Influence of O2/CO2 mixtures on the fluid-dynamics of an oxy-fired fluidized bed reactor

This paper addresses the mathematical development and the experimental validation of a semi-empirical model designed to characterize the fluid-dynamic response of a fluidized bed reactor under oxy-fuel operation. The objective is to survey the main differences between a conventional air operation and a novel O-2/CO2 operation, as for the interactions of solid-phase and gas-phase. The model provides all the relevant variables describing the fluid-dynamics, and it is conceived to simulate the performance of a lab-scale facility. Data gathered from the cold- and hot-operation of a 90 kW(th), oxy-fired fluidized bed are used for validation purposes. Bed porosity, minimum fluidization velocity and bubbles' size are detected to change under oxy-firing conditions. Once validated, the tool will he used to predict the performance under new fluidizing atmospheres and will be integrated within an entire model coupling fluid-dynamics, combustion and heat transfer phenomena. (C) 2011 Elsevier B.V. All rights reserved.