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Investigation of catalytic phenomena...

Kuhn, John N.

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Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers./
Author:	Kuhn, John N.
Description:	363 p.
Notes:	Adviser: Umit S. Ozkan.
Contained By:	Dissertation Abstracts International68-07B.
Subject:	Chemistry, Inorganic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3275236
ISBN:	9780549164524

Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers.
Kuhn, John N.

Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers. - 363 p.

Adviser: Umit S. Ozkan.

Thesis (Ph.D.)--The Ohio State University, 2007.

Solid oxide fuel cells (SOFCs) show promise for generating clean power from a variety of fuels. The major roadblocks to their implementation are a large cathodic resistance, which causes insufficient power densities and high fabrication costs, and anodic deactivation caused by carbon-based fuels such as coal and biomass-derived gases and their sulfur impurities. The large cathodic resistance is caused by slow oxygen activation kinetics and oxide ion transport of the current manganite-based cathode. At the anode, deactivation occurs through the conventional nickel-based material's poor sulfur tolerance and tendency to form carbon fibers. Thus, the development of catalytically active materials suitable for use as electrodes is needed to help SOFCs realize their full potential.

ISBN: 9780549164524Subjects--Topical Terms:

517253
Chemistry, Inorganic.

Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers.
LDR:04769nam 2200349 a 45 001 939641
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008 110517s2007 ||||||||||||||||| ||eng d
020 $a 9780549164524
035 $a (UMI)AAI3275236
035 $a AAI3275236
040 $a UMI $c UMI
100 1 $a Kuhn, John N. $3 1263746
245 1 0 $a Investigation of catalytic phenomena for solid oxide fuel cells and tar removal in biomass gasifiers.
300 $a 363 p.
500 $a Adviser: Umit S. Ozkan.
500 $a Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4470.
502 $a Thesis (Ph.D.)--The Ohio State University, 2007.
520 $a Solid oxide fuel cells (SOFCs) show promise for generating clean power from a variety of fuels. The major roadblocks to their implementation are a large cathodic resistance, which causes insufficient power densities and high fabrication costs, and anodic deactivation caused by carbon-based fuels such as coal and biomass-derived gases and their sulfur impurities. The large cathodic resistance is caused by slow oxygen activation kinetics and oxide ion transport of the current manganite-based cathode. At the anode, deactivation occurs through the conventional nickel-based material's poor sulfur tolerance and tendency to form carbon fibers. Thus, the development of catalytically active materials suitable for use as electrodes is needed to help SOFCs realize their full potential.
520 $a Replacing manganite with reducible transition metals (e.g., cobalt) leads to mixed (electronic and ionic) conductivity and improved performance through the enlargement of the electrochemically active area. However, further improvements are limited because the oxygen reduction kinetics and oxygen-surface interactions are poorly understood. The present work examines the catalytic phenomena of doped-lanthanum ferrites for use as cathode materials in intermediate temperature (500 and 800°C) applications. The kinetics and energetics of the oxygen reduction reaction is related to surface and bulk structural changes that occur as a function of environment and dopant levels.
520 $a Oxygen reduction kinetic measurements are made using simultaneous thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses and isotopic oxygen exchange studies. The kinetic results are supported by a thorough surface characterization by using methanol as a probe molecule and X-ray photoelectron spectroscopy (XPS). The nature and quantity of active surface sites and their surface chemistry are determined by pulsed methanol chemisorption and reaction studies, respectively. Further insight is provided by bulk characterization through X-ray diffraction (XRD) and temperature-programmed techniques.
520 $a The current research also focuses on understanding deactivation of conventional anode materials in the presence of carbon fuels with sulfur impurities. The results show formation of adsorbed sulfur and surface sulfides even when the bulk phase is stable. The use of this information to modify conventional anode materials is still an active area of research. Characterization is performed by XRD, XPS, and vibrational spectroscopy to complement the oxidation results.
520 $a Another environmental area is using biomass to generate chemicals and fuels. When biomass, woodchips mainly in this case, is gasified, tar compounds form. Tar compounds lead to deactivation through coking in many downstream applications such as shift reactors and fuel cells. Thus, the removal of tar compounds is necessary. An efficient approach is tar reforming because the cleanup can be done at the stream temperatures and hydrogen is produced via the reaction. These advantages lead to improved carbon conversions and improved heat integration with the gasifier. The only downside is that the competing technology, wet scrubbing, is commercially available so that uncertainties about catalyst cost and lifetime are important and need to be quantified. These topics are the primary goals for us and our collaborators.
520 $a Since gasification of biomass takes place in a fluidized bed reactor, attrition resistance is important to eliminate the loss of catalyst. Dolomite catalysts have been tried, but generally are not attrition resistant. With our collaborators, the use of Ni-doped olivine catalysts is examined. These catalysts have proved to be attrition resistant and possess adequate reforming activity.
590 $a School code: 0168.
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Physical. $3 560527
650 4 $a Engineering, Chemical. $3 1018531
690 $a 0488
690 $a 0494
690 $a 0542
710 2 $a The Ohio State University. $3 718944
773 0 $t Dissertation Abstracts International $g 68-07B.
790 $a 0168
790 1 0 $a Ozkan, Umit S., $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3275236