Table 4 Properties of biochar derived from oleaginous yeast at different pyrolysis temperatures
Properties | Pyrolysis temperature (°C) | ||||
|---|---|---|---|---|---|
Proximate analysis (wt%) | 400 | 450 | 500 | 550 | 600 |
Moisture content | 1.8 | 2.3 | 5.3 | 4.4 | 4.0 |
Volatile matter | 51.1 | 33.7 | 22.9 | 17.3 | 19.6 |
Fixed carbon | 31.1 | 47.0 | 53.2 | 57.0 | 49.1 |
Ash content | 16.0 | 17.0 | 18.6 | 21.3 | 27.3 |
Ultimate analysis (wt%) | |||||
 Carbon | 65.8 | 65.5 | 63.3 | 61.5 | 57.7 |
 Hydrogen | 6.5 | 5.6 | 3.5 | 3.1 | 2.6 |
 Nitrogen | 2.7 | 4.4 | 5.9 | 4.5 | 3.1 |
 Oxygen | 9.0 | 7.6 | 8.8 | 9.6 | 9.3 |
Heating value (MJ/kg) | 28.8 | 27.9 | 27.7 | 24.3 | 21.8 |
Surface characteristics | |||||
BET surface area (m2/g) | 4.1 | 2.6 | 5.0 | 2.6 | 8.4 |
External surface (m2/g) | 6.3 | 3.8 | 4.2 | 2.5 | 7.6 |
Total pore volume (mm3/g) | 1.2 | 0.9 | 2.2 | 1.1 | 3.6 |
Average pore diameter (Ã…) | 62.2 | 110.1 | 125.6 | 187.6 | 130.7 |