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United States Department of Agriculture

Agricultural Research Service

Research Project: DISTRIBUTED-SCALE PYROLYSIS OF AGRICULTURAL BIOMASS FOR PRODUCTION OF REFINABLE CRUDE BIO-OIL AND VALUABLE COPRODUCTS

Location: Sustainable Biofuels and Co-Products

Title: Life cycle environmental and economic tradeoffs of using fast pyrolysis products for power generation

Authors
item Pourhashem, Ghasideh -
item Spatari, Sabrina -
item Boateng, Akwasi
item McAloon, Andrew
item Mullen, Charles

Submitted to: Energy and Fuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2013
Publication Date: March 19, 2013
Citation: Pourhashem, G., Spatari, S., Boateng, A.A., Mcaloon, A.J., Mullen, C.A. 2013. Life cycle environmental and economic tradeoffs of using fast pyrolysis products for power generation. Energy and Fuels. 27:2578-2587.

Interpretive Summary: Fast pyrolysis is a thermal process involving the rapid heating of biomass in the absence of oxygen to produce a liquid product (pyrolysis oil, bio-oil) from agricultural residues. The liquid can be a supplemental and renewable fuel resource for production of electricity. To be classified as renewable fuel greenhouse gas emissions associated with the production and use of pyrolysis oil must be markedly reduced compared with fossil fuel use in its life cycle. In this study we examined the life cycle ramifications of producing pyrolysis oils from corn stover, and cofiring such oils and the biochar accompanying the bio-oil with coal in existing oil and coal power plants for energy generation. We also explored the use of the biochar in amending soils within the agricultural sector instead of burning it. In the latter, two greenhouse gas (GHG) emission scenarios for bio-char use were evaluated, whether to use the pyrolysis co-product as fuel co-fired in coal power plants or for soil amendment. We found out that GHG emissions for the former was about twice that of the latter scenario. We also found that the electricity produced from burning pyrolysis oil and char with variable operating costs can successfully compete with the fuel oil and coal in the electricity market. This information is useful to farmers and the power industry stakeholders who are interested in venturing into renewable fuel markets.

Technical Abstract: Bio-oils produced from small-scale pyrolysis technology may have economic and environmental benefits for both densifying agricultural biomass and supplying local bio-energy markets (e.g., Renewable Portfolio Standards). This study presents a life cycle assessment (LCA) of a farm-scale bio-oil production via fast pyrolysis and subsequent utilization for power generation in the state of Pennsylvania. The study examines life cycle ramifications of producing pyrolysis oils from corn stover, and cofiring such oils and the bio-char with coal in existing oil and coal power plants for energy generation, or land amending the bio-char within the agricultural sector. Two greenhouse gas (GHG) emission scenarios for bio-char use were evaluated, whether to use the pyrolysis co-product as fuel co-fired in coal power plants or for soil amendment. The results show GHG emissions of -32 and -17gCO2e/MJ of bio-oil for former and the latter scenarios respectively. Cumulative energy demand analysis suggest that cofiring bio-char with coal consumes less energy than land application of bio-char. We discuss the potential for bio-oil and bio-char penetrating electricity markets in the near-term (c. 2015). Analysis shows that the electricity produced from burning pyrolysis oil and char with variable operating costs of $92.5-$92.7/MWh and $17.6-$18/MWh, respectively, can successfully compete with the fuel oil and coal in electricity market. Small scale pyrolysis oil production can offer a viable near-term fossil fuel replacement.

Last Modified: 10/25/2014
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