Effect of different conditions on the combustion interactions of blended coals in O2/CO2 mixtures

The combination of oxy-fuel and blended-coal combustion may be one of these effective methods to both reduce CO₂ emissions and improve energy utilization efficiency in coal-fired power stations. The aim of this study is to investigate oxy-fuel combustion interactions of blended coals under different conditions using a thermo-gravimetric analyzer. The results show that compared with those in an O₂/N₂ mixture, the promotive and inhibitive effect and the comprehensive interactions are considerably weaker in an O₂/CO₂ mixture. In the O₂/CO₂ mixture, both increasing the O₂ concentration and decreasing the particle size result in decreasing the promotive effect but increasing the inhibitive effect and the comprehensive interactions, which increase the non-additive combustion characteristics. Enhancement of the heating rate increases the promotive effect but decreases the inhibitive effect and the comprehensive interactions, which weaken the non-additive combustion characteristics. Of these factors, the effects of the oxygen concentration and heating rate on comprehensive interactions are greater than that of particle size. This study provides useful information for the design and optimization of thermo-chemical conversion systems of coal blends in the O₂/CO₂ atmosphere.