Multi-channel ortho-parahydrogen conversion catalyst evaluation device

Abstract

The invention discloses a multi-channel ortho-parahydrogen conversion catalyst evaluation device. The device comprises a hydrogen generation and purification system, a nitrogen purging system and a pipeline vacuum system which are connected in parallel, the three are sequentially connected with a catalytic conversion system and a parahydrogen detection system after being connected in parallel; the catalytic conversion system is also connected with the tail gas treatment system; the ortho-parahydrogen catalytic conversion device with a multi-path simultaneous activation function is built for the first time, activation treatment of four catalysts can be achieved at the same time, then ortho-parahydrogen catalytic conversion performance evaluation is conducted in batches, and the efficiency of catalytic performance testing is greatly improved; by measuring the peak height of the parahydrogen spectrum in the gas chromatograph, the concentration of the parahydrogen can be accurately calculated.

Description

Technical Field

[0001] The present application relates to a multi-channel normal-parahydrogen conversion catalyst evaluation device, belonging to the technical field of hydrogen liquefaction. Background Art

[0002] Greenhouse gas emissions caused by energy use are the main driving force of global climate change, among which carbon dioxide emissions account for more than two-thirds of global greenhouse gas emissions. Therefore, the adoption of zero-carbon energy is crucial to reducing greenhouse gas emissions. Hydrogen stands out among new energy sources due to its advantages such as renewability and high energy density, becoming a top energy carrier, and liquid hydrogen is highly valued for its strategic value in the fields of aerospace and hydrogen energy. A hydrogen molecule consists of two hydrogen atoms, and the nuclear spin directions of these atoms determine the two different forms of hydrogen: orthohydrogen and parahydrogen. The nuclear spin directions of orthohydrogen are consistent, while the nuclear spin directions of parahydrogen are opposite. At room temperature, hydrogen contains about 75% orthohydrogen and 25% parahydrogen, and this mixture is called normal hydrogen. However, when the temperature is lowered, the proportion of parahydrogen will increase accordingly. For example, in the liquid nitrogen temperature zone, the proportion of parahydrogen is about 49%; while in the liquid hydrogen temperature zone, the proportion of parahydrogen can be as high as 99%.

[0003] The conversion of ortho-parahydrogen in the hydrogen liquefaction process is an exothermic reaction, and the heat released is much greater than its latent heat of vaporization (447kJ / kg). Therefore, even in an ideal insulated container, liquid hydrogen will vaporize. In order to reduce the evaporation loss of liquid hydrogen caused by the heat release of ortho-parahydrogen conversion, the parahydrogen content in the liquid hydrogen product is generally required to be above 95%. Therefore, one of the main indicators of hydrogen liquefaction is the parahydrogen content, and the parahydrogen content must be determined according to the process requirements. The key to the determination of parahydrogen content is the need to equip a complete ortho-parahydrogen conversion device containing a catalyst to obtain the parahydrogen content at a specific temperature. As a standard sample, it is analyzed and determined using a thermal conductivity gas chromatography analysis method with a liquid hydrogen sample, and the parahydrogen content in the sample is calculated using a standard curve method or a calculation coefficient method.

[0004] However, the repeated activation of the existing device structure takes too long, which greatly reduces the efficiency of screening high-performance catalysts; and it is impossible to accurately measure the concentration of parahydrogen in real time, so the catalytic performance test results lack reliability.

[0005] Therefore, designing a device that can activate multiple catalysts simultaneously, efficiently complete catalytic performance testing, and accurately measure the concentration of parahydrogen is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0006] According to one aspect of the present application, a multi-channel normal-parahydrogen conversion catalyst evaluation device is provided, comprising a hydrogen generation and purification system, a nitrogen purge system, and a pipeline vacuum system connected in parallel;

[0007] After the three are connected in parallel, they are connected in turn to the catalytic conversion system and the parahydrogen detection system;

[0008] The catalytic conversion system is also connected to the exhaust gas treatment system.

[0009] Optionally, the catalytic conversion system comprises four quartz tubes connected in parallel, and a heating jacket and a Dewar flask are arranged outside the quartz tubes;

[0010] When the gas enters or flows out of the four-way quartz tube, it passes through a gas control valve;

[0011] The heating jacket and the Dewar flask containing the low-temperature medium are manually placed at the bottom of the quartz tube in sequence according to the reaction progress:

[0012] Specifically, when the catalyst is activated, the quartz tube is inside the heating jacket; during low-temperature reaction, the quartz tube is inside a Dewar flask containing a low-temperature medium;

[0013] The activation treatment of four catalysts can be achieved simultaneously, and then the catalytic conversion performance of normal and para hydrogen can be evaluated in batches, which greatly improves the efficiency of catalytic performance testing.

[0014] Optionally, the Dewar flask contains a low-temperature medium to provide a cold source for the reaction;

[0015] Preferably, the cryogenic medium may include but is not limited to liquid nitrogen or liquid helium.

[0016] Optionally, the heating jacket is equipped with a thermocouple to monitor the internal temperature of the heating jacket in real time.

[0017] Optionally, the quartz tube is a U-shaped tube, and the catalyst is filled in the quartz tube to catalytically convert the hydrogen in the tube, and then the para-hydrogen concentration is accurately detected by the para-hydrogen detection system;

[0018] The quartz tube can be filled with either powdered catalyst or granulated catalyst.

[0019] Optionally, the hydrogen generation and purification system includes a hydrogen generator, a hydrogen purifier and a flow controller connected in sequence;

[0020] The hydrogen generator first electrolyzes water to produce raw hydrogen, which is then removed from the hydrogen purifier to produce high-purity hydrogen, which then enters the catalytic conversion system through a hydrogen flow controller.

[0021] Optionally, the pipeline vacuum system includes a gas pressure sensor and a vacuum pump;

[0022] The vacuum pump is connected to the catalytic conversion system via a vacuum control valve.

[0023] Optionally, the nitrogen purge system comprises a nitrogen source;

[0024] The nitrogen source is connected to the catalytic conversion system via a flow controller.

[0025] Optionally, the parahydrogen concentration detection system includes a gas chromatograph connected to the outlet of the catalytic conversion system;

[0026] When the gas flows out of the catalytic conversion system, one path leads to the exhaust gas treatment system and the other path leads to the parahydrogen detection system.

[0027] Optionally, the hydrogen generation and purification system, the nitrogen purge system, the pipeline vacuum system, the catalytic conversion system, and the parahydrogen detection system are respectively provided with gas inlet and outlet control valves to improve the safety of the entire pipeline.

[0028] Working principle:

[0029] Before the evaluation device activates the catalyst, nitrogen is first introduced into the entire device and then enters the exhaust gas treatment device through the catalytic conversion system. This can effectively replace the residual hydrogen in the pipeline after the last reaction and avoid safety hazards.

[0030] First, turn on the switch of the nitrogen source, enter the gas flow controller through the gas inlet and outlet control valve, adjust the appropriate flow, and enter the catalytic conversion system of the device through the gas inlet and outlet control valve; at this time, ensure that the gas inlet and outlet control valves of the hydrogen generation and purification system, the gas inlet and outlet control valves of the parahydrogen detection system, and the vacuum control valve remain tightly closed, and the gas inlet and outlet control valves in the catalytic conversion system are all open, and at this time the outlet gas of the catalytic conversion system is all led to the exhaust gas treatment device).

[0031] When evacuating the evaluation device, it is necessary to ensure that the gas inlet and outlet control valves of the hydrogen generation and purification system, the gas inlet and outlet control valves of the nitrogen purge system, the gas inlet and outlet control valves of the catalytic conversion system, and the gas inlet and outlet control valves of the parahydrogen detection system are tightly closed. After starting the vacuum pump, slowly open the vacuum control valve, and then slowly open the gas inlet and outlet control valves at the inlet end of the catalytic conversion system in turn, slowly evacuate the inside of the device to a vacuum state, and then activate the catalyst.

[0032] After the catalyst is activated, the vacuum control valve, the gas inlet and outlet control valves at the inlet of the catalytic conversion system and the vacuum pump must be closed in time to keep the U-shaped quartz tube in a relative vacuum environment to protect the activation state of the catalyst. After the catalyst is naturally cooled to room temperature, the catalyst performance can be evaluated.

[0033] When evaluating the performance of the catalyst, it is necessary to turn on the hydrogen purifier switch, adjust the appropriate gas flow rate through the flow controller, and then enter the catalytic conversion system. At this time, slowly open the gas inlet and outlet control valve at the entrance of the quartz tube at the top. After the hydrogen enters the U-shaped quartz tube, slowly immerse it in a Dewar flask containing a low-temperature medium (including but not limited to liquid nitrogen, liquid helium, etc.). When the gas pressure sensor detects that the air pressure in the pipeline is greater than 0, the gas inlet and outlet control valve at the outlet of the route and the gas inlet and outlet control valve of the parahydrogen detection system can be slowly opened in turn, and the hydrogen after the reaction is passed to the gas chromatograph for parahydrogen concentration detection.

[0034] After the evaluation of the catalyst in this line is completed, close the gas inlet and outlet control valve at the inlet of the quartz tube, open the gas inlet and outlet control valve at the outlet to the exhaust gas treatment system, and then slowly open the gas inlet and outlet control valve at the inlet of the next quartz tube, and repeat the above steps to evaluate the catalysts in the other three lines.

[0035] After the evaluation of the four-way catalyst is completed, close the flow controller in the hydrogen generation and purification system, and open the gas inlet and outlet control valves at the outlets of the four-way quartz tubes to the exhaust gas treatment system, slowly empty the residual hydrogen in the pipeline, pass nitrogen for 2-3 minutes, and then close the flow controller and all other valves in the hydrogen generation and purification system.

[0036] The beneficial effects of this application include:

[0037] The present application provides a multi-channel para-hydrogen conversion catalyst evaluation device, which is the first to build a para-hydrogen catalytic conversion device with a multi-channel simultaneous activation function. It can simultaneously activate four catalysts, and then conduct para-hydrogen catalytic conversion performance evaluation in batches, which greatly improves the efficiency of catalytic performance testing; by measuring the para-hydrogen spectrum peak height in the gas chromatograph, the para-hydrogen concentration can be accurately calculated. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of an evaluation device provided in one embodiment of the present application;

[0039] Figure 2 A detailed structural schematic diagram of an evaluation device provided in one embodiment of the present application.

[0040] List of parts and reference numerals:

[0041] 1. Hydrogen generator; 2. Hydrogen purifier; 3. Nitrogen source; 4. Vacuum pump; 5. Quartz tube; 6. Heating jacket; 7. Gas chromatograph; 8. Tail gas treatment device; 9. Flow controller; 10. Vacuum control valve; 11. Hydrogen generation and purification system; 12. Nitrogen purge system; 13. Pipeline vacuum system; 14. Catalytic conversion system; 15. Parahydrogen detection system; 16. Tail gas treatment system. DETAILED DESCRIPTION

[0042] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0043] like Figure 1 and Figure 2 As shown, a multi-channel normal-parahydrogen conversion catalyst evaluation device includes a hydrogen generation and purification system 11, a nitrogen purge system 12, and a pipeline vacuum system 13 connected in parallel;

[0044] After the three are connected in parallel, they are connected in sequence to the catalytic conversion system 14 and the parahydrogen detection system 15;

[0045] The catalytic conversion system 14 is also connected to an exhaust gas treatment system 16 .

[0046] The catalytic conversion system 14 comprises four quartz tubes 5 connected in parallel, and a heating jacket 6 and a Dewar flask are arranged outside the quartz tubes 5;

[0047] When the gas enters or flows out of the four-way quartz tube 5, it will pass through a gas control valve;

[0048] The heating jacket 6 and the Dewar flask containing the low-temperature medium are manually placed at the bottom of the quartz tube 5 in sequence according to the reaction progress:

[0049] Specifically, when the catalyst is activated, the quartz tube 5 is inside the heating jacket 6; during low-temperature reaction, the quartz tube 5 is inside the Dewar flask containing low-temperature medium;

[0050] The activation treatment of four catalysts can be achieved simultaneously, and then the catalytic conversion performance of normal and para hydrogen can be evaluated in batches, which greatly improves the efficiency of catalytic performance testing.

[0051] The Dewar flask contains a low-temperature medium to provide a cold source for the reaction;

[0052] The cryogenic medium may include but is not limited to liquid nitrogen or liquid helium.

[0053] The heating jacket 6 is equipped with a thermocouple, which can monitor the internal temperature of the heating jacket 6 in real time.

[0054] The quartz tube 5 is a U-shaped tube, and the catalyst is filled in the quartz tube 5 to catalytically convert the hydrogen in the tube, and then the parahydrogen concentration is accurately detected by the parahydrogen detection system;

[0055] The quartz tube 5 may be filled with a powder catalyst or a granulated catalyst.

[0056] The hydrogen generation and purification system 11 comprises a hydrogen generator 1, a hydrogen purifier 2 and a flow controller 9 which are connected in sequence;

[0057] First, the hydrogen generator 1 electrolyzes water to produce raw hydrogen, which is then removed from the hydrogen purifier 2 to produce high-purity hydrogen, which then enters the catalytic conversion system 14 through the hydrogen flow controller 9.

[0058] The pipeline vacuum system 13 includes a gas pressure sensor and a vacuum pump 4;

[0059] The vacuum pump 4 is connected to the catalytic conversion system 14 via a vacuum control valve 10 .

[0060] The nitrogen purge system 12 includes a nitrogen source 3;

[0061] The nitrogen source 3 is connected to the catalytic conversion system 14 via a flow controller 9 .

[0062] The parahydrogen concentration detection system includes a gas chromatograph 7 connected to the outlet of the catalytic conversion system 14;

[0063] When the gas flows out of the catalytic conversion system 14 , one path leads to the exhaust gas treatment system 16 , and the other path leads to the parahydrogen detection system 15 .

[0064] The hydrogen generation and purification system 11, the nitrogen purge system 12, the pipeline vacuum system 13, the catalytic conversion system 14, and the parahydrogen detection system 15 are respectively provided with gas inlet and outlet control valves to improve the safety of the entire pipeline.

[0065] Working principle:

[0066] Before the evaluation device performs catalyst activation, nitrogen is first introduced into the entire device and enters the tail gas treatment device 8 through the catalytic conversion system 14, which can effectively replace the residual hydrogen in the pipeline after the last reaction and avoid safety hazards.

[0067] First, turn on the switch of the nitrogen source 3, pass the gas inlet and outlet control valve, enter the gas flow controller 9, adjust the appropriate flow rate, and enter the catalytic conversion system 14 of the device through the gas inlet and outlet control valve; at this time, ensure that the gas inlet and outlet control valves of the hydrogen generation and purification system 11, the gas inlet and outlet control valves of the parahydrogen detection system 15, and the vacuum control valve 10 remain tightly closed, and the gas inlet and outlet control valves in the catalytic conversion system 14 are all opened, and at this time, the outlet gas of the catalytic conversion system 14 is all led to the exhaust gas treatment device 8).

[0068] When the evaluation device is evacuated, it is necessary to ensure that the gas inlet and outlet control valves of the hydrogen generation and purification system 11, the gas inlet and outlet control valves of the nitrogen purge system 12, the gas inlet and outlet control valves of the catalytic conversion system 14, and the gas inlet and outlet control valves of the parahydrogen detection system 15 are tightly closed. After starting the vacuum pump 4, slowly open the vacuum control valve 10, and then slowly open the gas inlet and outlet control valves at the inlet end of the catalytic conversion system 14 in turn, slowly evacuate the inside of the device to a vacuum state, and then activate the catalyst.

[0069] After the catalyst is activated, the vacuum control valve 10, the gas inlet and outlet control valve at the inlet of the catalytic conversion system 14 and the vacuum pump 4 must be closed in time to keep the U-shaped quartz tube 5 in a relatively vacuum environment to protect the activation state of the catalyst. After the catalyst is naturally cooled to room temperature, the catalyst performance is evaluated.

[0070] When evaluating the performance of the catalyst, it is necessary to turn on the switch of the hydrogen purifier 2, adjust the appropriate gas flow rate through the flow controller 9, and then enter the catalytic conversion system 14. At this time, slowly open the gas inlet and outlet control valve at the entrance of the quartz tube 5 at the top. After the hydrogen enters the U-shaped quartz tube 5, slowly immerse it in a Dewar flask containing a low-temperature medium (including but not limited to liquid nitrogen, liquid helium, etc.). When the gas pressure sensor detects that the air pressure in the pipeline is greater than 0, the gas inlet and outlet control valve at the outlet of the road and the gas inlet and outlet control valve of the parahydrogen detection system 15 can be slowly opened in turn, and the hydrogen after the reaction is passed to the gas chromatograph 7 for parahydrogen concentration detection.

[0071] After the evaluation of the catalyst of this route is completed, close the gas inlet and outlet control valve at the inlet of the quartz tube 5 of this route, open the gas inlet and outlet control valve at the outlet to the exhaust gas treatment system 16, and then slowly open the gas inlet and outlet control valve at the inlet of the next quartz tube 5, and repeat the above steps to evaluate the catalysts of the other three routes.

[0072] After the evaluation of the four-way catalyst is completed, close the flow controller 9 in the hydrogen generation and purification system 11, and open the gas inlet and outlet control valves at the outlets of the four-way quartz tube 5 to the tail gas treatment device 8, slowly empty the residual hydrogen in the pipeline, pass nitrogen for 2-3 minutes, and then close the flow controller 9 and all other valves in the hydrogen generation and purification system 11.

[0073] Example 1

[0074] The catalyst is amorphous ferric oxide, and the activation conditions are: 140°C under vacuum for 2 hours, and the catalyst dosage is 0.2g powder. When the reaction tube cools to room temperature, the hydrogen flow rate is set to 100ml / min, and it is placed in a Dewar flask filled with liquid nitrogen. According to calculations, the parahydrogen content reaches 48%.

[0075] Example 2

[0076] The catalyst is commercial hydrated iron oxide, the activation conditions are: 140°C for 2 hours, the catalyst dosage is 0.5g of particles (30-50 mesh), when the reaction tube is cooled to room temperature, the hydrogen flow rate is set to 100ml / min, and it is placed in a Dewar flask filled with liquid nitrogen. It is calculated that the parahydrogen content reaches 50%.

[0077] The above description is only a partial embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A multi-channel normal-parahydrogen conversion catalyst evaluation device, characterized in that: It includes a hydrogen generation and purification system, a nitrogen purge system, and a pipeline vacuum system connected in parallel; After the three are connected in parallel, they are connected in turn to the catalytic conversion system and the parahydrogen detection system; The catalytic conversion system is also connected to the exhaust gas treatment system.

2. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The catalytic conversion system comprises four quartz tubes connected in parallel, and a heating jacket and a Dewar flask are arranged outside the quartz tubes.

3. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 2, characterized in that: The Dewar flask contains a cryogenic medium; Preferably, the cryogenic medium is selected from liquid nitrogen or liquid helium.

4. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 2, characterized in that: The heating mantle was equipped with a thermocouple.

5. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 2, characterized in that: The quartz tube is a U-shaped tube, and the quartz tube is filled with a catalyst.

6. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The hydrogen generation and purification system comprises a hydrogen generator, a hydrogen purifier and a flow controller which are connected in sequence.

7. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The pipeline vacuum system includes a gas pressure sensor and a vacuum pump; The vacuum pump is connected to the catalytic conversion system via a vacuum control valve.

8. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The nitrogen purge system includes a nitrogen source; The nitrogen source is connected to the catalytic conversion system via a flow controller.

9. A multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The parahydrogen concentration detection system comprises a gas chromatograph connected to the outlet of the catalytic conversion system.

10. The multi-channel normal-parahydrogen conversion catalyst evaluation device according to claim 1, characterized in that: The hydrogen generation and purification system, the nitrogen purge system, the pipeline vacuum system, the catalytic conversion system, and the parahydrogen detection system are each provided with a gas inlet and outlet control valve.

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