Model studies on fluidized bed reactors : steam-oxygen-char gasification in a nonslagging: fluidized bed

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dc.contributor.advisorAmundson, Neal R.
dc.contributor.committeeMemberWheeler, Lewis T.
dc.creatorSundaresan, S.
dc.date.accessioned2022-12-20T17:29:14Z
dc.date.available2022-12-20T17:29:14Z
dc.date.issued1978
dc.description.abstractThe gasification of char in a steam-oxygen fluidized bed was studied. The char was assumed to be composed of base carbon and ash. The gaseous compounds found were limited to CO, CO2, H2, H2O, O2 and CH4. As the oxygen and hydrogen were assumed not to co-exist, the bed was divided into a shallow combustion zone where the carbon combustion would take place and a gasifictition zone where no oxygen would be found. A CSTR model and the Davidson-Harrison two-phase reactor model were formulated. The validity of the assumption that the thickness of the combustion zone is negligible compared to the total height of the reactor was verified using a plug-flow reactor model in which the gases were assumed to be in plug-flow while the solids were well-mixed. All chemical changes in the gasification zone were described by three reactions: steam gasification, carbon hydrogasification and water-gas shift reaction. In all the models studied the bed was assumed to be at uniform temperature. From the results of the CSTR model calculations, it was concluded that one should use the fairly complicated empirical kinetic equations developed by Johnson for reliability over a wide range of pressures and residence times. It was also observed that the residence time has a remarkably small effect on the carbon conversion. Only at high pressures, the residence time may have a strong effect on the carbon conversion by bringing into play the methane formation, important only at low temperatures. A decrease in char conversion resulted when the bubble size was increased. The plug-flow reactor model consistently predicted a higher conversion than the other models suggesting that the reactor should be staged to increase the conversion attained in the reactor.
dc.description.departmentChemical and Biomolecular Engineering, Department of
dc.format.digitalOriginreformatted digital
dc.format.mimetypeapplication/pdf
dc.identifier.other4079318
dc.identifier.urihttps://hdl.handle.net/10657/12972
dc.language.isoen
dc.rightsThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. Section 107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.
dc.titleModel studies on fluidized bed reactors : steam-oxygen-char gasification in a nonslagging: fluidized bed
dc.type.dcmiText
dc.type.genreThesis
thesis.degree.collegeCullen College of Engineering
thesis.degree.departmentChemical Engineering, Department of
thesis.degree.disciplineChemical Engineering
thesis.degree.grantorUniversity of Houston
thesis.degree.levelMasters
thesis.degree.nameMaster of Science

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