Synthesis and Optimization of Biodiesel from Croton macrostachyus Hochst. ex Delile seed oil using Calcium oxide-chicken eggshell waste as a heterogeneous catalyst

Abstract

Biodiesel is an alternative energy source and has the promising potential that grows rapidly, due to its great contribution to the environment, renewable energy resource spectrum, non-toxicity, biodegradability, and its role as a strategic source of renewable energy to substitute petro diesel while contributing a minimal amount of net greenhouse gases. Since petroleum resources are believed to last only for a few decades, alternative sources of biofuel production should be exploited. In the present study, the synthesis of biodiesel from Croton macrostachyus Hochst.ex Delile (C.M) seed oil was investigated in the laboratory setting which can help to increase the use of biodiesel. After the seed samples are collected and purified, it’s physicochemical properties are determined. Synthesis of biodiesel process through transesterification method includes C.M seed oil extraction and CaO-chicken eggshell waste as a heterogeneous catalyst preparation. The effects of catalyst load from 2% to 6%(w/w) of the weight of oil, ethanol to oil ratio from 9:1 to 12:1(v/v), reaction temperature from 60 to 80℃, and reaction time 0.45 to 2hr. variations on yield have been investigated. Central composite design(CCD) using design-expert 11.1.2 was implemented to characterize, the effects of different process parameters for the synthesis of biodiesel and to find the optimum conditions to maximize the yield. The conversion to biodiesel via calcium oxide-heterogeneous catalyzed transesterification route has achieved 91% yield under the following optimum conditions: reaction temperature of 70℃ ethanol-to-oil ratio of 10.5:1, 1.375hr. of reaction time, and catalyst load of 4%w/w .The composition and functional groups of synthesized biodiesel under optimum reaction conditions were confirmed by the FTIR spectrum. Physicochemical properties (density(878kg/m3 ), moisture content (0.047%), kinematic viscosity(3.54mm2 /s), Acid value(0.87mgKOH/g), ash content (0.023%), saponification number(120mgKOH/g), Iodine value (102.1mgI2/g), higher heating value(40.2MJ/kg), PH (7.83) and flashpoint (198℃), of synthesized C.M biodiesel are determined and the results are compared with the biodiesel standard specifications. The result showed that C.M can be a very viable feedstock for biodiesel industry which could be exploited as an alternative source of fuel and majority of the fuel properties are in agreement with the standards.