Studies on the Co-combustion Behaviour of Coal/biomass Blends Using Thermogravimetric Analysis

In relation to future energy demand and fossil fuel crisis particularly in India, biomass is gaining its importance for possible utilization as co-fuel. This study focuses the use of „low temperature biomass char‟ instead of raw biomass in the blends to extract some specific advantages like lowering of grinding energy, intensification of heat energy, proper adjustment of „VM and fuel ratio‟ etc. In the present investigation corn cob char and saw dust char were examined for their possible use in co-combustion with a typical high ash Indian coal. Combustion behaviour of different binary blends of „coal and biomass chars‟ were examined in detail with the help of simultaneous DSC/TGA (Differential Scanning Calorimetry/Thermogravimetric Analyser) instrument. Characteristic combustion parameters of parent coal, biomass char and their blends were compared. Kinetic parameters for the combustion of all the blend samples were evaluated in the defined burning zone. Deviation of the experimentally observed burning rate curves from theoretically evaluated rate pattern for all the blends have been shown in this paper and synergistic effects of co-combustion were highlighted which signifies improvement of reactivity. Lowering of activation energy in major combustion zone was also observed for the coal/ biomass char blends in most of the cases. On overall basis, this study reflects the improvement of combustion performance with the increase in proportion of biomass char. As a matter of fact such study helps in the process of the identification potential blend-combination and selection of blend proportion to derive some specific advantages with respect to particular combustion practice.