Blended aviation biofuel from esterified Jatropha curcas and waste vegetable oils Saeid Baroutian , Mohamed K. Aroua , Abdul Aziz Abdul Raman , Azzahra Shafie , Raja Adeliza Ismail , Hartini Hamdan Today world’s population growth has caused in a surge of energy demand, especially in transportation sector. Air transpor-tation throughout the world requires high consumption of petroleum-based fuels. According to the U.S. Department of Energy, global consumption of jet fuel is about 190 million gallons per day [1]. This huge volume of consumption illustrates the necessity of displacement even a small percentage with a renewable alternative fuel. The International Air Transport Association (IATA) has set an ambitious goal of reduction in CO2 emissions of 50% by 2050, relative to 2005 levels [2]. One option to achieve this goal, besides the improvement in aircraft technology is switching to biofuel. Among the different commercially available jet fuels, kerosene-type Jet A-1 is predominant fuel in the world. Jet fuel is a combination of a large number of different hydrocarbons. Kerosene-type Jet A-1 aviation fuel has a wide range of fractions between about 8 and 16 carbon numbers. Tables 1 and 2 list the different hydrocarbons exist in Jet A-1 fuel and the properties of Jet A-1, respectively [3]. Conventional petroleum-based jet fuels, including Jet A-1, are not renewable and generate a considerable amount of particulate and gaseous pollutants. Thus, it is important to find an alternative aviation fuel that is renewable and environmentally benign. The use of alternative fuels for aviation industries has been studied since the early days of turbine engines. Cryogenic fuels such as liquid hydrogen and other more exotic fuels such as boron compounds were studied in the 1950s and 1960s [4]. The use of alternative fuels to compete with petroleum based fuel was proposed after the 1973 U.S. energy crisis when fuel prices increased dramatically. During that time some researches were conducted on biomass conversion to fuel [5,6]. However, only petroleum-based jet fuels have been found to be economically practical for extensive and regular use. Recently vegetable oil is receiving increasing attention as an environmental friendly and promising source of energy to replace the petroleum based fuel. Vegetable oil is considered to be a pivotal solution to combat global warming and to stabilize the climate, through the reduction of carbon dioxide emissions. Newly, it has been proven that modern jet engines can run satisfactorily on fuels derived from vegetable oils, rather than petroleum based fuels. A variety of vegetable oils can be used to produce biofuel. These include virgin vegetable oils and waste vegetable oils. Even with several advantages of biofuel over petroleum based fuel, the local cost of is higher than that of fossil based when virgin vegetable oils are used as feedstock. Also, the current demand for edible oils such as soybean, corn, and palm oil for biofuel is growing fast and their prices are rising [7]. Development of nonedible oil-based jet fuel production can decrease the risk of food security [7]. One of the solutions to these disadvantages is to employ a cheaper and non-edible feedstock such as waste vegetable oil or jatropha oil. Recently, United States Environmental Protection Agency (EPA) reported that US restaurant produces more than 1,000,000 m3 of waste vegetable oil every year [8]. This feedstock from waste is preferred over virgin oils because of its sustainability, viability in economy [9], improvement in waste management and [10] higher net energy ratio [11]. Although it is economically profitable to use waste vegetable oil to produce jet fuel, it is even more profitable to convert waste vegetable oil into other products such as soap. Therefore, most waste vegetable oil that is not dumped into landfills can be used for these other purposes. Waste vegetable oil as a source of biofuel has undergone plenty of research and development studies for the past years [12–15]. Waste vegetable oil is usually generated by the frying process. This used oil