(2021) ACS Sustainable Chemistry and Engineering_Biofuel Production as an Example of Virtuous Valorization of Swine Manure

Cho S.-H., Jung S., Park Y.-K., Lin K.-Y.A., Chen W.-H., Tsang Y.F., Kwon E.E.

(American Chemical Society) ACS Sustainable Chemistry and Engineering ISSN: 21680485 Vol.9 Issue.41 Article No. DOI: 10.1021/acssuschemeng.1c04382

The recovery of energy from organic waste opens a chance to promote the renewable energy production, reducing the use of fossil-based fuels. This study is focused on the virtuous valorization of swine manure, which is conventionally used as a fertilizer. An integrated valorization process of swine manure via transesterification and CO₂-assisted pyrolysis was suggested to maximize the recovery of energy-intensive and value-added products, such as biodiesel, biochar, and syngas. Lipid fraction in the swine manure was transformed into biodiesel through thermally induced transesterification. The yield of biodiesel was ≥94 wt % (based on the lipid content) in the existence of silica and swine manure biochar at 400 and 220 °C, respectively. The biochar acted as a porous medium and alkaline catalyst for transesterification. The residual solid after transesterification (i.e., lipid-extracted swine manure) was valorized with pyrolysis. CO₂ was fed as a co-reactant to carry out the process in a more sustainable manner. In the presence of CO₂, the enhancement of CO production was observed because of the homogeneous reactions of CO₂ with gaseous pyrogenic products derived from swine manure, compared to pyrolysis in a N₂ atmosphere. To expedite the reaction rates affecting the homogeneous reaction, a Ni/SiO₂ catalyst was adopted. Syngas formations were significantly enhanced through the synergistic effects of CO₂ and the Ni/SiO₂ catalyst. All experimental observations signified that swine manure could be considered a useful resource that can be valorized into value-added fuels and chemicals. © 2021 American Chemical Society.

This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIT) (no. NRF-2019R1A4A1027795). This work was supported by the State Key Laboratory of Marine Pollution (SKLMP) Seed Collaborative Research Fund (no. SCRF/0026) and the Dean’s Research Fund (no. IRS-12/ROP-16/RMP-7) of The Education University of Hong Kong. S.-H.C. acknowledges financial support from Hyundai Motor Chung Mong-Koo Foundation.