Thesis
A comparison of LSCF-6428 and BYS for the oxidative conversion of methane and ethane
Washington State University
Master of Science (MS), Washington State University
2002
Handle:
https://hdl.handle.net/2376/78
Abstract
Results are reported for a comparative study of two materials, which have been proposed as catalytic, dense phase ion conducting membranes for the oxidative coupling of methane (OCM). These two materials, Bi1.5Y0.3Sm0.2O3-d (BYS) and La0.6Sr0.4Co0.2Fe0.8O3-d (LSCF-6428), have been evaluated for their respective OCM activities, their interaction with ethane, and their stability in reducing environments. The results show that BYS is a superior OCM catalyst, having rates that are nearly six times greater and yields that are over twice as high as LSCF-6428. On the other hand, using insitu, dynamic XRD, BYS was observed to undergo a phase transformation at about 700°C. This transformation was absent in an inert environment, but occurred in the presence of methane, even at methane pressures as low as 0.1atm. Higher methane pressures resulted in more severe crystalline changes and could not be inhibited by the addition of 3% oxygen. Since OCM occurs at temperatures above 700°C, the catalytically active species appear to be related to the oxides of its constituent cations, all of which are known OCM catalysts. LSCF-6428, on the other hand, is somewhat more resistant to methane and can be stabilized at high methane pressures by the addition of 3% oxygen. At OCM temperatures, neither material catalyzed ethane reactions. Instead, ethane underwent gas phase oxidative dehydrogenation and thermal cracking reactions.
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Details
- Title
- A comparison of LSCF-6428 and BYS for the oxidative conversion of methane and ethane
- Creators
- Codruta Elena Platon
- Contributors
- William J. Thomson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525150301842
- Language
- English
- Resource Type
- Thesis