When coal is traded in its specifications two types
of moisture values are mentioned. This
is very important as it affects the cost of fuel per unit of power generated or
per kg of steam produced by the boiler. i.e. it affects the boiler efficiency.
The moisture in Coal consists of two parts.
 |
| Profit is in moisture than coal for mine owners |
- One is the moisture held within the molecular
structure of the coal called “inherent moisture.” Removal takes place only
at temperatures greater than 100 deg C.
- The second part is the moisture that is on the surface
of the coal. This is normally due to the conditions and locations of the
mines. This moisture can evaporate in exposed atmospheric conditions. How
much evaporates depends on
- The time of exposure,
- Atmospheric contact
because of spreading,
- Ambient temperature and
humidity.
TM – IM is the surface
moisture, which is not liked by boiler engineers.
