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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Heat transfer between a supernatant gas and a flowing shallow gas- fluidized bed of solids

Boyd, John H. January 1984 (has links)
A novel concept (called “heat tray”) is proposed for heat recovery from hot gases and for heat management in exothermic catalytic reactions, which involves a supernatant gas (S-gas) flowing over a shallow fluidized bed of solids. This thesis presents the results of bench-scale and pilot-scale experimental studies that quantify heat transfer between the S-gas and the shallow fluidized bed. A fractional-factorial design of experiments was performed on two heat-tray systems using three different results showed that fine fluid cracking catalyst (FCC) particles out-performed larger alumina spheres as a fluidized solid. Heat transfer coefficients between the supernatant gas and the shallow fluidized bed approached 440 W/m²-K using FCC. Various S-gas inlet nozzle configurations were studied, with a nozzle height equal to one-half of the static bed height (0.051 m) giving the best results. The study showed that short heat-tray lengths (<0.8 m) are desirable and that S-gas redistributors are needed to compartmentalize the unit. An economic analysis showed that the proposed heat tray would be economically feasible for adaption as a boiler feedwater preheater in a small steam-generation facility, using boiler combustion gases as the S-gas. The payback time for the system would be as short as 1.9 years when used continuously. The heat transfer results from a S-gas to a flowing shallow fluidized bed represent the only data reported thus far, and have led to a better understanding of the new shallow fluidized-bed system for heat-exchange applications. / Master of Science

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