Development of a microreactor system for unsteady-state Fischer- Tropsch synthesis
dc.contributor.author | Whiting, Gary Ken | en |
dc.contributor.committeecochair | Squires, Arthur M. | en |
dc.contributor.committeecochair | Liu, Y.A. | en |
dc.contributor.committeemember | Beyer, Gerhard H. | en |
dc.contributor.committeemember | Davis, Mark E. | en |
dc.contributor.committeemember | Konrad, Kenneth | en |
dc.contributor.department | Chemical Engineering | en |
dc.date.accessioned | 2017-03-10T15:15:10Z | en |
dc.date.available | 2017-03-10T15:15:10Z | en |
dc.date.issued | 1985 | en |
dc.description.abstract | Vibrofluidized microreactor systems have been developed for studies of unsteady-state Fischer-Tropsch synthesis. This development is aimed at preventing carbon deposition on a fused-iron catalyst in a novel reactor called the “heat-tray.” This reactor involves a supernatant gas flowing over a shallow fluidized bed of catalyst particles. Three systems were built: (1) a vibrofluidized-bed microreactor system for obtaining baseline carbon deposition infonnation under industrially important reaction conditions; (2) a sliding-plug vibrofluidized-bed microreactor system for rapid switching of feed gases in the F-T synthesis; and (3) a cold-flow microreactor model for studying the gas mixing characteristics of the sliding-plug vibrofluidized-bed microreactor. The results show that catalyst defluidization occurred under steady-state synthesis conditions below 395°C using a feed gas of H₂/CO ratio of 2:1 or less. Above 395°C, the probability of hydrocarbon chain growth (α) on the fused-iron catalyst was low enough (α < 0.50) to prevent accumulation of high-molecular-weight species that cause defluidization. Carbon deposition was rapid above 395°C when a feed gas of H₂/CO ratio of 2:1 or less was used. Spent catalyst fractions in the form of free-flowing catalyst and "bugdust" were quantitatively analyzed for carbon and iron. Mössbauer spectroscopic analysis of free-flowing catalyst showed mainly Hägg carbide (x-Fe₅C₂) and magnetite (Fe₃O₄) with a smaller fraction present as α-Fe. Scanning electron microscopic analysis of the bugdust revealed a mass of highly porous, fine particles with a high carbon content (18-30 wt%). Cold-flow microreactor model studies show that rapid (on the order of seconds), quantitative switching of feed gases over a vibrofluidized-bed of catalyst could be achieved. Vibrofluidization of the catalyst bed induced little backmixing of feed gas over the investigated flow-rate range of 417 to 1650 actual mm³/s. Further, cold-flow microreactor model studies showed intense solid mixing when a -150+300 µ bed of fused-iron catalyst was vibrofluidized at 24 cycles per second with a peak-to-peak amplitude of 4 mm. The development of this microreactor system has provided an easy way of accurately determining integral fluid-bed kinetics in a laboratory reactor. Further, the unique ability of the microreactor system to rapidly switch feed gases over an intensely-mixed solid has important applications in chemical kinetics and reaction engineering. | en |
dc.description.degree | Ph. D. | en |
dc.format.extent | xxviii, 434 leaves | en |
dc.format.mimetype | application/pdf | en |
dc.identifier.uri | http://hdl.handle.net/10919/76086 | en |
dc.language.iso | en_US | en |
dc.publisher | Virginia Polytechnic Institute and State University | en |
dc.relation.isformatof | OCLC# 12442608 | en |
dc.rights | In Copyright | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
dc.subject.lcc | LD5655.V856 1985.W547 | en |
dc.subject.lcsh | Fischer-Tropsch process -- Equipment and supplies | en |
dc.title | Development of a microreactor system for unsteady-state Fischer- Tropsch synthesis | en |
dc.type | Dissertation | en |
dc.type.dcmitype | Text | 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 |
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