(559ab) Development of a High-Purity Hydrogen Production Skid Unit for Hydrogen Refueling Stations

A high-purity hydrogen (99.999 %) production skid unit (200 kg hydrogen/day, called as KIER HyPU-100), comprising natural gas-steam reforming, water-gas shift reactors and vacuum pressure-swing adsorption (VPSA) process, for hydrogen refueling stations has been developed. The system should satisfy the main prerequisites for actual application such as 1) higher than 80 % hydrogen production efficiency on the basis of higher heating values (HHV) and 2) lower than 1 ppm of CO concentration at the final outlet of the hydrogen refining process. In order to guarantee the high efficiency, the heat exchanging network in the reforming process was optimized by the commercial process simulation software package and the heat and mass transport phenomena in the reformer were also intensively studied by the computational fluid dynamic models. In addition, the optimal VPSA process has also been developed to purify the hydrogen from the product gas of the water-gas shift reactor. The performance of the VPSA is not only related to the hydrogen purity but also to the hydrogen production efficiency since the recovery ratio of high-purity hydrogen to the total reformate affects the amount of both product hydrogen and make-up natural gas fed into the burner of the reformer. The developed system showed consistently reliable performance within the long-term test sessions (hydrogen production efficiency: > 80 %_HHV, hydrogen purity: 99.999 %) and the operating data was compared with the mathematically predicted values to prove the feasibility of the design concepts.