Continuous Biodiesel Production from Animal Fats and Waste Cooking Oil Using Supercritical Methanol and Nanostructured Heterogeneous Catalysts, 01-R8145
Printer Friendly VersionPrincipal Investigators
Chee Kai Tan
Maoqi Feng
Inclusive Dates: 04/01/10 – Current
Background - In the conventional transesterification of fats/vegetable oils for biodiesel production, free fatty acids and water always present a problem, resulting in a low conversion. The objective of this study was to investigate the yield of methyl esters treated by acid-free and alkaline-free supercritical methanol with heterogeneous catalysts.
Approach - Glyceride tributyrate was used as a model compound for waste cooking oil and animal fats to study transesterification with methanol at supercritical condition (239.4 °C and 8.0 MPa) with and without solid catalysts. The transesterification reaction was studied with an automatic controlled tubular reactor in a continuous mode, as shown in Figure 1. The reactor was constructed from a 3/8-in. OD by 4-ft. long stainless tube with wall thickness of 0.049 in. (reactor volume = 47.4 mL). This system was used for the biodiesel synthesis from glyceride tributyrate, waste cooking oil, and animal fats.
Figure 1. Continuous Process Flow Diagram for Biodiesel Production
with Supercritical Methanol
Accomplishments - For glyceride tributyrate, the conversion was 100 percent under supercritical methanol (SCM) condition. For waste cooking oil (WCO), the fatty acid methyl ester (FAME) yield was > 90 percent at the following reaction conditions: reaction temperatures = 300 °C and 250 °C; reaction pressures = 2,000 psi, 2,500 psi, and 3,000 psi; residence time = 18 minutes; molar ratio of methanol to oil = 40:1; and flow rate = 2.5 mL/min. At 250 °C and 2,500 psi, the WCO flow rates were increased to 4.5mL/min and 6.5mL/min, and FAME yields were > 90 percent for the flow rates. The findings demonstrated that using a supercritical methanol and solid catalytic approach, vegetable oil and its wastes could be readily used for biodiesel fuel production in a simple, cleaner, continuous, economically effective and automatic process.
