Abstract
There are four alternative fuels that can be relatively easily used in conventional compression ignition engines (CIE): vegetable oil, biodiesel, Fischer-Tropsch (F-T) diesel, and dimethyl ether (DME). Vegetable oils, such as palm, soybean, sunflower, peanut, and olive, can be used as alternative fuels for diesel engines. Both F-T and DME can be manufactured from natural gas and are therefore not limited by feedstock availability. Fischer-Tropsch product composition strongly influenced by catalyst composition: product from cobalt catalyst higher in parafins and product from iron catalyst higher in olefins and oxygenates. Vegetable oil (m)ethyl esters, commonly referred to as biodiesel, are prominent candidates as alternative diesel fuels. Biodiesel is technically competitive with and offers technical advantages compared to conventional petroleum diesel fuel. The vegetable oils as alternative engine fuels are all extremely viscous with viscosities ranging from 10 to 20 times greater than petroleum diesel fuel. The purpose of the transesterification process is to lower the viscosity of the oil.