Boise Paper Mill Saves Money by Making Its Pumping System More Energy-Efficient
May 4, 2006
In a recent project at the Boise Paper mill in Wallula, Washington, engineers assessed the efficiency of the process pumping system in the mill's bleach plant and then made several improvements to the system. As a result, the plant now saves 498,000 kWh and $15,157 in energy costs annually. Maintenance costs are lower by $2,500 per year, and production losses are significantly reduced.
This improvement project followed an evaluation carried out during a training course taught by Don Casada, a DOE Qualified Pumping System Assessment Tool (PSAT) Specialist, which was co-sponsored by several northwestern organizations, including the Northwest Energy Efficiency Alliance. The results of the PSAT assessment were later corroborated in an evaluation performed by Compression Engineering Corporation and funded by the mill's electric utility, Pacific Power.
The bleach plant had been depending on one 150-horsepower (hp) pump to meet a variety of process requirements. During peak production, some of these requirements—such as providing make-up water for filtrate chests—could not be met, and this was leading to costly production bottlenecks. Engineers found that the current pumping system could not meet the peak demand and that other system problems were starting to cause some damage to the pipes.
They recommended dedicating a smaller, 50-hp pump to low-head applications and using the 150-hp pump for high-head ones. They also suggested retrofitting the motors of both pumps with variable-speed drives so they would operate more efficiently. These improvements were made, and they greatly increased the efficiency and reliability of the plant's process pumping system and eliminated many problems.
Boise Paper manufactures specialty and premium paper products. The Wallula mill, in operation since 1958, has 400 employees and produces 375 tons per day of paper pulp, among other products. In addition to saving energy, industrial energy efficiency projects like this one can reduce operating costs, boost the reliability of production processes, and eliminate the bottlenecks that hamper productivity.