In this analysis moisture, volatile matter, ash and fixed carbon can be determined.
Moisture: A known amount of finely powdered air-dried coal sample is taken in crucible. The crucible is placed inside an electric hot air-oven, at \(105^o to 110^oC\) for 1 hour. The crucible is then taken out, cooled in desiccators and weighed. Difference in the weight of sample gives the information about the weight loss due to removal of moisture.
![](https://blogger.googleusercontent.com/img/a/AVvXsEhEKUw-KOFIQdAlRdBCwcGcAvsBMTITklNAC1j2_ZXZWV-j5jSIBYM8iZyjQm8fm6eK3kWF2TH9DZVzFBvDV_5ijnPspecnKjBpySkNMC7nIJBz-cg8ZDqzpmzzCR08FfZi44D8gKKbFC-Z3Q63Nnc71lJuLzUs6R85RAUgqN1MaeJK_0_ulyVwwV-y)
Lesser the amount of moisture content, better the quality of fuel
Volatile matter: The moisture free coal sample is taken in a crucible, covered with a lid and placed in muffle furnace (electric furnace) at 950oC for 7 minutes and then remove the crucible from the oven and cooled first in air, then cooled in a desiccator and weighed again. Loss in weight is due to presence of volatile matter in coal sample
![](https://blogger.googleusercontent.com/img/a/AVvXsEjCLLIMB1XvgZKe1bCmDnN2v4RuLkElynBspp_Eq4wHgb17pFiLLnkSA4UT4ZvAaMqxoiHjrfWae1iuHP4gzKuD25tL8gck8arH_N7fvjza6hOfYX-2VIwIKGs7GOtp5Hnh4kRIP7u2SGzzJdvugvZ0KpyoK0F076l41dCFGx_xV8F0z8p65x_EzU3A)
Low quantity of volatile matter, better the quality of a coal.
Ash: The residual coal sample taken in a crucible and then heated without lid in a muffle furnace at 700-750oC for an hour. The crucible is then taken out, cooled first in air, then in desiccators and weighed again. The process of heating, cooling and weighing are repeated until a constant weight is not obtained. The residue is reported as ash on percentage-basis.
![](https://blogger.googleusercontent.com/img/a/AVvXsEjRrkunWEb37kD5_o7GgLpidMdTJID64p7xbDX9CCq5HQ9ZPhUdOlxc4SGwFyF6SXBSmHPLmlTg9UgHBDi7nPeu7230EcOZJHlVrEPG6NnEkUubFn6TYfF0648iPZsFcyLi8P9RW7scG6jd5PoKH--F3JmYDsErQU-HvwarpBTFyeTHd7FvslPBx9s0)
Ash is non-combustible substance which reduces the calorific value of a coal. Therefore, low quantity of ash contents, better the quality of a coal.
Fixed carbon: The fixed carbon percentage is determined by following equation
![](https://blogger.googleusercontent.com/img/a/AVvXsEi2GdFqjVek61lb6o-_Yz-iVDa-Bu8gcegaD51XSGMpKZME3F3I5mWHlpflkHoyC_vu9gWmF3yct3I9OZthsY7Yq4_KMdfHZnS1UMTBbBKv6AF-5rwkrbQI8HjL3Xdb7yHvnFqoe9MStprjUDMPrqI_DrnJyIPhzQfQajQgNmNQx9st6xaHaE50ZTCr)
Greater the calorific value, higher the % of fixed carbon.