SINGLE STEP TRANSESTERIFICATION OF COTTONSEED OIL AND USED FRYING OIL USING HETEROGENEOUS Sr(NO3)_2/ Al2O3 CATALYST

摘要

The worldwide worry about the protection of environment and the conservation of non-renewable natural resources, has given rise to the development of alternative sources of energy as substitute of traditional fossil fuels. Among the most used fuels, the diesel oils of automotive industry are the more important. Diesel fuels are used in passenger vehicles, city buses, locomotives, electric generators, etc., and they have an essential function in the industrial economy of a country. The alternatives to diesel fuel must be technically feasible, economically competitive, environmentally acceptable, and readily available. Many of these requisites are satisfied by vegetable oils or, in general, by triglycerides. Indeed, vegetable oils are widely available from a variety of sources, and they are renewable. As indicated by Boehman, vegetable oil and animal fat based biodiesel fuels, as methyl or ethyl esters, have the following advantages over diesel fuel: as a neat fuel or in blends with diesel fuel they produce less smoke and particulates, have higher cetane numbers, produce lower carbon monoxide and hydrocarbon emissions, are biodegradable and non-toxic, and provide engine lubricity to low sulfur diesel fuels. Conversely, they present other technical challenges such as: low volatility; high pour points, cloud points and cold filter plugging temperatures; elevated NOx emissions; and incomplete combustion. Their advantages as cetane improvers and lubricity additives for diesel fuels have not been fully appreciated, but the advent of ultra low sulfur diesel fuels and their reduced lubricity may motivate use of low concentration biodiesel blends to ensure adequate lubricity. Consequently, these products can be considered viable alternatives for diesel fuel7,8. Their main drawback is price, which is higher than for oil-derived diesels. In consequence, their use must be accompanied by a policy oriented towards their total tax exemption.