Thermo gravimetric analyses on the coal and other biomass were performed using a TA SDT Q600 TGA-DSC instrument. Around 10 mg fuel sample was heated at a rate of 20 K/min from ambient to high temperature (above 1000°C) in an inert (nitrogen) environment. The mass of the sample as a function of temperature was recorded. All fuels were analyzed as received. A reference pan was also heated in the same furnace at the same rate. The temperature of the reference pan was recorded with the temperature of the sample pan. The difference in the temperatures between the two pans can be used to create a DTA trace (Martinez, 2012 and Lawrence, 2007)). Figure 3.15 gives the TGA (ABCDEWF) and DTA traces (A’B’C’D’E’F’) for the fuels considered.

Point A marks the beginning of the traces. Point B (B’ on DTA) marks the peak of the drying (endothermic) process. Point C marks the beginning of the pyrolytic exothermic. Point D marks the peak of the pyrolytic exothermic. Point E marks the end of the pyrolytic exothermic. Following pyrolysis, only fixed carbon and ash remained in the pan. Point F marks the end of the trace. Of par­ticular interest are the temperatures at which pyrolysis began, ended, and the percentage of mass lost due to pyrolysis. The portion between points A and B on the TGA trace defines the amount of mass lost due to drying (moisture loss). The portion between points C and E on the TGA trace defines the amount of mass lost due to pyrolysis. The temperature and remaining mass at this point have been marked in Figure 3.15. The pyrolysis data for several fuels are summarized in Table 3.4.