The technology of biodiesel preparation from abandoned edible oil developed by the National Engineering Research Center of Fine Petrochemical Intermediates received a national invention patent on August 18, 2010. (Patent No. ZL200610043018.5) 

As described in the patent, researchers remove impurities from the abandoned edible oil and dehydrate it, and then add ethanol as an extractant to deacidificate the oil. With the alkaline compound catalyst and methanol solution added, the oil is esterified under 30℃ to 60℃ for 0.5 to 1.5 hours and the biodiesel is obtained after separation and distillation. The maximum yield rate of biodiesel gained in this way can reach 92.4%.

The raw materials of the technology can be oil scrap, waste cooking oil or the mixture of the two. Compared with other technologies in China, it has the advantages of high efficiency, short reaction time and low reaction temperature.

According to statistics, China consumed 1,200 million tons of plant oil each year. If the abandoned edible oil can be supplied in a reasonable price, the scale of biodiesel production industry can be expanded in the future, experts predict.