Industrial byproduct hydrogen purification system and control method thereof

Abstract

The invention belongs to the field of industrial byproduct hydrogen purification, and particularly relates to an industrial byproduct hydrogen purification system and a control method thereof.The system comprises a reaction tower, a cooling tower, a purification tower, a hydrogen tower, a waste gas tower and a heat exchange medium tank, industrial raw materials are mixed in the reaction tower, and high-temperature gas is generated; the cooling tower is connected with the reaction tower and is used for cooling the high-temperature gas; the purification tower is connected with the cooling tower, and after the mixed gas is introduced, the magnesium-based solid hydrogen storage material is used for adsorbing hydrogen and a small amount of impurity gas in the mixed gas; the hydrogen tower is connected with the purification tower, after waste gas in the purification tower is discharged, hydrogen in the magnesium-based solid hydrogen storage material is pumped out through the vacuum pump and collected in the hydrogen tower, and the purpose of purifying hydrogen is achieved; and the waste gas tower treats the exhausted waste gas and discharges the waste gas after reaching the standard. The magnesium-based solid material is used for absorbing and purifying hydrogen, the material can be re-smelted and recycled after being poisoned by impurity gas, and the recovery and purification cost of industrial byproduct hydrogen is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of industrial by-product hydrogen purification, and in particular relates to an industrial by-product hydrogen purification system and an operation method thereof. Background Art

[0002] Industrial by-product hydrogen refers to the hydrogen generated by existing industries in the process of producing target products. Every year, a large amount of industrial by-product hydrogen in my country is not recycled and is burned and discharged in vain, resulting in a waste of resources. According to statistics, the current output of unused industrial by-product hydrogen discharged in my country is about 4.5 million tons, of which about 2.71 million tons are mainly coke oven gas by-product hydrogen, and about 1.18 million tons are by-product hydrogen such as synthetic ammonia.

[0003] Hydrogen purification technology is a key link from hydrogen production to hydrogen utilization. High-purity hydrogen refers to hydrogen with a purity of more than 99.999%. High-purity hydrogen has a wide range of applications in the industrial field. At present, the most mature technology for hydrogen purification is pressure swing adsorption technology, which has the characteristics of low operating cost and long service life. However, it is difficult to achieve high standards for the removal of specific impurities. Cryogenic distillation is also suitable for large-scale production, but the standard hydrogen purity is 85%~99%, which cannot meet application requirements.

[0004] my country has abundant magnesium resources, and the material is cheap and easy to obtain. Pure magnesium can react with hydrogen under high temperature conditions, and the theoretical hydrogen storage capacity can reach 7.6 wt.%. By increasing the temperature and pressure, hydrogen reacts with magnesium to separate the impurity gas. By increasing the temperature and reducing the pressure, the hydrogen atoms adsorbed inside the magnesium-based hydrogen storage material can escape to obtain high-purity hydrogen, reducing the cost of recovering industrial by-product hydrogen. The development and exploration of the process route and professional equipment for purifying hydrogen with magnesium-based hydrogen storage materials is of great significance to the recovery and utilization of industrial by-product hydrogen and the development of the hydrogen energy industry. Summary of the invention

[0005] The purpose of the present invention is to provide an industrial by-product hydrogen purification system and an operation method thereof, which utilizes magnesium-based solid hydrogen storage material pressed tablets in a purification tower to adsorb hydrogen and a small amount of impurity gas in the mixed gas, and then separates the hydrogen in the hydrogen storage material by reducing the pressure to the hydrogenation reaction platform pressure, thereby achieving the purpose of recovering and purifying industrial by-product hydrogen.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: An industrial by-product hydrogen purification system, comprising a reaction tower, a cooling tower, a purification tower, a hydrogen tower, and a heat exchange system; The reaction tower, cooling tower, purification tower and hydrogen tower are connected by pipelines in sequence; Industrial raw materials are put into the reaction tower, and a reaction tower outlet valve and a compressor are arranged in sequence on the pipeline between the reaction tower and the cooling tower; the industrial raw materials are fossil fuels, and the reforming hydrogen production temperature is 800-1000℃.

[0007] The cooling tower pressure gauge and the purification tower inlet valve are arranged on the pipeline between the cooling tower and the purification tower in sequence; The pipeline between the purification tower and the hydrogen tower is provided with a purification tower outlet valve, a vacuum pump, and a hydrogen tower inlet valve in sequence; The heat exchange system is installed in the purification tower and is used to heat the purification tower. The heat exchange system is connected to an external heat source; The purification tower is equipped with magnesium-based solid hydrogen storage material tablets. There are gaps between the tablets to facilitate the contact between hydrogen and the magnesium-based solid material, thereby improving the adsorption efficiency. The maximum temperature in the purification tower is above 300°C.

[0008] As a further preferred solution, the heat exchange system includes an external heat medium circulation pipeline and a capillary heat exchange pipeline placed in the purification tower, the outlet of the heat medium circulation pipeline is connected to the inlet of the capillary heat exchange pipeline, and the outlet of the capillary heat exchange pipeline is connected to the inlet of the heat medium circulation pipeline; As a further preferred solution, a heat exchange medium tank and a heat exchange medium outlet valve are provided on the heat medium circulation pipeline; As a further preferred solution, a purification tower heat exchange medium outlet valve and a purification tower heat exchange medium inlet valve are respectively provided at the pipe connection of the heat medium circulation pipe and the capillary heat exchange pipe; a heat exchange medium pump is provided at the purification tower heat exchange medium outlet valve of the heat medium circulation pipe, and when the heat exchange medium pump is working, the heat exchange medium is discharged from the purification tower through the purification tower heat exchange medium outlet valve; As a further preferred solution, a heat exchanger is also provided on the heat medium circulation pipeline, and the heat source is heat supplied by the heat exchanger, and the heating temperature is 300~400℃.

[0009] As a further preferred solution, the heat source is the waste heat of the industrial raw materials in the reaction tower, a waste heat heating pipeline is provided between the reaction tower and the heat exchanger, and a heat exchange valve is provided on the waste heat heating pipeline.

[0010] As a further preferred solution, the purification system further comprises a waste gas tower, the vacuum pump pipeline is connected to the waste gas tower, the pipeline is provided with a waste gas tower inlet valve, and the gas outlet of the waste gas tower is provided with a waste gas tower outlet valve; Either the waste gas tower or the hydrogen tower is connected to the gas outlet of the vacuum pump.

[0011] As a further preferred solution, a purification tower pressure gauge and a one-way valve are also provided on the pipeline between the purification tower outlet valve and the vacuum pump.

[0012] As a further preferred embodiment, a reaction tower pressure valve is provided on the reaction tower.

[0013] As a further preferred solution, the heat exchanger is provided with a heat exchanger thermometer, the cooling tower is provided with a cooling tower thermometer, and the purification tower is provided with a purification tower thermometer.

[0014] A control method for an industrial byproduct hydrogen purification system comprises the following steps: Step 1: After the industrial raw materials enter the reaction tower, high-temperature gas is generated. The outlet valve of the reaction tower is opened, and the gas is pressurized to 3~5 MPa through a compressor; Step 2: The pressurized high-temperature and high-pressure gas enters the cooling tower and is cooled to 300~400℃; Step 3: Open the heat exchange valve on the reaction tower, and the heat exchanger uses the system preheating to raise the temperature of the heat exchange medium to 300-400°C. The heat exchange medium enters the purification tower and preheats the purification tower to above 300°C. Step 4: Open the inlet valve of the purification tower, and the mixed gas in the cooling tower enters the purification tower. The mixed gas reacts with the magnesium-based solid hydrogen storage material tablets in the purification tower to absorb hydrogen and a small amount of impurity gas in the mixed gas; Step 5: The compressor keeps working to maintain the pressure of the cooling tower at 3MPa. When the pressure gauge drops less than 0.1MPa within half an hour, the material is saturated with hydrogen. The inlet valve of the purification tower is closed. After the adsorption is completed, the inlet valve of the heat exchange medium of the purification tower is closed, and the outlet valve of the heat transfer tower is opened to drain the heat exchange medium in the purification tower and cool the purification tower to room temperature. Step 6: Open the outlet valve of the purification tower, turn on the vacuum pump, open the inlet valve of the exhaust tower, and the impurity gas that is not adsorbed will be pumped into the exhaust tower by the vacuum pump. Open the outlet valve of the exhaust tower and carry out subsequent treatment of the exhaust gas that meets the standards; Step 7: Open the heat exchange medium inlet valve of the purification tower, heat exchange medium reheats the purification tower to above 300°C, open the purification tower outlet valve, turn on the vacuum pump, open the hydrogen tower inlet valve, the hydrogen in the magnesium-based solid hydrogen storage material tablets is pumped into the hydrogen tower, and the purification is completed. Beneficial Effects

[0015] 1. Use magnesium-based solid hydrogen storage material to compress tablets to absorb hydrogen. Magnesium metal has low cost, abundant resources and low recycling cost. After the material is poisoned by impurity gases, it can be re-smelted and recycled.

[0016] 2. Use magnesium-based solid hydrogen storage material to press and purify the hydrogen, so the hydrogen purity is high.

[0017] 3. Use the waste heat from the reaction tower to heat the heat exchange medium, and further make the purification tower reach the reaction temperature, which has high system efficiency and reduces resource waste. The purification process is simple, has no special technical requirements, and is highly feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a process flow of an industrial by-product hydrogen purification system according to the present invention; Figure 2 This is a schematic diagram of the distribution of magnesium-based solid hydrogen storage material tablets inside the purification tower; Among them: 1-reaction tower, 2-reaction tower outlet valve, 3-compressor, 4-cooling tower, 5-cooling tower thermometer, 6-cooling tower pressure gauge, 7-purification tower inlet valve, 8-purification tower, 9-purification tower outlet valve, 10-purification tower pressure gauge, 11-check valve, 12-vacuum pump, 13-waste gas tower inlet valve, 14-waste gas tower, 15-waste gas tower outlet valve, 16-hydrogen tower inlet valve, 17-hydrogen tower, 18-purification tower thermometer, 19-purification tower heat exchange medium outlet valve, 20-purification tower heat exchange medium inlet valve, 21-heat exchange medium pump, 22-heat exchange medium tank, 23-heat exchange medium outlet valve, 24-heat exchanger thermometer, 25-heat exchanger, 26-reaction tower pressure valve, 27-heat exchange valve, 801-magnesium-based solid hydrogen storage material tablet. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] The present invention provides an industrial by-product hydrogen purification system and an operation method thereof, such as Figure 1 As shown, it mainly includes a reaction tower 1, a compressor 3, a cooling tower 4, a purification tower 8, a vacuum pump 12, a hydrogen tower 17, an exhaust tower 14, a heat exchange medium tank 22, and a heat exchanger 25.

[0021] After adding industrial raw materials into the reaction tower 1, a high-temperature mixed gas of 700~800℃ is generated. Taking the by-product hydrogen of coke oven gas, which accounts for the largest proportion in industry, as an example, the main components of the mixed gas are hydrogen 55%~60%, oxygen 0.3%~0.8%, nitrogen 3%~7%, methane 23%~27%, carbon monoxide 5%~8%, carbon dioxide 1.5%~3%, and other impurity gases 2%~4%. The reaction tower 1 is provided with a reaction tower pressure valve 26 for detecting the pressure of the reaction tower 1.

[0022] The heat exchange valve 27 is opened, and the heat exchanger 25 heats the heat exchange medium to 300-400°C. Then, the purification tower heat exchange medium inlet valve 20 is opened, and the heat exchange medium heats the purification tower 8 to above 300°C.

[0023] The high-temperature mixed gas in the reaction tower 1 is pressurized to 3-5 MPa by the compressor 3 and then enters the cooling tower 4 to be cooled to 300-400°C. The cooling tower 4 is provided with a cooling tower thermometer 5 and a cooling tower pressure gauge 6.

[0024] The mixed gas then enters the purification tower 8. Among the mixed gas components, hydrogen and oxygen react with the magnesium-based solid hydrogen storage material tablet (801) to generate magnesium hydride and magnesium oxide, and the remaining impurity gases do not react with magnesium. The reaction is as follows: .

[0025] The compressor (3) operates continuously to maintain the pressure of the cooling tower (4) at 3 MPa. When the pressure gauge (6) drops by less than 0.1 MPa within half an hour, the material is saturated with hydrogen.

[0026] After the reaction is completed, the purification tower heat exchange medium outlet valve 19 is opened, the heat exchange medium pump 21 is started, and the heat exchange medium is discharged from the purification tower 8 into the heat exchange medium tank 22 to carry out the next cycle of heat exchange circulation.

[0027] After the purification tower 8 is cooled to room temperature, the purification tower outlet valve 9 is opened, and the vacuum pump 12 is operated to extract the waste gas in the purification tower 8. A one-way valve 11 is provided between the vacuum pump 12 and the purification tower outlet valve 9 to prevent gas backflow. The waste gas tower inlet valve 13 is opened, and the waste gas enters the waste gas tower 14. After being treated by the waste gas tower 14 and meeting the standards, the waste gas is discharged through the waste gas tower outlet valve 15.

[0028] Close the exhaust tower inlet valve 13 and the purification tower outlet valve 9, open the purification tower heat exchange medium inlet valve 20, and allow the heat exchange medium to enter the purification tower 8. The temperature of the purification tower 8 rises to above 300°C, the purification tower outlet valve 9 opens, the hydrogen tower inlet valve 16 opens, and the vacuum pump 12 starts to work, reducing the pressure in the purification tower 8 to below the equilibrium pressure of the hydrogenation reaction. The metal hydride decomposes, and hydrogen escapes and enters the hydrogen tower 17. During this process, magnesium oxide does not decompose, and the purity of hydrogen purification can reach above 99.999%.

[0029] For ease of understanding, further explanation will be given below in conjunction with specific embodiments, and each embodiment does not constitute a limitation of the present invention. Example

[0030] The exhaust gas purification and recovery process of the industrial by-product hydrogen purification system of the present invention comprises the following specific steps: After the industrial raw materials are added to the reaction tower 1, the reaction tower 1 generates a high-temperature mixed gas, which enters the compressor 3 through the reaction tower outlet valve 2. The compressor 3 raises the pressure of the mixed gas to 3-5 MPa, and then it is pumped into the cooling tower 4 to be cooled to 300℃-400℃. The cooling tower thermometer 5 and the cooling tower pressure gauge 6 monitor the status of the cooling tower 4 in real time. The reaction tower 1 is provided with a heat exchange valve 27. When the heat exchange valve 27 is opened, the heat exchanger 25 starts to work, the heat exchange medium outlet valve 23 is opened, and the heat exchanger 25 uses the waste heat of the reaction tower 1 to heat the heat exchange medium. The heat exchanger thermometer 24 monitors the temperature of the heat exchange medium in the heat exchanger 25. After the heat exchange medium is heated to 300°C~400°C, the purification tower heat exchange medium inlet valve 20 is opened, the heat exchange medium heats the purification tower 8, and the purification tower thermometer 18 monitors the purification tower temperature; After the temperature of the purification tower 8 rises to 300°C, the purification tower inlet valve 7 is opened, and the mixed gas in the cooling tower 4 enters the purification tower 8. At this time, the cooling tower 4 and the purification tower 8 are an integral space, and hydrogen, a small amount of oxygen and a small amount of impurity gas react with the magnesium-based solid hydrogen storage material tablet 801 to generate compounds, and the remaining gas is enriched in the cavity of the purification tower 8; After the designed amount of mixed gas is injected, the purification is completed, the heat exchange medium outlet valve 19 of the purification tower is opened, the heat exchange medium pump 21 is started, the heat exchange medium is discharged from the purification tower 8 and enters the heat exchange medium tank 22, and the purification tower 8 starts to cool down; After the purification tower 8 is cooled to room temperature, the purification tower outlet valve 9 is opened, and the waste gas in the cavity of the purification tower 8 is pumped out by the vacuum pump 12 through the one-way valve 11, and the waste gas tower inlet valve 13 is opened, and the waste gas enters the waste gas tower 14, and is discharged through the waste gas tower outlet valve 15 after being treated as qualified; The heat exchange medium enters the heat exchanger 25 again through the heat exchange medium outlet valve 23 to be heated. After being heated to 300-400°C, it passes through the purification tower heat exchange medium inlet valve 20 to heat the purification tower 8. After the purification tower 8 is heated to above 300° C., the purification tower outlet valve 9 and the hydrogen tower inlet valve 16 are opened, and the purification tower inlet valve 7 is closed. The purification tower 8 and the hydrogen tower 17 form a space, and the vacuum pump 12 is operated to reduce the pressure in the purification tower 8 to below the equilibrium pressure of the hydrogenation reaction. The metal hydride begins to decompose, and hydrogen escapes from the magnesium-based solid hydrogen storage material pressed tablet (801) and enters the hydrogen tower 17 through the one-way valve 11, the vacuum pump 12, and the hydrogen tower inlet valve 16; The purification tower pressure gauge 10 displays a value of 0, and after it continues to display the value, it indicates that the hydride decomposition is complete, the purification tower heat transfer medium outlet valve 19 is opened, the heat exchange medium pump 21 works, the heat transfer medium is discharged from the purification tower 8, and the valve and vacuum pump 12 are closed. At this point, the hydrogen purification and recovery is completed.

[0031] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An industrial by-product hydrogen purification system, characterized by: It comprises a reaction tower (1), a cooling tower (4), a purification tower (8), a hydrogen tower (17), and a heat exchange system; The reaction tower (1), cooling tower (4), purification tower (8), and hydrogen tower (17) are sequentially connected by pipelines; Industrial raw materials are put into the reaction tower (1), and a reaction tower outlet valve (2) and a compressor (3) are sequentially arranged on the pipeline between the reaction tower (1) and the cooling tower (4); A cooling tower pressure gauge (6) and a purification tower inlet valve (7) are provided in sequence on the pipeline between the cooling tower (4) and the purification tower (8); A purification tower outlet valve (9), a vacuum pump (12), and a hydrogen tower inlet valve (16) are sequentially provided on the pipeline between the purification tower (8) and the hydrogen tower (17); The heat exchange system is installed on the purification tower (8) and is used to heat the purification tower (8), and the heat exchange system is connected to an external heat source; The purification tower (8) has a magnesium-based solid hydrogen storage material pressed sheet (801) built in, and the maximum temperature in the purification tower (8) is above 300°C.

2. An industrial by-product hydrogen purification system according to claim 1, characterized in that: The heat exchange system comprises an external heat medium circulation pipeline and a capillary heat exchange pipeline placed in the purification tower (8), the outlet of the heat medium circulation pipeline is connected to the inlet of the capillary heat exchange pipeline, and the outlet of the capillary heat exchange pipeline is connected to the inlet of the heat medium circulation pipeline; The heat medium circulation pipeline is provided with a heat exchange medium tank (22) and a heat exchange medium outlet valve (23); A purification tower heat exchange medium outlet valve (19) and a purification tower heat exchange medium inlet valve (20) are respectively provided at the connection point between the heat medium circulation pipeline and the capillary heat exchange pipeline; A heat exchange medium pump (21) is provided at the purification tower heat exchange medium outlet valve (19) of the heat medium circulation pipeline. When the heat exchange medium pump (21) is in operation, the heat exchange medium is discharged from the purification tower (8) through the purification tower heat exchange medium outlet valve (19); A heat exchanger (25) is also provided on the heat medium circulation pipeline, and the heat source is provided by the heat exchanger (25) at a heating temperature of 300-400°C.

3. An industrial by-product hydrogen purification system according to claim 2, characterized in that: The heat source is the waste heat of the industrial raw materials in the reaction tower (1), and a waste heat heating pipeline is provided between the reaction tower (1) and the heat exchanger (25), and a heat exchange valve (27) is provided on the waste heat heating pipeline.

4. The industrial by-product hydrogen purification system according to claim 2, characterized in that: The purification system further comprises an exhaust tower (14); the vacuum pump (12) is connected to the exhaust tower (14) by a pipeline, the pipeline is provided with an exhaust tower inlet valve (13), and the exhaust tower (14) has an exhaust tower outlet valve (15) at its gas outlet; Either the waste gas tower (14) or the hydrogen tower (17) is connected to the gas outlet of the vacuum pump (12).

5. The industrial by-product hydrogen purification system according to claim 4, characterized in that: A purification tower pressure gauge (10) and a one-way valve (11) are also provided on the pipeline between the purification tower outlet valve (9) and the vacuum pump (12).

6. The industrial by-product hydrogen purification system according to claim 4, characterized in that: The reaction tower (1) is provided with a reaction tower pressure valve (26).

7. The industrial by-product hydrogen purification system according to claim 4, characterized in that: The heat exchanger (25) is provided with a heat exchanger thermometer (24), the cooling tower (4) is provided with a cooling tower thermometer (5), and the purification tower (8) is provided with a purification tower thermometer (18).

8. A control method for an industrial by-product hydrogen purification system according to any one of claims 4, 5, 6 or 7, characterized in that: The following steps are involved: Step 1: After the industrial raw materials enter the reaction tower (1), high-temperature gas is generated. The outlet valve (2) of the reaction tower is opened, and the gas is pressurized to 3-5 MPa through the compressor (3); Step 2: The pressurized high-temperature and high-pressure gas enters a cooling tower (4) and is cooled to 300-400° C. Step 3: Open the heat exchange valve (27) on the reaction tower (1), and the heat exchanger (25) uses the system preheating to raise the temperature of the heat exchange medium to 300-400° C. The heat exchange medium enters the purification tower (8), and the purification tower (8) is preheated to above 300° C.; Step 4: Open the purification tower inlet valve (7), and the high-pressure mixed gas in the cooling tower (4) enters the purification tower (8). The mixed gas reacts with the magnesium-based solid hydrogen storage material pressed tablet (801) in the purification tower (8), adsorbs hydrogen and a small amount of impurity gas in the mixed gas, and the internal pressure continues to decrease; Step 5: The compressor (3) continues to work to maintain the pressure of the cooling tower (4) at 3 MPa. When the pressure gauge (6) of the cooling tower drops by less than 0.1 MPa within half an hour, the material is saturated with hydrogen. The purification tower inlet valve (7) is closed, and the adsorption is completed. The purification tower heat exchange medium inlet valve (20) is closed, and the heat transfer tower medium outlet valve (19) is opened. The heat exchange medium pump (21) is operated to empty the heat exchange medium in the purification tower (8), so that the purification tower (8) is cooled to room temperature. Step 6: Open the outlet valve (9) of the purification tower, turn on the vacuum pump (12), open the inlet valve (13) of the waste gas tower, and the impurity gas that is not adsorbed is pumped into the waste gas tower (14) by the vacuum pump (12). Open the outlet valve (15) of the waste gas tower, and carry out subsequent treatment on the waste gas that meets the standards; Step 7: Open the heat exchange medium inlet valve (20) of the purification tower, and the heat exchange medium reheats the purification tower (8) to above 300° C., open the purification tower outlet valve (9), turn on the vacuum pump (12), open the hydrogen tower inlet valve (16), and the hydrogen in the magnesium-based solid hydrogen storage material pressed tablet (801) is pumped into the hydrogen tower (17), and the purification is completed.

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