1. Impacts of pre-treatment technologies and co-products on greenhouse gas emissions and energy use of lignocellulosic ethanol production.
- Author
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Pourbafrani, Mohammad, McKechnie, Jon, Shen, Timothy, Saville, Bradley A., and MacLean, Heather L.
- Subjects
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GREENHOUSE gases , *GASES from plants , *ENERGY consumption , *LIGNOCELLULOSE , *ETHANOL , *ELECTRICITY - Abstract
Life cycle environmental performance of lignocellulosic ethanol produced through different production pathways and having different co-products has rarely been reported in the literature, with most studies focusing on a single pre-treatment and single co-product (electricity). The aim of this paper is to understand the life cycle energy use and greenhouse gas (GHG) emissions implications of alternative pre-treatment technologies (dilute acid hydrolysis, ammonia fiber expansion and autohydrolysis) and co-products (electricity, pellet, protein and xylitol) through developing a consistent life cycle framework for ethanol production from corn stover. Results show that the choices of pre-treatment technology and co-product(s) can impact ethanol yield, life cycle energy use and GHG emissions. Dilute acid pathways generally exhibit higher ethanol yields (20-25%) and lower net total energy use (15-25%) than the autohydrolysis and ammonia fiber expansion pathways. Similar GHG emissions are found for the pre-treatment technologies when producing the same co-product. Xylitol co-production diverts xylose from ethanol production and results in the lowest ethanol yield (200 L per dry t of stover). Compared to producing only electricity as a co-product, the co-production of pellets and xylitol decreases life cycle GHG emissions associated with the ethanol, while protein production increases emissions. The life cycle GHG emissions of blended ethanol fuel (85% denatured ethanol by volume) range from -38.5-37.2 g CO2 eq/MJ of fuel produced, reducing emissions by 61-141% relative to gasoline. All ethanol pathways result in major reductions of fossil energy use relative to gasoline, at least by 47%. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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