A method for source apportionment in biomass/coal blends using thermogravimetric analysis

Coal/biomass blends are increasingly important in meeting targets for renewable energy utilisation. This paper presents the initial findings of a new thermogravimetric analysis (TGA) method for characterising biomass materials that can also be used to accurately predict biomass/coal blend compositions.The proposed TGA method uses a heating rate of 5 °C/min from ambient to 900 °C in nitrogen at a flow rate of 30 ml/min. The gas is then changed to air at 30 ml/min to burn off the fixed carbon and finally determine the ash content. Particle size (53–75, 106–150 and 150–212 μm) was found to have a limited effect on weight loss profile at these conditions.Four different biomass types, palm kernel expeller, cereal co-product, sawdust and olive cake were all blended with a typical UK high volatile coal in proportions of 5%, 10%, 15%, and 20% (wt/wt% basis) with a particle size of 106–150 μm.The devolatilisation profiles of the blends appear to be strictly additive allowing blend proportions to be calculated using three different approaches. The mapping of component profiles onto actual profiles allows the biomass type and blend proportions to be accurately determined.