Purification device and purification method for removing NO2 and N2O from NO

Abstract

The invention discloses a purification device and a purification method for removing NO2 and N2O from NO. The purification device for removing NO2 and N2O from NO comprises: a primary refrigeration device for freezing and solidifying NO2 and N2O in raw gas; a secondary refrigeration device connected to the gas outlet of the primary refrigeration device by pipes, and used for secondary freezing and solidifying the unsolidified NO2 and N2O in the primary refrigeration device; a negative pressure sampling and analysis device connected to the gas outlet of the secondary refrigeration device, and used for sampling and analyzing the gas discharged from the secondary refrigeration device; and a product tank connected to the gas outlet of the negative pressure sampling and analysis device by pipes, and used for storing and analyzing qualified NO gas. The device has low equipment investment, low cost, high recovery rate, and is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the field of NO purification, and in particular to a purification device and a purification method for removing NO2 and N2O from NO. Background Art

[0002] At present, NO has played a unique role in various fields such as medicine, electronics, and chemical industry. In medicine, it is used for auxiliary diagnosis and treatment in clinical experiments and as a stabilizer for organic reactions. In semiconductors, it is used for oxidation and chemical vapor deposition processes in production, and is used as a standard mixed gas for atmospheric monitoring.

[0003] In the chemical industry, it can be used to manufacture nitric acid, silicone oxide film and carbonyl nitrosyl, and can also be used as a bleaching agent for rayon, a stabilizer for propylene and dimethyl ether, and an emergency terminator in PVC production. For example, NO, which is used as an emergency terminator in PVC production, quickly terminates the polymerization of PVC monomers in the reactor when there is a power outage or an emergency accident to prevent the reactor from exploding due to excessive temperature. NO has obvious advantages over previous liquid terminators. It does not require N2 as a carrier gas, has a strong ability to bind PVC monomers, is fast, and has a long shelf life. However, the methods for producing NO gas widely now all contain NO2 gas, which combines with PVC monomers to form explosive chelates, posing a great safety hazard. Therefore, the NO2 gas content in NO gas must be strictly controlled (≤50ppm) when used, and the removal of NO2 and N2O impurities in NO is the main direction and difficulty of technical research at home and abroad.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0005] The object of the present invention is to provide a purification device for removing NO2 and N2O from NO, which can effectively alleviate the problem of difficulty in removing NO2 and N2O from NO.

[0006] To achieve the above-mentioned purpose, an embodiment of the present invention provides a purification device for removing NO2 and N2O from NO, comprising: a primary refrigeration device, used to freeze and solidify NO2 and N2O gases in raw gas; a secondary refrigeration device, pipe-connected to the gas outlet end of the primary refrigeration device, the secondary refrigeration device is used to perform secondary freeze-solidification on NO2 and N2O that are not completely solidified in the primary refrigeration device; a negative pressure sampling and analysis device, connected to the gas outlet end of the secondary refrigeration device, the negative pressure sampling and analysis device is used to sample and analyze the gas discharged from the secondary refrigeration device; and a product tank, pipe-connected to the gas outlet end of the negative pressure sampling and analysis device, the product tank is used to store NO gas that passes the analysis.

[0007] In one or more embodiments of the present invention, the primary freezing device includes a primary freezing tank, which is provided with a primary freezing feed inlet and a primary freezing discharge port, wherein the primary freezing feed inlet is connected to a raw material tank via a seventh pipeline.

[0008] In one or more embodiments of the present invention, the primary freezing tank is also provided with a primary refrigerant feed pipe and a primary refrigerant discharge pipe, and a primary refrigerant coil is provided inside the primary freezing tank, and both ends of the primary refrigerant coil are respectively connected to the primary refrigerant feed pipe and the primary refrigerant discharge pipe.

[0009] In one or more embodiments of the present invention, the secondary refrigeration device also includes a secondary refrigeration tank, which is provided with a secondary refrigeration feed port and a secondary refrigeration discharge port, wherein the secondary refrigeration feed port and the primary refrigeration discharge port are connected to a first pipe, and a fourth valve and a fifth valve are provided on the first pipe, and the secondary refrigeration discharge port and the primary refrigeration feed port are connected to a third pipe.

[0010] In one or more embodiments of the present invention, the secondary refrigeration tank is also provided with a secondary refrigerant feed pipe and a secondary refrigerant discharge pipe, and a secondary refrigerant coil is provided inside the secondary refrigeration tank. Both ends of the secondary refrigerant coil are respectively connected to the secondary refrigerant feed pipe and the secondary refrigerant discharge pipe.

[0011] In one or more embodiments of the present invention, the third pipeline is connected to the feed port of the product tank via a second pipeline, and the negative pressure sampling and analysis device is connected to the second pipeline.

[0012] In one or more embodiments of the present invention, the negative pressure vacuum device is connected to the primary freezing outlet and the secondary freezing outlet via a fourth pipeline and a fifth pipeline, and a third valve and a sixth valve are provided on the fourth pipeline and the fifth pipeline, respectively.

[0013] In one or more embodiments of the present invention, the primary freezing tank is provided with a first thermometer, a second thermometer, a third thermometer and a first pressure meter.

[0014] In one or more embodiments of the present invention, the secondary freezing tank is provided with a fourth thermometer, a fifth thermometer, a sixth thermometer and a second pressure meter.

[0015] In one or more embodiments of the present invention, a purification method of a purification device for removing NO2 and N2O from NO comprises the following steps:

[0016] The primary refrigeration device and the secondary refrigeration device are vacuumed under negative pressure to remove impurities;

[0017] The primary refrigeration device and the secondary refrigeration device are cryogenically treated to a certain temperature;

[0018] First, the raw gas is introduced into the primary refrigeration device. The NO2 and N2O in the raw gas solidify at low temperature and remain in the primary refrigeration tank. The incompletely solidified NO2 and N2O gases enter the secondary refrigeration device with the remaining gas for secondary solidification treatment.

[0019] The purified and qualified gas is collected and stored.

[0020] Compared with the prior art, the purification device for removing NO2 and N2O from NO according to the embodiment of the present invention has the following advantages:

[0021] 1. The gas is separated and purified by utilizing the difference in melting points of NO (melting point: -163.6°C), NO2 (melting point: -11°C) and N2O (melting point: -90.8°C), which solves the current technical problems of the disproportionation reaction of NO and the removal of NO2 and N2O impurities produced by the disproportionation reaction. The principle is simple and the implementation requirements are low.

[0022] 2. This device not only solves the technical problem of the difficulty in removing NO2 and N2O impurities in NO, but can also remove impurities such as SO2 (melting point: -75.5℃), CO2 (melting point: -56.6℃), and H2O (melting point: 0℃).

[0023] 3. The device includes a primary freezing and separation device, a secondary freezing and separation device, a negative pressure vacuum device, a negative pressure sampling and analysis device, and a product tank. The operation process is simple and safe, the cost is low, the equipment is small, the energy consumption is low, the economy is good, the NO2 and N2O removal effect is good, the yield is high, and it is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic flow diagram of a purification device for removing NO2 and N2O from NO according to one embodiment of the present invention.

[0025] Description of main reference numerals:

[0026] 1. Raw material tank; 2. First valve; 3. Second valve; 4. First-level refrigeration sewage outlet; 5. First-level refrigeration feed inlet; 6. First thermometer; 7. Second thermometer; 8. First-level refrigerant feed pipe; 9. First-level refrigerant discharge pipe; 10. First-level refrigeration tank; 11. First-level refrigerant coil; 12. Third thermometer; 13. First pressure gauge; 14. First-level refrigeration discharge port; 15. Third valve; 16. Fourth valve; 17. Second-level refrigeration sewage outlet; 18. Fifth valve; 19. Second-level refrigeration feed inlet; 20. Fourth thermometer; 21. Fifth thermometer; 22. Second-level refrigerant feed pipe; 23. Second-level refrigerant discharge pipe ; 24. Secondary refrigerant coil; 25. Sixth thermometer; 26. Secondary freezing tank; 27. Second pressure gauge; 28. Secondary freezing outlet; 29. ​​Sixth valve; 30. Seventh valve; 31. Eighth valve; 32. Ninth valve; 33. Tenth valve; 34. Negative pressure sampling and analysis device; 35. Eleventh valve; 36. Twelfth valve; 37. Product tank; 38. Negative pressure vacuum device; 39. First pipeline; 40. Second pipeline; 41. Third pipeline; 42. Fourth pipeline; 43. Fifth pipeline; 44. Sixth pipeline; 45. Seventh pipeline; 46. First negative pressure pump; 47. Second negative pressure pump. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0028] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0029] like Figure 1 As shown, the purification device for removing NO2 and N2O from NO according to the preferred embodiment of the present invention comprises: a primary refrigeration device, a secondary refrigeration device, a negative pressure sampling and analysis device 34 and a product tank 37. The raw gas is frozen by the primary refrigeration device and the secondary refrigeration device to solidify NO2 and N2O and retain them in the refrigeration device. At this time, NO is still in gaseous state and can be introduced into the product tank 37. The obtained purified gas is introduced into the product tank 37 after being tested by the negative pressure sampling and analysis device 34 and is qualified. If it is unqualified, it is frozen again by the primary refrigeration device and the secondary refrigeration device until it is qualified and then introduced into the product tank 37.

[0030] like Figure 1As shown, in a specific embodiment, the primary refrigeration device includes a primary refrigeration tank 10, and the primary refrigeration tank 10 is provided with a primary refrigeration feed port 5 and a primary refrigeration discharge port 14, wherein the primary refrigeration feed port 5 is connected to the raw material tank 1 through a seventh pipeline 45. The raw material tank 1 can introduce the raw material gas into the primary refrigeration tank 10 through the primary refrigeration feed port 5.

[0031] The first-level freezing tank 10 is also provided with a first-level refrigerant feed pipe 8 and a first-level refrigerant discharge pipe 9, and a first-level refrigerant coil 11 is provided inside the first-level freezing tank 10. The two ends of the first-level refrigerant coil 11 are respectively connected to the first-level refrigerant feed pipe 8 and the first-level refrigerant discharge pipe 9, and the first-level refrigerant feed pipe 8 and the first-level refrigerant discharge pipe 9 are connected to an external refrigeration equipment for providing refrigerant medium to the first-level refrigerant coil 11, so that the first-level freezing tank 10 is cooled to a specified temperature.

[0032] The first-stage freezing tank 10 is provided with a first thermometer 6, a second thermometer 7, a third thermometer 12 and a first pressure gauge 13, and the first thermometer 6, the second thermometer 7 and the third thermometer 12 are distributed at the upper, middle and lower positions of the tank body. When the temperature inside the tank body is consistent, the freezing operation is performed. The first pressure gauge is used to monitor the pressure inside the tank in real time and make relevant adjustments in time.

[0033] The secondary refrigeration device also includes a secondary freezing tank 26, which is provided with a secondary freezing feed port 19 and a secondary freezing discharge port 28. The secondary freezing feed port 19 and the primary freezing discharge port 14 are connected to a first pipeline 39, and a fifth valve 18 and a fourth valve 16 are provided on the first pipeline 39, and the fifth valve 18 and the fourth valve 16 are respectively arranged near the secondary freezing feed port 19 and the primary freezing discharge port 14. A third pipeline 41 is connected between the secondary freezing discharge port 28 and the seventh pipeline 45, and a seventh valve 30 and an eighth valve 31 are provided on the third pipeline 41. A second negative pressure pump 47 is also provided on the third pipeline 41 between the eighth valve 31 and the seventh pipeline 45, and the connection between the third pipeline 41 and the seventh pipeline 45 divides the third pipeline 41 into two parts, and a first valve 2 and a second valve 3 are respectively provided on each part of the pipeline, which are used to control the gas of the raw material tank 1 and the secondary freezing tank 26 to enter the primary freezing tank 10.

[0034] The secondary freezing tank 26 is also provided with a secondary refrigerant feed pipe 22 and a secondary refrigerant discharge pipe 23. A secondary refrigerant coil 24 is provided inside the secondary freezing tank 26, and both ends of the secondary refrigerant coil 24 are connected to the secondary refrigerant feed pipe 22 and the secondary refrigerant discharge pipe 23 respectively. The secondary refrigerant feed pipe 22 and the secondary refrigerant discharge pipe 23 are connected to an external refrigeration device. It is used to provide a refrigerant medium for the secondary refrigerant coil 24, so that the secondary freezing tank 26 is cooled to a specified temperature (i.e., lower than the melting point temperature of N2O and NO2, and higher than the melting point temperature of NO), and the temperature is generally controlled between -91°C and -100°C.

[0035] The second-stage freezing tank 26 is provided with a fourth thermometer 20, a fifth thermometer 21, a sixth thermometer 25 and a second pressure gauge 27, and the fourth thermometer 20, the fifth thermometer 21 and the sixth thermometer 25 are distributed at the upper, middle and lower positions of the tank body. When the temperature inside the tank body is consistent, the freezing operation is performed. The second pressure gauge 27 is used to monitor the pressure inside the tank in real time and make relevant adjustments in time.

[0036] The third pipeline 41 between the seventh valve 30 and the eighth valve 31 is connected to the feed port of the product tank 37 by a second pipeline 40, and the negative pressure sampling and analysis device 34 is connected to the second pipeline 40. The air inlet end of the negative pressure sampling and analysis device 34 is provided with an eleventh valve 35, the second pipeline 40 between the negative pressure sampling and analysis device 34 and the product tank 37 is provided with a twelfth valve 36, and the air inlet end of the product tank 37 is also provided with a first negative pressure pump 46. When the negative pressure sampling and analysis device 34 detects that the purified gas is qualified, the twelfth valve 36 is opened, and the first negative pressure pump 46 draws the gas in the secondary refrigeration tank 26 into the product tank 37.

[0037] The negative pressure vacuum device 38 is respectively connected to the first-level freezing outlet 14 and the second-level freezing outlet 28 via a fourth pipe 42 and a fifth pipe 43, and the fourth pipe 42 and the fifth pipe 43 are respectively provided with a third valve 15 and a sixth valve 29. The negative pressure vacuum device 38 is used to evacuate the first-level freezing tank 10 and the second-level freezing tank 26.

[0038] A sixth pipeline 44 is also connected between the second pipeline 40 and the negative pressure vacuum device 38, and a ninth valve 32 is provided on the sixth pipeline 44. When the first valve 2, the third valve 15, the fourth valve 16, the sixth valve 29, the seventh valve 30 and the tenth valve 33 are closed, and the second valve 3, the eighth valve 31 and the ninth valve 32 are opened, the negative pressure vacuum device 38 can reversely evacuate the primary freezing tank 10 and the secondary freezing tank 26 to discharge impurities.

[0039] The primary freezing tank 10 and the secondary freezing tank 26 are also provided with a primary freezing sewage outlet 4 and a secondary freezing sewage outlet 17, wherein the primary freezing sewage outlet 4 and the secondary freezing sewage outlet 17 are also provided with valves correspondingly for discharging sewage from the primary freezing tank 10 and the secondary freezing tank 26.

[0040] The purification device for removing NO2 and N2O from NO of the present invention has the following steps:

[0041] First, the third valve 15 and the sixth valve 29 are opened, and the other valves are closed. Then, the first-stage freezing tank 10 and the second-stage freezing tank 26 are vacuumed by the negative pressure vacuum device 38 to discharge the gas in the tank, and then the third valve 15 and the sixth valve 29 are closed. Then, the refrigerant is introduced into the first-stage refrigerant coil 11 and the second-stage refrigerant coil 24 through the external refrigeration equipment to realize the freezing treatment of the first-stage freezing tank 10 and the second-stage freezing tank 26. At this time, the temperature in the tank is controlled at a specified temperature (i.e., lower than the melting point of N2O and NO2, and higher than the melting point of NO), and the general temperature is controlled between -91°C and -100°C.

[0042] Then open the first valve 2 and the second valve 3, and use the negative pressure suction of the primary freezing tank 10 to pass the raw material tank 1 into the primary freezing tank 10. At this time, due to the different melting points of NO2, N2O and NO (NO melting point: -163.6°C, NO2 melting point: -11°C, N2O melting point: -90.8°C), N2O and NO2 will be solidified by cold and remain at the bottom of the primary freezing tank 10, and discharged through the primary freezing sewage outlet 4. Then close the first valve 2 and the second valve 3, open the fourth valve 16 and the fifth valve 18, at this time, under the action of negative pressure, the gas after the freezing treatment of the primary freezing tank 10 will be passed into the secondary freezing tank 26, and the fifth valve 18 will be closed after the air pressure of the primary freezing tank 10 and the secondary freezing tank 26 are balanced. Then the secondary freezing tank 26 uses low temperature to perform secondary freezing treatment on the treated gas in the primary freezing tank 10, so that the untreated N2O and NO2 are secondary solidified into solids and retained at the bottom of the secondary freezing tank 26 and discharged through the secondary freezing sewage outlet 17.

[0043] Then open the seventh valve 30, the tenth valve 33 and the eleventh valve 35, and perform sampling and analysis on the secondary freezing tank 26 after secondary treatment through the negative pressure sampling and analysis device 34. If qualified, close the eleventh valve 35, open the twelfth valve 36, and use the first negative pressure pump 46 to pass the gas in the secondary freezing tank 26 into the product tank 37. If unqualified, close the tenth valve 33, open the eighth valve 31 and the second valve 3 and the second negative pressure pump 47, and introduce the unqualified gas in the secondary freezing tank 26 into the primary freezing tank 10 for recirculation and freezing treatment.

[0044] Among them, when the first valve 2, the third valve 15, the fourth valve 16, the sixth valve 29, the seventh valve 30 and the tenth valve 33 are closed, and the second valve 3, the eighth valve 31 and the ninth valve 32 are opened, the negative pressure vacuum device 38 can reversely vacuum the first-level freezing tank 10 and the second-level freezing tank 26 to discharge impurities.

[0045] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A purification device for removing NO2 and N2O from NO, characterized in that: include: The primary refrigeration device is used to freeze and solidify NO2 and N2O gases in the raw gas; A secondary refrigeration device is connected to the gas outlet of the primary refrigeration device through a pipe, and is used to perform secondary refrigeration and solidification on the unsolidified NO2 and N2O in the primary refrigeration device; A negative pressure sampling and analysis device connected to the gas outlet of the secondary refrigeration device, the negative pressure sampling and analysis device is used to sample and analyze the gas discharged from the secondary refrigeration device; and A product tank is pipe-connected to the gas outlet end of the negative pressure sampling and analysis device, and the product tank is used to store NO gas that has passed the analysis. The first-level refrigeration device includes a first-level refrigeration tank, and the first-level refrigeration tank is provided with a first-level refrigeration feed port and a first-level refrigeration discharge port, wherein the first-level refrigeration feed port is connected to the raw material tank through a seventh pipeline, and the first-level refrigeration tank is also provided with a first-level refrigerant feed pipe and a first-level refrigerant discharge pipe, respectively. A first-level refrigerant coil is provided inside the first-level refrigeration tank, and the two ends of the first-level refrigerant coil are respectively connected to the first-level refrigerant feed pipe and the first-level refrigerant discharge pipe, and the second-level refrigeration device also includes a second-level refrigeration tank, and the second-level refrigeration tank is provided with a second-level refrigeration feed port and a second-level refrigeration discharge port, wherein the second-level refrigeration feed port and the first-level refrigeration discharge port are connected to a first pipeline, and the first pipeline is provided with a fourth valve and a fifth valve, and the second-level refrigeration discharge port is connected to the first-level refrigeration feed port A third pipeline is connected, and a secondary refrigerant feed pipe and a secondary refrigerant discharge pipe are respectively provided on the secondary freezing tank. A secondary refrigerant coil is provided inside the secondary freezing tank, and both ends of the secondary refrigerant coil are respectively connected to the secondary refrigerant feed pipe and the secondary refrigerant discharge pipe. The third pipeline is connected to the feed port of the product tank with a second pipeline, and the negative pressure sampling and analysis device is connected to the second pipeline. The negative pressure vacuum device is respectively connected to the primary freezing discharge port and the secondary freezing discharge port with a fourth pipeline and a fifth pipeline, and the fourth pipeline and the fifth pipeline are respectively provided with a third valve and a sixth valve, the primary freezing tank is provided with a first thermometer, a second thermometer, a third thermometer and a first pressure gauge, and the secondary freezing tank is provided with a fourth thermometer, a fifth thermometer, a sixth thermometer and a second pressure gauge. A purification method for removing NO2 and N2O from NO by a purification device comprises the following steps: The primary refrigeration device and the secondary refrigeration device are vacuumed under negative pressure to remove impurities; The primary refrigeration device and the secondary refrigeration device are cryogenically treated to a certain temperature; First, feed the raw gas into the primary refrigeration device, and the NO2 and N2O in the raw gas solidify at low temperature. The solid NO2 and N2O remain in the primary refrigeration tank, and the incompletely solidified NO2 and N2O gases enter the secondary refrigeration device with the remaining gas for secondary solidification treatment; The purified and qualified gas is collected and stored, specifically: First, open the third valve and the sixth valve, and close the other valves. Then, use the negative pressure vacuum device to vacuum the primary and secondary freezing tanks to discharge the gas in the tanks. Then, close the third valve and the sixth valve. Then, use the external refrigeration equipment to pass the refrigerant medium into the primary and secondary refrigerant coils to achieve freezing treatment of the primary and secondary freezing tanks. At this time, the temperature in the tank is controlled at a specified temperature between -91°C and -100°C. Then open the first valve and the second valve, and use the negative pressure suction of the primary freezing tank to pass the raw material tank into the primary freezing tank. Due to the different melting points of NO2, N2O and NO, N2O and NO2 will be solidified by cold and remain at the bottom of the primary freezing tank and discharged from the primary freezing sewage outlet. Then close the first valve and the second valve, open the fourth valve and the fifth valve. Under the action of negative pressure, the gas after freezing treatment in the primary freezing tank will be passed into the secondary freezing tank. After the air pressure of the primary freezing tank and the secondary freezing tank is balanced, Close the fifth valve, and then the secondary freezing tank uses low temperature to perform secondary freezing treatment on the treated gas in the primary freezing tank, so that the untreated N2O and NO2 are secondary solidified into solids and retained at the bottom of the secondary freezing tank and discharged through the secondary freezing sewage outlet, and then open the seventh valve, the tenth valve and the eleventh valve, and use the negative pressure sampling and analysis device to sample and analyze the secondary treatment in the secondary freezing tank. If it is qualified, close the eleventh valve and open the twelfth valve, and use the first negative pressure pump to pass the gas in the secondary freezing tank into the product tank. If it is unqualified, close the tenth valve, and open the eighth valve, the second valve and the second negative pressure pump to introduce the unqualified gas in the secondary freezing tank into the primary freezing tank for recycling freezing treatment. Among them, when the first valve, the third valve, the fourth valve, the sixth valve, the seventh valve and the tenth valve are closed, and the second valve, the eighth valve and the ninth valve are opened, the negative pressure vacuum device can reversely vacuum the primary freezing tank and the secondary freezing tank to discharge impurities.

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