scholarly journals Transport in a Microfluidic Catalytic Reactor

2003 ◽  
Author(s):  
Hyung Gyu Park ◽  
Jaewon Chung ◽  
Costas P. Grigoropoulos ◽  
Ralph Greif ◽  
Mark Havstad ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Processing System ◽  
Proton Exchange ◽  
Reacting Flow ◽  
Fuel Processing ◽  
Methanol Reforming ◽  
Numerical Studies ◽  
Exchange Membrane ◽  
Optimized Conditions

A study of the heat and mass transfer, flow, and thermodynamics of the reacting flow in a catalytic micro-reactor is presented. Methanol reforming is utilized in the fuel processing system driving a micro-scale proton exchange membrane fuel cell. Understanding the flow and thermal transport phenomena as well as the reaction mechanisms is essential for improving the efficiency of the reforming process as well as the quality of the processed fuel. Numerical studies have been carried out to characterize the transport in a silicon microfabricated reactor system. On the basis of these results, optimized conditions for fuel processing are determined.

Transport in a Methanol Steam Reformer as the Fuel Processor for Fuel Cell Systems

2004 ◽  
Author(s):  
Hyung Gyu Park ◽  
Ming-Tsang Lee ◽  
Frank K. Hsu ◽  
Costas P. Grigoropoulos ◽  
Ralph Greif ◽  
...  
Keyword(s):  
Analytical Study ◽  
Processing System ◽  
Reacting Flow ◽  
Hydrogen Fuel Cells ◽  
Catalytic Reactor ◽  
Hydrogen Fuel ◽  
Fuel Processing ◽  
Fuel Processor ◽  
Optimized Conditions

An experimental and analytical study of the reacting flow in a catalytic reactor is presented. Methanol-steam reforming may be utilized in the fuel processing system for hydrogen fuel cells. Understanding the flow and transport phenomena as well as the reaction mechanisms is essential for improving the efficiency of the reforming process as well as the quality of the processed fuel. Utilizing the results obtained, optimized conditions for fuel processing are discussed.

A Solar Powered Microreactor for Hydrogen Production by Methanol Reforming

2008 ◽  
Author(s):  
Rau´l Zimmerman ◽  
Graham Morrison ◽  
Gary Rosengarten
Keyword(s):  
Proton Exchange Membrane ◽  
Fast Response ◽  
Proton Exchange ◽  
Fluid Temperature ◽  
Methanol Reforming ◽  
Exothermic Reactions ◽  
Micro Channels ◽  
Solar Powered ◽  
Exchange Membrane ◽  
Micro Reactor

Proton exchange membrane fuel cells (PEMFC) are good candidates for portable energy sources with a fast response to load changes, while being compact as a result of their capability to provide a high power density. Hydrogen constitutes the fuel for the PEMFC and can be obtained in situ to avoid transportation and safety problems. An efficient method to produce hydrogen is by methanol steam reforming in a micro-reactor, an endothermic reaction for which the highest efficiency occurs between 250°C and 300°C. Different methods have been used to reach and maintain these temperatures, including electrical heaters and exothermic reactions. We propose to use solar energy to increase the efficiency of the micro-reactor while taking advantage of a free, renewable energy source. The micro-channels, where the water-methanol mixture flows, are insulated from the surroundings by a thin vacuum layer coated with a selective material. This coating has a high absorptance for short wavelength incoming radiation and low emmitance for infrared radiation, reducing the heat losses. By using these coated insulation layers, the fluid temperature in the microchannels is predicted to be higher than 250°C. Hence, it is expected that the solar powered micro-reactor will produce hydrogen with a higher overall efficiency than the present reactors by taking advantage of the solar radiation.

Deformation Prediction of the Bipolar Plate Stamping

2014 ◽  
Vol 971-973 ◽  
pp. 270-274
Author(s):  
Hao Gao ◽  
Jian Lan ◽  
Lin Hua
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Channel Number ◽  
Forming Process ◽  
Dimensional Error ◽  
The Right ◽  
Exchange Membrane

Bipolar plate is the key component of proton exchange membrane (PEM) fuel cell and represents a significant part of the overall cost and the total weight in a fuel cell stack. Many research have been done on the manufacturing methods of bipolar plate, among which stamping is very popular. With the increasing of the channel number and complexity, its dimensional error caused by sprinkback will change a lot, even under the same forming process. And the risk of crack is also different. These all impact the quality of bipolar plate. In order to predict deformation of channels and the plate’s quality, the displacement along X-axis, the strain and stress state, and the displacement along Z-axis are measured. The results show that 1) the risk of crack increases with the increasing of channel number; 2) the springbacks increase with the increasing of channel number; 3) the most dangerous point locates on the right internal fillet of the plate’s last section.

A Microsolar Collector for Hydrogen Production by Methanol Reforming

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Raúl Zimmerman ◽  
Graham Morrison ◽  
Gary Rosengarten
Keyword(s):  
Proton Exchange Membrane ◽  
Fast Response ◽  
Proton Exchange ◽  
Fluid Temperature ◽  
Methanol Reforming ◽  
Exothermic Reactions ◽  
Solar Powered ◽  
Exchange Membrane ◽  
Low Emittance

Proton exchange membrane fuel cells (PEMFCs) are good candidates for portable energy sources with a fast response to load changes, while being compact as a result of their capability to provide a high power density. Hydrogen constitutes the fuel for the PEMFC and can be obtained in situ to avoid transportation and safety problems. An efficient method to produce hydrogen is by methanol steam reforming in a microreactor, an endothermic reaction for which the highest efficiency occurs between 250°C and 300°C. Different methods have been used to reach and maintain these temperatures including electrical heaters and exothermic reactions. We propose to use solar energy to increase the efficiency of the microreactor while taking advantage of a free renewable energy source. The microchannels, where the water-methanol mixture flows, are insulated from the surroundings by a thin vacuum layer coated with a selective material. This coating has a high absorptance for short wavelength incoming radiation and low emittance for infrared radiation, reducing the heat losses. By using these coated insulation layers, the fluid temperature in the microchannels is predicted to be higher than 250°C. Hence, it is expected that the solar-powered microreactor will produce hydrogen with a higher overall efficiency than the present reactors by taking advantage of the solar radiation.

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