dc.contributor.author	Hacarlioglu, Pelin	en
dc.contributor.committeechair	Oyama, Shigeo Ted	en
dc.contributor.committeemember	Gibbs, Gerald V.	en
dc.contributor.committeemember	Marand, Eva	en
dc.contributor.committeemember	Cox, David F.	en
dc.contributor.department	Chemical Engineering	en
dc.date.accessioned	2014-03-14T20:18:32Z	en
dc.date.adate	2007-12-10	en
dc.date.available	2014-03-14T20:18:32Z	en
dc.date.issued	2007-11-12	en
dc.date.rdate	2008-12-10	en
dc.date.sdate	2007-11-14	en
dc.description.abstract	This dissertation describes the preparation of a novel inorganic membrane for hydrogen permeation and its application in a membrane reactor for the study of the methane steam reforming reaction. The investigations include both experimental studies of the membrane permeation mechanism and theoretical modeling of mass transfer through the membrane and simulation of the membrane reactor with 1-D and 2-D models. A hydrothermally stable and hydrogen selective membrane composed of silica and alumina was successfully prepared on a macroporous alumina support by chemical vapor deposition in an inert atmosphere at high temperature. Before the deposition of the silica-alumina composite, multiple graded layers of alumina were coated on the alumina support with a mean pore size of 100 nm by the sequential application of three boehmite sols with gradually decreasing sol particle sizes of 630, 200 and 40 nm, respectively. The resulting supported composite alumina-silica membrane had high permeability for hydrogen in the order of 10-7 mol m-2 s-1 Pa-1 at 873 K with a H2 /CH4 selectivity of 940 and exhibited much higher stability to water vapor at the high temperature of 873 K. In addition, the same unusual permeance order of Heï¼ H2ï¼ Ne previously observed for the pure silica membrane was also observed for the alumina-silica membrane, indicating that the silica structure did not change much after introduction of the alumina. The permeation of hydrogen and helium through vitreous glass and silica membranes was modeled using ab initio density functional calculations. Comparison of the calculated activation energies to those reported for vitreous glass (20—40 kJ mol -1) indicated the presence of 5- and 6-membered siloxane rings, consistent with the accepted structure of glass as a disordered form of cristobalite. The experimental studies of the steam reforming of methane were examined at various temperatures (773-923 K) and pressures (1-20 atm) with a commercial Ni/MgAl2O4 catalyst in a hydrogen selective silica-alumina membrane reactor and compared with a packed bed reactor. One-dimensional and two-dimensional modeling of the membrane rector and the packed bed reactor were performed at the same conditions and their performances were compared with the values obtained in the experimental study. Improved methane conversions and hydrogen yields were obtained in the membrane reactor compared to the packed bed reactor at all temperatures and pressures. From the two modeling studies, it was also found out that the two-dimensional model performed better in the membrane reactor case especially at higher pressures.	en
dc.description.degree	Ph. D.	en
dc.identifier.other	etd-11142007-101423	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-11142007-101423/	en
dc.identifier.uri	http://hdl.handle.net/10919/29580	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	chp1rev1.pdf	en
dc.relation.haspart	chp6rev1.pdf	en
dc.relation.haspart	chp4rev1.pdf	en
dc.relation.haspart	chp3rev1.pdf	en
dc.relation.haspart	chp2rev1.pdf	en
dc.relation.haspart	chp5rev1.pdf	en
dc.relation.haspart	Vitarev1.pdf	en
dc.relation.haspart	chp7rev1.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	steam reforming of methane	en
dc.subject	one-dimensional model	en
dc.subject	two-dimensional model	en
dc.subject	silica-alumina membrane	en
dc.subject	hydrogen	en
dc.title	Experimental and Modeling Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor	en
dc.type	Dissertation	en
thesis.degree.discipline	Chemical Engineering	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en

Experimental and Modeling Studies of the Methane Steam Reforming Reaction at High Pressure in a Ceramic Membrane Reactor

Files

Original bundle

Collections