A Comparative Study on Thermochemical Valorization Routes for Spent Coffee Grounds

Jie Yang, Hao Chen, Haibo Niu, Josiah McNutt and Quan He
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Jie Yang: Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada
Hao Chen: Wuhan Second Ship Design and Research Institute, Wuhan 430064, China
Haibo Niu: Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada
Josiah McNutt: Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada
Quan He: Department of Engineering, Faculty of Agriculture, Dalhousie University, Truro, NS B2N 5E3, Canada

Energies, 2021, vol. 14, issue 13, 1-10

Abstract: Extracting oil from spent coffee grounds (SCG) for biodiesel production has recently attracted much research interest. Large amounts of organic solvents are involved for oil extraction and biodiesel synthesis. Hydrothermal liquefaction (HTL) is an emerging thermochemical technology with great potential for biocrude production from a broad range of feedstocks. This study attempted to compare two SCG valorization options: route 1, oil extraction for biodiesel production followed by HTL of defatted SCG; and route 2, direct HTL of raw SCG. The microwave-assisted extraction conditions were optimized to effectively remove oil from SCG using response surface methodology. Under optimal conditions, an SCG oil yield of 8.4 wt.% could be achieved. HTL of defatted SCG generated less biocrude (18.9 wt.%) than that of raw SCG (28.1 wt.%). The biochemical compositions of resultant biocrudes were largely different from each other. The life cycle assessment was conducted on each of the SCG valorization routes and showed that the greenhouse gas emissions from direct HTL of raw SCG were only 35% of the other valorization route, suggesting that direct HTL is a favorable valorization route for SCG within this study’s scope.

Keywords: hydrothermal liquefaction; biocrude; biodiesel; life cycle assessment; spent coffee grounds; extraction (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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