Title: Sugarcane bagasse and vinasse conversion to electricity and biofuels: an exergoeconomic and environmental assessment

Authors: Rafael Nogueira Nakashima; Daniel Flórez-Orrego; Hector Ivan Velásquez; Silvio De Oliveira Junior

Addresses: Department of Mechanical Engineering, University of São Paulo, Av. Prof. Mello Moraes, 2231 – 05508-030 São Paulo – SP, Brazil ' Department of Mechanical Engineering, University of São Paulo, Av. Prof. Mello Moraes, 2231 – 05508-030 São Paulo – SP, Brazil; Faculty of Minas, National University of Colombia, Av. 80 # 65, 223 – Medellín, Colombia ' Faculty of Minas, National University of Colombia, Av. 80 # 65, 223 – Medellín, Colombia ' Department of Mechanical Engineering, University of São Paulo, Av. Prof. Mello Moraes, 2231 – 05508-030 São Paulo – SP, Brazil

Abstract: Biomass conversion into either electricity or biofuels requires various energy intensive processes that may drastically affect its technical and environmental competitiveness against their non-renewable counterparts. Therefore, in this paper, a comparative assessment between the total (c_T) and non-renewable (c_NR) unit exergy costs and specific CO₂ emissions (c_CO2) of the electricity, methane and hydrogen produced from sugarcane vinasse and bagasse is presented and compared with the conventional (fossil fuel-based) supply chains. As a result, the non-renewable unit exergy costs and specific CO₂ emissions for the transportation service in all cases analysed are 3.1 to 4.7 times lower compared with conventional fossil fuels (e.g., diesel, gasoline, natural gas and hydrogen). Among the waste upgrade alternatives, methane production is able to maximise the exergy flow rate of products in the transformation stage (52.4-58.6 MW), while hydrogen and electricity production can substantially increase the transportation service in the end-use stage (51.7-52.1%) and the operational revenues (2,706-2,889 EUR/h).

Keywords: sugarcane bagasse; vinasse; ethanol; biofuels; electricity; exergoeconomy; waste upgrade; environmental assessment; greenhouse gas emissions; biorefinery; anaerobic digestion; biomass gasification; hydrogen; biomethane; synthetic natural gas.

DOI: 10.1504/IJEX.2020.109623

International Journal of Exergy, 2020 Vol.33 No.1, pp.44 - 75

Received: 04 Jan 2020
Accepted: 16 Mar 2020
Published online: 17 Sep 2020 *

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