Sappi North America, Inc. is a market leader in converting wood fiber into superior products that customers demand worldwide. The success of the company’s four diversified businesses —high-quality Coated Printing Papers, Dissolving Wood Pulp, Packaging and Specialty Papers, and Casting and Release Papers—is driven by strong customer relationships, best-in-class people and advantaged assets, products, and services. As the world is demanding more and more from the planet and resources are being consumed at unprecedented rates, Sappi is dedicated to operating its manufacturing sites in a highly sustainable manner.
The pulp and paper industry is water and energy intensive, and Sappi North America’s Somerset Mill saw an opportunity to reduce both its energy associated footprint and its costs. The Maine-based mill was built in the 1970s and 1980s and wanted to improve upon many of its older practices. A project was developed to provide process hot water for Paper Machine No. 2 (PM2) and Paper Machine No. 3 (PM3) using recovered heat to offset the use of low-pressure steam.
Originally, the Somerset Mill was designed to generate hot water for its paper machines using low pressure steam, which was produced by way of burning fuels, a costly method. Now, newly installed heat exchangers capture wasted heat and use it to heat the water needed elsewhere in the manufacturing process.
The update included adding heat exchangers, ductwork, pumps, and a great deal of piping, instruments, and controls. Modifications were also made to the PM3’s dryer steam system to reduce blow-through steam that was being used to generate hot water in the dryer section vacuum condenser. All of this enabled greater use of hot water generated from recovered heat and a reduction in steam use.
This project was commissioned to remain competitive with newer pulp and paper mills by reducing the operating costs of PM2 and PM3, decreasing traditional fossil fuel use, allowing for reduced purchased electricity, reducing waste, and lessening greenhouse gas emissions.
Sappi leveraged a program administered by Efficiency Maine, which provides incentive grants to fund projects that reduce greenhouse gas emissions. This grant reduced the estimated project costs and increased its return significantly, making it a good business decision as well as falling in line with the company’s sustainability goals.
Because the project reduces the mill’s steam production requirements and fuel use in its power boilers, it is projected to save more than 3,700 tons annually of greenhouse gas emissions. By supplying PM2 and PM3 hot water tanks with water heated by recovered heat sources instead of steam, the steam valves that previously heated the water are now closed most of the time—thereby reducing low pressure steam requirements.
In the first three months of operation, the project saved Sappi North America more than 39,500 gigajoules of energy derived primarily from a reduction of fossil fuel use by the power boilers and the generation of additional electrical power in the mill’s steam turbine generators to offset purchased power. The project was estimated to save 158,000 gigajoules of energy annually, and although this is less than 2% of the Somerset Mill’s energy use, it equates to hundreds of thousands of dollars in annual savings. This is equivalent to the annual energy to heat 1,600 single family homes.
Sappi North America hopes that these experiences encourage other companies in the pulp and paper industry—and any energy intensive industry—to make similar, sustainable changes.
