High pressure hydrogen storage gas adsorption analyzerIt is a key equipment used to evaluate the gas adsorption performance of materials under high pressure conditions, and plays an important role in the development of hydrogen energy technology. This instrument is based on the principle of static capacity method. By accurately controlling the temperature and pressure environment, it measures the hydrogen adsorption desorption isotherm and PCT curve of the material, and evaluates key parameters such as hydrogen storage capacity, adsorption desorption pressure/temperature curve, and cycling stability of the material. Its pressure range can reach high vacuum up to 690 bar, and its temperature range covers -196 ℃ to 900 ℃, which can meet the testing needs under various extreme conditions.
High pressure hydrogen storage gas adsorption analyzerOperation guide:
1、 Preparation before the experiment
Safety preparation
Ensure good ventilation in the laboratory (preferably operated in an explosion-proof fume hood).
Check and wear personal protective equipment (PPE), such as safety goggles and lab coats.
Confirm that there are no open flames, spark sources, or high-temperature objects around the instrument.
Check if safety facilities such as fire extinguishers and hydrogen alarms are functioning properly.
Air source inspection
Check that hydrogen (H ₂), high-purity helium (He, used for dead volume calibration), or nitrogen (N ₂, used for purging) cylinders have sufficient pressure.
Check if the output pressure of the pressure reducing valve is within the required range of the instrument (usually 0.4-0.6 MPa).
Use a leak detector to check for any leaks in all air circuit joints.
Sample preparation
Fill the sample (powder or particle) to be tested evenly in the sample tube to avoid bridging.
Use a sample spoon and filling rod to ensure consistent filling density.
Record the sample quality (accurate to 0.1 mg).
Install a glass wool or stainless steel filter at the bottom of the sample tube to prevent the sample from being blown out by airflow.
Instrument status check
Turn on the main power of the instrument and control the computer.
Start the instrument control software.
Check the oil level and cooling water of the vacuum pump (if using liquid nitrogen Dewar, check the liquid nitrogen level).
Confirm that all valves and sensors are in normal condition.
2、 Sample degassing (pretreatment)
Purpose: To remove impurities such as moisture and air adsorbed on the surface of the sample, and expose a clean adsorption surface.
Install sample tube
Carefully insert the sample tube containing the sample into the heating sleeve of the degassing station.
Connect the vacuum pipeline properly.
Set degassing parameters
Select the sample in the software and set the degassing program:
Degassing temperature: Set according to the properties of the sample (such as activated carbon 300 ° C, MOFs 150 ° C), and it is strictly prohibited to exceed the temperature resistance limit of the sample or sample tube.
Degassing time: usually 2-12 hours.
Vacuum degree: Set the target vacuum degree (such as 10 ⁻ ² Pa or higher).
Heating program: Gradient heating can be set.
Start degassing
Start the vacuum pump and start vacuuming.
The software automatically controls heating, heating, holding, and cooling according to the set program.
Cooling stage: The sample must be cooled to room temperature under vacuum or inert atmosphere to prevent oxidation or water absorption when exposed to air at high temperatures.
Complete degassing
After cooling to room temperature, high-purity inert gas (such as He) can be introduced into the sample tube to atmospheric pressure.
Be careful when removing the sample tube.
3、 Adsorption measurement
Install samples to the analysis station
Remove the sample tube that has been degassed and cooled from the degassing station, quickly transfer it to the analysis station, and install and fix it.
Connect the gas pipeline of the analysis station.
Set experimental parameters
Create a new adsorption experiment in the software.
Choose gas: Hydrogen (H ₂).
Set temperature: usually 77K (liquid nitrogen temperature) or 298K (room temperature), depending on research needs.
Set pressure range: from 0 to the target maximum pressure (such as 100 bar).
Set pressure points: The software can automatically plan (such as logarithmic distribution) or manually set key pressure points.
Set equilibrium time: the time required for each pressure point to reach adsorption equilibrium (usually several minutes).
(Optional) Set dead volume calibration: Use He gas to measure the dead volume of the system at low pressure.
Start adsorption measurement
Confirm that the liquid nitrogen Dewar has been filled with liquid nitrogen (for 77K testing).
Start the experimental program.
The instrument automatically executes the following steps:
Vacuumize and confirm the system seal.
(Optional) Introduce He gas for dead volume calibration.
Introduce H ₂ gas and gradually increase the pressure according to the set pressure point.
At each pressure point, wait for the pressure to stabilize (reach equilibrium).
Record the adsorption amount under this pressure.
Repeat until the maximum pressure is reached.
(Optional) Perform desorption measurement, gradually reduce pressure, and record desorption data.
Monitor the experimental process
Real time monitoring of pressure, temperature, and adsorption capacity changes through software interface.
Pay attention to whether there is any abnormal sound in the system.
Observe for any signs of leakage.
4、 Post experiment operation
End the experiment
After the experimental program is automatically completed, the system will automatically release pressure to atmospheric pressure.
Blow the system multiple times with high-purity inert gas (He or N ₂) to thoroughly remove residual hydrogen gas.
Remove the sample
After confirming that there is no pressure in the system, remove the sample tube.
The sample can be sealed and stored or subjected to subsequent analysis.
Shut down the system
Close the main valve of the H ₂ steel cylinder.
After the residual hydrogen gas in the system is completely purged, turn off the main power of the instrument.
Timely supplement liquid nitrogen or remove the Dewar vessel (if using liquid nitrogen).
data processing
Export raw data in the software.
Perform data processing: deduct dead volume, calculate adsorption capacity (mmol/g or cm ³/g), and plot adsorption isotherms.
Further calculations can be made for specific surface area (such as DFT model), pore size distribution, and equivalent adsorption heat.