Energy efficiency in a dual engine using biogas and waste frying oil biodiesel

The generation of electric energy using alternative energy sources has been constantly studied by researchers owing to concerns regarding energy supply alternatives and the desire to reduce environmental impacts in its generation. This study evaluated the performance of an electricity generator operating in dual mode using biogas and biodiesel blends, which were obtained from a swine-waste biodigester and residual frying oil, respectively. The experiment was performed using blends B8, B20, B50, B80, and B100. The electrical power generated was higher in the dual mode corresponding to a load of 5.0 kW, showing differences of 18.7% for B8 and 21.7% for B100. In normal and dual modes, the B8 blend exhibited the lowest specific consumption of liquid fuel with values of 389.2 and 270.2 g kWh-1, respectively. The efficiency was higher in the normal mode, showing results of 22.0 and 24,7% using B8 and B100, respectively, compared to 17 and 20% in the dual mode corresponding to a load of 5.0 kW. These results indicate that biodiesel from residual frying oil can be used in normal mode and in combination with biogas in dual mode.