hydrocarbon system that uses a catalytic method to remove hydrocarbons, oxygen and part of carbon monoxide in the filtered raw gas, and the secondary purification system is an adsorption dehydration and decarbonization system that uses an adsorption method to remove carbon dioxide and water in the preliminarily purified raw gas.

8. The single crystal furnace tail gas purification device according to claim 7, characterized in that: The heat exchanger group includes: The first main heat exchanger is used to cool the purified tail gas of the auxiliary pump, reheating and cooling the first path of the crude argon product gas, and reheating the second path of the crude argon product gas; The second main heat exchanger is used to cool the thoroughly purified raw material gas and reheat the high-purity argon product gas; The gas outlet of the auxiliary pump purification system is connected to the gas inlet of the first rectification column through the first main heat exchanger. The gas outlet of the first rectification column is connected to the gas inlet of the auxiliary pump compressor through the first main heat exchanger. The gas outlet of the auxiliary pump compressor is connected to the gas inlet of the first rectification column evaporator through the first main heat exchanger. The gas outlet of the first rectification column is connected to the gas inlet of the main pump filter compression system through the first main heat exchanger; The gas outlet of the secondary purification system is connected to the gas inlet of the second rectification column through the second main heat exchanger. The gas outlet of the second rectification column is connected to the user through the second main heat exchanger.

9. The single crystal furnace tail gas purification device according to claim 8, characterized in that: The single crystal furnace tail gas purification device further includes a nitrogen circulation system, which is used to provide heat source and cold source for the second rectification column and provide regeneration gas for the secondary purification system.

10. The single crystal furnace tail gas purification device according to claim 9, wherein: The nitrogen circulation system includes a circulating nitrogen compressor, a second rectification column evaporator, a second rectification column condenser, an expander, and a cooler; the circulating nitrogen compressor has a gas inlet and a gas outlet, the second rectification column evaporator has a gas inlet and a liquid outlet, the second rectification column condenser has a liquid inlet and a gas outlet, the expander has a compression end and an expansion end, the compression end has a gas inlet and a gas outlet, the expansion end has a gas inlet and a gas outlet, the cooler has a gas inlet and a gas outlet; the secondary purification system has a regeneration gas inlet; The heat exchanger group further includes an auxiliary heat exchanger and a liquid nitrogen subcooler; Make-up nitrogen and circulating nitrogen are introduced into the gas inlet of the circulating nitrogen compressor. The gas outlet of the circulating nitrogen compressor is connected to the gas inlet of the second rectification column evaporator through the auxiliary heat exchanger. The liquid outlet of the second rectification column evaporator is connected to the liquid inlet of the second rectification column condenser through the liquid nitrogen subcooler. The gas outlet of the second rectification column condenser is connected to the gas inlet of the circulating nitrogen compressor through the liquid nitrogen subcooler and then through the auxiliary heat exchanger respectively, and is connected to the gas inlet of the compression end through the second main heat exchanger. The gas outlet of the compression end is connected to the gas inlet of the cooler. The gas outlet of the cooler is connected to the gas inlet of the expansion end through the second main heat exchanger. The gas outlet of the expansion end is connected to the regeneration gas inlet of the secondary purification system through the second main heat exchanger.

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