Interpreting Differential Pressure Signals for Particle Properties and Operating Conditions in a Pilot-Scale Circulating Fluidized Bed Riser

• Published in: Industrial & engineering chemistry research 2016-08, Vol.55 (31), p.8659-8670
• Main Authors: Anantharaman, Aditya, Karri, S. B. Reddy, Findlay, John G, Hrenya, Christine M, Cocco, Ray A, Chew, Jia Wei
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.6b00956

Pressure taps are ubiquitous in fluidized bed reactors. Unfortunately, attention is typically paid only to the mean or standard deviation of the fluctuations in practical operations, which leads to a loss in the wealth of information contained therein. This effort is targeted at assessing the hydrodynamic characteristics that can be understood from a comprehensive data set of pressure signals via wavelet decomposition. Differential pressure (ΔP) signals were recorded at 11 axial positions along a pilot-scale CFB riser for five particle systems (namely, three monodisperse materials and two binary mixtures) and four operating conditions. The effects of material property, operating condition, and riser axial position on the differential pressure (ΔP) signals were evaluated by comparing the energy contained in the wavelet-decomposed signals (E Dj ). Results indicate the following: (i) whereas the averaged ΔP values and power spectra of the signals were largely invariant, E Dj values tended to be sensitive to material property and operating conditions throughout the riser; (ii) under conditions of lower solid loading, higher E Dj values were obtained and E Dj was more sensitive to material properties; (iii) among monodisperse particles, the larger and denser particles tended to be most sensitive to operating conditions; (iv) among the five particle systems, monodisperse small glass and monodisperse large glass systems gave, respectively, the lowest and highest E Dj values; (v) particle density exerts a more dominant influence than particle diameter on E Dj ; and (vi) the effect of axial position on E Dj was secondary compared to that of operating condition and material property. The observations provide insights into ΔP signals from CFB risers, which find value spanning a mechanistic understanding of the relationship between the gas phase and particles and process monitoring in practical operations.