Monitoring the quality of fluidization using the short‐term predictability of pressure fluctuations

Schouten, JC Jaap; Bleek, CM van den

doi:10.1002/aic.690440107

Cited by 109 publications

(71 citation statements)

References 20 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…hydrodynamics. Schouten and Van den Bleek 1998 showed that it is not: the agglomeration of plastic particles in a laboratory-scale fluidized bed at elevated temperature was not detected by monitoring the average pressure drop until defluidization has occurred. In that case it is often too late; a functional monitoring method should give an early warning such that defluidization can be pre®ented.…”

Section: Pressure Dropmentioning

confidence: 94%

Early warning of agglomeration in fluidized beds by attractor comparison

Ommen¹,

Coppens²,

Bleek³

et al. 2000

AIChE Journal

Self Cite

162

123

View full text Add to dashboard Cite

Section: Pressure Dropmentioning

confidence: 94%

Early warning of agglomeration in fluidized beds by attractor comparison

Ommen¹,

Coppens²,

Bleek³

et al. 2000

AIChE Journal

Self Cite

162

123

View full text Add to dashboard Cite

“…This will benefit several different areas of work associated with fluidized beds, including issues related to hydrodynamic and heat-transfer similitude, 1,2 chemical processes occurring in fluidized beds, 3,4 and the use of pressure fluctuations as a diagnostic tool for the fluidized bed's performance and fluidization regime identification. [5][6][7][8] The testing and analysis methods used to evaluate fluidized-bed pressure fluctuations have varied widely among researchers. Brue and Brown investigated sampling and analysis techniques traditionally used to measure and interpret pressure fluctuations.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Pressure Fluctuations in Fluidized Beds

Falkowski

Brown

2004

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Pressure fluctuations were measured in a fluidized bed and evaluated in the frequency domain. The objective of this research was to determine the effect of bed parameters on the power spectra from the corresponding pressure fluctuations. The motivation for this work is to develop pressure fluctuations as a diagnostic tool for fluidized-bed reactors and combustors. Pressure fluctuation data for a range of bed heights, fluidization velocities, particle sizes, particle densities, and bed temperatures were taken to determine the effect of these parameters on the power spectrum. The dominant frequency was a function of the height of the fluidized bed. Secondary peaks were not influenced by the height of the bed, although they did depend on the position of the probe in the bed. Peaks in power spectra were observed to shift in frequency as the gas superficial velocity through the bed was changed. Powders of different classification had distinctive power spectra. Group A powders behaved like first-order linear systems; group B powders showed similarities to second-order linear systems; and group D powders exhibited harmonic behavior in their power spectra. When pressure fluctuations were measured over a temperature range from ambient to above 500 °C, power spectra varied little when the ratio of the superficial velocity to the minimum fluidization velocity was held relatively constant. Pressure fluctuations were measured in a fluidized bed and evaluated in the frequency domain. The objective of this research was to determine the effect of bed parameters on the power spectra from the corresponding pressure fluctuations. The motivation for this work is to develop pressure fluctuations as a diagnostic tool for fluidized-bed reactors and combustors. Pressure fluctuation data for a range of bed heights, fluidization velocities, particle sizes, particle densities, and bed temperatures were taken to determine the effect of these parameters on the power spectrum. The dominant frequency was a function of the height of the fluidized bed. Secondary peaks were not influenced by the height of the bed, although they did depend on the position of the probe in the bed. Peaks in power spectra were observed to shift in frequency as the gas superficial velocity through the bed was changed. Powders of different classification had distinctive power spectra. Group A powders behaved like first-order linear systems; group B powders showed similarities to second-order linear systems; and group D powders exhibited harmonic behavior in their power spectra. When pressure fluctuations were measured over a temperature range from ambient to above 500°C, power spectra varied little when the ratio of the superficial velocity to the minimum fluidization velocity was held relatively constant.

show abstract

“…18 Pressure fluctuations can also be employed to characterize the quality of fluidization or the performance of a fluidized bed. [19][20][21][22][23] For example, low amplitudes and higher frequencies of the pressure fluctuations tend to manifest the occurrence of small gas pockets (bubbles) or small particle clusters that can lead to intensive heat and mass transfer in the bed.…”

Section: Introductionmentioning

confidence: 99%

Physical characteristics of fluidized beds via pressure fluctuation analysis

Hartman

Trnka

2008

AIChE Journal

View full text Add to dashboard Cite

in Wiley InterScience (www.interscience.wiley.com).During various applications of gas fluidized units, the state/quality of the fluidized bed of solids can change due to changes in operation conditions or variations in the gas or solid feed. An analysis method is developed and applied which employs spectra of the fast Fourier transform of measured pressure fluctuations within the fluidized bed. The procedure is based upon the spectral analysis of successive time series of pressure fluctuations reflecting the actual hydrodynamic state (regime) of the bed. Practical application of the method is illustrated for fluidization at ambient temperature and pressure of spherical particles (glass beads) as well as irregularly shaped particles (limestone, sulfated limestone, and dried sewage sludge), in an 8-cm-ID fluidized bed. Using air, experiments were conducted with different fractions of the materials spanning a very wide range of 0.28-4.5 mm. The evolution was explored of bed behavior from the onset of fluidization to the pneumatic transport (elutriation) of solids from the bed. The method recognizes alterations of the hydrodynamic state of the bed caused by minor changes in the bed mass and/or in the granularity of the bed material.

show abstract

Monitoring the quality of fluidization using the short‐term predictability of pressure fluctuations

Cited by 109 publications

References 20 publications

Early warning of agglomeration in fluidized beds by attractor comparison

Early warning of agglomeration in fluidized beds by attractor comparison

Analysis of Pressure Fluctuations in Fluidized Beds

Physical characteristics of fluidized beds via pressure fluctuation analysis

Contact Info

Product

Resources

About