A Novel System for Measuring Solids Dispersion In Circulating Fluidized Beds

Date

2008-05-08

Author

Külah, Görkem
Bi, H T
Lim, C J
Grace, J R

Metadata

Show full item record

Item Usage Stats

135
views

0
downloads

A novel, simple and accurate experimental measurement system with fast response was developed to measure transient local solid tracer concentration distributions to obtain information on solids mixing and dispersion in risers of circulating fluidized beds operating at a wide range of operating conditions. Phosphorescent-coated FCC particles, used as the tracer, were activated by high intensity UV light and injected at the return leg of high-density circulating fluidized bed (HDCFB) unit. The tracer concentration was measured by detection systems at three radial positions and three axial locations in the riser of the HDCFB unit operating at superficial gas velocities of 4 to 8 m/s and solids fluxes up to 450 kg/m2s. An axial dispersion model was utilized to determine axial solids dispersion coefficients, and the results were interpreted with the help of hydrodynamic data obtained in the same column. Comparison of the axial dispersion coefficients at different operating conditions revealed that axial dispersion tended to decrease with increasing overall solids circulation flux and decreasing superficial gas velocity. Low solids dispersion coefficients at high suspension densities resulted from the disappearance of the net downward flow of particles at the riser walls signifying the existence of the dense suspension upflow regime.

Subject Keywords

Risers, Fluidized beds, Solids flow

URI

0
https://hdl.handle.net/11511/85060

Conference Name

Proceedings of the 9th International Conference on Circulating Fluidized Beds, (13 - 16 Ocak 2008)

Collections

Department of Chemical Engineering, Conference / Seminar

Suggestions

OpenMETU
Core

A comprehensive fluidized bed combustion model coupled with a radiation model Alagoz, D. Ece; Külah, Görkem; Selçuk, Nevin (2008-01-01) A freeboard model of an overall FBC system model where radiation between particle and gas is accounted for through Stefan-Boltzmann law was modified by incorporation of a radiation model based on method of lines solution of discrete ordinates method. The predictive accuracy of the coupled code was tested by comparing its predictions with measurements taken on a refractory-lined, hybrid, pilot scale FBC as well as with predictions of unmodified system model. Comparisons show good agreement particularly for t...
A novel method of porosity measurement utilizing computerized tomography Akın, Serhat; Okandan, E (1996-01-01) The use of X-ray computerized tomography scanning with a new dual-scan technique to measure porosity that is suitable for nondestructive characterization of cores, which are the main sources of data for reservoir characterization, is investigated. Scanning experiments to measure the porosity of a Berea sandstone core as well as a full-size limestone core are performed to compare conventional techniques with the proposed method. It has been found that the proposed method is faster and more accurate. The meth...
A NOVEL COMPUTER SOFTWARE FOR CALCULATING OPTIMUM LOCATION AND RATINGS OF A SHUNT CAPACITOR FOR LOSS REDUCTION IN DISTRIBUTION FEEDERS TRIPATHY, SC; HARIDAS, M (Elsevier BV, 1994-02-01) The different methods of analysis for the problem of installing shunt capacitors on distribution systems have been discussed, and a computer software is developed for calculation of the optimum size and location of a shunt capacitor on a distribution feeder for maximum reduction in power loss from standard distribution system parameters. This program can be easily used for a practical system consisting of non-uniform loads and sections of different wire sizes.
A Novel Experimental Method for Microwave Dielectric Characterization of Flexible or Rigid Thin Sheets Hajisaeid, Ehsan; Dericioğlu, Arcan Fehmi; Akyurtlu, Alkim (2017-06-09) This work demonstrates a novel experimental method coupled with analytical extraction codes to determine dielectric properties of flexible or rigid thin sheets in a waveguide measurement setup. This method is based on measuring the transmission phase shift with and without the material under test which is placed in the middle of two polymeric sample holder blocks. These blocks are 3D printed according to the thickness of the thin sheet sample and the complex dielectric properties are calculated by removing ...
A novel cfd code based on method of lines for reacting flows: Verification on methane/air diffusion flame Tarhan, Tanil; Selçuk, Nevin (2007-01-01) A novel parallel computational fluid dynamic (CFD) code based on method of lines (MOL) approach was developed for the numerical simulation of multi-component reacting flows using detailed transport and thermodynamic models. The code was applied to the prediction of a confined axi-symmetric laminar co-flowing methane-air diffusion flame for which experimental data were available in the literature. 1-, 5- and 10-step reduced finite-rate reaction mechanisms were employed for methane-air combustion sub-model. S...

Citation Formats

G. Külah, H. T. Bi, C. J. Lim, and J. R. Grace, “A Novel System for Measuring Solids Dispersion In Circulating Fluidized Beds,” presented at the Proceedings of the 9th International Conference on Circulating Fluidized Beds, (13 - 16 Ocak 2008), 2008, Accessed: 00, 2021. [Online]. Available: 0.