System and method for testing hydrogen isotope effect of hydrogen storage metal

Abstract

The invention discloses a hydrogen isotope effect test system for hydrogen storage metal, which adopts a specific combination mode of an adsorption isotherm automatic tester, an online hydrogen isotope chromatograph, a heating and cooling integrated machine and the like to realize the hydrogen isotope effect test of the hydrogen storage metal. And the change condition of the hydrogen isotope effect of the hydrogen storage metal in the quartz sample tube in the process of adsorbing and desorbing the protium-deuterium mixed gas is obtained. The invention further discloses a method for testing the hydrogen isotope effect in the hydrogen storage metal adsorption-desorption protium-deuterium mixed gas, the adsorption-desorption balance is judged by using the adsorption isotherm tester, the total adsorption-desorption amount of protium and deuterium is obtained, and the protium-deuterium mixed gas proportion during adsorption-desorption balance is analyzed by using the online gas chromatograph. And calculating the protium adsorption-desorption amount and the deuterium adsorption-desorption amount. According to the system, the adsorption-desorption conditions of protium and deuterium can be tested, the adsorption-desorption conditions of protium deuterium (HD) molecules can be observed, and the hydrogen isotope effect shown during chemical adsorption-desorption of hydrogen storage metal can be reflected more accurately.

Description

Technical Field

[0001] The invention belongs to the research field of hydrogen storage materials, and in particular relates to a hydrogen storage metal hydrogen isotope effect testing system and method. Background Art

[0002] The study of hydrogen isotope effect is of great significance in both basic research and technical fields. At present, the most studied hydrogen isotope effect hydrogen storage metal system is palladium-protium (Pd-H) system. Usually, the adsorption-desorption isotherms (PCT curves) of palladium-protium gas (Pd-H2) system and palladium-deuterium gas (Pd-D2) system are compared, and the hydrogen isotope effect is evaluated by the equilibrium pressure difference of PCT curve. Studies have found that the adsorption-desorption PCT curve of Pd and H2-HD-D2 mixed gas will deviate significantly from the PCT curves of Pd-H2 system and Pd-D2 system. This deviation will provide useful information for understanding the mechanism of hydrogen isotope exchange reaction. At the same time, this deviation is very helpful for improving the hydrogen isotope enrichment and separation process. Pd tends to enrich protium, and a hydrogen storage metal that can enrich deuterium is needed to be used in combination with it to improve the protium-deuterium separation efficiency and product purity. At present, hydrogen storage metals enriched with deuterium at room temperature are under development, and a suitable hydrogen isotope effect test system is needed. The traditional test system for testing the PCT curve can only measure the total pressure of the hydrogen-deuterium mixture, but cannot distinguish the H / D ratio. The low-temperature online gas chromatograph can distinguish the content of H2, HD, and D2 at the same time, but cannot test the PCT curve. Therefore, in order to distinguish the partial pressure of the hydrogen-deuterium mixture and test the PCT curve at the same time, it is necessary to design the coupling between the PCT test system and the online gas chromatograph. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a hydrogen storage metal hydrogen isotope effect test system, which adopts the following technical scheme:

[0004] A hydrogen storage metal hydrogen isotope effect test system comprises a vacuum unit, a sample unit, an adsorption isotherm automatic tester and an online hydrogen isotope gas chromatograph, wherein the vacuum unit is connected to the sample unit through a pneumatic valve I and a pneumatic valve II, the adsorption isotherm automatic tester is connected to the online hydrogen isotope gas chromatograph through a pneumatic valve III and a pneumatic valve IV, and the pneumatic valves I, II, III and IV are connected through a four-way piece; the sample unit comprises a quartz sample tube, a sample chamber and a heating and cooling integrated machine, the quartz sample tube is sealed and connected to the sample chamber, the sample chamber is connected to the heating and cooling integrated machine through a circulating heat-conducting oil pipe, and the quartz sample tube is connected to the pneumatic valve II through a bellows; the adsorption isotherm automatic tester is connected to the quartz sample tube through the pneumatic valve II and the pneumatic valve III; and the online hydrogen isotope gas chromatograph is connected to the quartz sample tube through the pneumatic valve II and the pneumatic valve IV.

[0005] Furthermore, the vacuum unit includes a dry mechanical pump and a molecular pump, the dry mechanical pump is connected to the molecular pump via a solenoid valve, and the molecular pump is connected to the pneumatic valve I via a bellows.

[0006] Furthermore, the heating and cooling integrated machine is filled with silicone oil, the operating temperature range is -90°C to 200°C, and the temperature stability is ±0.01°C.

[0007] Furthermore, the adsorption isotherm automatic tester and the online hydrogen isotope gas chromatograph are connected via a control software circuit.

[0008] Furthermore, the chromatographic column of the online hydrogen isotope gas chromatograph is a modified alumina filling column.

[0009] The beneficial effects of the above-mentioned test system are: the system can distinguish the partial pressure of the hydrogen-deuterium mixture while testing the PCT curve; it can observe the adsorption-desorption of protium (H2) and deuterium (D2) molecules while testing the adsorption-desorption of protium (H2) and deuterium (D2), and more accurately reflect the hydrogen isotope effect manifested during the chemical adsorption of hydrogen storage metals.

[0010] The present invention also provides a method for testing the hydrogen isotope effect of hydrogen storage metal adsorption-desorption in a protium-deuterium mixed gas using the above hydrogen storage metal hydrogen isotope effect testing system, comprising the following steps:

[0011] (a) Activating the sample to be tested by the protium-deuterium mixed gas: opening the pneumatic valve I and the pneumatic valve II, the vacuum unit draws the sample chamber to a preset vacuum degree, the heating and cooling integrated machine heats the sample chamber to a first preset temperature, and after a preset time, cools the sample chamber to a second preset temperature; closing the pneumatic valve I; then opening the pneumatic valve III, the adsorption isotherm automatic tester releases the protium-deuterium mixed gas until the quartz sample tube reaches a preset pressure value, and the total amount of protium-deuterium adsorption of the sample is measured;

[0012] (b) repeating step (a) several times until the total amount of protium-deuterium adsorption of the sample remains constant; closing pneumatic valve II and pneumatic valve III;

[0013] (c) performing an adsorption test on the protium-deuterium mixed gas of the sample to be tested: opening pneumatic valve I and pneumatic valve II, the vacuum unit draws the sample chamber to a preset vacuum degree, the heating and cooling integrated machine heats the sample chamber to a first preset temperature, and after a preset time, cools the sample chamber to a third preset temperature; closing pneumatic valve I; then opening pneumatic valve III and pneumatic valve IV, the adsorption isotherm automatic tester releases a preset quantitative protium-deuterium mixed gas to the quartz sample tube, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph through the control software circuit of the adsorption isotherm automatic tester; after the online hydrogen isotope gas chromatograph completes sampling for 0.5 minutes, it starts to automatically analyze the sample and records the gas chromatogram; the adsorption isotherm automatic tester repeatedly releases the protium-deuterium mixed gas to the quartz sample tube according to the preset quantitative several times until the total amount of protium-deuterium adsorption of the sample reaches a maximum value;

[0014] (d) performing a desorption test on the protium-deuterium mixed gas of the sample to be tested: the adsorption isotherm automatic tester extracts a preset quantitative protium-deuterium mixed gas, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph through the control software circuit of the adsorption isotherm automatic tester. After the online hydrogen isotope gas chromatograph completes sampling for 0.5 minutes, it starts to automatically analyze the sample and record the gas chromatogram;

[0015] (e) Repeat step (d) several times until the protium and deuterium adsorbed in the sample are completely desorbed; and obtain the pressure, content and chromatogram in the gas phase at each desorption point.

[0016] Furthermore, the preset vacuum degree is 5×10 -4 Pa, the first preset temperature is 120°C, the preset time is 1 hour, the second preset temperature is -50°C, the preset pressure value is 50kPa~80kPa, the third preset temperature is -50°C~20°C, and the preset quantitative hydrogen-deuterium mixed gas is 1.2mmol.

[0017] Furthermore, the step (a) is repeated 5 to 10 times.

[0018] The above test method uses an online hydrogen isotope gas chromatograph to simultaneously observe the changes of three hydrogen isotope molecules H2, HD, and D2 in the gas phase, and combines the total released gas volume and the remaining gas volume recorded by the adsorption isotherm automatic tester to indirectly calculate the changes in the H and D content in the hydrogen storage metal. The changes in gas and solid phase hydrogen isotopes reflect the hydrogen isotope effect exhibited by the hydrogen storage metal during chemical adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structural composition of a hydrogen storage metal hydrogen isotope effect test system;

[0020] In the figure: 1-pneumatic valve I; 2-pneumatic valve II; 3-pneumatic valve III; 4-pneumatic valve IV; 5-dry mechanical pump; 6-solenoid valve; 7-molecular pump; 8-quartz sample tube; 9-sample chamber; 10-heating and cooling integrated machine; 11-adsorption isotherm automatic tester; 12-online hydrogen isotope gas chromatograph;

[0021] Figure 2 The online hydrogen isotope gas chromatograph simultaneously observes the spectra of three hydrogen isotope molecules: H2, HD, and D2. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Example 1

[0024] The test method and results of hydrogen isotope effect in Pd adsorption-desorption mixed gas of protium and deuterium are as follows:

[0025] (a) Activation of Pd by protium-deuterium mixed gas: 6.0 g of Pd sample was placed in a quartz sample tube 8 and then placed in a sample chamber 9 to seal it; the pneumatic valve I1 and pneumatic valve II2 were opened, and the vacuum unit (the dry mechanical pump 5, the solenoid valve 6, and the molecular pump 7 were opened in sequence) was used to pump the quartz sample chamber 8 to 5×10 -4 Pa, the heating and cooling integrated machine 10 heats the sample chamber 9 to 120°C, and after 1 hour, cools the sample chamber to -50°C; closes the pneumatic valve I1; opens the pneumatic valve III 3, and the adsorption isotherm automatic tester 11 releases the hydrogen-deuterium mixed gas until the quartz sample tube 8 reaches 80kPa, and the adsorption isotherm automatic tester 11 measures the total amount of hydrogen-deuterium adsorption of the sample, and the adsorption amount is obtained by the PVT method;

[0026] (b) repeating the above activation step 5 times until the total amount of protium and deuterium adsorption of the sample remains constant; then closing pneumatic valve II and pneumatic valve III;

[0027] (c) Protium-deuterium mixed gas adsorption test of LaNi5: Open the pneumatic valve I1, pneumatic valve II 2, vacuum unit (open the dry mechanical pump 5, solenoid valve 6, molecular pump 7 in sequence) and pump the sample chamber 9 to 5×10 -4Pa, the heating and cooling integrated machine 10 heats the sample chamber 9 to 120°C, and after 1h, cools the sample chamber to 20°C; closes the pneumatic valve I1; opens the pneumatic valve III 3 and the pneumatic valve IV4, and the adsorption isotherm automatic tester 11 quantitatively releases 1.2mmol of hydrogen-deuterium mixed gas to the quartz sample tube 8, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph 12 through the adsorption isotherm automatic tester control software circuit; after the online hydrogen isotope gas chromatograph completes sampling for 0.5min, it starts to automatically analyze the sample and record the gas chromatogram; the adsorption isotherm automatic tester 11 repeats the quantitative release of 1.2mmol of hydrogen-deuterium mixed gas several times, and the chromatographic test of the hydrogen-deuterium ratio is performed once after each equilibrium, until the total amount of hydrogen-deuterium adsorption of the sample reaches the maximum value, and the equilibrium pressure exceeds 1.2bar, the adsorption test is automatically ended, and the desorption test is automatically started;

[0028] (d) Desorption test of hydrogen-deuterium mixed gas of the sample: the adsorption isotherm automatic tester 11 extracts 1.2 mmol of hydrogen-deuterium mixed gas, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph 12. After the online hydrogen isotope gas chromatograph 12 completes sampling for 0.5 min, it starts to automatically analyze the sample and record the gas chromatogram;

[0029] (e) Repeat the quantitative desorption of 1.2 mmol of hydrogen-deuterium mixed gas several times until the hydrogen-deuterium adsorbed amount of the sample is completely desorbed. When the desorption amount is less than 1.2 mmol, the desorption test stops automatically.

[0030] The instrument finally gives the equilibrium adsorption point data and equilibrium desorption point data of LaNi5 adsorbing different amounts of hydrogen-deuterium mixed gas at -50℃, as well as the chromatograms of H2, HD, and D2 in the gas phase at each equilibrium point (such as Figure 2 ).

[0031] Example 2

[0032] The test method and results of the hydrogen isotope effect in LaNi5 adsorption-desorption mixed gas of protium and deuterium are as follows:

[0033] (c) Activation of LaNi5 by protium-deuterium mixed gas: 4.0 g of LaNi5 sample was placed in a quartz sample tube 8 and then placed in a sample chamber 9 to seal it; the pneumatic valve I1 and pneumatic valve II2 were opened, and the vacuum unit (the dry mechanical pump 5, the solenoid valve 6, and the molecular pump 7 were opened in sequence) was used to pump the quartz sample chamber 8 to 5×10 -4 Pa, the heating and cooling integrated machine 10 heats the sample chamber 9 to 120°C, and after 1 hour, cools the sample chamber to -50°C; closes the pneumatic valve I1; opens the pneumatic valve III 3, and the adsorption isotherm automatic tester 11 releases the hydrogen-deuterium mixed gas until the quartz sample tube 8 reaches 50kPa, and the adsorption isotherm automatic tester 11 measures the total amount of hydrogen-deuterium adsorption of the sample, and the adsorption amount is obtained by the PVT method;

[0034] (d) repeating the above activation step 10 times until the total amount of protium and deuterium adsorption of the sample remains constant; then closing pneumatic valve II and pneumatic valve III;

[0035] (c) Protium-deuterium mixed gas adsorption test of LaNi5: Open the pneumatic valve I1, pneumatic valve II 2, vacuum unit (open the dry mechanical pump 5, solenoid valve 6, molecular pump 7 in sequence) and pump the sample chamber 9 to 5×10 -4 Pa, the heating and cooling integrated machine 10 heats the sample chamber 9 to 120°C, and after 1 hour, cools the sample chamber to -50°C; closes the pneumatic valve I1; opens the pneumatic valve III 3 and the pneumatic valve IV4, and the adsorption isotherm automatic tester 11 quantitatively releases 1.2mmol of the hydrogen-deuterium mixed gas to the quartz sample tube 8, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph 12; after the online hydrogen isotope gas chromatograph completes sampling for 0.5min, it starts to automatically analyze the sample and record the gas chromatogram; the adsorption isotherm automatic tester 11 repeats the quantitative release of 1.2mmol of the hydrogen-deuterium mixed gas several times, and performs a chromatographic test of the hydrogen-deuterium ratio once after each equilibrium, until the total amount of hydrogen-deuterium adsorption of the sample reaches the maximum value, and the equilibrium pressure exceeds 1.2bar, the adsorption test is automatically ended, and the desorption test is automatically started;

[0036] (d) Desorption test of hydrogen-deuterium mixed gas of the sample: the adsorption isotherm automatic tester 11 extracts 1.2 mmol of hydrogen-deuterium mixed gas, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph 12. After the online hydrogen isotope gas chromatograph 12 completes sampling for 0.5 min, it starts to automatically analyze the sample and record the gas chromatogram;

[0037] (e) Repeat the quantitative desorption of 1.2 mmol of hydrogen-deuterium mixed gas several times until the hydrogen-deuterium adsorbed amount of the sample is completely desorbed. When the desorption amount is less than 1.2 mmol, the desorption test stops automatically.

[0038] The instrument finally gives the equilibrium adsorption point data and equilibrium desorption point data of LaNi5 adsorbing different amounts of hydrogen-deuterium mixed gas at -50℃, as well as the chromatograms of H2, HD, and D2 in the gas phase at each equilibrium point (similar to Figure 2 ).

[0039] The present invention is described in detail above in combination with specific implementation methods and exemplary examples. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments; the above description cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, the technical solution of the present invention and its implementation methods may be subjected to a variety of equivalent substitutions, modifications or improvements, all of which fall within the scope of the present invention; the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A hydrogen storage metal hydrogen isotope effect test system, characterized in that: The test system comprises a vacuum unit, a sample unit, an adsorption isotherm automatic tester and an online hydrogen isotope gas chromatograph, wherein the vacuum unit is connected to the sample unit via a pneumatic valve I and a pneumatic valve II, the adsorption isotherm automatic tester is connected to the online hydrogen isotope gas chromatograph via a pneumatic valve III and a pneumatic valve IV, and the pneumatic valve I, the pneumatic valve II, the pneumatic valve III and the pneumatic valve IV are connected via a four-way piece; The sample unit includes a quartz sample tube, a sample chamber and a heating and cooling integrated machine, the quartz sample tube is sealed and connected to the sample chamber, the sample chamber is connected to the heating and cooling integrated machine through a circulating heat transfer oil pipe, and the quartz sample tube is connected to the pneumatic valve II through a bellows; The adsorption isotherm automatic tester is connected to the quartz sample tube via pneumatic valve II and pneumatic valve III; The online hydrogen isotope gas chromatograph is connected to the quartz sample tube via pneumatic valve II and pneumatic valve IV.

2. A hydrogen storage metal hydrogen isotope effect testing system according to claim 1, characterized in that: The vacuum unit comprises a dry mechanical pump and a molecular pump, wherein the dry mechanical pump is connected to the molecular pump via a solenoid valve, and the molecular pump is connected to the pneumatic valve I via a bellows.

3. A hydrogen storage metal hydrogen isotope effect testing system according to claim 1, characterized in that: The heating and cooling integrated machine is filled with silicone oil, has an operating temperature range of -90°C to 200°C, and a temperature stability of ±0.01°C.

4. A hydrogen storage metal hydrogen isotope effect testing system according to claim 1, characterized in that: The adsorption isotherm automatic tester and the online hydrogen isotope gas chromatograph are also connected via a control software circuit.

5. A hydrogen storage metal hydrogen isotope effect testing system according to claim 1, characterized in that: The chromatographic column of the online hydrogen isotope gas chromatograph is a modified alumina filling column.

6. A method for testing the hydrogen isotope effect of hydrogen storage metal adsorption-desorption in a protium-deuterium mixed gas using the hydrogen storage metal hydrogen isotope effect testing system according to claim 4, characterized in that: The steps include: (a) Activating the sample to be tested by the protium-deuterium mixed gas: opening the pneumatic valve I and the pneumatic valve II, the vacuum unit draws the sample chamber to a preset vacuum degree, the heating and cooling integrated machine heats the sample chamber to a first preset temperature, and after a preset time, cools the sample chamber to a second preset temperature; closing the pneumatic valve I; then opening the pneumatic valve III, the adsorption isotherm automatic tester releases the protium-deuterium mixed gas until the quartz sample tube reaches a preset pressure value, and the total amount of protium-deuterium adsorption of the sample is measured; (b) repeating step (a) several times until the total amount of protium-deuterium adsorption of the sample remains constant; closing pneumatic valve II and pneumatic valve III; (c) performing an adsorption test on the protium-deuterium mixed gas of the sample to be tested: opening pneumatic valve I and pneumatic valve II, the vacuum unit draws the sample chamber to a preset vacuum degree, the heating and cooling integrated machine heats the sample chamber to a first preset temperature, and after a preset time, cools the sample chamber to a third preset temperature; closing pneumatic valve I; then opening pneumatic valve III and pneumatic valve IV, the adsorption isotherm automatic tester releases a preset quantitative protium-deuterium mixed gas to the quartz sample tube, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph through the control software circuit of the adsorption isotherm automatic tester; after the online hydrogen isotope gas chromatograph completes sampling for 0.5 min, it starts to automatically analyze the sample and record the gas chromatogram, and the adsorption isotherm automatic tester repeatedly releases the protium-deuterium mixed gas to the quartz sample tube according to the preset quantitative several times until the total amount of protium-deuterium adsorption of the sample reaches a maximum value; (d) performing a desorption test on the protium-deuterium mixed gas of the sample to be tested: the adsorption isotherm automatic tester extracts a preset quantitative protium-deuterium mixed gas, records the equilibrium pressure value, and sends a sampling instruction to the online hydrogen isotope gas chromatograph through the control software circuit of the adsorption isotherm automatic tester. After the online hydrogen isotope gas chromatograph completes sampling for 0.5 minutes, it starts to automatically analyze the sample and record the gas chromatogram; (e) Repeat step (d) several times until the protium and deuterium adsorbed in the sample are completely desorbed; and obtain the pressure, content and chromatogram in the gas phase at each desorption point.

7. The method for testing the hydrogen isotope effect in the hydrogen storage metal adsorption-desorption protium-deuterium mixed gas according to claim 6, characterized in that: The preset vacuum degree is 5×10 -4 Pa, the first preset temperature is 120°C, the preset time is 1 hour, the second preset temperature is -50°C, the preset pressure value is 50-80kPa, the third preset temperature is -50°C-20°C, and the preset quantitative hydrogen-deuterium mixed gas is 1.2mmol.

8. The method for testing the hydrogen isotope effect in the hydrogen storage metal adsorption-desorption protium-deuterium mixed gas according to claim 6, characterized in that: The step (a) is repeated 5 to 10 times.

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