A hydrogen generator coupled to a hydrogen heater for small scale portable applications

¹ Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla), Avda. Américo Vespucio 49, 41092-Sevilla, Spain.
² Departamento de Química Inorgánica, Facultad de Química, Universidad de Sevilla, C/Profesor García González 1, 41012-Sevilla, Spain.

^* Corresponding author: asuncion@icmse.csic.es

Abstract

This study aims to build and test a small scale portable device able to couple a hydrogen generation system (based on a NaBH₄ solution as liquid H₂ carrier) to a hydrogen heater (based on the exothermic catalytic combustion of the released H₂). The hydrogen generating system is based on the hydrolysis of stabilized solutions of NaBH₄ (fuel solutions) which are pumped into the hydrolysis reactor. The generated H₂ feeds the catalytic combustor. Two catalysts have been developed for the H₂ generation and the combustion reactions able to operate at room temperature without need of additional energy supply. For the NaBH₄ hydrolysis a Co-B catalyst was supported on a perforated and surface treated stainless steel (SS316) home-made monolith. For the flameless H₂ catalytic combustion a Pt catalyst was prepared on a commercial SiC foam. The device was automatized and tested for the on-demand production of heat at temperatures up to 100ºC. In steady state conditions the NaBH₄ solution flow is controlling the H2 flux and therefore the heater temperature. Once the steady-state is reached the system responds in a few minutes to up and down temperature demands from 80 to 100 ºC. The catalysts have shown no deactivation during the tests carried out in several days.