Modeling of the reaction-front propagation during the fixed-bed combustion of solid fuel

A one-dimensional, steady-state mathematical model of solid-fuel combustion in a fixed bed is presented. The model equations and boundary conditions as well as the solution method are presented. Calculation results are shown to agree very well with the experimental data. Calculations indicate that during fixed-bed cocurrent flow combustion a reaction front is formed that propagates in the direction opposite to air and fuel flow. In order to determine the main factors influencing the reaction-front propagation velocity a sensitivity analysis is applied. Sensitivity analysis results show that the reaction-front velocity is controlled by heat transfer in the solid phase. The obtained results prove that it is possible to extend the concept of the burning velocity from gaseous to solid fuels. Practical implications are mentioned.