Waste frying oil with high levels of free fatty acids as one of the prominent sources of biodiesel production

The decrease of fossil fuel resources and the awareness of the impact of greenhouse gases emissions on the environment have created a need to find alternative energy sources to replace traditional ones. thus,recent years have seen the development of several sectors of renewable energy production with the government incentives. the biodiesel production is an alternative of non-toxic,clean,renewable and biodegradable fuels production. the aim of this work was to develop a procedure for the biodiesel production from waste frying oil having an acid value of 32.82 mg koh/g. the optimum conditions of the biodiesel production from waste frying oil in two-step catalyzed process were investigated. in the first step,the sulfuric acid was used as a catalyst for the esterification reaction to reduce the free fatty acids content in the oil under 2%,which was with different dosages. the next base catalyzed transesterification process converted the pretreated frying oil into biodiesel and glycerol in the optimum and non-optimum ffa conditions. in the optimum ffa condition the highest biodiesel yield was 98% with 0.214% of free fatty acid. the results depicted that the esterification reaction is an indispensable step as it leads to the production of an intermediary product with a low content of free fatty acid that can be directly used for the biodiesel production through the transesterification reaction.