Method and device for purifying hydrogen sulfide gas

Abstract

This invention relates to a method for purifying hydrogen sulfide gas, comprising the following steps: crude hydrogen sulfide gas is passed into a first adsorption tower containing modified 5A molecular sieves; the hydrogen sulfide gas after adsorption in the first adsorption tower is passed into a second adsorption tower containing modified 5A molecular sieves; the hydrogen sulfide gas after adsorption in the second adsorption tower is passed into a cryogenic storage tank, where it condenses into a solid state; the cryogenic storage tank is evacuated to a negative pressure, and then the temperature of the cryogenic storage tank is slowly increased, causing the hydrogen sulfide in the cryogenic storage tank to vaporize and be filled into a product collection bottle, yielding a hydrogen sulfide product with a purity greater than 99.99%. By sequentially setting up the first and second adsorption towers, and using modified 5A molecular sieves to sequentially adsorb hydrogen sulfide at room temperature and cryogenically, impurities such as carbon dioxide and moisture in the hydrogen sulfide gas can be effectively removed. Vacuuming the cryogenic storage tank can effectively remove low-boiling-point impurities such as hydrogen and nitrogen, which is beneficial for improving product purity.

Description

Technical Field

[0001] This invention relates to the field of gas purification, and more particularly to a method and apparatus for purifying hydrogen sulfide gas. Background Technology

[0002] High-purity hydrogen sulfide is an important electronic gas used in CVD, doping, and other processes to fabricate optical and electronic devices. Besides semiconductors, hydrogen sulfide gas plays a crucial role in defense chemicals, electroluminescence, photoconductors, and photovoltaics.

[0003] Patent CN108392948A discloses a process and apparatus for purifying hydrogen sulfide. It involves multi-stage pressure swing adsorption (PSA) of methanol-washed acidic gas, using different molecular sieves such as alumina, silica gel, zeolite, and activated carbon to adsorb gaseous impurities, yielding a hydrogen sulfide product with a purity greater than 92%. This method is complex and produces a product with relatively low purity.

[0004] Patent CN112408336A provides a process combining liquid-phase absorption and distillation. In this process, some impurities in crude hydrogen sulfide are adsorbed and liquefied to obtain a first crude hydrogen sulfide product. The first crude hydrogen sulfide product is then fractionated to obtain a second crude hydrogen sulfide product and light waste gas. The second crude hydrogen sulfide product is then fractionated to obtain hydrogen sulfide gas and heavy impurities, resulting in a hydrogen sulfide product with a purity of 99.99%. This method is relatively complex and energy-intensive.

[0005] One of the most difficult problems to solve in the purification of hydrogen sulfide gas is how to remove impurities such as water, carbon dioxide, and hydrogen. Therefore, there is an urgent need to invent a method for purifying hydrogen sulfide gas that can remove impurities simply, economically, and efficiently. Summary of the Invention

[0006] In order to overcome the above-mentioned problems in the prior art, the purpose of this invention is to provide a method and apparatus for purifying hydrogen sulfide gas, which can remove impurities simply, economically and efficiently.

[0007] To achieve the objectives of this invention, the specific technical solution provided by this invention is as follows:

[0008] An apparatus for purifying hydrogen sulfide gas includes a first adsorption tower, a second adsorption tower, and a cryogenic storage tank connected in sequence.

[0009] The first adsorption tower has a feed inlet at the bottom and a discharge outlet at the top.

[0010] The second adsorption tower has a feed inlet at the bottom and a discharge outlet at the top.

[0011] The top of the cryogenic storage tank is provided with a cryogenic storage tank inlet and a cryogenic storage tank outlet;

[0012] The feed inlet of the first adsorption tower is connected to the crude hydrogen sulfide gas source through a pipeline, the discharge outlet of the first adsorption tower is connected to the feed inlet of the second adsorption tower through a pipeline, the discharge outlet of the second adsorption tower is connected to the feed inlet of the cryogenic storage tank through a pipeline, and the discharge outlet of the cryogenic storage tank is connected to the product collection bottle.

[0013] Preferably, the second adsorption tower is externally wound with a silicone coil, which is connected to a low-temperature constant-temperature reaction bath. The silicone coil contains a 60% concentration ethylene glycol aqueous solution that circulates through the low-temperature constant-temperature reaction bath. The diameter of the silicone coil is 12 mm, and the ratio of the diameter of the silicone coil to the diameter of the second adsorption tower is 0.26:1.

[0014] Preferably, the top of the cryogenic storage tank is also provided with a cryogenic storage tank exhaust port, which is connected to a vacuum pump through a pipeline.

[0015] Preferably, the cryogenic storage tank is provided with a jacket, which has a liquid nitrogen inlet and a cold nitrogen outlet, and the liquid nitrogen inlet of the jacket is connected to the liquid nitrogen tank.

[0016] Preferably, the liquid nitrogen tank has a liquid nitrogen tank outlet at the bottom, and the liquid nitrogen tank outlet is connected to the liquid nitrogen inlet of the cryogenic storage tank jacket through a pipeline.

[0017] Preferably, the ratio of the diameter to the height of the first adsorption tower to the second adsorption tower is 45:1000, and both the first and second adsorption towers are filled with modified 5A molecular sieves.

[0018] The present invention also provides a method for purifying hydrogen sulfide gas, which is implemented using an apparatus for purifying hydrogen sulfide gas, and includes the following steps:

[0019] S1. The crude hydrogen sulfide gas is introduced into the first adsorption tower containing modified 5A molecular sieve. The temperature of the first adsorption tower is controlled at 15℃~35℃ and the pressure is controlled at 0.6MPa~1MPa.

[0020] S2. The hydrogen sulfide gas after being adsorbed by the first adsorption tower is passed into the second adsorption tower containing modified 5A molecular sieve. The temperature is controlled at -50℃ to -30℃ and the pressure is controlled at 0.5MPa to 0.8MPa.

[0021] S3. The hydrogen sulfide gas after adsorption in the second adsorption tower is introduced into a cryogenic storage tank, where it condenses into a solid state.

[0022] S4. Evacuate the cryogenic storage tank to negative pressure and continue for 10 minutes. Then stop evacuating and close the liquid nitrogen inlet of the cryogenic storage tank jacket. Slowly raise the temperature of the cryogenic storage tank. After the hydrogen sulfide in the cryogenic storage tank is vaporized, it is filled into the product collection bottle to obtain hydrogen sulfide product with a purity greater than 99.99%.

[0023] Preferably, the modification method of the 5A molecular sieve is as follows: the 5A molecular sieve is immersed in a mixed solution of 10% dilute nitric acid and saturated hydrosulfuric acid with a volume ratio of 10:1 to 30:1 for 2-4 hours, and then placed in a forced-air drying oven and dried at 80℃-100℃ for 8-10 hours.

[0024] Preferably, in step S1, the flow rate of the crude hydrogen sulfide gas is 3-5 L / min, and the purity of the hydrogen sulfide is 99.5%.

[0025] Preferably, in step S3, the cryogenic storage tank is cooled by liquid nitrogen, and the temperature of the storage tank is controlled to be -120℃ to -90℃.

[0026] The method and apparatus for purifying hydrogen sulfide gas according to the present invention have the following advantages:

[0027] 1. This invention utilizes the adsorption properties of modified 5A molecular sieves by sequentially setting up a first adsorption tower and a second adsorption tower, which can effectively remove impurities from hydrogen sulfide gas and improve the purity of hydrogen sulfide gas. By using modified 5A molecular sieves to sequentially adsorb hydrogen sulfide at room temperature and cryogenically, the adsorption capacity of conventional 5A molecular sieves for hydrogen sulfide is reduced, while the adsorption effect on carbon dioxide and water is enhanced.

[0028] 2. The present invention further ensures the purity of hydrogen sulfide gas by setting up a low-temperature storage tank, resulting in higher quality of the final product. The method of freezing and vacuuming to treat the adsorbed gas can effectively remove low-boiling-point impurities such as hydrogen and nitrogen that are difficult to remove by adsorption, which is conducive to improving product purity.

[0029] 3. The method and apparatus of this invention have a simple structure and are easy to operate, requiring no complex equipment or processes, thus reducing production costs. Furthermore, through a rational pipeline design and the size ratio of the adsorption tower, the entire purification process is more efficient, reducing energy and resource waste. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the apparatus for purifying hydrogen sulfide gas according to the present invention;

[0031] The markings in the diagram are as follows: 1. Crude hydrogen sulfide gas source; 2. First adsorption tower; 3. Second adsorption tower; 4. Silica gel coil; 5. Low-temperature constant temperature reaction bath; 6. Low-temperature storage tank; 7. Vacuum pump; 8. Product collection bottle; 9. Liquid nitrogen tank. Detailed Implementation

[0032] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0033] Device Example 1

[0034] like Figure 1 The diagram shown is a schematic of the apparatus for purifying hydrogen sulfide gas according to the present invention.

[0035] An apparatus for purifying hydrogen sulfide gas includes a crude hydrogen sulfide gas source 1, a first adsorption tower 2, a second adsorption tower 3, a cryogenic storage tank 6, and a product collection bottle 8 connected in sequence.

[0036] The first adsorption tower 2 has a feed inlet at the bottom and a discharge outlet at the top.

[0037] The second adsorption tower 3 is provided with a feed inlet at the bottom and a discharge outlet at the top.

[0038] The top of the cryogenic storage tank 6 is equipped with a cryogenic storage tank inlet, a cryogenic storage tank outlet, and a cryogenic storage tank vent.

[0039] The feed inlet of the first adsorption tower is connected to the crude hydrogen sulfide gas source 1 via a pipeline; the discharge outlet of the first adsorption tower is connected to the feed inlet of the second adsorption tower via a pipeline; the second adsorption tower 3 is externally wound with a silicone coil 4, which is connected to a low-temperature constant-temperature reaction bath 5; the silicone coil 4 contains a 60% concentration ethylene glycol aqueous solution circulating through the low-temperature constant-temperature reaction bath 5; the diameter of the silicone coil 4 is 12 mm, and the ratio of the diameter of the silicone coil 4 to the diameter of the second adsorption tower 3 is 0.26:1; the diameter-to-height ratio of the first adsorption tower 2 is 45:1000, and the diameter-to-height ratio of the second adsorption tower 3 is 45:1000.

[0040] By using a reasonable pipeline design and adsorption tower size ratio, the entire purification process becomes more efficient, reducing the waste of energy and resources.

[0041] The first adsorption tower 2 and the second adsorption tower 3 are both filled with modified 5A molecular sieves.

[0042] By using the first adsorption tower 2 and the second adsorption tower 3 arranged in sequence, the adsorption performance of the modified 5A molecular sieve can effectively remove impurities from hydrogen sulfide gas and improve the purity of hydrogen sulfide gas. The modified 5A molecular sieve is used to perform room temperature adsorption and cryogenic adsorption of hydrogen sulfide in sequence, which reduces the adsorption capacity of conventional 5A molecular sieve for hydrogen sulfide, while enhancing the adsorption effect on carbon dioxide and water.

[0043] The outlet of the second adsorption tower is connected to the inlet of the cryogenic storage tank via a pipeline. The exhaust port of the cryogenic storage tank is connected to the vacuum pump 7 via a pipeline. The outlet of the cryogenic storage tank is connected to the product collection bottle 8. The cryogenic storage tank 6 is equipped with a jacket, which has a liquid nitrogen inlet and a cold nitrogen outlet. The liquid nitrogen inlet of the jacket is connected to the liquid nitrogen tank 9. The bottom of the side wall of the liquid nitrogen tank 9 has a liquid nitrogen outlet. The liquid nitrogen outlet of the liquid nitrogen tank is connected to the liquid nitrogen inlet of the jacket via a pipeline.

[0044] The use of cryogenic storage tank 6 further ensures the purity of hydrogen sulfide gas, resulting in higher quality final products. The use of refrigerated vacuum extraction to treat the adsorbed gas can effectively remove low-boiling-point impurities such as hydrogen and nitrogen that are difficult to remove by adsorption, which is beneficial to improving product purity.

[0045] Valves are installed on the connecting pipelines between the crude hydrogen sulfide gas source 1, the first adsorption tower 2, the second adsorption tower 3, the cryogenic storage tank 6, and the product collection bottle 8.

[0046] This application discloses a device for purifying hydrogen sulfide gas. It has a simple structure, is easy to operate, requires no complex equipment or processes, and reduces production costs.

[0047] The modification method for 5A molecular sieve is as follows: 5A molecular sieve is immersed in a mixed solution of 10% dilute nitric acid and saturated hydrosulfuric acid at a volume ratio of 20:1 for 3 hours. After immersion, it is placed in a forced-air drying oven and dried at 95°C for 10 hours. Examples 1-3 of this application all use this method to prepare modified 5A molecular sieves.

[0048] Method Example 1

[0049] A method for purifying hydrogen sulfide gas, utilizing an apparatus for purifying hydrogen sulfide gas according to an embodiment, includes the following steps:

[0050] S1. Crude hydrogen sulfide gas with a purity of 99.5% is introduced into the first adsorption tower 2, which is equipped with modified 5A molecular sieve, at a flow rate of 5L / min. The temperature of the first adsorption tower 2 is controlled at 20℃ and the pressure is controlled at 0.6MPa~1MPa.

[0051] S2. The hydrogen sulfide gas after being adsorbed by the first adsorption tower 2 is passed into the second adsorption tower 3, which is equipped with modified 5A molecular sieve. The temperature is controlled at -50℃ and the pressure is controlled at 0.5MPa to 0.8MPa.

[0052] S3. The hydrogen sulfide gas after adsorption by the second adsorption tower 3 is introduced into the cryogenic storage tank 6. The hydrogen sulfide gas is condensed into a solid in the cryogenic storage tank 6. The refrigerant of the cryogenic storage tank 6 is liquid nitrogen, and the temperature of the storage tank is controlled at -90℃.

[0053] S4. Evacuate the cryogenic storage tank 6 to a negative pressure and continue for 10 minutes. Then stop evacuating and close the liquid nitrogen inlet on the jacket. This will allow the temperature of the cryogenic storage tank 6 to rise slowly. The hydrogen sulfide in the cryogenic storage tank 6 will vaporize and be filled into the product collection bottle 8 to obtain a hydrogen sulfide product with a purity of 99.992%.

[0054] Method Example 2

[0055] A method for purifying hydrogen sulfide gas, utilizing an apparatus for purifying hydrogen sulfide gas according to an embodiment, includes the following steps:

[0056] S1. Crude hydrogen sulfide gas with a purity of 99.5% is introduced into the first adsorption tower 2, which is equipped with modified 5A molecular sieve, at a flow rate of 4L / min. The temperature of the first adsorption tower 2 is controlled at 35℃ and the pressure is controlled at 0.6MPa~1MPa.

[0057] S2. The hydrogen sulfide gas after being adsorbed by the first adsorption tower 2 is introduced into the second adsorption tower 3, which is equipped with modified 5A molecular sieve. The temperature is controlled at -40℃ and the pressure is controlled at 0.5MPa to 0.8MPa.

[0058] S3. The hydrogen sulfide gas after adsorption by the second adsorption tower 3 is introduced into the cryogenic storage tank 6. The hydrogen sulfide gas is condensed into a solid in the cryogenic storage tank 6. The refrigerant of the cryogenic storage tank 6 is liquid nitrogen, and the temperature of the storage tank is controlled at -100℃.

[0059] S4. Evacuate the cryogenic storage tank 6 to a negative pressure, and then slowly raise the temperature of the cryogenic storage tank 6. After the hydrogen sulfide in the cryogenic storage tank 6 is vaporized, it is filled into the product collection bottle 8 to obtain a hydrogen sulfide product with a purity of 99.994%.

[0060] Method Example 3

[0061] A method for purifying hydrogen sulfide gas, utilizing an apparatus for purifying hydrogen sulfide gas according to an embodiment, includes the following steps:

[0062] S1. Crude hydrogen sulfide gas with a purity of 99.5% is introduced into the first adsorption tower 2, which is equipped with modified 5A molecular sieve, at a flow rate of 3L / min. The temperature of the first adsorption tower 2 is controlled at 15℃ and the pressure is controlled at 0.6MPa~1MPa.

[0063] S2. The hydrogen sulfide gas after being adsorbed by the first adsorption tower 2 is introduced into the second adsorption tower 3, which is equipped with modified 5A molecular sieve. The temperature is controlled at -30℃ and the pressure is controlled at 0.5MPa to 0.8MPa.

[0064] S3. The hydrogen sulfide gas after adsorption by the second adsorption tower 3 is introduced into the cryogenic storage tank 6. The hydrogen sulfide gas is condensed into a solid in the cryogenic storage tank 6. The refrigerant of the cryogenic storage tank 6 is liquid nitrogen, and the temperature of the storage tank is controlled at -120℃.

[0065] S4. Evacuate the cryogenic storage tank 6 to a negative pressure, and then slowly raise the temperature of the cryogenic storage tank 6. After the hydrogen sulfide in the cryogenic storage tank 6 is vaporized, it is filled into the product collection bottle 8 to obtain a hydrogen sulfide product with a purity of 99.995%.

[0066] Comparative Example 1

[0067] Unlike Method Example 1, ordinary 5A molecular sieve adsorbent is used in the first adsorption tower 2 and the second adsorption tower 3. The remaining steps and parameters remain unchanged, and hydrogen sulfide product with a purity of 99.94% is finally obtained.

[0068] Comparative Example 2

[0069] Unlike Method Example 1, the temperature of the second adsorption tower 3 was also controlled at room temperature (20°C), while the other steps and parameters remained unchanged, ultimately yielding a hydrogen sulfide product with a purity of 99.98%.

[0070] This invention utilizes the adsorption properties of modified 5A molecular sieves by sequentially setting up a first adsorption tower 2 and a second adsorption tower 3. This effectively removes impurities from hydrogen sulfide gas, improves the purity of hydrogen sulfide gas, and uses modified 5A molecular sieves to perform room temperature adsorption and cryogenic adsorption of hydrogen sulfide. This reduces the adsorption capacity of conventional 5A molecular sieves for hydrogen sulfide while enhancing the adsorption effect on carbon dioxide and water.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An apparatus for purifying hydrogen sulfide gas, characterized in that, It includes a first adsorption tower, a second adsorption tower, and a cryogenic storage tank connected in sequence; The first adsorption tower has a feed inlet at the bottom and a discharge outlet at the top. The second adsorption tower has a feed inlet at the bottom and a discharge outlet at the top. The top of the cryogenic storage tank is provided with a cryogenic storage tank inlet and a cryogenic storage tank outlet; The feed inlet of the first adsorption tower is connected to the crude hydrogen sulfide gas source through a pipeline, the discharge outlet of the first adsorption tower is connected to the feed inlet of the second adsorption tower through a pipeline, the discharge outlet of the second adsorption tower is connected to the feed inlet of the low temperature storage tank through a pipeline, and the discharge outlet of the low temperature storage tank is connected to the product collection bottle. Both the first and second adsorption towers are filled with modified 5A molecular sieves. The modification method of the 5A molecular sieve is as follows: the 5A molecular sieve is immersed in a mixed solution of dilute nitric acid and saturated hydrosulfuric acid with a volume ratio of 10:1 to 30:1 for 2-4 hours. After immersion, it is placed in a forced-air drying oven and dried at 80℃-100℃ for 8-10 hours.

2. The apparatus for purifying hydrogen sulfide gas according to claim 1, characterized in that, The second adsorption tower is externally wound with a silicone coil, which is connected to a low-temperature constant-temperature reaction bath. The silicone coil contains a 60% volume concentration ethylene glycol aqueous solution that circulates through the low-temperature constant-temperature reaction bath. The diameter of the silicone coil is 12 mm, and the ratio of the diameter of the silicone coil to the diameter of the second adsorption tower is 0.26:

1.

3. The apparatus for purifying hydrogen sulfide gas according to claim 1, characterized in that, The top of the cryogenic storage tank is also provided with a cryogenic storage tank exhaust port, which is connected to a vacuum pump through a pipeline.

4. The apparatus for purifying hydrogen sulfide gas according to claim 1, characterized in that, The cryogenic storage tank is equipped with a jacket, which has a liquid nitrogen inlet and a cold nitrogen outlet. The liquid nitrogen inlet of the jacket is connected to the liquid nitrogen tank.

5. The apparatus for purifying hydrogen sulfide gas according to claim 4, characterized in that, The liquid nitrogen tank has a liquid nitrogen tank outlet at the bottom, and the liquid nitrogen tank outlet is connected to the liquid nitrogen inlet of the cryogenic storage tank jacket through a pipeline.

6. The apparatus for purifying hydrogen sulfide gas according to claim 1, characterized in that, The ratio of the diameter to the height of the first adsorption tower to the second adsorption tower is 45:1000.

7. A method for purifying hydrogen sulfide gas, using the apparatus for purifying hydrogen sulfide gas according to any one of claims 1-6, characterized in that, Includes the following steps: S1. The crude hydrogen sulfide gas is introduced into the first adsorption tower containing modified 5A molecular sieve. The temperature of the first adsorption tower is controlled at 15℃~35℃ and the pressure is controlled at 0.6MPa~1MPa. S2. The hydrogen sulfide gas after being adsorbed by the first adsorption tower is passed into the second adsorption tower containing modified 5A molecular sieve. The temperature is controlled at -50℃ to -30℃ and the pressure is controlled at 0.5MPa to 0.8MPa. S3. The hydrogen sulfide gas after adsorption in the second adsorption tower is introduced into a cryogenic storage tank, where it condenses into a solid state. S4. Evacuate the cryogenic storage tank to negative pressure and continue for 10 minutes. Then stop evacuating and close the liquid nitrogen inlet of the cryogenic storage tank jacket. Slowly raise the temperature of the cryogenic storage tank. After the hydrogen sulfide in the cryogenic storage tank is vaporized, it is filled into the product collection bottle to obtain hydrogen sulfide product with a purity greater than 99.99%.

8. The method for purifying hydrogen sulfide gas according to claim 7, characterized in that, In step S1, the flow rate of the crude hydrogen sulfide gas introduced is 3-5 L / min, and the purity of the hydrogen sulfide is 99.5%.

9. The method for purifying hydrogen sulfide gas according to claim 7, characterized in that, In step S3, the cryogenic storage tank is cooled by liquid nitrogen, and the temperature of the storage tank is controlled to be -120℃ to -90℃.

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