Electronic-grade high-purity hydrogen sulfide and carbon dioxide product and production method thereof
By using polyethylene glycol dimethyl ether absorbent in an absorption tower through absorption and distillation, and combining compression and distillation steps, the problem of separating hydrogen sulfide and carbon dioxide in existing technologies has been solved. This has enabled the efficient and economical production of electronic-grade high-purity hydrogen sulfide and carbon dioxide, which is suitable for large-scale industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI QIYUAN GAS DEV
- Filing Date
- 2026-01-26
- Publication Date
- 2026-04-17
AI Technical Summary
Existing technologies are insufficient for the efficient and economical simultaneous large-scale production of electronic-grade high-purity hydrogen sulfide and electronic-grade ultrapure carbon dioxide from hydrogen sulfide-rich carbon dioxide tail gas. Furthermore, existing methods suffer from poor selectivity in separating hydrogen sulfide and carbon dioxide, resource waste, and substandard purity.
An absorption and distillation method is adopted, using polyethylene glycol dimethyl ether as the absorbent. Hydrogen sulfide is selectively absorbed in the absorption tower. Combining compression, liquefaction and distillation steps, deep separation and purification of carbon dioxide and hydrogen sulfide are achieved. The absorbent is recycled to reduce costs.
It achieves efficient separation of high-purity carbon dioxide and hydrogen sulfide, with a product purity of 99.9%, reducing production costs and energy consumption, making it suitable for large-scale industrial production and meeting the high purity requirements of the precision electronics industry.
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Figure CN121872385A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of gas separation and purification, and more specifically, it relates to an electronic-grade high-purity hydrogen sulfide and carbon dioxide product and a method for producing the same. Background Technology
[0002] In industrial processes such as ammonia synthesis, methanol production, synthetic petroleum, and natural gas production, the off-gas produced during carbon dioxide removal contains a large amount of carbon dioxide. Its specific concentration varies considerably depending on the raw materials, decarbonization methods, regeneration processes, and process conditions. Simultaneously, sulfides, primarily hydrogen sulfide, in the raw material gas are transferred to the off-gas during decarbonization, causing the sulfur content in the off-gas to increase with the sulfur content of the raw material gas, especially when no desulfurization treatment is performed before decarbonization. Direct emissions of large amounts of carbon dioxide exacerbate the greenhouse effect, while the combustion of hydrogen sulfide causes air pollution; therefore, thorough desulfurization and purification of the exhaust gas is essential.
[0003] However, hydrogen sulfide and carbon dioxide are important chemical raw materials. High-purity hydrogen sulfide can be used in the electronics industry for plasma etching in semiconductor device processes. Carbon dioxide is widely used in many fields such as carbonated beverages, gas shielded welding, tertiary oil recovery, supercritical fluid extraction, gas fertilizer, preservation, and tobacco puffing. Its demand is increasing day by day. In particular, in the manufacturing technology of ultra-large-scale integrated circuits, processes such as electronic component cleaning have put forward extremely high requirements for the purity of carbon dioxide.
[0004] In existing technologies, selectively removing hydrogen sulfide from high-concentration carbon dioxide gas streams to achieve high-purity separation of the two faces numerous challenges. Conventional distillation methods are difficult to directly separate high concentrations of carbon dioxide and hydrogen sulfide. Many desulfurization methods irreversibly lose carbon dioxide while removing hydrogen sulfide, affecting process economics. For low-concentration hydrogen sulfide, solid desulfurizing agents can be used for purification, but when treating high-concentration hydrogen sulfide, problems arise such as high desulfurizing agent consumption, high regeneration energy consumption, and difficulty in efficiently recovering sulfur resources, which are usually only converted into sulfur. Traditional chemical absorption methods, such as amine methods, can capture carbon dioxide, but their selective separation ability for hydrogen sulfide and carbon dioxide is poor, and the absorbent enriches both simultaneously, failing to achieve effective separation.
[0005] Polyethylene glycol dimethyl ether (NHD or DEPG, CAS: 24991-55-7), as a physical solvent, has a high absorption capacity for both hydrogen sulfide and carbon dioxide, and exhibits good selectivity for hydrogen sulfide. It has been used to concentrate acidic gases. Existing research, through process simulation optimization, can increase the concentration of hydrogen sulfide to 98.7% and carbon dioxide to 99.6%. However, this type of process based on multiple flash evaporation has inherent limitations and cannot achieve the deep separation required for electronic-grade purity. The resulting carbon dioxide product still has a high residual hydrogen sulfide, and the carbon dioxide content in the hydrogen sulfide product does not meet the standards, requiring further purification.
[0006] In conventional industrial or food-grade carbon dioxide production, desulfurization agents are typically used to reduce sulfur content, molecular sieves are used for dehydration, single-tower distillation is used to remove non-condensable gases, and even precious metal catalysts are used to remove hydrocarbons. However, the carbon dioxide produced by these technologies is mostly collected from the bottom of the distillation column and contains a large number of high-boiling-point impurities, making it difficult to meet electronic-grade purity standards.
[0007] Therefore, existing technologies lack an industrial method that can efficiently and economically produce both electronic-grade high-purity hydrogen sulfide and electronic-grade ultra-pure carbon dioxide from hydrogen sulfide-rich carbon dioxide tail gas on a large scale. Developing an integrated process that combines high-selectivity separation and deep purification capabilities to achieve the dual goals of resource utilization and pollution control has become a difficult point and an urgent need in the current technological research and development in this field. Summary of the Invention
[0008] To meet the demand for large-scale use of ultrapure CO2 and H2S in fields such as precision electronics, this application provides an electronic-grade high-purity hydrogen sulfide and carbon dioxide product and its production method.
[0009] In a first aspect, this application provides a method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products, employing the following technical solution: A method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products includes the following steps: (1) Pretreatment: The high-concentration hydrogen sulfide and carbon dioxide mixture is cooled and separated into gas and liquid in sequence, and the condensate is discharged. Then, it is pressurized and cooled, and then separated into gas and liquid again and the condensate is discharged to obtain mixed gas A. Mixed gas A is then introduced into the absorption tower. (2) Carbon dioxide separation and purification: Mixed gas A contacts the lean absorbent liquid at the top of the absorption tower. High-purity carbon dioxide gas is obtained at the top of the absorption tower, while a rich absorbent liquid containing hydrogen sulfide and a small amount of carbon dioxide is obtained at the bottom of the absorption tower. The high-purity carbon dioxide gas is compressed to obtain compressed carbon dioxide gas. The compressed carbon dioxide gas is liquefied to obtain liquid carbon dioxide. The liquid carbon dioxide enters the carbon dioxide distillation tower for distillation. Non-condensable gas is discharged at the top of the carbon dioxide distillation tower, while electronic-grade high-purity carbon dioxide is obtained at the bottom of the carbon dioxide distillation tower. (3) Hydrogen sulfide desorption and absorbent circulation: The rich absorbent solution is pressurized and heated and then separated into gas and liquid by a flash tank. The gas phase of the flash tank is cooled and returned to the absorption tower. The liquid phase of the flash tank is depressurized by a valve and enters the upper part of the regeneration tower. It is condensed to desorb sulfur dioxide and carbon dioxide. A crude hydrogen sulfide mixture B containing a small amount of carbon dioxide is obtained at the top of the regeneration tower. The crude absorbent solution is obtained at the bottom of the regeneration tower. After being cooled twice, the crude absorbent solution is pressurized and returned to the top of the absorption tower for continued use as a lean absorbent solution. (4) Hydrogen sulfide purification: After the mixed gas B is compressed, it is dehydrated and then enters the upper part of the hydrogen sulfide distillation column for distillation. The hydrogen sulfide distillation column obtains impure hydrogen sulfide mixed gas C containing carbon dioxide. After the mixed gas C is depressurized and reheated to room temperature, it is returned to the front of the absorption tower for recycling. Electronic grade high-purity hydrogen sulfide is obtained at the bottom of the hydrogen sulfide distillation column and is stored in the storage tank.
[0010] By adopting the above technical solution, in the pretreatment step, the high-concentration hydrogen sulfide and carbon dioxide mixed gas raw materials are cooled and separated into liquid and gas in sequence. This can effectively remove the condensate in the mixed gas. Cooling can reduce the temperature of the mixed gas, causing the water vapor in it to condense into liquid water, which is then discharged through gas-liquid separation. This reduces the impact of moisture on the equipment and process in subsequent treatment. The pressurization operation can increase the pressure of the mixed gas, which is beneficial to the absorption and separation process in equipment such as the absorption tower. The secondary gas-liquid separation further ensures that the moisture in the mixed gas is fully removed, resulting in a relatively dry mixed gas A, which creates favorable conditions for subsequent separation and purification.
[0011] In the carbon dioxide separation and purification step, mixed gas A contacts the lean absorbent solution at the top of the absorption tower. The lean absorbent solution has a good selective absorption capacity for hydrogen sulfide. During the contact process, the hydrogen sulfide in the mixed gas is absorbed by the lean absorbent solution, thereby obtaining high-purity carbon dioxide gas at the top of the absorption tower. The high-purity carbon dioxide gas undergoes compression, liquefaction, and distillation to further remove impurities such as non-condensable gases. Finally, electronic-grade high-purity carbon dioxide is obtained at the bottom of the carbon dioxide distillation tower. The compression operation can increase the pressure and density of the carbon dioxide gas, which facilitates the subsequent liquefaction process. Liquefaction changes the carbon dioxide from a gaseous state to a liquid state, which is more conducive to distillation separation. The distillation process utilizes the difference in boiling points of different substances to separate carbon dioxide from other impurities, thereby improving the purity of carbon dioxide.
[0012] In the hydrogen sulfide desorption and absorbent recycling process, the rich absorbent solution undergoes gas-liquid separation after pressurization and heating. Pressurization and heating facilitate the desorption of gases such as hydrogen sulfide and carbon dioxide from the absorbent. The gas phase from the flash tank is cooled and returned to the absorption tower, enabling the recycling of carbon dioxide and reducing resource waste. The liquid phase from the flash tank is depressurized by a valve and enters the upper part of the regeneration tower, where hydrogen sulfide and carbon dioxide are desorbed. The top of the regeneration tower yields a crude hydrogen sulfide mixture B containing a small amount of carbon dioxide, while the bottom yields a crude absorbent solution. After two cooling cycles, the crude absorbent solution is pressurized and returned to the top of the absorption tower as a lean absorbent solution for continued use, thus achieving the recycling of the absorbent and reducing production costs.
[0013] In the hydrogen sulfide purification step, the mixed gas B is compressed and then dehydrated to remove moisture. The dehydrated mixed gas enters the upper part of the hydrogen sulfide distillation column for distillation. Utilizing the temperature and pressure differences in different parts of the distillation column, hydrogen sulfide is separated from impurities such as carbon dioxide. The impure hydrogen sulfide mixed gas C containing carbon dioxide is depressurized and reheated to room temperature before being returned to the front of the absorption tower for recycling, further improving the extraction rate of hydrogen sulfide. Electronic-grade high-purity hydrogen sulfide is obtained at the bottom of the hydrogen sulfide distillation column and is stored in a storage tank, meeting the demand for high-purity hydrogen sulfide in fields such as precision electronics.
[0014] Preferably, the absorbent lean solution is polyethylene glycol dimethyl ether, the water content in the absorbent lean solution is <1 ppm, and the water, hydrogen sulfide and polyethylene glycol dimethyl ether in the high-purity carbon dioxide gas are all <0.5 ppm.
[0015] By adopting the above technical solution and using polyethylene glycol dimethyl ether as the lean absorbent, this solvent exhibits excellent selective absorption and removal capabilities for carbon dioxide and hydrogen sulfide, and possesses stable chemical properties, good thermal stability, and minimal volatilization loss. Controlling the water content in the lean absorbent solution to <1 ppm avoids excessive moisture affecting the absorption of carbon dioxide and hydrogen sulfide. Because polyethylene glycol dimethyl ether has a high selective absorption capacity for hydrogen sulfide, it can effectively separate hydrogen sulfide from the mixed gas, while its own volatilization loss is minimal, ensuring a low solvent residue in the high-purity carbon dioxide gas. Furthermore, strictly controlling the water content in the lean absorbent solution minimizes the amount of moisture introduced into the carbon dioxide gas during absorption, thus achieving low levels of various impurities in the high-purity carbon dioxide gas, meeting the quality requirements for electronic-grade high-purity carbon dioxide.
[0016] Preferably, in step (3), the water content in the crude absorbent solution is controlled to be ≤0.1ppm, and / or the temperature of the lean absorbent solution is controlled to be 5-10°C above its freezing point.
[0017] By adopting the above technical solutions, controlling the water content in the crude absorbent liquid or controlling the temperature of the lean absorbent liquid, the high purity of the carbon dioxide gas obtained at the top of the absorption tower is achieved. At the same time, the loss of absorbent is reduced, allowing more absorbent to be recycled. Furthermore, by reducing impurities in the high purity carbon dioxide gas, the distillation difficulty of the subsequent carbon dioxide distillation tower is reduced.
[0018] Preferably, before the mixed gas A enters the absorption tower, it undergoes a dehydration treatment to remove moisture, so the hydrogen sulfide dehydration treatment in step (4) is not performed. After compression, the mixed gas B directly enters the upper part of the hydrogen sulfide distillation tower for distillation.
[0019] By adopting the above technical solution, the moisture content in the mixed gas B can be significantly reduced by dehydrating the mixed gas A before it enters the absorption tower. Since the moisture has been removed in advance, there is no need to perform hydrogen sulfide dehydration treatment in the subsequent step (4). In this way, the mixed gas B can directly enter the upper part of the hydrogen sulfide distillation tower for distillation after compression, avoiding additional dehydration operations, simplifying the process flow, reducing the use and operation of equipment, and reducing energy consumption and production costs. At the same time, because the dehydration step is eliminated, the loss of hydrogen sulfide during the dehydration process is reduced, the extraction rate of hydrogen sulfide is improved, and thus the production efficiency and product purity are improved, ultimately enabling the more efficient production of electronic-grade high-purity hydrogen sulfide.
[0020] Preferably, the high-purity carbon dioxide gas is first passed into a fine removal tank before compression. The fine removal tank is filled with an adsorbent, which is used to adsorb polyethylene glycol dimethyl ether and hydrogen sulfide from the high-purity carbon dioxide gas.
[0021] By adopting the above technical solution, high-purity carbon dioxide gas is first passed into a fine removal tank filled with adsorbent before compression. The adsorbent can adsorb polyethylene glycol dimethyl ether and hydrogen sulfide in the high-purity carbon dioxide gas. Since polyethylene glycol dimethyl ether and hydrogen sulfide are impurities, they can affect the purity of electronic-grade high-purity carbon dioxide. Through the adsorption effect of the adsorbent in the fine removal tank, these impurities can be effectively removed. In subsequent compression, liquefaction and distillation processes, the interference of polyethylene glycol dimethyl ether and hydrogen sulfide on the process can be avoided. This prevents the need to use a double tower to remove heavy components polyethylene glycol dimethyl ether and hydrogen sulfide during carbon dioxide distillation due to the presence of these impurities, simplifies the carbon dioxide liquefaction and distillation process, and further improves the purity of electronic-grade high-purity carbon dioxide, meeting the high purity requirements of ultra-pure carbon dioxide in fields such as precision electronics.
[0022] Secondly, this application provides an electronic-grade high-purity hydrogen sulfide and carbon dioxide product, employing the following technical solution: An electronic-grade high-purity hydrogen sulfide and carbon dioxide product is prepared according to a production method for an electronic-grade high-purity hydrogen sulfide and carbon dioxide product, wherein the extraction rates of both the electronic-grade high-purity carbon dioxide and electronic-grade high-purity hydrogen sulfide are >99.9%.
[0023] Preferably, the electronic-grade high-purity carbon dioxide contains less than 0.5 ppm hydrogen sulfide, less than 0.1 ppm water, and less than 0.01 ppm polyethylene glycol dimethyl ether.
[0024] Preferably, the electronic-grade high-purity hydrogen sulfide contains carbon dioxide < 0.1 ppm, water < 0.5 ppm, and polyethylene glycol dimethyl ether < 0.01 ppm.
[0025] By adopting the above technical solution, it can be seen that the technical solution provided by the present invention achieves the one-time removal of hydrogen sulfide in the absorption tower by absorption and distillation, obtaining high-purity carbon dioxide with hydrogen sulfide content <0.1ppm. The carbon dioxide contains extremely low levels of water, hydrogen sulfide, and polyethylene glycol dimethyl ether impurities. Moreover, the investment and operating costs of the equipment and systems required for the production method are low. The production method of electronic-grade ultrapure hydrogen sulfide and carbon dioxide is suitable for large-scale industrial production, safe and reliable, and meets the stringent standards and large-scale demands of the precision electronics industry and other fields.
[0026] In summary, this application has the following beneficial effects: Addressing the drawback of existing processes where hydrogen sulfide and carbon dioxide products are difficult to separate, this application successfully developed and implemented a process that uses absorption and distillation to remove hydrogen sulfide in a single step in an absorption tower, yielding high-purity carbon dioxide with <0.1 ppm hydrogen sulfide. The carbon dioxide contains extremely low levels of water, hydrogen sulfide, and polyethylene glycol dimethyl ether (PEG-DME) impurities. Specifically, this application provides a method and corresponding system for producing electronic-grade ultrapure hydrogen sulfide and carbon dioxide. The investment and operating costs of the equipment and systems required for this production method are low. The method for producing electronic-grade ultrapure hydrogen sulfide and carbon dioxide is suitable for large-scale industrial production, is safe and reliable, and meets the stringent standards and large-scale demands of the precision electronics industry and other fields. Attached Figure Description
[0027] Figure 1 This is a flowchart of the method provided in this application.
[0028] Explanation of reference numerals in the attached diagram: 101, Cooler I; 102, Primary gas-liquid separator; 103, Mixed gas compressor; 104, Secondary gas-liquid separator; 201, Absorber; 202, Fine removal tank; 203, Carbon dioxide compressor; 204, Liquefaction unit; 205, Carbon dioxide distillation column; 206, Storage tank I; 207, Buffer tank; 301, Rich liquid circulation pump; 302, Regenerator; 303, Flash tank; 304, Cooler II; 401, Regeneration column; 402, Cooler III; 403, Lean liquid circulation pump; 501, Hydrogen sulfide compressor; 502, Hydrogen sulfide dryer; 503, Hydrogen sulfide distillation column; 504, Heat exchanger I; 505, Storage tank II; 506, Heater; 507, Heat exchanger II. Detailed Implementation
[0029] The following is in conjunction with the appendix Figure 1 The present application will be further described in detail with reference to the embodiments. Example
[0030] The high-concentration hydrogen sulfide and carbon dioxide mixture feedstock consists of 48% CO2, 14% H2O, 38% H2S, and 10 ppm N2, at a temperature of 300℃ and a flow rate of 1100 Nm³. 3 / h, and all units ppm used in this application are ppm(V).
[0031] (1) Pretreatment: The high-concentration hydrogen sulfide and carbon dioxide mixture is sequentially fed into cooler 101 and first-stage gas-liquid separator 102. After cooling to 40°C, gas-liquid separation is performed and the condensate is discharged. Then, the mixture is pressurized and cooled by mixed gas compressor 103 and enters second-stage gas-liquid separator 104. After the condensate is discharged, mixed gas A is obtained. Mixed gas A is fed into absorption tower 201. (2) Carbon dioxide separation and purification: Mixed gas A contacts the lean absorbent solution at the top of absorber tower 201. The flow rate of the lean absorbent solution is 2153 Nm. 3 / h, the absorbent lean solution is polyethylene glycol dimethyl ether, with a water content of <1ppm; high-purity carbon dioxide gas is obtained at the top of absorption tower 201, while 2212Nm of purified gas is obtained at the bottom of absorption tower 201. 3 The absorbent solution contains hydrogen sulfide and a small amount of carbon dioxide at a concentration of 99.9968%, water <0.01ppm, hydrogen sulfide <0.01ppm, polyethylene glycol dimethyl ether <0.131ppm, and nitrogen 22.75ppm. The high-purity carbon dioxide gas enters a purification tank 202 filled with activated carbon to remove polyethylene glycol dimethyl ether and hydrogen sulfide. It then enters a carbon dioxide compressor 203 and is compressed to 23MPa to obtain compressed carbon dioxide gas. This compressed carbon dioxide gas is stored in a buffer tank 207. The compressed carbon dioxide gas is then cooled to -20℃ by refrigerant in a liquefaction unit 204 to obtain liquid carbon dioxide. The liquid carbon dioxide enters a carbon dioxide distillation column 205 for distillation, and 0.453 Nm³ is discharged from the top of the column. 3 / h, containing non-condensable gas of 96.4% carbon dioxide and 2.42% nitrogen, the bottom of the carbon dioxide distillation column 205 yields 527.9 Nm³. 3 / h of electronic-grade high-purity carbon dioxide, with a carbon dioxide content of 99.9999%, hydrogen sulfide <0.015ppm, water <0.01ppm, polyethylene glycol dimethyl ether <0.01ppm, and nitrogen <0.01ppm, is stored in storage tank 206. (3) Hydrogen sulfide desorption and absorbent recycling: 2212 Nm 3The absorbent rich solution is pressurized to 1.35 MPa by the rich solution circulation pump 301, then heated to 212°C by the regenerator 302, and then enters the flash tank 303 for gas-liquid separation. The gas phase in the flash tank 303, rich in carbon dioxide evaporates, is cooled by the second cooler 304 and returned to the absorption tower 201. The liquid phase in the flash tank 303 is depressurized by a valve and enters the upper part of the regeneration tower 401, where it contacts the condenser for desorption of sulfur dioxide and carbon dioxide. The liquid phase flow rate in the flash tank 303 is 2646 Nm³. 3 / h, containing 0.0197% carbon dioxide, 16.29% hydrogen sulfide, and 81.36% polyethylene glycol dimethyl ether; The top of the regeneration tower 401 achieved 493.4 Nm. 3 / h of crude hydrogen sulfide mixture B containing a small amount of carbon dioxide, the bottom of regeneration tower 401 yields 2153 Nm³. 3 / h of absorbent crude liquid, the absorbent crude liquid contains 99.9999% polyethylene glycol dimethyl ether, water <1ppm, hydrogen sulfide <0.1ppm, after being cooled to 45°C by heat exchanger 302, and then cooled to 15°C by cooler 402, and then pressurized to 1.16MPa by lean liquid circulation pump 403 and returned to the top of absorption tower 201 as absorbent lean liquid for continued use; (4) Hydrogen sulfide purification: Component B of the mixed gas consists of 10.59% carbon dioxide, 2.05% water, 87.35% hydrogen sulfide, and 1.48 ppm polyethylene glycol dimethyl ether. 493.4 Nm 3 The mixed gas B is compressed to 2.3 MPa by the hydrogen sulfide compressor 501, then dehydrated in the hydrogen sulfide dryer 502 until the water content is <1 ppm. It then enters the upper part of the hydrogen sulfide distillation column 503 for distillation. The hydrogen sulfide distillation column 503 yields an impure hydrogen sulfide mixed gas C containing carbon dioxide. Mixed gas C is reheated to room temperature by the pressure reducing and heat exchanger 504 and then returned to the front of the absorption column 201 for recycling. The bottom of the hydrogen sulfide distillation column 503 yields 415.2 Nm³ of hydrogen sulfide. 3 Electronic-grade high-purity hydrogen sulfide at a pressure of 1.97 MPa is introduced into storage tank 2505 for storage. The electronic-grade high-purity hydrogen sulfide contains 99.9999% hydrogen sulfide, <0.5 ppm water, <0.1 ppm carbon dioxide, and <0.01 ppm polyethylene glycol dimethyl ether.
[0032] In this embodiment, the temperature of the absorbent lean solution is controlled at 15°C in step (3), and the water content in the crude absorbent solution is controlled to be ≤0.1ppm.
[0033] In this embodiment, the mixed gas A is not dehydrated before entering the absorption tower 201. In step (4), the hydrogen sulfide dryer 502 is used to dehydrate the compressed mixed gas B. Alternatively, the mixed gas A can be dehydrated before entering the absorption tower 201. In this case, the hydrogen sulfide dryer 502 may not be required. After compression, the mixed gas B directly enters the upper part of the hydrogen sulfide distillation tower 503 for distillation.
[0034] In this embodiment, a hydrogen sulfide dryer 502 is selected. The hydrogen sulfide dryer 502 is a regenerative dryer. The regeneration gas of the hydrogen sulfide dryer 502 is compressed carbon dioxide gas in the buffer tank 207. After the compressed carbon dioxide gas is heated in the heater 506, it flows into the hydrogen sulfide dryer 502. The regenerated gas is cooled by the second heat exchanger 507 and then returned to the absorption tower 201 for recycling.
[0035] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products, characterized in that: Includes the following steps: (1) Pretreatment: The high-concentration hydrogen sulfide and carbon dioxide mixture raw material is cooled and separated into gas and liquid in sequence, and the condensate is discharged. Then, it is pressurized and cooled, and then separated into gas and liquid again and the condensate is discharged to obtain mixed gas A. Mixed gas A is then introduced into the absorption tower (201). (2) Carbon dioxide separation and purification: Mixed gas A contacts the lean absorbent liquid at the top of the absorption tower (201). High-purity carbon dioxide gas is obtained at the top of the absorption tower (201), while a rich absorbent liquid containing hydrogen sulfide and a small amount of carbon dioxide is obtained at the bottom of the absorption tower (201). The high-purity carbon dioxide gas is compressed to obtain compressed carbon dioxide gas. The compressed carbon dioxide gas is liquefied to obtain liquid carbon dioxide. The liquid carbon dioxide enters the carbon dioxide distillation tower (205) for distillation. Non-condensable gas is discharged at the top of the carbon dioxide distillation tower (205), while electronic-grade high-purity carbon dioxide is obtained at the bottom of the carbon dioxide distillation tower (205). (3) Hydrogen sulfide desorption and absorbent circulation: The rich absorbent solution is pressurized and heated and then separated into gas and liquid by a flash tank (303). The gas phase of the flash tank (303) is cooled and returned to the absorption tower (201). The liquid phase of the flash tank (303) is depressurized by a valve and enters the upper part of the regeneration tower (401) for desorption of sulfur dioxide and carbon dioxide. The top of the regeneration tower (401) obtains a crude hydrogen sulfide mixture B containing a small amount of carbon dioxide. The bottom of the regeneration tower (401) obtains the crude absorbent solution. After being cooled twice, the crude absorbent solution is pressurized and returned to the top of the absorption tower (201) for continued use as a lean absorbent solution. (4) Hydrogen sulfide purification: After the mixed gas B is compressed, it is dehydrated by hydrogen sulfide and then enters the upper part of the hydrogen sulfide distillation column (503) for distillation. The hydrogen sulfide distillation column (503) obtains impure hydrogen sulfide mixed gas C containing carbon dioxide. After the mixed gas C is depressurized and reheated to room temperature, it is returned to the front of the absorption column (201) for recycling. Electronic grade high-purity hydrogen sulfide is obtained at the bottom of the hydrogen sulfide distillation column (503) and stored in the storage tank.
2. The method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products according to claim 1, characterized in that: The absorbent lean solution is polyethylene glycol dimethyl ether, and the water content in the absorbent lean solution is <1 ppm. In the high-purity carbon dioxide gas, the water, hydrogen sulfide and polyethylene glycol dimethyl ether are all <0.5 ppm.
3. The method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products according to claim 1, characterized in that: In step (3), the water content in the crude absorbent solution is controlled to be ≤0.1ppm, and / or the temperature of the lean absorbent solution is controlled to be 5-10°C above its freezing point.
4. The method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products according to claim 1, characterized in that: Before entering the absorption tower (201), the mixed gas A is dehydrated to remove moisture, so the hydrogen sulfide dehydration treatment in step (4) is not performed. After compression, the mixed gas B directly enters the upper part of the hydrogen sulfide distillation tower (503) for distillation.
5. The method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide products according to claim 1, characterized in that: Before compression, the high-purity carbon dioxide gas is first introduced into a fine removal tank (202), which is filled with an adsorbent used to adsorb polyethylene glycol dimethyl ether and hydrogen sulfide from the high-purity carbon dioxide gas.
6. An electronic-grade high-purity hydrogen sulfide and carbon dioxide product, characterized in that: The product is prepared by a method for producing electronic-grade high-purity hydrogen sulfide and carbon dioxide according to any one of claims 1-5, wherein the extraction rates of both electronic-grade high-purity carbon dioxide and electronic-grade high-purity hydrogen sulfide are >99.9%.
7. The electronic-grade high-purity hydrogen sulfide and carbon dioxide product according to claim 6, characterized in that: The electronic-grade high-purity carbon dioxide contains less than 0.5 ppm hydrogen sulfide, less than 0.1 ppm water, and less than 0.01 ppm polyethylene glycol dimethyl ether.
8. The electronic-grade high-purity hydrogen sulfide and carbon dioxide product according to claim 6, characterized in that: The electronic-grade high-purity hydrogen sulfide contains carbon dioxide <0.1ppm, water <0.5ppm, and polyethylene glycol dimethyl ether <0.01ppm.