Pulverised coal/biomass co-fire modelling in a full scale corner-fired boiler

The practice of co-firing biomass in full-scale coal utility plants is gradually increasing. This is mainly because of the benefits associated in reducing the coal based CO2 and biomass based SOx and NOx emissions. Significant numbers of existing coal power stations are suitable for co-firing with small/no changes in the original infrastructures. In order to demonstrate this, combustion modelling of a 300MWe, widely used tangentially fired furnace for pulverised coal has been undertaken in this work. Typical Chinese fuels, Huating coal and wheat straw, were burned at 100% coal and under coal/wheat straw co-firing (up to ≈12.5% on a thermal basis). In the experiments, wheat straw has been handled by the existing coal mills and feeding system to a set of dedicated burners. CFD predications are in good agreement in general with the measured data such as temperature, furnace exit oxygen, unburnt carbon in the ash and NOx emissions.