Effect of electrostatic precipitator on exhaust emissions in biodiesel fuelled CI engine

Abstract

The exhaust emissions from the compression ignition engines are harmful to both human beings and the environment. After-treatment devices placed in the exhaust are designed to reduce these emissions. These devices have significant conversion efficiency but have various drawbacks such as the cost and availability of the precious catalyst for catalytic converters. In this work, an emission reduction setup was developed that can reduce NO, HC, CO and smoke simultaneously. The emission reduction setup is based on the concept of an electrostatic precipitator (ESP) and plasma generation by corona discharge technique. Both diesel and waste cooking oil biodiesel (WCO) were separately used for the test. The results show that HC emissions at full load with ESP system reduced from 0.71 to 0.27 g/kWh for diesel and for WCO it reduced from 0.81 to 0.31 g/kWh. Similarly, the CO emissions reduced from 1.50 to 0.6 g/kWh for diesel and from 1.95 to 0.92 g/kWh for WCO. The smoke emission and NO emission were also reduced by 30.86 and 29.3% for diesel and WCO and 17 and 18% for diesel and WCO, respectively. However, the carbon dioxide emissions were found to increase as the HC and CO generated were also converted to CO₂. The study shows that the emission reduction setup can effectively reduce the emissions without any effect on the engine performance.

Appendix 1

Sample calculation for the uncertainty analysis

Uncertainty in brake power = $\sqrt{{\left(\frac{\Delta V}{V}\right)}^2+{\left(\frac{\Delta I}{I}\right)}^2}$ = 1.2%

Uncertainty in fuel consumption = $\sqrt{{\left(\frac{\Delta A}{A}\right)}^2+{\left(\frac{\Delta t}{t}\right)}^2}$ = 1.5%

Uncertainty in brake thermal efficiency =$\sqrt{{\left(\frac{\Delta \mathrm{BP}}{\mathrm{BP}}\right)}^2+{\left(\frac{\Delta \mathrm{FC}}{\mathrm{FC}}\right)}^2}$ = 1.12%

Uncertainty in oxides of nitrogen =$\sqrt{{\left(\frac{\Delta \mathrm{BP}}{\mathrm{BP}}\right)}^2+{\left(\frac{\Delta \mathrm{NO}}{\mathrm{NO}}\right)}^2}$ = 1.1%

Uncertainty in carbon monoxide =$\sqrt{{\left(\frac{\Delta \mathrm{BP}}{\mathrm{BP}}\right)}^2+{\left(\frac{\Delta \mathrm{CO}}{\mathrm{CO}}\right)}^2}$ = 1.12%

Uncertainty in unburnt hydrocarbon =$\sqrt{{\left(\frac{\Delta \mathrm{BP}}{\mathrm{BP}}\right)}^2+{\left(\frac{\Delta \mathrm{HC}}{\mathrm{HC}}\right)}^2}$ = 1.14%

Uncertainty in carbon dioxide =$\sqrt{{\left(\frac{\Delta \mathrm{BP}}{\mathrm{BP}}\right)}^2+{\left(\frac{\Delta {\mathrm{CO}}_2}{{\mathrm{CO}}_2}\right)}^2}$ = 1.15%

Uncertainty in smoke = 1.0%

Where V—the voltage available from the generator, I—the current available from the generator, A—graduated burette, t—time, BP—brake power, FC—fuel consumption, NO—oxides of nitrogen, CO—carbon monoxide, HC—unburnt hydrocarbon, and CO₂—carbon dioxide.