Production of biodiesel from food processing waste using response surface methodology

The optimum conditions for biodiesel production by the transesterification of waste oil form the pork grilling process in the food factory in Udon Thani, Thailand, using NaOH and KOH as catalysts, has been investigated. A Box–Behnken Design (BBD) followed by a Response Surface Methodology (RSM) with 30 runs was used to assess the significance of three factors: the methanol to oil molar ratio, the amount of NaOH and KOH used, and the reaction time required to achieve the optimum percent fatty acid methyl ester (%FAME). The measured %FAME following transesterification using NaOH as a catalyst was an optimum 95.6% with a methanol to oil molar ratio of 12.2:1, a NaOH percentage mass fraction of 0.49% and a reaction time of 63 min. Using KOH as a catalyst, the %FAME was an optimum 93.0% with a methanol to oil molar ratio of 12:1, a KOH percentage mass fraction of 0.61% and a reaction time of 72 min. The coefficient of determination (R²) for regression equations were 98.55% and 93.99%, respectively. The probability value (P<0.05) demonstrated a very good significance for the regression model. The physicochemical properties of the biodiesel obtained from the waste oil met the ASTM 6751 biodiesel standard, illustrating that waste oil from the pork grilling process can be used as a raw material for biodiesel production by transesterification.     

The utilization of waste egg and cockle shell as catalysts for biodiesel production from food processing waste oil using stirring and ultrasonic agitation

The use of calcined egg and cockle shell as heterogeneous solid catalysts for a transesterification reaction to produce biodiesel from food processing waste has been investigated in this work. The CaO catalysts were obtained from the calcination of egg and cockle shell and were characterized by surface analysis, X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The experiments employed stirring and ultrasonic agitation, which proved to be a time-efficient approach for biodiesel production from food processing waste oil. A response surface methodology (RSM) was used to evaluate the effects of the process variables methanol to oil molar ratio, catalyst concentration, and reaction time on biodiesel production. The optimal % fatty acid methyl ester values obtained when using egg and cockle shells as catalysts were found to be 94.7% and 94.4% when the methanol to oil molar ratios were 9.3:1 and 8.5:1, egg and cockle shell catalyst mass fraction percentages were 3.8% and 3.5%, and reaction times were 47 and 44 min, respectively. The study has shown that ultrasonic agitation might be employed in a practical pilot reactor for biodiesel production.