Estimation of the temperature field in an industrial bubbling fluidised bed Development of a diffusion-type reduced-order model with input from Eulerian-Eulerian multiphase simulation

Abstract

Fluidised bed reactors are widely used in industry today, not at least in the energy sector. A common use case is the combustion and gasification of solid fuels such as coal, but also waste and biomass. Recently, a design proposing a fluidised bed divided into two chambers was presented. The proposed design could be beneficial for processes such as gasification where the residence time of fuel and char should be controlled. This work investigates the feasibility of the proposed design. The main point of investigation is whether the heat transfer between the two chambers will be sufficient as well as whether any gas leakage between the two chambers will occur. As a step in the investigation, a design tool to estimate the average temperature differences in the fluidised bed is developed. In addition, the effective conductivity of such a fluidised bed is investigated by means of Eulerian-Eulerian multiphase simulation. The results indicate that any eventual gas leakage would be minor and that the heat transfer might very well be enough, however further work is needed.