Influence of the Inner and Outer Secondary Air Ratios on the Combustion Characteristic and Flame Shape of a Swirl Burner with a Prechamber

Table 1

The basic characteristics of experimental coal.

Proximate analysis (as received wt %, ad)
Volatiles	33.60
Ash	7.02
Moisture	5.62
Fixed carbon	53.76
Net heating value (kJ/kg)	27200
Ultimate analysis (as received wt %, ad)
Carbon	61.54
Hydrogen	4.16
Oxygen	11.64
Nitrogen	0.82
Sulfur	0.43