Enhancing Emissions Reduction and Combustion Processes for Biomass in a Fluidized Bed

Abstract

The present paper reports on an experimental study on staged-air combustion of rice-straw pellets in a new fluidized-bed configuration. The conventional method and the staged-air technique of secondary air feeding are applied for comparison. The results confirm that the new fluidized bed is more effective in controlling NOx for all considered operating conditions. SO2 emission exhibits reduction at lower secondary air; however, it increases at higher ratio for the conventional method. With the new configuration, the concentration of exhausted SO2 decreases as the amount of secondary air increases. The results also show that CO emission does not change with the amount of secondary air for the new configuration, while it increases as the amount of secondary air increases in the conventional method. With the conventional method, fixed carbon loss tends to decrease at lower secondary air ratios while combustion efficiency suffers a decrease at higher values. Alternatively, in the case of the new configuration, fixed carbon loss steadily decreases while combustion efficiency improves monotonically as the amount of secondary air increases.