Vapor phase batch hydrolysis of NaBH sub(4 at elevated temperature and pressure)

• Published in: International journal of hydrogen energy Vol. 36; no. 11; pp. 6472 - 6477
• Main Authors: Liu, Hong, Boyd, Christopher M, Beaird, Amy M, Matthews, Michael A
• Format: Journal Article
• Language: English
• Published: 01-05-2011
• Subjects: Energy density; Hydrides; Hydrogen storage; Hydrolysis; Sodium; Stores; Vapor phases; Water vapor
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2011.02.104

Complex chemical hydrides are a means to store hydrogen in the solid state near ambient temperatures and pressures. Hydrolysis of hydrides has the potential to provide high gravimetric and volumetric energy densities if water consumption can be minimized. At low temperatures (110[inline image]140 [deg]C), the product of NaBH sub(4 hydrolysis is NaBO) sub(2) super(.2H) sub(2)O (dihydrate), consuming 2 mol of unutilized water. The objective of this work was to conduct water vapor hydrolysis of NaBH sub(4 at elevated pressure and temperature above 150 [deg]C. It was hypothesized that this would yield a solid borate with decreased water bound in the crystal structure. A series of batch reactions were conducted to verify the hypothesis. Experimental characterization of the sodium metaborate byproducts indicated that the primary product of water vapor hydrolysis was NaBO) sub(2) super(.1/3H) sub(2)O (hemihydrate) under a variety of reaction conditions. For the most cases, the conversion of NaBH sub(4 approached 100%.)