Julien Blondeau's PhD Thesis

Among the renewable sources of energy, biomass solid fuels hold a special place. They are indeed at the crossroads between the need for renewable sources on the one hand, and the established know-how on solid fuel combustion on the other hand. Moving from coal to biomass (co-)combustion in an existing pulverised-fuel utility boiler is therefore an effective way to get closer to the current environmental targets.
However, biomass and coal present important differences. The size of the particles, the amount and the type of volatiles emitted during pyrolysis, and the composition of the inorganic compounds (ash) are the main differences that significantly impact the combustion of pulverised biomass.
A detailed numerical model of a biomass particle undergoing pyrolysis, called SPY, was developed. It combines a detailed chemical mechanism and a physical model of a fibrous particle. The use of apparent kinetic parameters derived from SPY in CFD simulations of utility boilers was proposed to improve their accuracy.
A Drop Tube Furnace was designed to reproduce the conditions encountered in utility boilers. Such an experimental tool is useful in the investigation of combustion kinetics and ash deposition phenomena. The fouling of heat exchangers was reproduced, and the deposits were analysed to obtain an insight into their formation and deposition mechanisms.
The developed numerical and experimental tools may accurately respond to the current needs in both applied and fundamental research on biomass combustion

Jury:
Prof. Hervé JEANMART (UCL), Promoteur
Prof. Grégoire WINCKELMANS (UCL), Président
Prof. François DUPRET (UCL), Secrétaire
Prof. Jacques DE RUYCK (VUB)
Dr Yves RYCKMANS (Laborelec, Belgique)
Dr Laurent VAN DE STEENE (CIRAD, France)