Design and Development of PSA System for Ultra Purification of Green Hydrogen

To ensure high-purity standards for Hydrogen used in fuel cell vehicles, the widely employed method of Pressure Swing Adsorption (PSA) effectively removes impurities from Hydrogen streams. This paper focuses on the design of a PSA cycle for Hydrogen purification using a system consisting of two beds packed with 4Å Molecular Sieve. The Hydrogen feed stream considered in this study contains water, the primary impurity resulting from the electrolysis process. The design of a PSA system involves three crucial steps to achieve optimal performance and efficiency. Firstly, the selection of the adsorbent material and particle size is based on factors like selectivity, capacity, and regenerative ability. Secondly, the superficial velocity of the gas flowing through the bed is determined, considering aspects such as mass transfer kinetics and pressure drop limitations. Finally, the bed length is chosen, considering factors such as desired efficiency, breakthrough time, and bed capacity. The model's results are compared with industrial data obtained from an Oxygen PSA system to validate their accuracy. Deviations from the industrial values may arise due to differences in adsorbent usage, superficial velocity, packing density of the adsorbent, assumptions of adiabatic and ideal gas behaviour, and unknown operating conditions. In the present case, the pressure drop across the bed is assumed to be zero. By applying the PSA design principles and evaluating the model's outputs, this study aims to contribute to the advancement of Hydrogen purification for fuel cell vehicle applications.