Thermally-driven physisorption-based hydrogen compressors

Abstract

Traditional energy sources that rely on fossil fuels have a harmful impact on the environment. The transportation sector contributes over one-fourth of this energy use and associated emissions. To reduce this impact, the automobile industry developed hydrogen-powered electric vehicles as sustainable replacements for fossil-fuelpowered vehicles. Keeping pace with these situations, by 2030, ca. 1000 hydrogen refueling stations will be built worldwide as many developed countries invest in hydrogen charging infrastructure to expand the supply of hydrogen-powered vehicles. Current hydrogen refueling stations use mechanical compressors to compress hydrogen to 900 bar and then charge hydrogen storage tanks for commercial vehicles to 700 bar. This method has a drawback in that it takes up to 20 min to recover the pressure to 900 bar after charging from the 900 bar reservoir tank to the 700 bar hydrogen vehicle tank. This delay, alongside challenges including safety and efficiency improvements to conventional mechanical compression techniques, limits the uptake of hydrogen refueling stations and the overall adoption of hydrogen-based technologies. Therefore, developing secure and efficient hydrogen compression methods to fill high-pressure hydrogen tanks in fuel cell cars is crucial to increasing the broad use of these vehicles. Physisorption-based hydrogen compressors are a developing technology for compressing high-pressure hydrogen in a short time with a high degree of safety. It is also highly compatible with liquefied hydrogen storage tanks used in large-capacity charging stations. Hydrogen is stored on the adsorbent at cryogenic temperatures from liquid hydrogen and released by applying heat to rapidly achieve very high pressures, driving the compressor thermally. This review begins by explaining how the physisorptionbased hydrogen compressor works and the physisorption process. Then, it explores suitable porous adsorbent materials, discussing potential methods to enhance the adsorption-desorption process. Additionally, it presents the latest advancements in creating physisorption-based hydrogen compressors. The proposed prototype concept involves a MOF-containing adsorbent bed to elevate hydrogen pressure to 900 bar in hydrogen refueling stations, enabling the rapid refilling of hydrogen tanks in fuel cell cars.