Design and Control of a Hydrogen Generation System using the Sodium Borohydride Hydrolysis Reaction
Date Issued
2010
Date
2010
Author(s)
Cheng, Ya-Ling
Abstract
NaBH4 hydrolysis for on-board hydrogen generation has received much attention recently due to its higher theoretical energy capacity and zero emissions. In this work, three different operating modes (adiabatic, isothermal, Partially-insulated) of a continuous hydrogen generation system using the NaBH4 hydrolysis reaction are explored. Partially-insulated operation is recommended for this system since it has a higher outlet temperature and lower temperature distribution in reactor, which both mitigate the NaBO2 precipitation problem so that a larger energy density can be achieved. A novel reactor design is proposed to overcome the effects of gas generation and multiphase flow from the NaBH4 hydrolysis reaction. With a pinhole membrane set in the middle of reactor tube to provide gas and liquid channels respectively, the multi-phase flow problem is reduced and energy capacity increased since a separator is not needed for gas-liquid separation. Next, two control structures are developed and both give reasonable dynamic results. The on-supply structure gives fast response while the on-demand structure provides a simple control loop to adjust hydrogen generation directly. After control policies are designed, a cold start-up strategy is developed using a pulse plus step function feed input and reserved hydrogen from previous reaction to give rapid and sufficient hydrogen gas to supply a PEM fuel cell.
Subjects
hydrogen storage
process design
modeling
control
start-up
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97524023-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):0d72f57083830d1a209fe3c6a2f1da98