High pressure hydrogen adsorption apparatus: Design and error analysis

In the present work, design and operation of a high pressure gas adsorption apparatus at room temperature and at pressures up to 100 bar are discussed. A theoretical and experimental error analysis is done to determine accuracy and robustness of the measurements. For this study, activated carbon was selected as the adsorbent and hydrogen as the adsorbate gas. A sensitivity analysis was done by taking into account the effects of temperature, pressure, volume and weight of the sample. The analysis shows that the volumes of the sample and reference cells as determined by helium-free space measurements have significant effect on the accuracy of the adsorption uptake measurement. For instance, a 0.1% error in the measurement of either volume led to approximately a 3% error in hydrogen uptake measurement at 298 K and 100 bar.

► Description of high pressure differential adsorption apparatus.
► Measuring H2 adsorption on PFA-derived activated carbon at room temperature and at the pressure range of 0–100 bar.
► Investigating the most influential parameters in the accuracy of the measurements by using linear differential error analysis.
► Comparison between the accuracy of differential pressure method and the Sieverts apparatus.
► Extension of the error analysis to measurements of differential quantities, like heat of adsorption.