North American Papermaking: Transforming Raw Materials into High-Quality Paper
The trees used to make our papers in the United States come from sources practicing responsible forest management—our triple chain-of-custody certifications ensure that. Practicing waste and water management and using environmentally friendly chemicals are all part of our smart manufacturing endeavor.
In a typical Kraft pulp and paper mill, the process of making paper from wood begins in the wood yard, moves to the pulp mill, then to papermaking and finally, to finishing. While making paper can’t be an entirely “clean” process, we are continually looking to employ greener methods whenever possible. Cogeneration, biofuels and water management are some of the ways Glatfelter approaches responsible manufacturing practices.
Environmentally Responsible Manufacturing Processes
Manufacturing Specialty Papers
DebarkingA debarking drum strips bark off the wood and sends logs to a chipper where one log is turned into thousands of chips in a couple of seconds. Good chips go directly to a chip pile for storage. Undersized chips, fines and sawdust are sent to a power boiler, along with bark from the debarking drum, where they are used as biofuel to generate approximately 50% of our electricity.
Reprocessing ChipsOversized chips are separated so they can be reprocessed. A uniform chip size is important in the pulping operation because it increases the yield and quality of wood fiber produced. Once the chips have been screened, they are stored for later entry into the pulping operation.
Pulp MillCellulous fiber is separated from the lignin (gluey substance that holds the fibers together) of the wood chips using the Kraft chemical process, which helps reduce carbon emissions and pollution while also producing strong fibers. In the pulp mill, the conversion of wood chips to individual fibers occurs in the digester, followed by washing and screening and, ultimately, a bleaching operation, where the fibers are brightened from brownish color to white.
Digester: Step 1Wood chips are converted to individual fibers in the digester. Under pressure, the white liquor dissolves, or “digests” the lignin that holds the individual cellulous fibers together, creating pulp.
Digester: Step 2Pulp from the digesters, along with the spent cooking chemicals, now called “black liquor,” are sent to the washing and screening area where the fibers are separated from the black liquor. The black liquor is recovered, recycled and converted back into white liquor for reuse.
Oxygen DelignificationOxygen delignification uses oxygen and white liquor, along with some steam to remove lignin from the pulp so that fewer chemicals are needed during bleaching. This is a significant environmental improvement.
BleachingPulp enters the bleaching area where it is brightened using chlorine dioxide and hydrogen peroxide. This elemental chlorine-free or EFC process improves fiber quality and reduces the possibility that dioxins and other undesirable chemicals are formed during the bleaching process.
Wet End: Step 1We recover, recycle and reuse the water and any other materials that drain through the wire mesh. When the furnish hits the wire mesh, it is approximately 99.5% water, .5% fiber, filler and additives and must be reduced to 4-5% water before the papermaking process is complete.
Wet End: Step 2Water recovery occurs several times during the wet end process. When the paper reaches the dryer, heat from the steam drives off the remaining moisture, leaving an even moisture profile. A good portion of this steam was produced using biomass (bark, saw dust, irregularly sized chips and spent cooking liquors).
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