Authors: Brassard, Patrick , Godbout, Stéphane , Raghavan, Vijaya , Pelletier, Frédéric , Palacios, Joahnn H.
Identifier: CSBE18147
Download file: https://library.csbe-scgab.ca/docs/meetings/2018/CSBE18147.pdf
Published in: CSBE-SCGAB Technical Conferences » AGM Guelph 2018

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Description: A life cycle approach was used to assess greenhouse gas (GHG) emissions and energy balances of switchgrass pyrolysis in an auger reactor for biochar production, with bio-oil and syngas as co-products. The system boundaries included the cultivation of switchgrass, handling, transport, conditioning, pyrolysis, the amendment of biochar in soil to sequester carbon (C) and to reduce N2O emissions, and the valorisation of bio-oil and syngas as energy sources. Two pyrolysis scenarios were evaluated. Scenario A involves a lower pyrolysis temperature (459°C) and a shorter solid residence (78 s) in the reactor as compared to scenario B (temperature and residence time of 591°C and 104 s, respectively). Biochars were amended in two agricultural soils (loamy sand and silt loam) at a rate of 2 % (w/w) with N fertilizer and incubated for 45 days in order to evaluate their impact on soil GHG emissions. A negative GHG emissions balance of -2105 and -2524 kg CO2e t-1 biochar was obtained for scenarios A and B, respectively. Biochar C sequestration contributed the most to the reduction of GHG emissions in scenario B due to the high C content and stability in biochar. However, scenario B resulted in a higher energy consumption (10,960 MJ t-1 biochar) than scenario A (2401 MJ t-1 biochar) due to a higher energy consumption of the pyrolysis unit. These results confirm that pyrolysis of switchgrass for biochar production can be a negative emission technology, but pyrolysis operating parameters should be selected carefully to minimize the energy consumption.

Keywords: Greenhouse gas, Energy, Pyrolysis, Biochar, Switchgrass
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Date: 2018-07-22
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Conference name: CSBE/SCGAB 2018 Annual Conference, School of Engineering, University of Guelph, Guelph, Ontario, July 22-25 2018.
Session name: Clean and Green Energy II

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Type: Text.Article
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Publication type: Technical conference
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Coverage: Canada
Language 1: en
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Rights: Canadian Society for Bioengineering
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