Synergetic and inhibition effects in carbon dioxide gasification of blends of coals and biomass fuels of Indian origin

• Focus on role of catalytic elements in ash in enhancing CO2 reactivity of fuels.
• Blends of chars of coals and biomasses of Indian origin studied experimentally.
• Systematic reactivity studies using isothermal thermogravimetric analysis.
• Established synergistic effect through 90% conversion time of coal char.
• Inhibition tendency noted at high temperatures for high ash coal.

The present study investigates the enhancement of CO2 gasification reactivity of coals due to the presence of catalytic elements in biomass such as K2O, CaO, Na2O and MgO. Co-gasification of three Indian coal chars with two biomass chars has been studied using isothermal thermogravimetric analysis (TGA) in CO2 environment at 900, 1000 and 1100 °C. The conversion profiles have been used to establish synergetic or inhibitory effect on coal char reactivity by the presence of catalytic elements in biomass char by comparing the 90% conversion time with and without biomass. It is concluded that both biomasses exhibit synergistic behavior when blended with the three coals with casuarina being more synergetic than empty fruit bunch. Some inhibitory effect has been noted for the high ash coal at the highest temperature with higher 90% conversion time for the blend over pure coal, presumably due to diffusional control of the conversion rate.