Characteristics of dried FS used for pyrolysis in this study in comparison to the range of mean literature values and characteristics of FS char produced at different hold times (10, 20, 40 min) and pyrolysis temperatures (350, 450, 600 °C). All results are for 100% dry feedstock and char. Standard deviations are included in parentheses for analyses conducted in triplicate
| . | . | FS feedstock . | Char . | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameter . | Unit . | This study . | Literaturea . | 350 °C 10 min . | 350 °C 20 min . | 350 °C 40 min . | 450 °C 10 min . | 450 °C 20 min . | 450 °C 40 min . | 600 °C 10 min . | 600 °C 20 min . | 600 °C 40 min . |
| Char yield | % | – | – | 70.4 | 70.1 | 69.3 | 62.6 | 61.3 | 61.2 | 58.3 | 57.8 | 57.7 |
| pH | – | – | – | 9.1 | 9.2( ± 0.02) | 9.3 | 9.7 | 9.7( ± 0.02) | 9.7 | 11.0 | 11.1( ± 0.01) | 11.2 |
| Ash | % | 40.1( ± 1.8) | 17–59 | 54.5 | 57.2( ± 1.8) | 57.5 | 65.6 | 66.9( ± 1) | 66.2 | 68.1 | 72.9( ± 0.9) | 73.8 |
| Volatile solids | % | 48.8( ± 1.5) | 43–75 | 26.1 | 23.9( ± 1.0) | 23.5 | 13.7 | 12.2( ± 0.1) | 13.0 | 8.6 | 6.7( ± 0.4) | 7.4 |
| Fixed carbon | % | 11.3( ± 0.7) | 8–9 | 19.4 | 18.9( ± 1.2) | 19.0 | 20.7 | 20.9( ± 0.9) | 20.8 | 23.3 | 20.3( ± 0.7) | 18.8 |
| CVb | MJ kg−1 | 13.4( ± 1.8) | 11–19 | 12.4(±0.8) | 10.9( ± 0.5) | 10.7 | 9.0 | 9.1( ± 1.0) | 9.1 | 9.3 | 8.8( ± 0.3) | 8.8 |
| CVb | MJ kg-1 ash-free | 22.3( ± 2.9) | 27.2 | 25.5 | 25.1 | 26.1 | 27.6 | 27.0 | 29.2 | 32.5 | 33.5 | |
| Carbon | % | 34.9( ± 3.3) | 28–42 | 33.3(±2.7) | 33.5( ± 2.4) | 34.9(±2.8) | 32.8(±1.2) | 27.4( ± 4.1) | 31.5(±4.1) | 29.8(±2.3) | 28.2( ± 2.2) | 27.4(±2.7) |
| Carbon stability | %carbon | – | – | 58.0 | 66.7( ± 9.0) | 66.9 | 82.6 | 75.8( ± 15.3) | 81.0 | 118.9* | 104.7*( ± 5.3) | 109.2* |
| Nitrogen | % | 2.4( ± 0.3) | 3–6 | 2.3(±0.0) | 2.3( ± 0.0) | 2.3(±0.0) | 2.0(±0.0) | 1.6( ± 0.0) | 1.8(±0.0) | 1.5(±0.0) | 1.3( ± 0.0) | 1.3(±0.0) |
| Phosphorus | % | 2.4( ± 0.0) | 1–3 | 3.2 (±0.2) | 3.3( ± 0.3) | 3.1(±0.0) | 3.6(±0.2) | 3.8( ± 0.1) | 3.5(±0.1) | 3.9(±0.2) | 4.0( ± 0.2) | 4.2(±0.3) |
| Plant-Pc | g kg−1 | – | – | 26.1 | 25.3( ± 1.4) | 28.1 | 32.6 | 30.5( ± 0.7) | 34.8 | 33.3 | 33.4( ± 1.4) | 36.0 |
| Plant-Pc | %Pd | – | – | 82.1 | 75.3 | 89.7 | 91.3 | 80.4 | 98.3 | 86.1 | 83.4 | 85.4 |
| CECd | cmol kg−1 | – | – | 9.8 | 13( ± 0.7) | 9.8 | 22.9 | 23.2( ± 0.9) | 23.5 | 24.6 | 26( ± 1.7) | 27.7 |
| Chromium | mg kg−1 | 73.5( ± 0.9) | 401–485 | 121.5(±7.1) | 124.9( ± 8.8) | 113.7(±4.0) | 125.2(±4.6) | 129( ± 3.5) | 152.6(±3.5) | 180(±4.8) | 151.9( ± 6.1) | 194.2(±6.7) |
| Copper | mg kg−1 | 65.4( ± 3.4) | 61–216 | 90.4(±3.9) | 86.6( ± 9.4) | 81.8(±1.9) | 96.7(±9.2) | 101.7( ± 1.6) | 91.5(±1.6) | 101.6(±4.3) | 110.1( ± 8.0) | 113.2(±7.9) |
| Lead | mg kg−1 | <12.5 | 2.4–59 | <5 | 21.5 | <5 | 14.9(±1.4) | 13.7( ± 2.4) | <5 | <5 | <5 | <5 |
| Nickel | mg kg−1 | 39.7( ± 1.9) | 24–77 | 63.7(±2.7) | 63.3( ± 5) | 57.4(±0.9) | 62.9(±3.8) | 66.6( ± 1.9) | 76(±1.9) | 89.8(±3.1) | 78( ± 3.5) | 96.5(±3.2) |
| Zinc | mg kg−1 | 669( ± 25) | 34–918 | 917.7 (±55.3) | 922.5 ( ± 58.3) | 872.9 (±4.8) | 970.9 ( ± 60.5) | 1,010.1 ( ± 13.7) | 948.4 (±13.7) | 1,056.6 (±16.8) | 1,088.6 ( ± 84.1) | 1,116 (±37.0) |
| . | . | FS feedstock . | Char . | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameter . | Unit . | This study . | Literaturea . | 350 °C 10 min . | 350 °C 20 min . | 350 °C 40 min . | 450 °C 10 min . | 450 °C 20 min . | 450 °C 40 min . | 600 °C 10 min . | 600 °C 20 min . | 600 °C 40 min . |
| Char yield | % | – | – | 70.4 | 70.1 | 69.3 | 62.6 | 61.3 | 61.2 | 58.3 | 57.8 | 57.7 |
| pH | – | – | – | 9.1 | 9.2( ± 0.02) | 9.3 | 9.7 | 9.7( ± 0.02) | 9.7 | 11.0 | 11.1( ± 0.01) | 11.2 |
| Ash | % | 40.1( ± 1.8) | 17–59 | 54.5 | 57.2( ± 1.8) | 57.5 | 65.6 | 66.9( ± 1) | 66.2 | 68.1 | 72.9( ± 0.9) | 73.8 |
| Volatile solids | % | 48.8( ± 1.5) | 43–75 | 26.1 | 23.9( ± 1.0) | 23.5 | 13.7 | 12.2( ± 0.1) | 13.0 | 8.6 | 6.7( ± 0.4) | 7.4 |
| Fixed carbon | % | 11.3( ± 0.7) | 8–9 | 19.4 | 18.9( ± 1.2) | 19.0 | 20.7 | 20.9( ± 0.9) | 20.8 | 23.3 | 20.3( ± 0.7) | 18.8 |
| CVb | MJ kg−1 | 13.4( ± 1.8) | 11–19 | 12.4(±0.8) | 10.9( ± 0.5) | 10.7 | 9.0 | 9.1( ± 1.0) | 9.1 | 9.3 | 8.8( ± 0.3) | 8.8 |
| CVb | MJ kg-1 ash-free | 22.3( ± 2.9) | 27.2 | 25.5 | 25.1 | 26.1 | 27.6 | 27.0 | 29.2 | 32.5 | 33.5 | |
| Carbon | % | 34.9( ± 3.3) | 28–42 | 33.3(±2.7) | 33.5( ± 2.4) | 34.9(±2.8) | 32.8(±1.2) | 27.4( ± 4.1) | 31.5(±4.1) | 29.8(±2.3) | 28.2( ± 2.2) | 27.4(±2.7) |
| Carbon stability | %carbon | – | – | 58.0 | 66.7( ± 9.0) | 66.9 | 82.6 | 75.8( ± 15.3) | 81.0 | 118.9* | 104.7*( ± 5.3) | 109.2* |
| Nitrogen | % | 2.4( ± 0.3) | 3–6 | 2.3(±0.0) | 2.3( ± 0.0) | 2.3(±0.0) | 2.0(±0.0) | 1.6( ± 0.0) | 1.8(±0.0) | 1.5(±0.0) | 1.3( ± 0.0) | 1.3(±0.0) |
| Phosphorus | % | 2.4( ± 0.0) | 1–3 | 3.2 (±0.2) | 3.3( ± 0.3) | 3.1(±0.0) | 3.6(±0.2) | 3.8( ± 0.1) | 3.5(±0.1) | 3.9(±0.2) | 4.0( ± 0.2) | 4.2(±0.3) |
| Plant-Pc | g kg−1 | – | – | 26.1 | 25.3( ± 1.4) | 28.1 | 32.6 | 30.5( ± 0.7) | 34.8 | 33.3 | 33.4( ± 1.4) | 36.0 |
| Plant-Pc | %Pd | – | – | 82.1 | 75.3 | 89.7 | 91.3 | 80.4 | 98.3 | 86.1 | 83.4 | 85.4 |
| CECd | cmol kg−1 | – | – | 9.8 | 13( ± 0.7) | 9.8 | 22.9 | 23.2( ± 0.9) | 23.5 | 24.6 | 26( ± 1.7) | 27.7 |
| Chromium | mg kg−1 | 73.5( ± 0.9) | 401–485 | 121.5(±7.1) | 124.9( ± 8.8) | 113.7(±4.0) | 125.2(±4.6) | 129( ± 3.5) | 152.6(±3.5) | 180(±4.8) | 151.9( ± 6.1) | 194.2(±6.7) |
| Copper | mg kg−1 | 65.4( ± 3.4) | 61–216 | 90.4(±3.9) | 86.6( ± 9.4) | 81.8(±1.9) | 96.7(±9.2) | 101.7( ± 1.6) | 91.5(±1.6) | 101.6(±4.3) | 110.1( ± 8.0) | 113.2(±7.9) |
| Lead | mg kg−1 | <12.5 | 2.4–59 | <5 | 21.5 | <5 | 14.9(±1.4) | 13.7( ± 2.4) | <5 | <5 | <5 | <5 |
| Nickel | mg kg−1 | 39.7( ± 1.9) | 24–77 | 63.7(±2.7) | 63.3( ± 5) | 57.4(±0.9) | 62.9(±3.8) | 66.6( ± 1.9) | 76(±1.9) | 89.8(±3.1) | 78( ± 3.5) | 96.5(±3.2) |
| Zinc | mg kg−1 | 669( ± 25) | 34–918 | 917.7 (±55.3) | 922.5 ( ± 58.3) | 872.9 (±4.8) | 970.9 ( ± 60.5) | 1,010.1 ( ± 13.7) | 948.4 (±13.7) | 1,056.6 (±16.8) | 1,088.6 ( ± 84.1) | 1,116 (±37.0) |
aBassan et al. (2013); Liu et al. (2014); Muspratt et al. (2014); Appiah Effah et al. (2015); Seck et al. (2015); Byrne et al. (2016); Gold et al. (2017a, 2017b).
bCalorific value.
cPlant available phosphorus.
dCation exchange capacity.
*Carbon stability values >100% are likely due to inaccuracies in the determination of carbon before and after H2O2 digestion.