TITLE: Fischer-Tropsch Synthesis from a Low H sub 2 :CO Gas in a Dry Fluidized-Bed System. Volume 3. Heat Transfer Between a Supernatant Gas and a Flowing Shallow Fluidized Bed of Solids. Final Technical Report, October 1, 1986.

AUTHOR: J. H. Boyd;   Y. A. Liu;   A. M. Squires.

INST.  AUTHOR: Virginia Polytechnic Inst. and State Univ., Blacksburg. Dept. of Chemical Engineering.

SPONSOR: Department of Energy, Washington, DC.


PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  1 Oct 86,  316p.



Volume II describes the details of heat-transfer studies in a dry fluidized-bed system (called ''heat tray''), which has been proposed for heat recovery from hot gases and for heat management in exothermic reactions. In particular, this report presents the results of bench-scale and pilot-scale experimental studies which quantify heat transfer between a hot supernatant gas (S-gas) and a flowing shallow fluidized bed of solids. A fractional-factorial design of experiments has been performed on two heat-tray systems using three different solids. The results show that fine fluid cracking catalyst (FCC) particles out-perform larger alumina spheres as a fluidized solid. Heat transfer coefficients between the supernatant gas and the shallow fluidized bed approaches 440 W/m sup 2 -K using FCC with a heat-exchange area of 0.124 m sup 2 . Various S-gas inlet nozzle configurations have been studied, with a nozzle height equal to one-half of the static bed height (0.051 m) giving the best results. The study shows that short heat-tray lengths (< 0.8 m) are desirable and that S-gas redistributors are needed to compartmentalize the unit. An economic analysis shows 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 supernatant gas to a flowing shallow fluidized bed represent the only data reported thus far, and have led to a better understanding of the heat management in the proposed ''heat-tray'' reactor for Fischer-Tropsch synthesis. 20 refs., 46 figs., 15 tabs. (ERA citation 12:010714)