(353e) Thermal Hydrolysis of Solid-State Sodium Borohydride
AIChE Annual Meeting
2022
2022 Annual Meeting
Topical Conference: Sustainable Pathways Toward Hydrogen and Synthetic Fuels
Sustainable Pathways to Clean Hydrogen and Synthetic Fuels II
Tuesday, November 15, 2022 - 2:10pm to 2:35pm
Hydrogen from sodium borohydride (NaBH4, SBH) can be generated by thermolysis or hydrolysis. Unfortunately, thermolysis of SBH requires high temperatures (>300 oC), while hydrolysis is conducted in the presence of catalyst and self-hydrolysis can cause safety concerns due to unexpected generation of hydrogen. In order for hydrolysis of SBH to be practical, efficient and safe methods to produce hydrogen are required. Here, we propose a new process, thermal hydrolysis of SBH, to generate hydrogen via hydrolysis in the solid phase. In this new process, SBH generates hydrogen by hydrolysis with water produced by thermal decomposition of boric acid (BA). Self-hydrolysis causing safety issues no longer occurs because the SBH-BA mixture in the solid phase is stable at below 80 oC. When heating the mixture, a rapid hydrogen evolution was observed at ~120 oC and a maximum H2 equivalent of 3.9 was achieved at 150 oC for SBH:BA = 1:4. BA is dehydrated to form metaboric acid with a release of 1 mol H2O at 150 oC and an additional 0.5 mol water at 200 oC. With recent progress in regeneration of SBH spent fuels, this newly proposed method is promising for hydrogen storage in proton exchange membrane fuel cell applications.
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