Green Hydrotec Inc. | Date: 2013-05-21
Wang H.H.F.,Chang Gung University |
Chen S.C.,Green Hydrotec Inc. |
Yang S.Y.,Green Hydrotec Inc. |
Yeh G.T.,Green Hydrotec Inc. |
Rei M.H.,Green Hydrotec Inc.
International Journal of Hydrogen Energy | Year: 2012
The effect of the heat transfer area and the thermal conductivity of the reactor materials are evaluated with three identical structured reactors having multiple columned-catalyst bed and using three different reactor materials, aluminum alloy, brass and stainless steel. A series of compact methanol reformers are then designed and fabricated with the use of large reactor surface area in catalyst beds and high heat transfer constant to produce hydrogen fuel with 2-4 ppm of CO for the fuel cell (FC) power generation. The same design principle is successfully used for easy scale up of the reactor capacity from 250 L/h to 10,000 L/h. This low CO hydrogen (68-70%) used as the fuel for the fuel cell power generation provides a very competitive cost of hydrogen and electric power, $0.20-0.23/m3 of H2 and $0.196/KWh, respectively. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Rei M.-H.,Green Hydrotec Inc. |
Yeh G.-T.,Green Hydrotec Inc. |
Tsai Y.-H.,Chang Gung University |
Kao Y.-L.,Green Hydrotec Inc. |
Shiau L.-D.,Chang Gung University
Journal of Membrane Science | Year: 2011
In this paper, the effect of varying the distance between a palladium membrane and the steam reforming catalyst in a packed bed catalytic membrane reactor is studied. A set of the specially structured palladium membrane tube is prepared and used for the steam reforming reaction of n-hexane and of methanol. This specially designed palladium membrane structure has a long tube at the upstream-end of membrane tube, and it is electroplated with thin nickel or palladium film. This nickel or palladium plated metal surface serves as a bridge for the surface diffusion of the nascent hydrogen atoms over a 10. cm distance to the membrane surface for permeation out of the system after they are formed on the catalyst site and spillover from the catalyst surface to the diffusion bridge. As a result, the conversion level of steam reforming reaction is increased while byproduct formation of methane is suppressed. Furthermore, it is believed that the direct migration of the nascent hydrogen atom from the catalyst site to the membrane surface via direct spillover or via surface diffusion brings about a stronger positive contribution to the steam reforming reaction than does the vapor phase diffusion of the molecular hydrogen on the reaction.This extension tube allows the membrane and the catalyst section to operate under mutually optimized temperatures in a single reaction chamber while preserving high membrane efficiency; thus the use of this new membrane structure makes design of a membrane reactor more flexible to maximize mutual efficiency of catalyst and the membrane. © 2010 Elsevier B.V.