Table 4.
Source composition | Lime-treated wheat straw solid fraction (experimental) | Lime-treated wheat straw solid fraction (corrected for 85% calcium recycle) | Wheat straw original feedstock (harvest 2003) | Wood (untreated, average) [28] | |
Parameter | Unit | ||||
Ash (550°C) | wt%dry | 27.2 | 12.6 | --- | |
Ash (815°C) | wt%dry | 27.0 | 19.5 | 11.5 | 1.5 |
Volatiles | wt%dry | 68.4 | 75.5 | 70.1 | 80.7 |
Moisture | wt%wet | 3.4a | 50b | 7.7 | 49.2 |
Higher heating value, measured | MJ/kgdry | 13.4 | 14.3 | 16.6 | 19.8 |
Lower heating value | MJ/kgdry | 12.4 | 13.2 | 15.6 | 18.5 |
Lower heating value (at 50% MC) | MJ/kgwet | 5.0 | 5.4 | 6.6 | 8.0 |
C | wt%daf | 43.1 | 44.9 | 46.5 | 51 |
H | wt%daf | 5.8 | 6.1 | 5.6 | 6.1 |
N | wt%daf | 1.5 | 1.5 | 1.7 | 0.3 |
O | wt%daf | 44.8 | 46.6 | 45.8 | 43 |
S | wt%daf | 4.56 | 0.71 | 0.15 | 0.06 |
Cl | wt%daf | 0.20 | 0.21 | 0.31 | 0.04 |
F | wt%daf | 0.0031 | 0.0031 | --- | 0.0024 |
Al | mg/kgdry | 121 | 133 | 185 | 211 |
As | mg/kgdry | 5.4 | 5.9 | < dl | less than dl |
B | mg/kgdry | 5.2 | 5.7 | 4.1 | 9 |
Ba | mg/kgdry | 3.2 | 3.5 | 3.6 | 143 |
Ca | mg/kgdry | 52000 | 8600 | 4700 | 13000 |
Cd | mg/kgdry | Less than dl | --- | 0.15 | 0.5 |
Co | mg/kgdry | 7.3 | 8.1 | 55 | 0.51 |
Cr | mg/kgdry | 10.2 | 11.2 | 0.2 | 5 |
Cu | mg/kgdry | 9.1 | 10.1 | 1.6 | 17 |
Fe | mg/kgdry | 160 | 170 | 220 | 120 |
K | mg/kgdry | 3000 | 3300 | 15000 | 2000 |
Li | mg/kgdry | Less than dl | --- | 0.2 | Less than dl |
Mg | mg/kgdry | 870 | 36 | 1105 | 769 |
Mn | mg/kgdry | 33 | 36 | 14 | 214 |
Mo | mg/kgdry | Less than dl | --- | 1.9 | 0.55 |
Na | mg/kgdry | 1500 | 1660 | 200 | 300 |
Ni | mg/kgdry | 5 | 5.8 | 0 | 8 |
P | mg/kgdry | 5100 | 5600 | 485 | 486 |
Pb | mg/kgdry | Less than dl | --- | 1.1 | 32 |
Sb | mg/kgdry | 1.4 | 1.6 | 1.8 | 1.8 |
Se | mg/kgdry | Less than dl | --- | 1.9 | 1 |
Si | mg/kgdry | 40000 | 44500 | 28000 | 900 |
Sn | mg/kgdry | 0 | 0 | 0.20 | 1.2 |
Sr | mg/kgdry | 23 | 25 | 18 | 14 |
V | mg/kgdry | 0.3 | 0.3 | --- | --- |
Zn | mg/kgdry | 25 | 27 | 0.6 | 0.4 |
aAfter thermal drying.
bAfter mechanical dewatering with Pneumapress.