An Assessment of Gasification-Based Biorefining at Kraft Pulp and Paper Mills in the United States, Part B: Results

Commercialization of black liquor and biomass gasification technologies is anticipated in the 2010–2015 timeframe, and synthesis gas from gasifiers can be converted into liquid fuels using catalytic synthesis technol-ogies that are already commercially established today in the gas-to-liquids or coal-to-liquids industries. This set of two papers describes key results from a major assessment of the prospective energy, environmental, and financial performance of commercial gasification-based biorefineries integrated with kraft pulp and paper mills. Seven detailed biorefinery designs were developed for a reference mill in the southeastern United States, together with the associated mass/energy balances, air emissions estimates, and capital investment requirements. The biorefineries provide chemical recovery services and co-produce process steam for the mill, some electricity, and one of three liq-uid fuels: a Fischer-Tropsch synthetic crude oil (which could be refined to vehicle fuels at an existing petroleum refin-ery), dimethyl ether (a diesel engine fuel or propane substitute), or an ethanol-rich mixed-alcohol product. Compared with installing new Tomlinson power/recovery systems, biorefineries would require more capital investment and greater purchases of woody residues for energy use. However, because biorefineries would be more efficient, have lower air emissions, and produce a more diverse product slate, for nearly all cases examined, the internal rate of return (IRR) on the incremental capital investment lies between 14% and 18%, assuming a $50/bbl world oil price. The IRRs would more than double if plausible federal and state financial incentives were captured. Industry-wide adoption of such biorefining in the United States would provide significant energy and environmental benefits to the country.