| 초록 |
With the increase in prices of feedstock for biodiesel and ethical controversy against edible feedstock, non-edible sustainable feedstock has attracted attention. Microalgae(MA), sewage sludge(SS), and waste coffee grounds(WCG) contained 16.1%, 14.5% and 16.4% of lipids with 15.8%, 40.5% and 2.0% of free fatty acids(FFAs), respectively. Waste cooking oil(WCO) has 2.3% of FFAs. The mixture of chloroform and methanol, with 2:1 ratio, showed the highest lipids extraction efficiency for MA(85.8%) and SS(92.9%) while hexane showed 98.5% for WCG. For MA and WCG, alkali catalyst yielded 74.2% and 95.3% biodiesel conversion, respectively while acid catalyst less than 10%. For SS, biodiesel conversion was 39.0% even under acid catalyst due to high content of unconvertible lipids. For WCO, 85% of biodiesel conversion was achieved under acid catalyst but only 5% under alkali catalyst. |
