Comparison of Raw and Torrefied Dichrostachys cinerea as a Fuel for Cogeneration Systems: A Life Cycle Assessment

• Published in: Waste and biomass valorization Vol. 13; no. 8; pp. 3653 - 3669
• Main Authors: Alba-Reyes, Yasmani, Pérez-Gil, Maylier, Barrera, Ernesto L., Casas-Ledón, Yannay, Arteaga-Pérez, Luis E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2022; Springer Nature B.V
• Subjects: Acidification; Alternative fuels; Alternatives; Ashes; Cogeneration; Dichrostachys cinerea; Drying; Electricity; Electricity generation; Emissions; Engineering; Environment; Environmental assessment; Environmental Engineering/Biotechnology; Environmental impact; Environmental performance; Fertilizers; Impact damage; Industrial Pollution Prevention; Invasive plants; Life cycle analysis; Life cycle assessment; Life cycles; Mineral fertilizers; Original Paper; Particulate emissions; Particulate matter; Pyrolysis; Renewable and Green Energy; Respiratory system; Steam electric power generation; Steam turbines; Subsystems; Sugar industry; Sugarcane; Waste Management/Waste Technology; Water consumption; Torrefaction; Combustion; Cogeneration; Life Cycle Assessment
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-022-01746-5

Purpose
This study aims to assess environmentally three different alternatives related to the valorization of
Dichrostachys cinerea
tree (an invasive plant) as a feedstock for cogeneration facilities installed in the sugarcane industry in Cuba.
Methods
The Life Cycle Assessment (LCA) methodology was applied to three cogeneration alternatives: (A-1) Electricity generation using raw
Dichrostachys cinerea
(marabou) as fuel in a back-pressure steam turbine cycle, (A-2) Electricity generation using torrefied marabou as fuel in a back-pressure steam turbine cycle, and (A-3) Electricity generation using torrefied marabou as fuel in an extraction-condensing turbines cycle. The SimaPro software was used for the inventory modeling and the ReCiPe method (midpoint and endpoint approach) was applied to estimate the environmental impacts associated with each case.
Results and Discussion
The LCA results showed that the electricity generation from torrefied marabou using extraction-condensing turbines (A-3) reduces the environmental impacts as compared with A-1 and A-2. This performance is explained by a lower marabou relative consumption (1.85 kg marabou/kWh generated), which leads to lower emissions associated with harvesting, transportation, and pre-processing stages. Fine Particulate Matter Formation, Terrestrial Acidification, and Water Consumption accounted the worst performance for all the scenarios. Marine Ecotoxicity was the impact category with better environmental performance due to the substitution of synthetic mineral fertilizers by the ashes produced during combustion. The Human health damage category reached the higher impacts on the torrefaction subsystem in the A-3 scenario, representing over 94% of the total environmental burden of the process, causing injuries in respiratory systems. The highest beneficial impact of the cogeneration stage was associated with the consideration of residual steam as an avoided product.
Conclusions
The use of torrefied marabou in extraction-condensing steam turbines can be considered as an environmental-friendly technology in the Cuban context.
Graphical Abstract