engleski

Numerical Study of Pulverized Biomass Combustion in an Experimental Drop Tube Furnace

Incineration of high share of biomass in existing pulverized coal furnaces still faces significant challenges, mainly because it is well known that the use of biomass instead of coal alters the flame shape, the temperature profile inside the furnace, and the burnout of the fuels used. A possibility for the ex-ante control and investigation of the incineration process are computational fluid dynamics - CFD simulations. CFD simulations have shown to be a powerful tool during the development and optimisation of chemical engineering processes and involved apparatuses. They can show some important flow characteristics and transport phenomena, which cannot be experimentally investigated, and because of that CFD together with experiments and theory, has become an integral component of combustion research. The main focus of this work is to present a numerically efficient method for simulation of thermo-chemical processes occurring inside an experimental furnace combusting pulverized biomass. In this work a numerical model of the pulverized biomass combustion was developed and implemented into a commercial CFD code AVL FIRE®, which was then used for the numerical analysis. Time-averaged conservation equations were solved for the gaseous and particulate phase, the former being treated by the Eulerian formulation, and the latter by the Lagrangian formulation. For biomass combustion, the effects of biomass drying, the degradation during devolatilization, generation of gaseous species and char combustion are taken into account. To represent the applicability of the modelling approach, a three dimensional geometry of an experimental furnace was used for the numerical simulation. To verify the accuracy of the modelling approach, the numerical predictions were compared with available experimental data. The results gained by this simulation can be used for the improving the understanding of the complex thermo-chemical phenomena occurring inside the calculated experimental furnace.

CFD; AVL FIRE; Biomass combustion; Experimental Furnace

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