Development of pulverized biomass combustor with a pre-combustion chamber

A 0.5 MW pre-combustion chamber for pulverized biomass burner was design based on a pulverized coal combustor design. The design concept, a 2D simulation guiding the construction and experimental results are discussed followed by an assessment of a 3D simulation. The difference in burning characteristics between coal and biomass were used to specify sizes of the air exits and the pre-combustion chamber. Simulation with pure biomass was used to guide fabrication of the test facility: the predicted temperature profiles suggested flame attachment within the specified operation range. Experimental results suggested that our design could achieve an anchoring flame as the measured temperature was above 800 °C within the pre-combustion chamber when operating between 0.3 and 0.5 MW. Maximum temperature at the last monitoring in the pre-combustion chamber was observed at 0.4 MW throughput, while the convection started to play negative impact at 0.5 M and the flame blow out occurred beyond this target. The 3D simulation under Reynolds-averaged Navier-Stokes assumption with its associated models agreed well with experiments which measured the axial temperature distribution in the pre-chamber. However, overestimation in the main combustion chamber suggested further improvement on model calibration as well as boundary conditions.