Open AccessBiorefining of Waste Coffee Grounds: Turning an Environmental Problem into an Opportunity
Author(s) -
Samir El Hajjaji,
Chaima Bouladab,
Sara Chergaoui,
Soukaina Fadli
Publication year - 2020
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.179
H-Index - 26
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/505/1/012026
Subject(s) - biorefining , coffee grounds , yield (engineering) , pulp and paper industry , biodiesel , biofuel , waste management , extraction (chemistry) , briquette , environmental science , work (physics) , vegetable oil , process engineering , chemistry , engineering , organic chemistry , food science , materials science , catalysis , biorefinery , coal , mechanical engineering , metallurgy
The work presented herein proposes to turn the growing environmental threat posed by coffee waste disposal into an opportunity by proposing a number of valorization routes of waste coffee grounds (WCG) through biorefining. In this process, various steps were studied: drying of WCG on small and medium scales, coffee oil extraction from small to large scale, conversion of coffee oil into biodiesel, and suggestions of designs for the recycling of de-oiled WCG into briquettes. Drying was found to be best performed using an elevated hot air tunnel rather an electric pan or a motorized stirrer. Solvent extraction of coffee oil from dried WCG on a 2000 g scale afforded a 9.2 wt% yield and a solvent recovery yield of 94 vol%. This oil was successfully converted into fatty acid methyl esters biodiesel with a 58% yield. Several original and cost-effective designs were tested, some of which being readily reproducible in most laboratory settings.