1D Modelling of Fuel Mixing and

Abstract

A one-dimensional model for fuel mixing and conversion in a bubbling fluidized bed has been developed. The model includes fuel particle size development and calculates the concentration profile for char, volatiles, moisture and ash as well as the fuel particle size distribution. Three different kinds of units have been modelled: gasification, combustion and chemical-looping combustion. Two types of fuels, wood and coal, have been used. Based on the results from the model, the addition of a fragmentation sub-model is very important to fully characterize the char composition in the outlet and the inclusion of particle size classes and particle size development has a large effect on the result. The model presents convergence problems for certain combinations of inputs, such as combustion of fragmenting wood. The model results are sensitive to the value of many inputs such as fuel specific parameters regarding fragmentation and reaction kinetics. Because of these inputs, the use of the model for non-characterized fuels can only be of more qualitative than quantitative use.