Q1(g). Proximate analysis by TGA

Answer in brief

Sequential mass changes give moisture, volatile matter, fixed carbon and ash.

Key points

• Heat a weighed coal sample initially under inert gas to about 105–110°C and hold to constant mass; the first loss estimates moisture.
• Continue heating under inert gas to the specified high temperature of the adopted coal-analysis method (commonly near 900–950°C). The additional loss is volatile matter.
• Change to an oxidising atmosphere to burn the remaining combustible carbon. This mass loss estimates fixed carbon.
• The final noncombustible residue is ash. Report percentages on a stated as-received or dry basis and use a validated temperature programme because operational definitions depend…