by Phillip Meeks
Phillip Meeks is a graduate forester and freelance writer offering writing services -- trade articles, press releases, reports, case histories, etc. -- to the forest products industry. His web site can be found at http://mypeoplepc.com/members/pmeeks/index.htm, or he can be contacted directly at pmeeks@peoplepc.com.
In 1998, the University of Georgia's Biological and Agricultural Engineering Department discussed wood waste recycling in the report, "Wood Biomass Production and Use in Georgia: Existing Situation and Estimates -- Uses of Wood Byproducts."
Two factors noted in the paper that determine the feasibility of wood waste reuse are processing and transportation costs and markets for the final product. In meeting these challenges through innovative engineering, Young Manufacturing, Inc., a manufacturer of oak millwork in Beaver Dam, Kentucky, has created an onsite market for its waste and, at the same time, has eliminated transportation costs otherwise associated with waste disposal. The process developed by the company has reduced other costs as well, including utilities.
The end of World War II saw the beginning of the Young family's oak millworks operation. Today, with 120 employees and customers all over the United States (until two years ago, Young's customer base was limited to the east of the Mississippi River), Young Manufacturing uses locally available red oak and yellow-poplar to produce stair treads, moldings and other wood products.
In the 1970s, a drive to increase the plant's efficiency eventually led to the installation of a dry kiln operation. While few primary and secondary wood industries in the region have their own lumber drying facility, Young's decision eliminated the transportation costs of carrying green lumber to and from a dry kiln.
At the same time, the dry kiln facility created a need for steam, a need that could easily be supplied with readily available wood waste. So in 1974, Young Manufacturing installed its first boiler, and in 1987, the company followed with a second larger one.
The availability of steam inspired the members of the Young family to take their plant to even higher levels of efficiency. With this goal in mind, Young Manufacturing installed two steam engines at the plant in the mid-1970s. "We made power with one of these engines," explains Plant Engineer Jeff Young, "and the other one turned the plant vacuum fan, which pulled in all the sawdust in the plant. These engines were in operation up until 1990, when the current co-generation system was put in place."
Young, who is also the grandson of the company's founder, says the development of the plant's co-generation system was the logical result of two factors. "Number one, you've got to get rid of wood waste," he said. "Secondly, the easiest and cheapest way to dry lumber is with steam. That's been our experience." Making the most of the available steam, the plant today uses turbines and generators in conjunction with the '74 and '87 boilers. Not only does the process meet waste management and lumber drying needs, but enough electricity is produced to supply 35 percent of the plant's power requirements."
Most of the development of the system took place at the plant, with additional technical input from Roy Shriner, a Charlotte, North Carolina-based engineer. The system was developed with a Kato generator and a Compass turbine purchased from a Deerfield, Massachusetts company, then called Ewing Power Systems.
Young Manufacturing's present co-generation operation is composed of one 260 KW machine and one 350 KW machine.
"We basically keep them maxed out," says Young. He adds that the electricity produced in the co-generation system is used for those operations that require a steady, 24-hour supply of power, such as the dry kiln operation and the boiler room.
The first phase of the operation virtually eliminates the plant's wood waste. Sawdust and other residuals are transported via pneumatic conveyors to storage silos. From the silos, fuel is fed automatically into the two boilers as needed. Steam generated by the boilers is used to turn the turbines and, in turn, generates the electricity.
The operation consumes approximately 50 tons of sawdust per day. Mark Kaser, executive director of the Kentucky Wood Products Competitiveness Corporation (KWPCC), has estimated that as high as 99 percent of Young's wood waste goes back into the co-generation process.
Efficiency is further demonstrated in the use of the steam. Most of the steam's energy is taken out to turn the turbines. In one of the two systems, 150 p.s.i. of steam goes in, while only five p.s.i. comes out. In the other, the difference is 250 p.s.i. going in and five p.s.i. coming out. The five p.s.i. remainder from each system is then used in the dry kiln operation.
When all is said and done, Young Manufacturing's innovative system of co-generation saves the company an estimated $156,000 annually in utility costs. Facility costs could be reduced even more should Young opt in the future to sell surplus power back to the utility company. For the time being, though, Young Manufacturing is 100 percent isolated. All electricity generated is used in the plant.
Cox Interior of Campbellsville, Kentucky, is another example of a secondary wood products company making use of a co-generation system. Plant Operator Jerry Pierce estimates that 75 to 80 percent of the plant's power needs are met through co-generation. Unlike Young Manufacturing, Cox Interior sells power back to the utility company.
Even with an efficient co-generation system in operation, Cox Interior still suffers from an over-abundance of wood waste. "There's been talk of bringing a press board plant to the area to do something with all the excess sawdust," said Pierce, "but for right now, we've got a lot more dust than we can use."
Keeping ahead of the game, the Young family said they do not intend to become complacent with their plant's technology. The developers of the system made allowances for future growth.
Jeff Young illustrates the family's visionary spirit in his explanation of the plant's most recent boiler. "The 1987 boiler", he says, "is big enough to run two turbines, so we're essentially running it at half mast for now. In the future, we want to install another."
Phillip Meeks is a graduate forester and freelance writer offering writing services -- trade articles, press releases, reports, case histories, etc. -- to the forest products industry. His web site can be found at http://mypeoplepc.com/members/pmeeks/index.htm, or he can be contacted directly at pmeeks@peoplepc.com.
