... with low calorific value of 1000 to 7000 kcal / kg (coal about 4187 ~ 29308KJ/kg) of low volatile fuel, not only good coal ... shale, the net calorific value of only 1000 kcal / kg (4187KJ about the coal / kg) can fire normal and stable combustion in a ... of low-grade fuel. Heat value in 6281 ~ 10468kJ/kg (1500 ~ 2500cal/kg) oil shale, coal, coal gangue, bituminous and anthracite blended ...