Optimization of biodiesel yield and diesel engine performance from waste cooking oil by response surface method (RSM)

Abstract

The aim of this study is to investigate optimization of biodiesel production process and the effects of biodiesel–diesel fuel blends on engine performance and exhaust emission parameters by using response surface methodology. Transesterification method was used in biodiesel production. The importance of four process parameters namely molar ratio, catalyst amount, reaction temperature, and reaction time on biodiesel conversion rate is determined. For the optimization process Box–Behnken design (BBD) based on RSM was used. An optimum biodiesel yield was 93.124% was obtained at 6.05:1 methanol to oil molar ratio, 0.77 wt% catalyst amount, 62.75 °C reaction temperature and 72.63 min reaction time. Engine operating parameters such as blend ratio of biodiesel fuel and engine speed have been optimized to obtain optimum performance and exhaust emission values. The experiments were designed using central composite design method based on RSM. The results revealed that when the engine was operated with 1943.51 rpm engine speed and fueled with a 9.17% biodiesel ratio as the optimal conditions, responses were determined as 44.8097 kW, 245.946 Nm 5.17481%, 262.235 ppm, and 810.227 ppm for power, torque, smoke opacity, CO, and NOx, respectively.