Charles E. Courchene

Production of ethanol from carbohydrates from loblolly pine : A technical and economic assessment

Ethanol from lignocellulosic biomass has the potential to contribute substantially to bioethanol for transportation. We have evaluated the technical and economic feasibility of producing ethanol from the carbohydrates in loblolly pine. In the process evaluated, prehydrolysis with dilute sulfuric acid was employed to hydrolyze hemicellulose and make the cellulose more accessible to hydrolysis by enzymes. Residual biomass from hydrolysis and extraction of carbohydrates was burned in a CHP plant to generate power and process steam. Our analysis indicates that ethanol can be produced at a cost of dollars 1.53/gal, based on a delivered wood cost of

PULPING AND BLEACHING OF PARTIALLY CAD-DEFICIENT WOOD

63.80/dry metric ton and 75% conversion of the carbohydrates in wood to sugars for ethanol production. Improving the conversion of wood carbohydrates to sugars to 95% would reduce the production cost to dollars 1.29/gal. These values are for a plant producing 74 million gal/yr and 93 million gal/yr, respectively. At current feedstock prices, ethanol produced from loblolly pine would be competitive with ethanol produced from corn or other lignocellulosic biomass. Based on our analysis, discounted cash flow rates of return would be 18% and 25%, respectively for plants of this capacity.

NATIONAL COUNCIL OF THE PAPER INDUSTRY FOR AIR AND STREAM IMPROVEMENT

ABSTRACT Mutant loblolly pine trees that are partially deficient in cinnamyl alcohol dehydrogenase (CAD) have been studied as a possible new source of pulpwood. Young (4- and 6-year-old) partially CAD-deficient pine trees are ˜20% more easily delignified (pulping and bleaching) and provide similar pulp yields to that of similarly aged normal pines grown on the same plots. Bleached pulp from a 6-year-old partially CAD-deficient pine tree displayed better strength properties than the same age normal pine tree; this probably reflects the milder pulping conditions needed in the case of the partially CAD-deficient tree. Studies also were conducted on a limited number of 14-year-old trees from a different genetic background. In contrast to the results with young trees, no real differences in ease of delignification, pulp yields, bleached pulp strength properties, and wood specific gravities were observed with the 14-year-old trees. There would likely be no penalty if partially CAD-deficient trees were used for lumber products. The rapid growth of partially CAD-deficient trees could make them a valuable pulpwood.