Complete utilization of spent coffee grounds to produce biodiesel, bio-oil, and biochar

Derek R. Vardon, Bryan R. Moser, Wei Zheng, Katie Witkin, Roque L. Evangelista, Timothy J. Strathmann, Kishore Rajagopalan, Brajendra K. Sharma

Research output: Contribution to journalArticle

Abstract

This study presents the complete utilization of spent coffee grounds to produce biodiesel, bio-oil, and biochar. Lipids extracted from spent grounds were converted to biodiesel. The neat biodiesel and blended (B5 and B20) fuel properties were evaluated against ASTM and EN standards. Although neat biodiesel displayed high viscosity, moisture, sulfur, and poor oxidative stability, B5 and B20 met ASTM blend specifications. Slow pyrolysis of defatted coffee grounds was performed to generate bio-oil and biochar as valuable co-products. The effect of feedstock defatting was assessed through bio-oil analyses including elemental and functional group composition, compound identification, and molecular weight and boiling point distributions. Feedstock defatting reduced pyrolysis bio-oil yields, energy density, and aliphatic functionality, while increasing the number of low-boiling oxygenates. The high bio-oil heteroatom content will likely require upgrading. Additionally, biochar derived from spent and defatted grounds were analyzed for their physicochemical properties. Both biochars displayed similar surface area and elemental constituents. Application of biochar with fertilizer enhanced sorghum-sudangrass yields over 2-fold, indicating the potential of biochar as a soil amendment.

Original languageEnglish (US)
Pages (from-to)1286-1294
Number of pages9
JournalACS Sustainable Chemistry and Engineering
Volume1
Issue number10
DOIs
StatePublished - Oct 7 2013

Keywords

  • Bio-oil
  • Biochar
  • Biodiesel
  • Coffee grounds
  • Coffee oil
  • Pyrolysis

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

Fingerprint Dive into the research topics of 'Complete utilization of spent coffee grounds to produce biodiesel, bio-oil, and biochar'. Together they form a unique fingerprint.

  • Cite this