Optimum Conditions For The Benchscale Production Of Biodiesel From Waste Frying Oil

 ABSTRACT

Waste frying oils (WFO) sourced from ten different locations using random sampling method were used for biodiesel production in this research. During the esterification process, the time required for mixing the catalyst and methanol mixture was varied between 15 – 30 mins. Hence, 31.5 cm³ of methanol (analytical grade) was added to 150 cm³ of the filtered WFO using 0.75 cm³ of H₂SO₄ (98%, v/v) as catalyst at 60 ^oC to reduce the free fatty acid contents of the oils. During the transesterification process, 20 cm³ of methanol was added to 100 cm³ of the WFO using 0.35 g of NaOH as catalyst at a temperature of 60 ^oC and a reaction time of 40 mins. Biodiesel yield of 17.543 % (lowest yield) and 83.074 % (highest yield) was obtained. The physical and chemical characteristics of the waste frying oil biodiesel were analysed and evaluated. Specific gravity at 20 ^oC (0.862 + 0.077 to 0.876 + 0.084), kinematic viscosity at 25 ^oC (18.275 + 1.095 to 82.124 + 5.729), moisture contents (0.246 + 0.060 to 1.333 + 0.049), iodine value (0.381 + 0.062 to 9.644 + 0.763), saponification value (175.311 + 11.130 to 221.605 + 6.240), acid value (0.137 + 0.016 to 1.641 + 0.182), flash point (131.283 + 8.145 to 207.340 + 15.614), cloud point (7.000 + 0.000 to 26.000 + 0.000),pour point (5.000 + 0.000 to 21.000 + 0.000). The conversion of WFO of the ten different WFO samples into valuable fatty acid methyl ester (biodiesel) was successfully conducted. The result obtained showed that the biodiesel from WFOs meets the required specifications if complete pre-treatment process is carried out.