Effect of heterogeneous catalyst during combustion of diesel fuel



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Texas Tech University


With the increase in number of vehicles using diesel engines, the contributions to environmental pollution made by diesel engines is also on the rise. Carbon monoxide, oxides of nitrogen and sulfur, hydrocarbons, and particulates are currently regulated as harmful emissions from diesel engines. Recent technologies to control harmful engine emissions have been almost exclusively directed towards gasoline engines. It is generally held that fuel quality will have to play an important role with all Internal Combustion (IC) engines to meet future stringent regulations.

The objective of the present study was to determine the effects of heterogeneous catalyst on combustion. Micron sized solid catalyst, suspended in a specific organic peroxide, has been found to promote better combustion by modifying kinetics and changing the thermodynamic pathways of the reactions. The catalyst reduces emissions without dramatically changing the properties of the fuel.

The characteristic parameters of a baseline fuel, and the same fuel with the additive, were analyzed. The dosage of additive used was found to be compatible with commercial diesel fuel. Diesel vehicles were driven unloaded atnormal road conditions during the experiments. Exhaust emissions were measured when the trucks were at static conditions and the engine running on idle and at 2000 rpm. The gaseous components in the exhaust, O2, CO2, CO, NO, NO2, NOx, SO2, and CxHy were monitored. Particulates were trapped on a pre-weighed glass filter. Some of the filters were sent to an Independent laboratory for microscopic and elemental analysis of the collected debris.

Zinc oxide/peroxide suspended in tert-butyl hydro peroxide were used as the heterogeneous fuel catalyst. This combination increased the cetane rating of a commercial diesel fuel from 45 to a level of 70 depending on treatment ratio. A treatment ratio of one ounce of the additive per 5 gallons of diesel fuel increased cetane number by an average of 5 points. Road mileage with the additive increased by an average of more than 10%. Gaseous and particulate emissions were reduced by more than 20%. Engine wear decreased due to increased lubricity of the fuel. A decrease in flash point of the diesel fuel may make the additive more suitable for cold weather operations.



Diesel motor, Spark ignition, Internal combustion engines, Diesel fuels, Combustion