skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report

Abstract

The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

Authors:
; ;
Publication Date:
Research Org.:
Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Chemical Engineering
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10156489
Report Number(s):
DOE/PC/89769-T11
ON: DE92016676
DOE Contract Number:
FG22-89PC89769
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Apr 1992
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; FLUIDIZED-BED COMBUSTORS; MATHEMATICAL MODELS; PRESSURE DROP; FREQUENCY MEASUREMENT; PROGRESS REPORT; FOURIER TRANSFORM SPECTROMETERS; KINETICS; 014000; 990200; COMBUSTION; MATHEMATICS AND COMPUTERS

Citation Formats

Gamwo, I.K., Miller, A., and Gidaspow, D.. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report. United States: N. p., 1992. Web. doi:10.2172/10156489.
Copy to clipboard
Gamwo, I.K., Miller, A., & Gidaspow, D.. Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report. United States. doi:10.2172/10156489.
Copy to clipboard
Gamwo, I.K., Miller, A., and Gidaspow, D.. Wed . "Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report". United States. doi:10.2172/10156489. https://www.osti.gov/servlets/purl/10156489.
Copy to clipboard
@article{osti_10156489,
title = {Spectral analysis of CFB data: Predictive models of Circulating Fluidized Bed combustors. 11th technical progress report},
author = {Gamwo, I.K. and Miller, A. and Gidaspow, D.},
abstractNote = {The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.},
doi = {10.2172/10156489},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Apr 01 00:00:00 EST 1992},
month = {Wed Apr 01 00:00:00 EST 1992}
}
Copy to clipboard
Technical Report:
View Technical Report (0.83 MB)
DOI:  10.2172/10156489
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • ; ;
    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Spectral analysis of CFB data obtained at Illinois Institute of Technology shows that the frequencies of pressure oscillations are less than 0.1 Hertz and that they increase with solids volume fraction to the usual value of one Hertz obtained in bubbling beds. These data are consistent with the kinetic theory interpretation of density wave propagation.

  • ;
    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Sorption of S0{sub 2} with calcined limestone was studied in a PYROFLOW type CFB loop at conditions approximating those found in a CFB combustor. Initially the CFB loop contained 150 micron CaO particles of a density of 3.3 g/cm{sup 3} and air at 1143{degrees}K and 3.25 atm. Atzero time, air containing 600 ppm SO{sub 2}, was introduced into the riser bottom at 1143{degrees}K. The effect of gas velocity, sorbent inventory and inlet pressure on the sorption of SO{sub 2}, were studied isothermallymore » by running our hydrodynamic code with the S0{sub 2} sorption conservation of species equation. At a velocity of 5m/sec., reported to be a typical velocity by PYROPOWER, there is reasonably good S0{sub 2} removal. At 10 m/sec the S0{sub 2} removal is poor. The best SO{sub 2}, removal is for a velocity of 5 m/s and a high bed inventory, initial bed height, H = 9m. Most of the S0{sub 2} is removed in the first two meters of the reactor. However, the S0{sub 2} removal is not complete at the bed outlet. This is due to mixing. At the left wall of the reactor (wall opposite the solids inlet) the S0{sub 2} removal was poor due to gas bypassing caused by the asymmetrical solids inlet. Simulation of the PYROPOWER loop with a symmetrical inlet gave us an order of magnitude improvement over the conventional PYROPOWER system. These results demonstrate the practical utility of the predictive model that we have developed over the last three years.« less

  • ;
    The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. Sorption of S0[sub 2] with calcined limestone was studied in a PYROFLOW type CFB loop at conditions approximating those found in a CFB combustor. Initially the CFB loop contained 150 micron CaO particles of a density of 3.3 g/cm[sup 3] and air at 1143[degrees]K and 3.25 atm. Atzero time, air containing 600 ppm SO[sub 2], was introduced into the riser bottom at 1143[degrees]K. The effect of gas velocity, sorbent inventory and inlet pressure on the sorption of SO[sub 2], were studied isothermallymore » by running our hydrodynamic code with the S0[sub 2] sorption conservation of species equation. At a velocity of 5m/sec., reported to be a typical velocity by PYROPOWER, there is reasonably good S0[sub 2] removal. At 10 m/sec the S0[sub 2] removal is poor. The best SO[sub 2], removal is for a velocity of 5 m/s and a high bed inventory, initial bed height, H = 9m. Most of the S0[sub 2] is removed in the first two meters of the reactor. However, the S0[sub 2] removal is not complete at the bed outlet. This is due to mixing. At the left wall of the reactor (wall opposite the solids inlet) the S0[sub 2] removal was poor due to gas bypassing caused by the asymmetrical solids inlet. Simulation of the PYROPOWER loop with a symmetrical inlet gave us an order of magnitude improvement over the conventional PYROPOWER system. These results demonstrate the practical utility of the predictive model that we have developed over the last three years.« less

  • The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. This report presents the author`s derivation of analytical solutions useful in understanding the operation of a CFB. The report is in a form of a chapter that reviews the kinetic theory applications.

  • Steady flows influenced by walls cannot be described by inviscid models. Flows in circulating fluidized beds have significant wall effects. Particles in the form of clusters or layers can be seen to run down the walls. Hence modeling of circulating fluidized beds (CFB) without a viscosity is not possible. However, in interpreting Equations (8-1) and (8-2) it must be kept in mind that CFB or most other two phase flows are never in a true steady state. Then the viscosity in Equations (8-1) and (8-2) may not be the true fluid viscosity to be discussed next, but an Eddy typemore » viscosity caused by two phase flow oscillations usually referred to as turbulence. In view of the transient nature of two-phase flow, the drag and the boundary layer thickness may not be proportional to the square root of the intrinsic viscosity but depend upon it to a much smaller extent. As another example, liquid-solid flow and settling of colloidal particles in a lamella electrosettler the settling process is only moderately affected by viscosity. Inviscid flow with settling is a good first approximation to this electric field driven process. The physical meaning of the particulate phase viscosity is described in detail in the chapter on kinetic theory. Here the conventional derivation resented in single phase fluid mechanics is generalized to multiphase flow.« less