Increasing Process and Energy Efficiency at a Plywood Plant

A plywood plant in Madison, Georgia, looking for ways to reduce the amount of fuel it must purchase to fuel its boilers, found that by improving process energy efficiency, it could virtually eliminate its purchases of fuel from outside sources. The plant, owned by Georgia Pacific Corporation, manufactures plywood using locally grown loblolly pine. It uses wood byproducts, such as bark and trimmings, to fuel its boilers, which provide the steam needed for the plywood production process. But at certain times of the year, not enough bark is available and the plant must purchase additional fuel. To address the problem, Georgia Pacific formed a project team consisting of members from the plywood plant, from the North American Insulation Manufacturers Association (NAIMA), and from Rock Wood Manufacturing, Inc. Representatives from the U.S. Department of Energy's (DOE) Steam Challenge program confirmed the energy savings produced by the project. The project team recommended insulating the steam [A1]lines from the boilers with mineral fiber and replacing 70 steam traps. The insulation and steam traps allowed the system to contain heat more effectively, thus reducing the amount of steam required. Therefore, the steam boilers fuel consumption was reduced, and Georgia Pacific no longer had to purchase fuel from outside sources. The project cost about $70,000 (USD), but total annual savings is about $139,000 (USD), resulting in a simple payback of about six months.

Technical Data

Approximately 1,500 feet (547 m) of steam lines carry steam from the boilers at the plywood plant to dryers, which are used the glued wood shavings which make up plywood panels. Heat loses in the steam lines increase the amount of time it takes for plywood panel to be properly dried. Based on the recommendations of the project team, nearly 970 feet (296 m) of steam lines were insulated with 2-inch (5-cm) mineral fiber. In addition, 70 steam traps were replaced with new traps, which in itself resulted in a 10% increase in condensate return. These two steps increased the dryers' operating temperature by 15 °F (8.3 °C).

Energy Data

Insulating the plant's steam lines and replacing old steam traps with new ones reduced steam usage by about 6,000 lbs (2,721 kg) per hour. In addition, the new steam traps increased condensate return by 10%. In total, about 17,000 tons of fuel are saved annually. Total annual energy savings is about 63,000 MMBtus.

Economic Data

The increased efficiency of the steam lines has increased productivity at the plant and has reduced the amount of fule consumed by about 17,000 tons. Based on a fuel cost of $8 (USD) a ton, total savings run about $139,000 (USD) annually. Because of the decreased fuel needs, Georgia Pacific no longer has to buy outside fuel, and in fact now often has a surplus it can sell itself. Total project cost was about $70,000 (USD), resulting in a simple payback of six months.

Environmental Data

The reduction in fuel use at the facility resulted in the annual prevention of 34,600,000 lbs (15,694,000 kg) of CO₂, 318 lbs (144 kg) of SO_x, 293 lbs (133 kg) of NO_x, and 23 lbs (10.5 kg) of CO. Emission reductions would have been greater, but more than half of the electricity saved at the facility was generated by hydroelectric plants.

Contacts:

Georgia-Pacific Corporation Paul Maxey 1400 Woodcraft Rd. Madison, GA 30650 706-342-4300 706-343-3918 (Fax) http://www.gp.com	North American Insulation Manufacturers Assoc. Stevie Jones 44 Canal Center Plaza, Suite 310 Alexandria, A 22314 703-684-0084 703-684-0427 (Fax) http://www.naima.org
Rock Wool Manufacturing Inc. William Brayman P.O.Box 506 Leeds, AL 35094 205-699-6121 205-699-3132 (Fax)

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