(41c) Oxy-Fuel Combustion Characteristics of Victorian Brown Coal

This paper introduced the R&D works in Monash University regarding the oxy-fuel combustion of Victorian brown coal. Victorian brown coal is the single largest source meeting >85% of the electricity in Victoria, Australia. Its high-moisture content (up to 65 wt%) however results in a notoriously high carbon footprint for the existing air-fired power generations burning this coal. A vareity of lab-scale facilities including drop-tube furnace and flat-flame burner reactor have been used to assess the combustion characeristics of both dry and wet brown coal in O2/CO2, as well as the ash formation mechanisms particularly upon the recirculation of impure flue gas. A disctinct flame propagation has been confirmed for brown coal in O2/CO2. In combination with the predominant CO2, the inherent moisture in coal played an important role in coal ignition, volatile flame intensity and char burn out. Pre-drying of brown coal is crutical in intensifying its combustion in a lower oxygen fraction. The organically bound metals are exclusively present in brown coal, the vaporisation extent of which upon combustion are promoted by coal pre-drying and use of high oxygen fraction. Apart from the knowledge achieved from lab-scale testing, the pilot-scale testing results for brown coal in a 3MWe furnace will also be introduced.