EXHAUST EMISSION CONTROL OF BIODIESEL FROM WVO USING ACETONE

                                                         INTRODUCTION

It is believed that crude oil and petroleum products will become very scarce and costly to find and produce. Increase in number of automobiles alone dictates that there will be a great demand for fuel in the near future. Because of high cost of petroleum products, some developing countries are trying to use alternate fuels for their vehicles. Another reason motivating the development of alternate fuels for the IC engine is concern over the emission problems of gasoline engines. A third reason is the fact that a large percentage of crude oil must be imported from other countries which control the larger oil fields.

The engines used for alternate fuels are modified engines which were originally designed for gasoline fuelling. They are, therefore, not the optimum design for the other fuels. Most alternate fuels are very costly at present. Another problem is lack of distribution points (service stations) where the fuel is available to the public.

Recently, biodiesel has become more attractive because of its environmental benefits and the facts that it is non-toxic, biodegradable and can be made from renewable resources. Biodiesel derived from vegetable oil and animal fats is being used in USA and Europe to reduce air pollution and dependence on fossil fuel, whose resources are limited. Biodiesel is considered to be a clean fuel since it has almost no sulphur, no aromatics and has about 10% built-in oxygen, which helps it to burn fully. Its higher cetane number improves the ignition quality even when blended with the petroleum diesel. Biodiesel has comparable energy density, cetane number, heat of vaporization, and stoichiometric air/fuel ratio with diesel oil. Biodiesel is considered to be cheap when comparing with other alternate fuels.

Acetone is added to improve mileage and to reduce exhaust emission. A certain amount of residual fuel in most engines remains liquid in the hot chamber. In order to be fully combusted, the fuel must be fully vaporized.

Surface tension presents an obstacle to vaporization. For instance the energy barrier from surface tension can sometimes force water to reach 300 degrees Fahrenheit before it vaporizes. Similarly with gasoline.

Acetone drastically reduces the surface tension. Most fuel molecules are sluggish with respect to their natural frequency.  Acetone has an inherent molecular vibration that "stirs up" the fuel molecules, to break the surface tension.  This results in a more complete vaporization with other factors remaining the same.  More complete vaporization means less wasted fuel, hence the increased gas mileage from the increased thermal efficiency. Acetone can reduce hydrocarbon emissions up to 60 percent.