Preparation device and method of high-purity hydrogen sulfide

Abstract

A preparation device and method of high-purity hydrogen sulfide, the device comprises a gas-liquid separator, a precision filter, a first heat exchanger, a light-removing tower, a heavy-removing tower, a azeotropic rectification tower, a second heat exchanger, an adsorption tower, an extraction tower, a distillation tower and a desulfurization tower, wherein the front end of the gas-liquid separator is connected with raw material gas, and the rear is sequentially connected with the precision filter, the first heat exchanger, the light-removing tower, the heavy-removing tower, the azeotropic rectification tower, the second heat exchanger and the adsorption tower, energy efficient utilization is realized through two-stage heat recovery, and environmental protection and economic win-win are realized through full-process closed loop.

Description

Technical Field

[0001] This invention belongs to the field of electronic gas technology, specifically relating to the preparation of high-purity hydrogen sulfide and a method for the synergistic treatment of waste gas and waste liquid. Background Technology

[0002] Hydrogen sulfide is an important chemical raw material, widely used in semiconductor manufacturing, pharmaceutical synthesis, and material surface treatment. Especially in the semiconductor industry, the purity requirements for hydrogen sulfide are extremely high (it needs to reach 5N or above, that is, purity ≥99.999%).

[0003] Currently, existing hydrogen sulfide purification methods have the following drawbacks: 1. Conventional low-temperature distillation can only improve the purity to 3N-4N, which is difficult to meet the requirements of 5N and above; 2. Adsorption methods rely on a single adsorbent (such as molecular sieves), which has poor selectivity for polar and non-polar impurities; 3. The process has high energy consumption, and traditional distillation needs to maintain a low temperature below -70℃, and waste liquid treatment is not considered. Summary of the Invention

[0004] This invention develops a method for preparing high-purity hydrogen sulfide that achieves efficient impurity removal, stable production, and environmental compliance. The method comprises: a high-purity hydrogen sulfide preparation apparatus, the apparatus including a gas-liquid separator, a precision filter, a first heat exchanger, a light-light gas removal tower, a heavy-light gas removal tower, an azeotropic distillation tower, a second heat exchanger, an adsorption tower, an extraction tower, a distillation tower, and a desulfurization tower. The gas-liquid separator is connected to the feed gas at its front end, and subsequently connected to the precision filter, the first heat exchanger, the light-light gas removal tower, the heavy-light gas removal tower, the azeotropic distillation tower, the second heat exchanger, and the adsorption tower. The product is connected after the adsorption tower. The tank, the heavy phase removal tower and the azeotropic distillation tower are each equipped with two pipes connected to the extraction tower. After extraction, the extraction tower discharges the wastewater. The organic phase is connected to the subsequent distillation tower, which is equipped with two reflux pipes. One reflux pipe is connected to the upstream raw material gas pipe for filtration after separation. The other pipe returns the gas to the extraction tower for further extraction. The light phase removal tower and the adsorption tower are both equipped with pipes connected to the desulfurization tower, and the tail gas from both is sent into the desulfurization tower. A sodium hydroxide inlet is also provided on the desulfurization tower. An oxidation and crystallization device is set after the desulfurization tower to extract sulfur.

[0005] Preferably, the adsorption tower has two independent double-layer beds: the upper layer is the second bed, the lower layer is the first bed, and a buffer space is reserved in between. A conical collector is installed above the second bed, with a discharge pipe at the top of the collector and a pressure sensor installed on the discharge pipe. The conical collector guides the airflow vertically through the bed, ensuring full utilization of the adsorbent. A perforated plate airflow distributor is installed below the second bed, with equilateral triangular perforations for uniform airflow distribution. Below the perforated plate airflow distributor is a feed pipe. Both the first and second beds have regenerator inlet pipes, and regeneration tail gas outlet pipes are located below them.

[0006] A method for preparing a high-purity hydrogen sulfide preparation apparatus, the method comprising the following steps: 1) Pretreatment: The crude hydrogen sulfide gas is first passed into a gas-liquid separator to separate free water and liquid sulfides; then it enters a precision filter to remove dust and solid particulate impurities. 2) A multi-stage distillation process, consisting of a light-boiling-heavy-boiling column and an azeotropic distillation column, is adopted to achieve the stepwise removal of impurities such as low-boiling-point, high-boiling-point, and azeotropic substances; 3) The hydrogen sulfide enters the adsorption tower for selective adsorption and deep purification to remove residual carbonyl sulfide impurities, ultimately obtaining hydrogen sulfide with 5N or higher; the bed is filled with Zr-MBI MOFs material; 4) After the waste liquid passes through the extraction vessel and distillation tower, the extractant and sulfides are recovered. The recovered sulfides are returned to the crude hydrogen sulfide raw material system for repurification. The raffinate is neutralized and discharged in compliance with standards. The non-condensable gas at the top of the light gas removal tower and the tail gas of the adsorption tower are collected and enter the desulfurization tower, where sodium hydroxide solution is used for absorption and desulfurization. The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain sulfur products.

[0007] Preferably, the gas-liquid separator operates at a pressure of 0.2-0.3 MPa and a temperature of 20-30°C, separating free liquid impurities through a baffle plate; the precision filter has a filtration accuracy of 0.1 μm, and the filter element is made of polytetrafluoroethylene, filtering solid particles to obtain pretreated gas, which then enters the first heat exchanger for preheating.

[0008] Preferably, in step 2), the top temperature of the light component removal column is -60~-50℃, the bottom temperature is -45~-35℃, the operating pressure is 0.5-0.7MPa, and the reflux ratio is 1.2-1.8; the bottom gas of the heavy component removal column is pressurized to 0.4-0.6MPa, the top temperature is -40~-30℃, the bottom temperature is -25~-15℃, and the reflux ratio is 0.8-1.2; the gas phase at the top of the heavy component removal column enters the first heat exchanger, and the residual heat is used to preheat the feed to the light component removal column to achieve heat recovery; the remaining gas enters the azeotropic distillation column.

[0009] Preferably, in step 2), the packing of the azeotropic distillation column is made of stainless steel corrugated, with N-methylpyrrolidone as the azeotropic agent, the amount added being 5%-8% of the feed. The column top temperature is -35~-25℃, the column bottom temperature is -20~-10℃, and the operating pressure is 0.3-0.5MPa. The azeotrope is discharged from the top of the column, and the intermediate product of hydrogen sulfide is obtained from the bottom of the column. The waste liquid at the bottom of the azeotropic distillation column is fed into the second heat exchanger to preheat the feed to the subsequent extraction vessel.

[0010] As a preferred embodiment, the adsorption tower in step 3) operates under the following conditions: temperature 5-30℃ and pressure 0.3-0.8MPa. First, the first bed adsorbs most of the impurities, and the second bed performs deep adsorption. The two beds operate alternately in an 8-hour cycle: the first bed adsorbs for 0-4 hours while the second bed is on standby; the first bed is regenerated with nitrogen for 4-6 hours while the second bed becomes the main adsorption bed; and the first bed is cooled to below 30℃ for standby while the second bed continues adsorption for 6-8 hours, thus achieving continuous operation.

[0011] As a preferred embodiment, the Zr-MBI MOFs material in the adsorption tower in step 3) is prepared by dissolving ZrCl4 and 2-mercaptobenzimidazole in N,N-dimethylformamide (DMF) to form ZrCl4. 4+ -DMF solution, ligand-DMF solution, slowly add ligand-DMF solution dropwise to Zr 4+ Add the Zr-MBIMOF solution to the DMF solution while stirring. After the addition is complete, continue stirring to ensure thorough mixing and form a uniform pale yellow suspension. Slowly pour the uniformly mixed suspension into a polytetrafluoroethylene-lined reactor and react at 120-150℃ for 24-36 h. Centrifuge, wash with anhydrous ethanol, filter and dry to obtain a pale yellow powder Zr-MBIMOF.

[0012] Preferably, during the preparation of the Zr-MBI MOF material, the molar ratio of 2-mercaptobenzimidazole to ZrCl4 is 1:2-1:3, anhydrous DMF is required, the total amount of DMF in the mixture is maintained at a solid-liquid ratio of 1:10-1:15, of which 70%-80% of the total DMF is used to dissolve ZrCl4, 20%-30% of the total DMF is used to dissolve the ligand, and the number of ethanol washings is ≥3 times.

[0013] Preferably, in step 4), the extractant in the extraction tower is diisopropyl ether, the extraction ratio is 1:3-1:5, and extraction is performed at 20-30℃ for 30-60 min. The extracted phase then enters the distillation tower, where the top temperature is 68-72℃. The packing material in the desulfurization tower is polypropylene packing, and absorption is performed using a 10%-15% sodium hydroxide solution with a liquid-to-gas ratio of 5-8 L / m³. 3 The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain the final sulfur product at a crystallization temperature of 40-50℃.

[0014] Compared with existing technologies, this invention uses Zr-MBI MOF material for fixed-bed adsorption. This MOF has a selectivity of ≥99% for COS impurities (traditional adsorbents easily adsorb other impurities and hydrogen sulfide), and a regeneration temperature of 80-100℃ (traditional adsorbents require >150℃ and are easily deactivated). It can reduce COS from 10 ppm to ≤0.5 ppm. This invention adopts a "multi-stage distillation + MOF adsorption" process. Distillation solves the removal of a large number of impurities, while MOF adsorption solves the removal of trace impurities, so that the product purity reaches 5N (99.999%). This invention achieves high-efficiency energy utilization through two-stage heat recovery. This invention achieves a win-win situation for environmental protection and economy through a closed-loop process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the invention's structure; Figure 2 These are cross-sectional views of the MOF adsorber. Figure 3 These are top views of the airflow distributor; Figure 4 X-ray diffraction pattern (PXRD) of the prepared Zr-MBI MOF. Detailed Implementation

[0016] The invention will now be described in detail with reference to the accompanying drawings: Figure 1 As shown, an apparatus for preparing high-purity hydrogen sulfide includes a gas-liquid separator, a precision filter, a first heat exchanger, a light-light gas removal tower, a heavy-light gas removal tower, an azeotropic distillation tower, a second heat exchanger, an adsorption tower, an extraction tower, a distillation tower, and a desulfurization tower. The gas-liquid separator is connected to the feed gas at its front end, and subsequently connected to the precision filter, the first heat exchanger, the light-light gas removal tower, the heavy-light gas removal tower, the azeotropic distillation tower, the second heat exchanger, and the adsorption tower. A product tank is connected downstream of the adsorption tower. The heavy-light gas removal tower and the azeotropic distillation tower are each equipped with two pipes. The system connects to an extraction tower, which discharges wastewater after extraction. The organic phase is connected to a subsequent distillation tower, which has two reflux pipes. One reflux pipe connects to the upstream raw material gas pipe for filtration after separation, while the other pipe returns the gas to the extraction tower for further extraction. Both the light odor removal tower and the adsorption tower are connected to the desulfurization tower via pipes, allowing their tail gases to be fed into the desulfurization tower. A sodium hydroxide inlet is also installed on the desulfurization tower. An oxidation and crystallization device is installed downstream of the desulfurization tower to extract sulfur.

[0017] like Figure 2-3As shown: The adsorption tower has two independent double-layer beds, with the upper layer being the second bed and the lower layer being the first bed, with a buffer space reserved in between. A conical collector is installed above the second bed, with a discharge pipe at the top of the collector and a pressure sensor installed on the discharge pipe. The conical collector guides the airflow vertically through the bed, ensuring full utilization of the adsorbent. A perforated plate airflow distributor is installed below the second bed, with equilateral triangular perforations to ensure uniform airflow distribution. Below the perforated plate airflow distributor is the feed pipe. Both the first and second beds have regenerator inlet pipes, and regeneration tail gas outlet pipes are located below them.

[0018] A method for preparing a high-purity hydrogen sulfide preparation apparatus, the method comprising the following steps: 1) Pretreatment: The crude hydrogen sulfide gas is first passed into a gas-liquid separator to separate free water and liquid sulfides; then it enters a precision filter to remove dust and solid particulate impurities. 2) A multi-stage distillation process, consisting of a light-boiling-heavy-boiling column and an azeotropic distillation column, is adopted to achieve the stepwise removal of impurities such as low-boiling-point, high-boiling-point, and azeotropic substances; 3) The hydrogen sulfide enters the adsorption tower for selective adsorption and deep purification to remove residual carbonyl sulfide impurities, ultimately obtaining hydrogen sulfide with 5N or higher; the bed is filled with Zr-MBI MOFs material; 4) After the waste liquid passes through the extraction vessel and distillation tower, the extractant and sulfides are recovered. The recovered sulfides are returned to the crude hydrogen sulfide raw material system for repurification. The raffinate is neutralized and discharged in compliance with standards. The non-condensable gas at the top of the light gas removal tower and the tail gas of the adsorption tower are collected and enter the desulfurization tower, where sodium hydroxide solution is used for absorption and desulfurization. The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain sulfur products.

[0019] The gas-liquid separator operates at a pressure of 0.2-0.3 MPa and a temperature of 20-30°C, separating free liquid impurities through a baffle plate. The precision filter has a filtration accuracy of 0.1 μm and the filter element is made of polytetrafluoroethylene, filtering solid particles to obtain pretreated gas, which then enters the first heat exchanger for preheating.

[0020] In step 2), the top temperature of the light component removal tower is -60~-50℃, the bottom temperature is -45~-35℃, the operating pressure is 0.5-0.7MPa, and the reflux ratio is 1.2-1.8; the bottom gas of the heavy component removal tower is pressurized to 0.4-0.6MPa, the top temperature is -40~-30℃, the bottom temperature is -25~-15℃, and the reflux ratio is 0.8-1.2; the gas phase at the top of the heavy component removal tower enters the first heat exchanger, and the residual heat is used to preheat the feed to the light component removal tower to achieve heat recovery; the remaining gas enters the azeotropic distillation tower.

[0021] In step 2), the azeotropic distillation column is packed with stainless steel corrugated material, and N-methylpyrrolidone is used as the azeotropic agent, with an addition amount of 5%-8% of the feed. The column top temperature is -35~-25℃, the column bottom temperature is -20~-10℃, and the operating pressure is 0.3-0.5MPa. The azeotrope is discharged from the top of the column, and the intermediate product of hydrogen sulfide is obtained from the bottom of the column. The waste liquid at the bottom of the azeotropic distillation column is fed into the second heat exchanger to preheat the feed to the subsequent extraction vessel.

[0022] In step 3), adsorption occurs in the adsorption tower at a temperature of 5-30℃ and a pressure of 0.3-0.8MPa. First, the first bed adsorbs most of the impurities, while the second bed performs deep adsorption. The two beds operate alternately in an 8-hour cycle. From 0 to 4 hours, the first bed adsorbs while the second bed is on standby. From 4 to 6 hours, the first bed is regenerated with nitrogen while the second bed becomes the main adsorption bed. From 6 to 8 hours, the first bed is cooled to below 30℃ and put into standby mode while the second bed continues adsorption, thus achieving continuous operation.

[0023] The preparation method of Zr-MBI MOFs material in the adsorption tower in step 3) is as follows: ZrCl4 and 2-mercaptobenzimidazole are dissolved in N,N-dimethylformamide (DMF) to form ZrCl4. 4+ -DMF solution, ligand-DMF solution, slowly add ligand-DMF solution dropwise to Zr 4+ Add the DMF solution dropwise while stirring. After the addition is complete, continue stirring to ensure thorough mixing and form a uniform pale yellow suspension. Slowly pour the uniformly mixed suspension into a polytetrafluoroethylene-lined reactor and react at 120-150℃ for 24-36 h. Centrifuge, wash with anhydrous ethanol, filter and dry to obtain a pale yellow powder Zr-MBI MOF.

[0024] In the preparation of the Zr-MBI MOF material, the molar ratio of 2-mercaptobenzimidazole to ZrCl4 is 1:2-1:3. Anhydrous DMF must be used. The total amount of DMF in the mixture is maintained at a solid-liquid ratio of 1:10-1:15. 70%-80% of the total DMF is used to dissolve ZrCl4, and 20%-30% is used to dissolve the ligands. The ethanol washing should be performed ≥3 times.

[0025] In step 4), the extractant in the extraction tower is diisopropyl ether, with an extraction ratio of 1:3 to 1:5. Extraction is carried out at 20-30°C for 30-60 minutes, and the extracted phase enters the distillation tower. The top temperature of the distillation tower is 68-72°C. The packing material in the desulfurization tower is polypropylene packing, and absorption is performed using a 10%-15% sodium hydroxide solution with a liquid-to-gas ratio of 5-8 L / m³. 3 The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain the final sulfur product at a crystallization temperature of 40-50℃.

[0026] The hydrogen sulfide feedstock gas used in the examples had a purity of 85.2%, with the remaining 14.8% being impurities, specifically including: low-boiling-point impurities, hydrogen (H2) 4.8%, methane (CH4) 3.1%; high-boiling-point impurities, carbonyl sulfide (COS) 3.9%; and other impurities, water (H2O) 0.52%, and solid particulate matter (catalyst dust) 120 particles / cm³. 3 .

[0027] Example 1 Preparation of Zr-MBI MOF material: Slowly add 2.33 g of ZrCl4 solid to 56 mL of DMF, and stir on a magnetic stirrer (300-500 r / min) for 15-20 min until ZrCl4 is completely dissolved (if a small amount of turbidity appears, the temperature can be appropriately increased to 40-50℃, and then cooled to room temperature after dissolution); Separately, add 14 mL of DMF to 3.90 g of 2-mercaptobenzimidazole, and stir for 10-15 min to form a ligand-DMF solution (if the ligand dissolves slowly, 1-2 drops of anhydrous ethanol can be added to promote dissolution); Slowly add the ligand-DMF solution dropwise to ZrCl4. 4+ Add the solution to DMF (dropping rate 1-2 d / s), stirring continuously during the addition process (500-800 r / min). After the addition is complete, continue stirring for 30-40 min to ensure thorough mixing and the formation of a uniform pale yellow suspension (at this point, the solution pH is approximately 3-4, requiring no additional adjustment; if pH < 3, a small amount of triethylamine can be added to adjust the pH to 3-4 to avoid strong acid damaging the ligand structure). Slowly pour the uniformly mixed suspension into a polytetrafluoroethylene-lined reactor. Seal the reactor and place it in a constant temperature oven. Set the heating program: increase the temperature from room temperature to 120-150℃ at a rate of 5-10℃ / h. After reaching the target temperature, maintain the temperature for 24-36 h. After the reaction is complete, wait for the temperature to drop to room temperature, then slowly open the reactor to release the pressure. Transfer the mixture from the reactor to centrifuge tubes and place them in a high-speed centrifuge. Set the speed to 8000-10000 r / min and centrifuge for 15-20 minutes. After 3-5 minutes, pour out the upper mother liquor, add anhydrous ethanol to the centrifuge tube, disperse by ultrasonication, and centrifuge again. Repeat the operation 3-5 times. Place the washed MOF material in a vacuum drying oven for 8-12 hours (80-100℃). After drying, a light yellow powdery MOF product is obtained. Seal and store in a desiccator. Figure 3 The PXRD pattern of the prepared Zr-MBI shows that the material has good crystallinity.

[0028] Example 2 Based on the above pretreated raw materials (H2S 85.2%, H2 4.8%, CH4 3.1%, COS 3.9%, free water 0.12%), after three-stage impurity removal (removal of light impurities → removal of heavy impurities → azeotropic distillation), the composition is compared with that of traditional methods (taking a simple double-tower and drying tower as examples) as follows.

[0029] Table 1 Comparison of Components

[0030] As shown in the table above, compared with the traditional method, this method can further improve product purity, reduce carbonyl sulfide content by 68%, introduce no salt impurities, and avoid subsequent MOF pore blockage. Further comparison of data after 720 hours of continuous operation with the traditional process yields the following results.

[0031] Table 2 Comparison of Process Stability and Energy Consumption

[0032] As shown in the table above, compared with the traditional method, this method has better stability. Due to the thermal integration and recovery of cold energy, the energy consumption is reduced by 41.4% compared with the traditional method.

[0033] Example 3 The method of this patent for hydrogen sulfide purification is compared with the traditional method (simple double tower + 13X molecular sieve / activated carbon adsorption) as follows.

[0034] Table 3 Comparison between this method and traditional methods

[0035] As shown in the table above, hydrogen sulfide purification using this method can yield 5N4 hydrogen sulfide, with a carbonyl sulfur removal rate as high as 99.9996%, which is far superior to the traditional method (99.2%). This method can avoid corrosion of downstream equipment and does not detect any salt, thus eliminating the need for additional filtration.

Claims

1. An apparatus for preparing high-purity hydrogen sulfide, characterized in that... The apparatus includes a gas-liquid separator, a precision filter, a first heat exchanger, a light gas removal tower, a heavy gas removal tower, an azeotropic distillation tower, a second heat exchanger, an adsorption tower, an extraction tower, a distillation tower, and a desulfurization tower. The gas-liquid separator is connected to the feed gas at its front end, and sequentially connected to the precision filter, the first heat exchanger, the light gas removal tower, the heavy gas removal tower, the azeotropic distillation tower, the second heat exchanger, and the adsorption tower. The adsorption tower is connected to a product tank. The heavy gas removal tower and the azeotropic distillation tower are each connected to the extraction tower via two pipes. After extraction, the extraction tower discharges wastewater, and the organic phase is connected to the subsequent distillation tower. The distillation tower has two reflux pipes: one connects to the feed gas pipe for filtration after separation, and the other returns the reflux gas to the extraction tower for further extraction. Both the light gas removal tower and the adsorption tower are connected to the desulfurization tower via pipes, sending their tail gases into the desulfurization tower. A sodium hydroxide inlet is also provided on the desulfurization tower. An oxidation and crystallization device is located after the desulfurization tower to extract sulfur.

2. The apparatus for preparing high-purity hydrogen sulfide according to claim 1, characterized in that... The adsorption tower has two independent double-layer beds: the upper layer is the second bed, and the lower layer is the first bed, with a buffer space in between. A conical collector is installed above the second bed, with a discharge pipe at the top and a pressure sensor installed on the discharge pipe. The conical collector guides the airflow vertically through the bed, ensuring full utilization of the adsorbent. A perforated plate airflow distributor is installed below the second bed, with equilateral triangular perforations for uniform airflow distribution. Below the perforated plate airflow distributor is the feed pipe. Both the first and second beds have regenerator inlet pipes, and regeneration tail gas outlet pipes are located below them.

3. The preparation method of any one of the apparatuses for preparing high-purity hydrogen sulfide according to claims 1-2, characterized in that... The method includes the following steps: 1) Pretreatment: The crude hydrogen sulfide gas is first passed into a gas-liquid separator to separate free water and liquid sulfides; then it enters a precision filter to remove dust and solid particulate impurities. 2) Multi-stage distillation using a "light weight removal tower - heavy weight removal tower - azeotropic distillation tower" is employed to achieve stepwise removal of impurities such as low-boiling-point, high-boiling-point, and azeotropic substances; 3) The hydrogen sulfide enters the adsorption tower for selective adsorption and deep purification to remove residual carbonyl sulfide impurities, ultimately obtaining hydrogen sulfide with 5N or higher; the bed is filled with Zr-MBI MOFs material; 4) After the waste liquid passes through the extraction vessel and distillation tower, the extractant and sulfides are recovered. The recovered sulfides are returned to the crude hydrogen sulfide raw material system for repurification. The raffinate is neutralized and discharged in compliance with standards. The non-condensable gas at the top of the light gas removal tower and the tail gas of the adsorption tower are collected and enter the desulfurization tower, where sodium hydroxide solution is used for absorption and desulfurization. The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain sulfur products.

4. The apparatus for preparing high-purity hydrogen sulfide according to claim 3, characterized in that... The gas-liquid separator operates at a pressure of 0.2-0.3 MPa and a temperature of 20-30°C, separating free liquid impurities through a baffle plate. The precision filter has a filtration accuracy of 0.1 μm and the filter element is made of polytetrafluoroethylene, filtering solid particles to obtain pretreated gas, which then enters the first heat exchanger for preheating.

5. The apparatus for preparing high-purity hydrogen sulfide according to claim 3, characterized in that... In step 2), the top temperature of the light component removal tower is -60~-50℃, the bottom temperature is -45~-35℃, the operating pressure is 0.5-0.7MPa, and the reflux ratio is 1.2-1.8; the bottom gas of the heavy component removal tower is pressurized to 0.4-0.6MPa, the top temperature is -40~-30℃, the bottom temperature is -25~-15℃, and the reflux ratio is 0.8-1.2; the gas phase at the top of the heavy component removal tower enters the first heat exchanger, and the residual heat is used to preheat the feed to the light component removal tower to achieve heat recovery; the remaining gas enters the azeotropic distillation tower.

6. The apparatus for preparing high-purity hydrogen sulfide according to claim 5, characterized in that... In step 2), the azeotropic distillation column is packed with stainless steel corrugated material, and N-methylpyrrolidone is used as the azeotropic agent, with an addition amount of 5%-8% of the feed. The column top temperature is -35~-25℃, the column bottom temperature is -20~-10℃, and the operating pressure is 0.3-0.5MPa. The azeotrope is discharged from the top of the column, and the intermediate product of hydrogen sulfide is obtained from the bottom of the column. The waste liquid at the bottom of the azeotropic distillation column is fed into the second heat exchanger to preheat the feed to the subsequent extraction vessel.

7. The apparatus for preparing high-purity hydrogen sulfide according to claim 3, characterized in that... In step 3), adsorption occurs in the adsorption tower at a temperature of 5-30℃ and a pressure of 0.3-0.8MPa. First, the first bed adsorbs most of the impurities, while the second bed performs deep adsorption. The two beds operate alternately in an 8-hour cycle. From 0 to 4 hours, the first bed adsorbs while the second bed is on standby. From 4 to 6 hours, the first bed is regenerated with nitrogen while the second bed becomes the main adsorption bed. From 6 to 8 hours, the first bed is cooled to below 30℃ and put into standby mode while the second bed continues adsorption, thus achieving continuous operation.

8. The apparatus for preparing high-purity hydrogen sulfide according to claim 3, characterized in that... The preparation method of Zr-MBI MOFs material in the adsorption tower in step 3) is as follows: ZrCl4 and 2-mercaptobenzimidazole are dissolved in N,N-dimethylformamide (DMF) to form ZrCl4. 4+ -DMF solution, ligand-DMF solution, slowly add ligand-DMF solution dropwise to Zr 4+ Add the DMF solution dropwise while stirring. After the addition is complete, continue stirring to ensure thorough mixing and form a uniform pale yellow suspension. Slowly pour the uniformly mixed suspension into a polytetrafluoroethylene-lined reactor and react at 120-150℃ for 24-36 h. Centrifuge, wash with anhydrous ethanol, filter and dry to obtain a pale yellow powder Zr-MBI MOF.

9. The apparatus for preparing high-purity hydrogen sulfide according to claim 8, characterized in that... In the preparation of the Zr-MBI MOF material, the molar ratio of 2-mercaptobenzimidazole to ZrCl4 is 1:2-1:

3. Anhydrous DMF must be used. The total amount of DMF in the mixture is maintained at a solid-liquid ratio of 1:10-1:

15. 70%-80% of the total DMF is used to dissolve ZrCl4, and 20%-30% is used to dissolve the ligands. The ethanol washing should be performed ≥3 times.

10. The apparatus for preparing high-purity hydrogen sulfide according to claim 3, characterized in that... In step 4), the extractant in the extraction tower is diisopropyl ether, with an extraction ratio of 1:3-1:

5. Extraction is carried out at 20-30℃ for 30-60 min, and the extracted phase enters the distillation tower. The top temperature of the distillation tower is 68-72℃. The packing material in the desulfurization tower is polypropylene packing, and absorption is performed using a 10%-15% sodium hydroxide solution with a liquid-to-gas ratio of 5-8 L / m³. 3 The desulfurization product, sodium sulfide solution, is oxidized and crystallized to obtain the final sulfur product at a crystallization temperature of 40-50℃.

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