A Study on 500 MW Coal Fired Boiler Unit's Bowl Mill …
coal passing through 200 mesh (75 µm) is weighed and the HGI is derived from the empirical equation: HGI = 6.93W +13 where W is the weight of crushed coal passing through 200 mesh (75 µm). Indian bituminous types of coal have an HGI ranging between 45 to 70. Moisture content and volatile matter in the coal also affect the HGI values.
