Releasing Hydrogen at High Pressures from Liquid Carriers: Aspects for the H2 Delivery to Fueling Stations

Abstract

Hydrogen fueling stations require multiple stages of compression to achieve the pressure needed to refuel hydrogen fuel cell electric vehicles at 700 bar. The physical compression equipment constitutes a large share of the total investment cost of hydrogen fueling stations. Hydrogen carriers, i.e., materials that carry either physisorbed or chemisorbed H2, provide an alternate approach to transport and deliver higher densities of hydrogen to the fueling station at lower pressures. Additionally, some liquid phase hydrogen carriers (LPHCs) are defined by thermodynamic properties that allow H2 release at elevated pressure, thus providing an opportunity to reduce the number of compressors at the fueling station. This study compares a series of LPHCs and evaluates the approach of using aqueous solutions of formic acid (FA) to deliver high volumetric densities of H2 to fueling stations and provide a first step of compression. While hydrogen release from most liquid carriers will provide hydrogen slightly above ...