The combustion of biomass not only falls in energy production, but also in the recovery of waste. The treatment method most used for the recovery of waste is incineration because this method of treatment can minimize the volume of waste. In this work, it comes to realize a numerical modeling of the combustion of biomass in a fixed grate furnace. A literature review allowed us to describe the stages of combustion in terms of mathematical equations. Taking into account the results of elemental analysis and immediate analysis, solid and gaseous species used to simulate their transport equations are: Dry fuel (biomass), char, CH4, O2, CO, H2O, CO2, and N2. From equations of energy transportation, we deducted the TS temperature of the solid fuel bed and Tg of gas. Subsequently, we simulated the resolution 1-D transport equations using a computer code written by us and this on the basis of mathematical modeling of the transport equations. This 1-D unstationnary model takes into account the different stages of load transformation. In this calculation code, we used the explicit Euler method for space discretization, and for the time resolution, we used an implicit method which solves stiff problems of differential equations to ordinary derivatives. The results are satisfactory because the calculated numerical profiles follow the experimental profiles, such as, the temperature profiles, the loss of mass of the fuel bed and the speed of propagation of the flame front.
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