(424b) Hydrogen and Carbon Monoxide Production By Novel Plasma Induced Microreactors

Hydrogen and Carbon Monoxide Production by Novel Plasma Induced Microreactors

Dr. Peter J. Lindner¹, Dr. Ronald S. Besser²

¹Department of Chemical Engineering

Manhattan College

4513 Manhattan College Parkway

Riverdale, NY 10471

²Department of Chemical Engineering and Material Science

Stevens Institute of Technology

One Castle Point on Hudson

Hoboken, NJ 07030

              Technological advancements in batteries have not been able to keep pace in the modern era.  Despite their low energy densities batteries still remain the only means of portable power.  Fuel cells are the logical evolution for a compact and light power source as they have high efficiencies, no moving parts, and can operate at low temperatures.  Regardless of these advantages fuel cell technology is not commonly used due to the lack of available hydrogen.  Although hydrogen can be produced at large chemical facilities and shipped to local filling stations, the element is very light and takes up a large amount of space even when compressed.  The requirement of a large storage volume makes transporting hydrogen impractical for portable applications. 

               Reforming hydrocarbons locally to feed hydrogen to a fuel cell has been studied to allow for portability.  Catalysis of these fuels into hydrogen is commonly used in large scale facilities; scaling them down into a catalytic microreactor seems to be the logical step.  Catalysts though suffer from many issues that are exacerbated in the micro-scale.  Specifically catalysts require long start up times, high processing temperatures, and become poisoned due to deposits of solid carbon as well as from sulfur components, commonly found with hydrocarbon fuels.  Plasma processing has also been studied as a means for locally reforming fuels into hydrogen.  Plasma devices typically require high electrical power inputs, making them energy inefficient.  Also plasmas generally require additional vacuum equipment, making the devices cumbersome and impractical for portable applications. 

               A solution that envelops the advantages of both of these systems while avoiding any of their issues is a microplasma reactor.  Microplasma reactors are not just miniature plasma reactors, but offer unique advantages such as increased electron density, atmospheric operation, and portability.  The microplasma reactors also operate at significantly reduced power requirements.  This allows for higher energy efficiency as a more reactive environment is created at a reduced energy cost. 

              Microplasma reactors have been developed using common microfabricaiton techniques.  These devices are produced from a silicon wafer and are smaller than a penny.  Previous works from the authors have proven the feasibility of reforming various hydrocarbons into hydrogen such as methane, butane, and methanol but been energy inefficient.  Mathematical modeling has shown how simple system modifications could improve efficiencies further.  Additionally, an analysis of repeatability of the devices using only carbon dioxide as a feed has demonstrated the decomposition into carbon monoxide, a potential fuel for solid oxide fuel cells. 

              The microplasma reactors suffer from unknown device failure.  This is likely due to electrical shorts, but further rigorous analysis of failed devices is planned.  These studies will involve testing the voltage and current characteristics of the terminated device as well as visually inspecting the chips using optical microscopes as well as scanning electron microscopes.  The reactors will also be analyzed to determine the chemical composition on the surface of the devices using energy dispersive x-ray spectroscopy. 

              We plan to present the results of various reforming experiments, our mathematical models, carbon dioxide repeatability tests and device analysis.  Future schematics of next generation reactors will also be presented with the aim to develop an all in one fuel processor-fuel cell system.