Particulate Systems' HPVA II Series of adsorption analyzers are designed to obtain high-pressure adsorption and desorption isotherms using the static volumetric technique.
This technique involves dosing gases such as carbon dioxide, methane and hydrogen of a known quantity into the chamber containing the sample. The final equilibrium pressure can be recorded when the sample achieves equilibrium with the adsorbate gas.
The data thus obtained can be used to quantify the amount of gas adsorbed by the sample. The process is carried out at given pressure intervals until reaching the maximum preselected pressure.
The pressure can then be reduced to achieve a desorption isotherm. The resulting equilibrium points (volume adsorbed and equilibrium pressure) are plotted to provide an isotherm. Independent transducers monitor high and low pressures, providing excellent accuracy and reproducibility.
Tables of raw data are used for report calculations. Isotherm and weight percentage plots are created automatically. Kinetic data are available for rate of adsorption calculations. Reports are provided in the form of interactive spreadsheets.
Features of the HPVA II high pressure volumetric analyzer include:
- Wide operating pressure range - high vacuum to 100 or 200 bar
- Wide temperature range, from cryogenic to 500 °C
- Heater controls manifold temperature for better accuracy and stability
- Dual free-space measurement provides accurate isotherm data – free space can be entered or measured
- Recirculating temperature bath, cryogen dewar, or furnace ensure excellent control of sample temperature
- Can use gas mixtures of up to three components
- Handles typical adsorbates to include carbon dioxide, methane, hydrogen, oxygen, nitrogen, and argon
- Hydrogen gas sensor prevents leakage of hydrogen gas
- Includes BET surface area, Langmuir surface area, and total pore volume calculations
- Software includes NIST REFPROP
Typical applications of the HPVA II high pressure volumetric analyzer include:
- Determination of hydrogen storage capacity of materials like metal organic frameworks and porous carbon
- Analyzing porous coal samples from underground beds to determine their methane capacity at high pressures
- Determination of methane capacity of the shale at specific pressures and temperatures
- Carbon dioxide sequestration