Correlation of Inlet-Pressure Fluctuations and the Fluidized-Bed Structure

Abstract The purpose of this work is to use an example of a sludge oxidation reactor with a capacity of 50 000 t/year to show the relationship between fluctuations in the reactor inlet pressure and the spatial structure of the fluidized bed. The reactor uses a tubular collector for fluidization, for which there are no similar data in the literature. The research was conducted using numerical 3D modeling. The inlet pressure monitoring data and video filming of the fluidized bed in the reactor were used for comparison with the calculations. It has been shown that the pressure fluctuations at the reactor inlet and at different points along the fluidized-bed height correlated with one another, and the degree of correlation decreases, as the distance from the reactor inlet increases. The spectral analysis of the inlet-pressure fluctuations has revealed the coincidence of the main frequencies of fluctuations in the range of 0.8–1.0 Hz for the calculation and experiment. Comparing the dynamics of the change in the bed surface in the calculation and experiment has shown that the process of formation of large bubbles, which is fundamental for the hydrodynamic pattern in the layer, is analogous in the calculation and experiment. The information on the degree of correlation of the inlet-pressure fluctuations and the structure of the fluidized bed is useful for determining the current state of the catalyst layer, which contributes to the reliable control of the reactor and the process as a whole.