Analysis of gas flow behavior in an annular fluidized-bed reactor for polystyrene waste treatment

Abstract

The characteristics of bubble properties and the chaotic fl ow behavior of gas were investigated in an annular fl uidized bed (0.102 m in inner diameter and 2 m in height) because the behavior of gas fl ow in such a reactor is one of the important factors governing reactor operation, reactor performance, and the reaction itself. Pressure fl uctuations as a state variable for the analysis of gas fl ow behavior were measured and analyzed. Bubble properties were determined by adopting the cross-correlation function of pressure fl uctuations. The resultant chaotic fl ow behavior of gas was interpreted by means of chaotic parameters such as the Kolmogorov entropy. It was found that the Kolmogorov entropy could be utilized effectively to explain the nonlinear dynamic behavior of gas-solid fl ow in the annular fl uidized bed. The pierced length and rising velocity of bubbles increased with increasing gas velocity, bed temperature, and particle size of the bed material. The bubble frequency increased with increasing gas velocity and bed temperature, while it decreased with increasing particle size of the bed material. Correlations to predict the bubble properties in annular fl uidized-bed reactors were suggested.