Optimal placement of probes for dynamic pressure measurements in large-scale fluidized beds |
| |
Authors: | J Ruud van Ommen John van der Schaaf Berend GM van Wachem Cor M van den Bleek |
| |
Affiliation: | a DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands b Laboratory of Chemical Reactor Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands c Department of Thermo and Fluid Dynamics, Chalmers University of Technology, Hörsalsvägen 7, S-412 96 Göteborg, Sweden |
| |
Abstract: | Pressure data sampled at sufficiently high frequency (typically 20 Hz or higher) can yield much information about the hydrodynamic state of a fluidized bed. Since part of the pressure waves travelling through large (industrial) fluidized beds is only detectable in a limited area of the bed, pressure measurements need to be performed at several positions to cover the whole bed. We examine these local pressure waves (caused by, e.g., passing bubbles or coalescing bubbles) in a 0.80 m i.d. bubbling fluidized bed of Geldart B particles. Experiments and simulations are performed to determine the intensity decrease as local pressure waves propagate from their origin. A new spectral method is applied to determine the degree of coherence for pressure signals measured at two different positions in a fluidized bed. For a superficial gas velocity of 5umf, local pressure waves can be detected up to a radial distance of about 0.5 m from their origin; this distance is somewhat lower for lower gas velocities. This means that the radial spacing of pressure probes should not exceed 1 m. For large diameter beds with a bed height below 1.5 m, a set of probes at a single level and at several radial positions is sufficient to observe or monitor the dynamic state of the complete bed; the probes should preferably be placed at a height of 30% to 40% of the total bed height. |
| |
Keywords: | Gas-solid fluidized beds Pressure fluctuations Pressure measurements Pressure probe spacing Monitoring Industrial installations |
本文献已被 ScienceDirect 等数据库收录! |
|