Hydrogen Production by Methanol Steam Reforming Using Microreactor

Abstract

A microreactor technology, in which a microchannel is used as a catalytic reaction field in order to supply hydrogen to a small polymer electrolyte fuel cell (PEFC) for portable electronic devices, was described. The reduction of heat loss in the microreactor is the primary requirement for improving system efficiency, since heat release in microreactors is higher than in conventional reactors due to the increased specific surface area. Therefore, the methanol steam reforming, operated below 300 , is an appropriate process for the hydrogen production using the microreactor. First, the high-performance Cu/ZnO/Al2O3 catalyst for methanol reforming at low temperature was developed under the optimized preparation condition. The miniaturized methanol reformer was then developed to utilize this Cu/ZnO/Al2O3 catalyst. The length of the microchannel was determined based on one-dimensional mass and heat balance analyses. The microreactor was fabricated from silicon and glass substrates using a number of microfabrication techniques. Methanol reforming using this reactor has been demonstrated to reach the levels necessary to power a 1 W-class small PEFC system. The multilayered integrating the miniature methanol reformer with a CO remover, a catalytic combustor as a heat source for methanol reforming, vaporizers, and several necessary functional elements for hydrogen production has also been successfully fabricated. Finally, the microreactor system has been demonstrated to produce hydrogen at a rate sufficient to generate electrical power of 2.5 W.

Direct conversion of methanol to n-C4H10 and H2 in a dielectric barrier discharge reactor

“…2 Steam reforming of methanol (reaction (R1)) and methanol decomposition (reaction (R2)) have so far been the main routes for methanol conversion into H 2 . 3 Considering the supply of hydrogen required for proton exchange membrane fuel cells (PEMFC), hydrogen generated in reaction (R2) has to be purified to reach the desired purity by transforming CO into CO 2 through water gas shift reaction (reaction (R3)), since the Pt-based anode in PEMFC can be easily poisoned when the CO concentration is higher than 10 ppm. Significant efforts have been devoted to catalytic conversion of methanol through reaction (R1), where copperbased and group 8-10 metal-based catalysts have been widely used.…”

“…5 Group 8-10 metal-based catalysts have high stability and similar selectivity, but hydrogen production using these catalysts is low compared with that using copper-based catalysts. 4 CH 3…”

Modeling the Reduction of Ship Exhaust Emissions through CO2 Capture/Chemical Conversion and SO2 Seawater Scrubbing

“…The balance equations of the coupled internal pore diffusion and catalytic RWGS reaction and the energy conservation equation within the spherical catalytic particles, considering the initial conditions and with the appropriate boundary conditions designed to account for particle symmetry and external mass and energy transport limitations, are listed in Table . The effective diffusivity in the Cu–ZnO–Al 2 O 3 catalyst particles was quantified taking into account both molecular and Knudsen diffusion, considering that the pore diameter of the catalyst particles is smaller than the mean free path …”

“…The effective diffusivity in the Cu−ZnO− Al 2 O 3 catalyst particles was quantified taking into account both molecular and Knudsen diffusion, considering that the pore diameter of the catalyst particles is smaller than the mean free path. 41 3.5. Adsorbent Particle Scale Model.…”

Enhanced Methanol Synthesis Process via an Integrated Process Involving CO2 Hydrogenation under Plasma Conditions

“…The catalyst particles are uniform and spherical. Both molecular and Knudsen diffusion (the average pore diameter of Cu–ZnO–Al 2 O 3 catalyst is smaller than mean free path) via effective diffusivity of species j inside the catalyst particle was considered. Simultaneous diffusion and reaction within the catalyst particles are represented by the following equations: …”