Volume 7, Issue 3 (March 2010)
Bioproducts Process Pathways for Kraft Paper Mills
Energy use in the United States is heavily reliant on imported fossil fuels. Finding a way to produce renewable fuels that can replace these fossil fuels will address national security threats, sustainability concerns inherent in the use of fossil fuels, and keep manufacturing in rural areas. An important alternative fuel for the near term is ethanol, and producing it from a cellulosic feedstock allows the fuel source to remain independent of the food chain. A solid body of research has made it clear that a brand-new stand-alone biorefinery using biomass is not cost-effective under current business conditions. In light of this, we have looked at the economic viability of a co-located facility, specifically Kraft pulp mills in the State of Maine. We have looked at the opportunity to utilize the “near-neutral” extraction process developed at the University of Maine, whereby Kraft pulp mills can begin to meet the demand for alternative fuels. By incorporating the near-neutral extraction process within the pulping process, ethanol and acetic acid can be produced as “first stage” products while still producing pulp, thereby expanding the product line of the pulp mill while addressing the need for finding alternative to petroleum feedstocks. This paper discusses both the near-neutral extraction process and a thermochemical process that can be utilized in a Kraft pulp mill based biorefinery to produce ethanol and acetic acid as initial products. We analyze potential investment and production costs for a biorefinery based on studies that have looked specifically at this type of evolution, as well as cellulosic biorefineries that are based on other types of processes. We also identify potential “second stage” fuels that could be produced, as well as the modes of transportation that can be used to get the fuels and products to the existing infrastructure.