May 22-27, 2016
The performance of gas-fluidized bed reactors depends significantly on their hydrodynamics. Among the important properties that dictate the characteristics of a gas-fluidized bed, local solid flux plays a significant role, influencing vital parameters such as bed-to-surface heat exchange and solid circulation rate. Developing techniques that can provide accurate measurements of solid flux is extremely important for: 1) assessing the accuracy of other measurement techniques applicable to industrial units, and 2) validation of CFD models.
Comparison of different measurement techniques that provide similar hydrodynamic information is helpful in assessing the errors associated with each methodology. Most measurement techniques for obtaining solid flux in gas-fluidized beds are based on intrusive probes that can simultaneously measure solid velocity and voidage. Previously (1), the novel travelling fluidized bed (TFB) was operated to determine particle velocity from radioactive particle tracking (RPT), positron emission particle tracking (PEPT) and borescopy with silica sand particles of mean diameter 292 μm at superficial gas velocities from 0.4 to 0.6 m/s. In this study, the TFB, operated under identical conditions, was deployed to compare RPT and PEPT for the investigation of solid flux in square-nosed slugging.
Both techniques provided solid flux data of the same order, but there were significant quantitative differences. Differing physical properties of tracer particles and the bed material, and differences in the tracer localization techniques are among the factors that contributed to the observed discrepancies. The results provide useful insights on the merits and challenges associated with advanced techniques for measuring solids flux in gas-fluidized beds.
S. Tebianian, K. Dubrawski, N. Ellis, R. A. Cocco, R. Hays, S.B.R. Karri, T. W. Leadbeater, D.J. Parker, J. Chaouki, R. Jafari, P. Garcia-Trinanes, J.P.K. Seville, J.R. Grace. Comparison of Particle Velocity Measurement Techniques in a Fluidized Bed Operating in the Square-Nosed Slugging Flow Regime. Powder Technol., 2015. doi:http://dx.doi.org/10.1016/j.powtec.2015.08.040.
Sina Tebianian, Kristian Dubrawski, Naoko Ellisa, John R. Grace, Thomas W. Leadbeater, David J. Parker, Rouzbeh Jafari, Jamal Chaouki, Pablo Garcia-Trinanes, and Jonathan P. K. Seville, "Solid flux in travelling fluidized bed operating in square-nosed slugging regime" in "Fluidization XV", Jamal Chaouki, Ecole Polytechnique de Montreal, Canada Franco Berruti, Wewstern University, Canada Xiaotao Bi, UBC, Canada Ray Cocco, PSRI Inc. USA Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/fluidization_xv/20