Volume 11 Issue 4 ( December 2024)

The purpose of this study is to find the optimal operating conditions for a Pd₈₂-Ag₁₈/α-Al₂O₃ membrane during transient start-up, resulting in the highest hydrogen recovery rate and the shortest time lag. Utilizing a configuration of membrane, flow meters and gas chromatography to analyze the effluent gas composition, the membrane's flow rate was adjusted, and temperature was varied from 325 to 375 ℃. The best outcome was achieved with a rate variation of the shell-side 150 mL/min and a tube-side flow rate variation of 200 mL/min at 375 °C, resulting in a 37% average hydrogen recovery rate and time lag of 2 hours. In short, the study found that temperature and flowrate affected time lag, with a linear relationship between temperature and hydrogen recovery with also considering the presence of other DRM gas that can decrease the membrane’s partial pressure which effects the permeability due to dilution and competitive inhibition.

Keywords: Pd-Ag membrane; transient start-up; DRM effluent; time lag; metallic membrane; hydrogen separation; flow rate