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Technologies and Equipment
Cogeneration Technologies | Generic Technologies
Transforming whole trees into lumber and wood products or into pulp and paper products requires significantly physical, chemical, and some biological processes that are highly energy-intensive. The forest products industries alone account for almost 14% of total industry energy demand; however, over 45% of this energy is generated onsite through the use of biomass byproducts for heat and steam. The technologies used by the lumber and wood products industry differ significantly from those used by the pulp and paper industry. Principal processes in lumber and wood products include debarking, log processing, drying, product fabrication, and finishing. Major pulp and paper processes include pulping and papermaking.
| Unit Operation |
Purpose |
Major Technologies |
| Pulp & Paper (NAICS 322) |
| Pulping |
Convert wood chips or wastepaper into fibers suitable for papermaking |
Chemical (Kraft, sulfite) – digesters, mechanical – refiners, semichemical – digesters & refiners |
Chemical Recovery
(Kraft Pulping) |
Recovery of inorganic chemicals from spent pulping liquor (black liquor) and combustion of organic residuals to produce energy |
Evaporation/concentration recovery boiler, causticizing, calcining (lime kiln) |
| Bleaching |
Brighten or whiten pulps by using chemicals to selectively remove lignin during the pulping process |
Chlorine dioxide, oxygen, hypochlorite, peroxide, ozone, or chlorination – upflow or downflow towers, vacuum washers, pumps, mixers |
| Paper Manufacture |
Chlorine dioxide, oxygen, hypochlorite, peroxide, ozone, or chlorination – upflow or downflow towers, vacuum washers, pumps, mixers |
Head box, sheet forming table (Fourdrinier, twin wire), vacuum system, press section (mechanical), dryer section (heat), calender, reel |
| Wood Products (NAICS 321) |
| Log Processing |
Production of roundwood (poles, posts, railroad ties), sawn-wood (lumber), veneers, chips (pressboard, plywood) |
Computer vision mechanical sawing, cutting and chipping |
| Drying |
Removing moisture from wood to facilitate shipping, handling, preservation and the application of treatments |
Kiln or air drying |
| Fabrication |
Additional processing to form desired end product |
Specialized mechanical sawing, drilling, sanding, high pressure chemical reformation (press/particle board), high-pressure chemical lamination (plywood), manual construction |
| Finishing |
Preserving and treating wood for final use |
Pressure treatment, chemical treatment, thermochemical treatments, coating |
| Both (NAICS 321 & 322) |
| Process Heating |
To drive pressure, steam and drying applications |
Direct heating: furnaces, kilns, dryers
Indirect heating: boilers, heat exchangers
Heat transfer fluids: steam, water, oils air |
| Debarking |
Removes bark from the whole log |
Barking drum, ring barker |
Source: Smook 1992
Steam turbines driven by bed boilers are the most prevalent in forest product facilities
Adjustable speed motors are the most commonly used energy-saving technology
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