Development of scale-up methodology and simulation tools for the demonstration of PC-FLOX burner technology in full-scale utility boilers (FLOX-COAL-II): final report

The FLOX-COAL-II project aimed for the development of a scale-up methodology and simulation tools for the demonstration of PC-FLOX burner technology in full scale boilers. Two prototype burners were tested at 500 kWth providing measurement data of gas temperature, of gas concentrations including NOx precursors HCN and NH3, of heat fluxes, of reaction zone topology and of velocities. The second prototype burner was developed using CFD simulation tools resulting in an improved performance (less NOx, same burnout). CFD simulation tools have been developed and implemented in two different CFD program codes: Ansys® FLUENT® and AIOLOS. The simulation results were cross compared disclosing code inherent differences, but showing good agreement with measurement data and among themselves. Both CFD sub-models – gas absorptivity and reduced NOx sub-model – have been further developed during the project using the results of measurements and CFD cross comparison. Experiments in a perfectly stirred reactor revealed information about the pyrolysis yield and the burnout characteristics of the coal in use. Experiences earned during former experiments at various scales led to the development of a scale-up methodology. This methodology uses a hybrid approach of wellknown scaling rules. Burners at industrial (2 MWth) and full scale (up to 67 MWth) were developed using this methodology. Full scale boiler simulations were finally conducted using the proposed burners for tangential, opposed wall and all-wall fired boilers. Simulations disclosed the main influencing. Techno-economic studies showed that FLOX technology is not cost competitive at its current status. However, its application to Oxy-fuel combustion is promising.