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Renewable diesel blendstocks produced by hydrothermal liquefaction of wet biowaste


Processing wet biowaste to create a useful product, a practice called valorization, is environmentally sustainable and has the potential to augment energy production. Biocrude converted from wet biowaste using hydrothermal liquefaction (HTL) has comparable heating values to petroleum crude. However, its composition is too complex for use as transportation fuels. Here, we show that distillation combined with esterification can effectively upgrade HTL biocrude oil into diesel blendstock. We demonstrate that the HTL biocrude oil converted from food processing waste and animal manure can be distilled into fractions with similar energy content to that of petroleum diesel. We then reduce the acidity of distillates through esterification to meet the diesel standard. Engine tests performed using 10–20% upgraded distillates blended with diesel show 96–100% power output, 101–102% NOx, 89–91% CO, 92–125% unburned hydrocarbon and 109–115% soot emissions, compared with regular diesel. HTL integrated with distillation and esterification has a higher energy recovery ratio than anaerobic digestion, lipid extraction, HTL combined with hydrotreating and producing diesel from petroleum. This approach realizes the potential of wet biowaste to alleviate petroleum consumption and to reduce greenhouse gas emissions.

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Fig. 1: Distillation of SDP- and swine manure-derived biocrude oil.
Fig. 2: Upgrading of SDP distillates.
Fig. 3: Power generations and pollutant emissions under all diesel engine test conditions.

Data availability

The data that support the findings of this study are available from the corresponding author upon request.


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We thank USDA, Illinois Sustainable Technology Center and the Snapshot Energy Gift Fund for providing experimental supplies for the research. We are grateful for financial support from the Graduate College of University of Illinois and the Ministry of Education of Taiwan (to W.-T.C.). We thank E. Eves and K. Subedi in the Microanalysis Laboratory (Urbana, IL) for their help on elemental analyses. We also thank A. Ulanov of the Roy J. Carver Biotechnology Center (Urbana, IL) for help received and discussions on GC–MS analysis. We acknowledge B. Banks from the National Center for Agricultural Utilization Research (Peoria, IL) for collecting surface tension data. We are grateful for assistance provided by B. Kunwar, T. Burton, K. Nithyanandan, P. Zhang and M. Swoboda during this project. We also thank M.-H. Lai for help setting up and troubleshooting the distillation apparatus.

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Authors and Affiliations



W.-T.C. designed and conducted experiments for distillation and esterification, analysed results from distillation, esterification, fuel specification and engine tests and wrote the manuscript. Y.Z. designed and supervised the overall project and contributed to data analysis and writing of the manuscript. T.L. and C.-F.L. designed and performed engine tests and contributed to experiments about engine tests and their data analysis. Z.W. conducted experiments for distillation and fuel specification and assisted in preparing samples for engine tests. B.S. contributed to data analysis and writing of the manuscript. A.L. performed experiments for distillation and fuel specification and contributed to writing of the manuscript. B.K.S. assisted with distillation experimental design and contributed to fuel specification analysis and writing of the manuscript.

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Correspondence to Yuanhui Zhang.

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Supplementary Figures 1–2, Supplementary Tables 1–13, Supplementary References 1–16

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Chen, WT., Zhang, Y., Lee, T.H. et al. Renewable diesel blendstocks produced by hydrothermal liquefaction of wet biowaste. Nat Sustain 1, 702–710 (2018).

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