From pulp to polymers


UMaine engineer developing integrated forest products refinery

Wood pulp might make the paper industry go around, but this renewable product has untapped potential for a variety of uses, according to a University of Maine professor. Adriaan van Heiningen works in the University of Maine Department of Chemical and Biological Engineering on ways to squeeze more energy and new products from pulp.

With a three year $1 million grant from the U.S. Department of Energy and a contract with International Paper, van Heiningen, who holds the J. Larcom Ober Chair in Chemical Engineering, is focusing on a portion of pulp that is known as hemicelluloses. In a pulp mill, most of the hemicelluloses end up in the spent pulping liquor and are burned. However hemicelluloses contain a considerable amount of oxygen and do not generate much heat when burned in industry boilers. Therefore van Heiningen wants to increase the value of hemicelluloses for the paper industry by using it for new value-added products ranging from ethanol to car fenders and table tops. "The paper industry in the United States needs new sources of revenue to compete internationally and the U.S. needs alternative fuels to reduce its dependence on fossil fuel," says van Heiningen. "The process that I am working on could use more of the biomass (in trees) and produce more products at competitive prices."

Van Heiningen has more than 20 years of experience in pulp and paper research. He is working with UMaine professors Douglas Gardner and Joseph Genco, Research Engineer Haixuan Zou and graduate students Sefik Tunc and Ryan Mills on new uses of hemicelluloses extracted from wood chips before the chips are turned into pulp. In the laboratories of UMaine's Pulp and Paper Process Development Center, the wood chips are chemically extracted at varying temperatures and pressures, while hemicellulose-based polymers will be used by Gardner's group in the Advanced Engineered Wood Composite Center (AEWC) to make new composite products such as table tops and car fenders. The trick, says van Heiningen, is to extract hemicelluloses in a way that preserves the quality of chips used in the standard Kraft chemical pulp process. After extracting hemicelluloses, the researchers run chips through that process to produce wood pulp. The extracted hemicelluloses may then be fermented into fuel ethanol and/or further converted into other chemicals to form industrial polymers. Van Heiningen's group is also looking into ways to add the hemicelluloses back into Kraft wood pulp to increase paper production.

Van Heiningen calls a future manufacturing plant that would use these technologies an "integrated forest products biorefinery." Just as in a petrochemical refinery, the amount of the different product streams produced by such a biorefinery would depend on the prices for pulp, ethanol, electricity and other products, van Heiningen explains.

"The basic concept is not new," says van Heiningen, "but we are developing new technologies that will make it economical, and keep our pulp and paper industry competitive."

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Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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