ENERGY CONSUMPTION IN SAWMILLING, PLYWOOD AND PARTICLEBOARD MANUFACTURE
Table 1. Approximate proportional energy consumption in sawmilling
|
Process energy |
Proportion of requirement |
||
|
Electrical |
Total Energy 1/ |
||
|
Air drying |
Kiln drying |
(%) |
|
|
(%) |
(%) |
||
|
Electrical |
|
|
|
|
Sorting and barking |
9.5 |
5.9 |
0.8 |
|
Sawing |
43.0 |
26.8 |
3.5 |
|
Chipping |
10.5 |
6.5 |
0.8 |
|
Materials handling |
32.5 |
20.2 |
2.6 |
|
Planing |
- |
12.8 |
1.7 |
|
Kiln fans |
- |
25.0 |
3.3 |
|
Miscellaneous |
4.5 |
2.8 |
0.3 |
|
|
100% |
100% |
13% |
|
Thermal |
|
|
|
|
Kiln drying |
- |
- |
87%* |
|
|
|
|
100% |
|
Unit energy consumption |
44 kWh/m3 |
70.7 kWh/m3 |
1.70 GJ/m3 |
|
TOTAL |
|
|
1.96 GJ/m3 |
1/ Applicable to kiln drying and not air drying
Sources: (100) (97) (52) (54)N.B. Based on a standard well operated hardwood sawmill of 100 m3/day capacity
Table 2. Approximate proportional energy consumption in the manufacture of plywood
|
Process energy |
Proportion of electrical requirement |
Proportion of total energy requirement |
Unit consumption |
|
(%) |
(%) |
|
|
|
Electrical |
|
|
|
|
Sorting & barking |
12.5 |
1.6 |
|
|
Peeling |
23.1 |
3.0 |
|
|
Reeling & clipping |
1.7 |
0.2 |
|
|
Drying |
7.5 |
1.0 |
|
|
Jointing & splicing |
3.9 |
0.5 |
|
|
Edge-gluing |
3.6 |
0.5 |
|
|
Pressing |
6.7 |
0.9 |
|
|
Trimming |
3.9 |
0.5 |
|
|
Sanding |
7.8 |
1.0 |
|
|
Materials handling |
15.6 |
2.0 |
|
|
Miscellaneous |
13.7 |
1.8 |
|
|
|
100% |
13% |
230 kWh/m3 |
|
Thermal |
|
|
|
|
Conditioning |
- |
14.9 |
0.95 GJ/m3 |
|
Drying |
- |
60.8 |
3.88 GJ/m3 |
|
Pressing |
- |
11.3 |
0.72 GJ/m3 |
|
Sub-total |
|
87% |
5.55 GJ/m3 |
|
Total |
|
100% |
6.38 GJ/m3 |
Sources: (100) (102) (23)
N.B. Based on a standard well operated plant of 100 m3/day capacity, producing 5 mm thick panels from hardwood
Table 3. Approximate proportional energy consumption in the manufacture of particleboard
|
Process energy |
Proportion of electrical requirement |
Proportion of total energy requirement |
Unit consumption |
|
(%) |
(%) |
||
|
Electrical |
|
|
|
|
Particle reduction |
30.0 |
5.4 |
|
|
Screening |
0.8 |
0.1 |
|
|
Drying |
2.7 |
0.5 |
|
|
Gluing |
4.2 |
0.8 |
|
|
Forming |
3.8 |
0.7 |
|
|
Pressing |
11.5 |
2.1 |
|
|
Finishing |
11.9 |
2.1 |
|
|
Materials handling |
20.5 |
3.7 |
|
|
Miscellaneous |
14.6 |
2.6 |
|
|
|
100% |
18% |
180 kWh/m3 |
|
Thermal |
|
|
|
|
Particle drying |
- |
61.5 |
2.21 GJ/m3 |
|
Hot pressing |
- |
20.5 |
0.74 GJ/m3 |
|
Sub-total |
|
82% |
2.95 GJ/m3 |
|
Total |
|
100% |
3.60 GJ/m3 |
Sources: (47)(102)(51)(89)
N.B. Based on a standard well operated plant of 100 m3/day capacity, producing 19 mm particleboard of 650 kg/m3 from hardwood
