Experimental and Modelling Study of an Electrochemical Hydrogen Compressor

The energy world is changing rapidly pushed also by the need for new green energy sources to reduce greenhouse gas emissions. The fast development of renewable energies has created many problems associated with grid management and stability, which could be solved with storage systems. The hydrogen economy could be an answer to the need of storage systems and clean fuel for transportation. The Electrochemical Hydrogen Compressor (EHC) is an electrochemical device, which could find a place in this scenario giving a solution for the hydrogen purification and compression for storage. This work analyzes, through experimental and modeling studies, the performance of the EHC in terms of polarization curve, Hydrogen Recovery Factor (HRF) and outlet hydrogen purity. The influence of many input parameters, such as the total inlet flow rate, the hydrogen inlet concentration, the contaminant in the feed, and the cathode pressure have been investigated. Furthermore, the EHC performance have been modelled in a 1D + 1D model implemented in Matlab® solving the Butler-Volmer system of equations numerically. The experimental campaign has shown that high purities can be obtained for the hydrogen separation from N2 and CH4 and purities over 98% feeding He. An increase in the cathode pressure has shown a slight improvement in the obtained purity. A comparison between PSA unit and EHC for a mixture 75% H2 – 25% CH4 at different outlet hydrogen pressure and purity was performed to analyze the energy consumption required. Results show PSA unit is convenient at large scale and high H2 concentration, while for low concentration is extremely energy intense. The EHC proved to be worthwhile at small scale and higher outlet hydrogen pressure.