Fuel and Combustion |
S. | Description | Symbol | Formula | Example |
No. | | | | | | | | |
1 | Gross calorific value | GCV | | | 80.8 * C + 22.45 * S + 339.53 * H – 35.89 * O | | C | 70.86 |
| | kcal/kg-fuel | | | | | S | 0.58 |
| | | | C | Carbon content in fuel, wt% | | H | 3.87 |
| | | | S | Sulphur content in fuel, wt% | | O | 6.08 |
| | | | H | Hydrogen content in fuel, wt% | | GCV | 6834 |
| | | | N | Nitrogen content in fuel, wt% | | Target | – |
2 | Net calorific value | NCV | | | GCV – 52.53 * H – 6 * m | | GCV | 6007 |
| | kcal/kg-fuel | | | | | H | 3.2 |
| | | | GCV | Gross calorific value of fuel, kcal/kg-fuel | | m | 1.3 |
| | | | H | Hydrogen content in fuel, wt% | | NCV | 5831 |
| | | | m | Moisture content in fuel, wt% | | Target | – |
3 | Useful heat value | UHV | | | 8900 – 138 * ( Ash + m ) | | Ash | 14.99 |
| | kcal/kg-fuel | | Ash | Ash content in fuel, wt% | | m | 1.93 |
| | | | m | Moisture content in fuel, wt% | | UHV | 6565 |
| | | | | | | Target | – |
4 | Standard coal factor | SCF | | | ( 1 – m / 100 ) * NCV / 7000 | | m | 1.93 |
| | – | | m | Moisture content in fuel, wt% | | NCV | 6500 |
| | | | NCV | Net calorific value of fuel, kcal/kg-fuel | | SCF | 0.911 |
| | | | | | | Target | – |
5 | Stoichiometric Combustion | SCA | Formula-1 | | NCV | 6500 |
| Air | kg/s | | | NCV * F | | F | 11000 |
| or | | | | 709 * 3600 | | SCA | 28.01 |
| Minimum Combustion | | | NCV | Net calorific value of fuel, kcal/kg-fuel | | Target | – |
| Air | | | F | Fuel rate in kiln, kg/hr | | | |
| | | | | | | | |
| | | Formula-2 | | C | 70.78 |
| | | | | [ 0.11594 * C + 0.34783 * ( H – O / 8 ) + 0.04348 * S ] * F | | H | 3.46 |
| | | | | 3600 | | O | 5.12 |
| | | | C | Weight% of Carbon in fuel | | S | 0.71 |
| | | | H | Weight% of Hydrogen in fuel | | F | 11000 |
| | | | O | Weight% of Oxygen in fuel | | SCA | 28.17 |
| | | | S | Weight% of Sulphur in fuel | | Target | – |
| | | | F | Fuel rate in kiln, kg/hr | | | |
| | | | | | | | |
| | | Formula-3 | | m | 1.9 |
| | | | | 10.478 * ( 100 – m ) * GCV * F | | GCV | 6700 |
| | | | | 100 * 7000 * 3600 | | F | 10500 |
| | | | m | Weight% of Moisture in fuel | | SCA | 28.70 |
| | | | GCV | Gross calorific value of fuel, kcal/kg-fuel | | Target | – |
| | | | F | Fuel rate in kiln, kg/hr | | | |
6 | Specific Stoichiometric | SSCA | Formula-1 | | NCV | 6500 |
| Combustion Air | kg/kg-fuel | | | NCV | | SSCA | 9.17 |
| or | | | | 709 | | Target | – |
| Specific Minimum | | | NCV | Net calorific value of fuel, kcal/kg-fuel | | | |
| Combustion Air | | | | | | | |
| | | Formula-2 | | C | 70.78 |
| | | | | 0.11594 * C + 0.34783 * ( H – O / 8 ) + 0.04348 * S | | H | 3.46 |
| | | | C | Weight% of Carbon in fuel | | O | 5.12 |
| | | | H | Weight% of Hydrogen in fuel | | S | 0.71 |
| | | | O | Weight% of Oxygen in fuel | | SSCA | 9.22 |
| | | | S | Weight% of Sulphur in fuel | | Target | – |
| | | | | | | | |
| | | Formula-3 | | m | 1.9 |
| | | | | 10.478 * ( 100 – m ) * GCV | | GCV | 6700 |
| | | | | 100 * 7000 | | SSCA | 9.84 |
| | | | m | Weight% of Moisture in fuel | | Target | – |
| | | | GCV | Gross calorific value of fuel, kcal/kg-fuel | | | |
| | | | | | | | |
| | | Formula-4 | | SCF | 0.925 |
| | | | | 10.478 * SCF | | SSCA | 9.69 |
| | | | SCF | Standard coal factor, – | | Target | – |
7 | Theoretical Flame Temperature | TFT | | | 3.107 * NCV | | NCV | 6500 |
| | deg.C | | | SCA | | SSCA | 9.28 |
| | | | NCV | Net calorific value of fuel, kcal/kg-fuel | | TFT | 2176 |
| | | | SSCA | Specific stoichiometric combustion air, kg/kg-fuel | | Target | – |
8 | True CO2 in kiln exit gas | TCO2 | | | 100 * ( CO2 + CO ) | | CO2 | 36.5 |
| | vol% | | | 100 + ( 1.89 * CO ) – ( 4.78 * O2 ) | | CO | 0.002 |
| | | | CO2 | Kiln exit gas CO2, vol% | | O2 | 4.2 |
| | | | CO2 | Kiln exit gas CO, vol% | | TCO2 | 45.7 |
| | | | O2 | Kiln exit gas O2, vol% | | Target | – |
9 | Burner Tip Velocity | BTV | | | 4 * Ps 0.5 | | Ps | 1800 |
| | m/s | | Ps | Static pressure in duct, mmWG | | BTV | 170 |
| | | | | | | Target | – |
10 | %Primary Air | %PA | | | PA * 100 | | PA | 2.05 |
| | % | | | SCA | | SCA | 27.24 |
| | | | PA | Primary air, kg/s | | %PA | 7.53 |
| | | | SCA | Stoichiometric combustion air, kg/s | | Target | – |
11 | Flame Momentum | FM | | | %PA * BTV | | %PA | 11.2 |
| or | %.m/s | | %PA | %Primary air, % | | BTV | 150 |
| Relative Impulse | | | BTV | Burner tip velocity, m/s | | FM | 1680 |
| (Source : F.L. Smidth) | | | | | | Target | 1000-2000 |