Introduction
Material and methods
Material
Briquette production
Physical properties of briquettes
Moisture content
Relaxed density
Shatter index
Thermal properties of briquettes
Design of experiments
Input factors | Coded values of input factors | ||
---|---|---|---|
x
i,min
|
x
i,0
|
x
i,max
| |
(−1) | (0) | (+1) | |
Compaction pressure, x1 (Mpa) | 50 | 100 | 150 |
Drying temperature, x2 (°C) | 25 | 62.5 | 100 |
Molasses mass, x3 (%) | 0 | 5 | 10 |
Sample | Compaction pressure (Mpa) | Drying temperature (°C) | Molasses mass (%) | Gross calorific value (MJ/kg) | Ash content (wt %) | Moisture content (wt %) | Relax density (g/cm3) | Shatter index (%) |
---|---|---|---|---|---|---|---|---|
1 | 150 | 62.5 | 0 | 29.75 | 1.3 | 11.2 | 1.017 | 34.7 |
2 | 50 | 100 | 5 | 27.15 | 1.7 | 9.4 | 0.976 | 82.8 |
3 | 100 | 100 | 10 | 27.20 | 3.9 | 11.1 | 1.076 | 94.1 |
4 | 100 | 25 | 10 | 28.27 | 4.0 | 16.3 | 1.147 | 66.7 |
5 | 50 | 25 | 5 | 29.37 | 2.7 | 16.1 | 1.053 | 57.4 |
6 | 150 | 100 | 5 | 27.87 | 2.6 | 10.1 | 1.025 | 57.4 |
7 | 100 | 100 | 0 | 29.14 | 1.5 | 8.3 | 0.976 | 23.4 |
8 | 100 | 25 | 0 | 30.67 | 1.6 | 14.6 | 1.030 | 32.2 |
9 | 100 | 62.5 | 5 | 27.96 | 3.1 | 12.8 | 1.067 | 52.8 |
10 | 150 | 25 | 5 | 29.01 | 1.8 | 15.0 | 1.115 | 60.6 |
11 | 50 | 62.5 | 0 | 29.73 | 1.3 | 11.4 | 0.935 | 22.6 |
12 | 150 | 62.5 | 10 | 27.70 | 4.6 | 13.1 | 1.106 | 61.1 |
13 | 100 | 62.5 | 5 | 28.47 | 2.8 | 12.0 | 1.070 | 54.3 |
14 | 50 | 62.5 | 10 | 28.55 | 2.8 | 13.0 | 1.081 | 92.7 |
15 | 100 | 62.5 | 5 | 28.21 | 2.8 | 12.6 | 1.044 | 53.8 |
16 | 100 | 62.5 | 5 | 28.52 | 3.4 | 12.3 | 1.035 | 52.0 |
17 | 100 | 62.5 | 5 | 28.33 | 3.0 | 12.0 | 1.030 | 52.2 |
Source | Response: gross calorific value (MJ/kg) | Response: ash content (wt %) | Response: moisture content (wt %) | Response: relaxed density (g/cm3) | Response: shatter index (%) | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sum of squares |
df
| Mean square | F value | Prob > F | Sum of squares |
df
| Mean square | F value | Prob > F | Sum of squares |
df
| Mean square | F value | Prob > F | Sum of squares |
df
| Mean square | F value | Prob > F | Sum of squares |
df
| Mean square | F value | Prob > F | |
Model | 13.5 | 9 | 1.5 | 17.35 | 0.0005 | 15.19 | 9 | 1.69 | 18.09 | 0.0005 | 74.73 | 3 | 24.91 | 137.06 | < 0.0001 | 0.042 | 3 | 0.014 | 49.94 | < 0.0001 | 6913.2 | 9 | 768.13 | 336.7 | < 0.0001 |
A
| 0.028 | 1 | 0.028 | 0.32 | 0.5896 | 0.41 | 1 | 0.41 | 4.34 | 0.0757 | 0.031 | 1 | 0.031 | 0.17 | 0.6852 | 0.006 | 1 | 0.006 | 21.12 | 0.0005 | 217.36 | 1 | 217.36 | 95.28 | < 0.0001 |
B
| 4.44 | 1 | 4.44 | 51.37 | 0.0002 | 0.02 | 1 | 0.02 | 0.21 | 0.6574 | 66.7 | 1 | 66.7 | 366.99 | < 0.0001 | 0.011 | 1 | 0.011 | 37.89 | < 0.0001 | 208.08 | 1 | 208.08 | 91.21 | < 0.0001 |
C
| 7.16 | 1 | 7.16 | 82.86 | < 0.0001 | 11.52 | 1 | 11.52 | 123.5 | < 0.0001 | 8 | 1 | 8 | 44.02 | < 0.0001 | 0.026 | 1 | 0.026 | 90.8 | < 0.0001 | 5085.4 | 1 | 5085.4 | 2229.1 | < 0.0001 |
AB | 0.29 | 1 | 0.29 | 3.37 | 0.1089 | 0.81 | 1 | 0.81 | 8.68 | 0.0215 | 204.49 | 1 | 204.49 | 89.63 | < 0.0001 | ||||||||||
AC | 0.19 | 1 | 0.19 | 2.19 | 0.1825 | 0.81 | 1 | 0.81 | 8.68 | 0.0215 | 477.42 | 1 | 477.42 | 209.27 | < 0.0001 | ||||||||||
BC | 0.053 | 1 | 0.053 | 0.61 | 0.4597 | 0 | 1 | 0 | 0 | 1 | 327.61 | 1 | 327.61 | 143.6 | < 0.0001 | ||||||||||
A
2
| 0.028 | 1 | 0.028 | 0.33 | 0.5839 | 1.21 | 1 | 1.21 | 12.92 | 0.0088 | 109.71 | 1 | 109.71 | 48.09 | 0.0002 | ||||||||||
B
2
| 0.004 | 1 | 0.004 | 0.045 | 0.8388 | 0.34 | 1 | 0.34 | 3.67 | 0.0971 | 174.06 | 1 | 174.06 | 76.29 | < 0.0001 | ||||||||||
C
2
| 1.28 | 1 | 1.28 | 14.86 | 0.0063 | 0.001 | 1 | 0.001 | 0.01 | 0.9226 | 120.31 | 1 | 120.31 | 52.74 | 0.0002 | ||||||||||
Residual | 0.61 | 7 | 0.086 | 0.65 | 7 | 0.093 | 2.36 | 13 | 0.18 | 0.004 | 13 | 0 | 15.97 | 7 | 2.28 | ||||||||||
Lack of fit | 0.4 | 3 | 0.13 | 2.66 | 0.1838 | 0.4 | 3 | 0.13 | 2.18 | 0.2333 | 1.85 | 9 | 0.21 | 1.61 | 0.3419 | 0.002 | 9 | 0 | 0.76 | 0.6638 | 11.99 | 3 | 4 | 4.02 | 0.1061 |
Pure error | 0.2 | 4 | 0.05 | 0.25 | 4 | 0.062 | 0.51 | 4 | 0.13 | 0.001 | 4 | 0 | 3.98 | 4 | 0.99 | ||||||||||
Cor Total | 14.11 | 16 | 15.84 | 16 | 77.1 | 16 | 0.046 | 16 | 6929.2 | 16 |
Results and discussions
Effect of binder on briquettes combustion properties
Molasses level (wt%) | Briquette combustion properties | |||
---|---|---|---|---|
Ash content (%) | Volatile matter (%) | Fixed carbon (%) | Gross calorific value (MJ/kg) | |
0 | 1.55 ± 0.03a | 23.03 ± 0.04a | 75.43 ± 0.02a | 30.56 ± 0.02a |
2 | 2.10 ± 0.04b | 23.73 ± 0.09b | 74.18 ± 0.05b | 29.85 ± 0.01b |
4 | 2.73 ± 0.02c | 23.92 ± 0.03c | 73.35 ± 0.02c | 29.25 ± 0.02c |
6 | 2.30 ± 0.04d | 24.40 ± 0.05d | 72.60 ± 0.03d | 28.88 ± 0.03d |
8 | 3.34 ± 0.07e | 24.67 ± 0.06e | 72.03 ± 0.07e | 28.69 ± 0.04e |
10 | 3.95 ± 0.05f | 25.33 ± 0.02f | 70.73 ± 0.03f | 28.29 ± 0.03f |
P value | 0.042 | 0.021 | 0.028 | 0.037 |