No.20 Combustion Characteristics on Blended Combustion of Sub-Bituminous Coal

Abstract

It is important to use sub-bituminous coal at power stations in Japan. But sub-bituminous coal contains more than 20% moisture. This makes heat capacity for drying moisture becomes insufficient. So, we use less than 30% of blended ratio of sub-bituminous coal. There are two methods to increase the ratio of sub-bituminous coal. The one method is to lower the temperature of primary air, another method is to increase Air/Coal. So, we investigated the effects of air injectioncondition on NOx concentration at the exit of furnace and unburned carbon concentration in fry ash.