Mckechnie J.,University of Toronto |
Zhang Y.,National Renewable Energy Laboratory |
Ogino A.,Japan National Agriculture and Food Research Organization |
Saville B.,University of Toronto |
And 4 more authors.
Biofuels, Bioproducts and Biorefining | Year: 2011
The performance of lignocellulosic ethanol in reducing greenhouse gas (GHG) emissions and fossil energy use when substituting for gasoline depends on production technologies and system decisions, many of which have not been considered in life cycle studies. We investigate ethanol production from short rotation forestry feedstock via an uncatalyzed steam explosion pre-treatment and enzymatic hydrolysis process developed by Mascoma Canada, Inc., and examine a set of production system decisions (co-location, co-production, and process energy options) in terms of their influence on life cycle emissions and energy consumption. All production options are found to reduce emissions and petroleum use relative to gasoline on a well-to-wheel (WTW) basis; GHG reductions vary by production scenario. Land-use-change effects are not included due to a lack of applicable data on short rotation forestry feedstock. Ethanol production with wood pellet co-product, displacing coal in electricity generation, performs best amongst co-products in terms of GHG mitigation (-109% relative to gasoline, WTW basis). Maximizing pellet output, although requiring import of predominately fossil-based process energy, improves overall GHG-mitigation performance (-130% relative to gasoline, WTW). Similarly, lower ethanol yields result in greater GHG reductions because of increased co-product output. Co-locating ethanol production with facilities exporting excess steam and biomass-based electricity (e.g. pulp mills) achieves the greatest GHG mitigation (-174% relative to gasoline, WTW) by maximizing pellet output and utilizing low-GHG process energy. By exploiting co-location opportunities and strategically selecting co-products, lignocellulosic ethanol can provide large emission reductions, particularly if based upon sustainably grown, high yield, low input feedstocks. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd.
Di Risio S.,Mascoma Canada Inc. |
Hu C.S.,Mascoma Canada Inc. |
Saville B.A.,University of Toronto |
Liao D.,Mascoma Canada Inc. |
Lortie J.,Mascoma Canada Inc.
Biofuels, Bioproducts and Biorefining | Year: 2011
Enzymatic hydrolysis at high solids loadings is key to scale-up of lignocellulosic biochemical conversion processes, because of potentially higher sugar and ethanol titers and lower hydraulic loads. However, high solids loadings can pose rheological challenges, reduce mass and heat transfer efficiency, and increase the concentration of enzyme inhibitors in the system, resulting in low conversion of glucan and xylan into fermentable sugars. In this study, ten batch enzymatic hydrolyses were conducted in a 200-liter reactor, while monitoring sugar and inhibitor profiles. The effects of enzyme cocktail, biomass loading, pre-treatment severity, and hydrolysis temperature were assessed using techno-economic indicators to evaluate the efficacy of the enzymatic hydrolysis. For similar experimental conditions, different enzyme cocktails produced distinct hydrolysis outcomes allowing cocktail optimization. In spite of a rapid initial reaction rate, fermentable sugars concentrations reached a plateau after about 48 h, indicating severe inhibition. Increased biomass loadings did not proportionally increase sugar production. Both observations indicated the presence of severe inhibition, likely endogenous. Pre-treatment at a lower severity (200°C for 8 min) led to the most efficient hydrolysis, while higher severities destroyed hemicellulose and led to lower overall sugar production. Lower saccharification temperatures (30-32°C) caused a 20% decrease in sugar conversion when compared to 50°C operation. Strategies to mitigate inhibition will be required if high-solids enzyme hydrolysis is to be successfully scaled up to commercially relevant levels. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd.
Liang C.,Mascoma Canada Inc. |
Yan N.,University of Toronto |
Vidal D.,Pulp and Paper Research Institute of Canada |
Zou X.,Pulp and Paper Research Institute of Canada
Nordic Pulp and Paper Research Journal | Year: 2012
The effects of coating formulation on thermal characteristics of coating layers (namely thermal diffusivity, specific heat capacity and heat conductivity) were systematically studied and their impact on xerography print quality was evaluated. Model coatings were prepared using ground calcium carbonate or kaolin pigment mixed with styrene butadiene latex binder in various proportions (from 6 to 25 pph). As expected, porosity was shown to be a key parameter for thermal conductivity of the coating layers, and is mainly determined by the latex concentration. Particle size distribution (PSD) and pigment morphology also affected the thermal characteristics of the coating layers. It was found that the bulk thermal conductivity of the coating layers can be accurately predicted by a geometric mean model based on the pigment, latex and air contents. Print quality on model coated papers was evaluated in terms of print gloss, toner adhesion and pairwise visual ranking. It was demonstrated that print gloss is improved by decreasing the bulk thermal conductivity of the coatings. The coating formulated with the pigments with the steepest PSD and 10 pph of latex had a relatively low thermal conductivity and the best print quality.
Mascoma Canada Inc. | Date: 2013-02-12
An apparatus for pre-treating a cellulosic feedstock are disclosed. Embodiments of the apparatus comprise a shell defining a treatment chamber having a lower inner surface. The treatment chamber has an inlet and an outlet spaced longitudinally apart from the inlet to define an axial length. A conveyance member is housed within the shell and is configured to sweep the lower inner surface. A plurality of injection ports are provided in at least one of the shell and the conveyance member.
Mascoma Canada Inc. | Date: 2012-04-12
A method and apparatus for preparing a cellulosic feedstock are disclosed. Embodiments of the method comprise passing the cellulosic feedstock through an optional impregnation chamber to an outlet of the impregnation chamber, passing the cellulosic feedstock from the outlet of the impregnation chamber to a holding tank having an inlet and an outlet, and conveying the cellulosic feedstock downwardly and laterally as it travels through the holding tank. Embodiments of the apparatus comprise at least one sidewall defining a passage. The passage has an upper portion and a lower portion, and the lower portion has a greater cross-sectional area than the upper portion. At least one inlet is provided adjacent the upper portion, and at least one outlet is provided adjacent the lower portion, at an elevation below the inlet.