| 초록 |
Biodiesel is a renewable and carbon-neutral fuel, and made from the transesterificaiton of mostly vegetable oil with methanol. For transesterification, chemcial catalysts such as sodium hydroxide and sulfuric acid have been conventionally used. However, these chemical catalysts should be supplied to each batch of transesterification, which causes wastewater discharge. In this study, solid catalyst was made from coal fly ash and applied to the biodiesel production. Na+ was found to be better alkali ion to modify coal fly ash than K+ and Ca+2. The optimal mass ratio of fly ash to NaOH was 1/3 to make solid catalyst. The optimal dosage of solid catalyst was 0.3 g/g-soybean oil, and 4 hr was enough for biodiesel production. Reaction time longer than 8 hr rather decreased biodiesel conversion. Temperature was very important factor on biodiesel conversion and 50 °C was found to be optimal one. Under these optimal condition, more than 97 % of biodiesel conversion was achieved. |
