Emulsification of waste cooking oil biodiesel blend with hydrogen peroxide to assess tailpipe emissions and performance of a compression ignition engine

Hydrogen peroxide (H2O2) is an excellent oxidant carrier that finds its use in combustion and fuel applications. In the present study, H2O2 (30% assay) is used as an emulsifier in waste cooking oil biodiesel blend (B20) and the emissions and performance in a compression ignition engine are assessed. Along with the neat B20, three blends of B20 with 0.5%, 1%, and 1.5% H2O2 concentrations are used. Increasing the concentration of H2O2 beyond 1.5% resulted in vapor lock in the fuel pump leading to a loss in injection pressure. An increase in the exhaust gas temperature was recorded with the increase inH(2)O(2) concentration due to improved fuel properties, like, cetane number, thermal conductivity, and microexplosions of fuel droplets. However, NOx emissions decreased mainly due to the presence of the hydroperoxyl group from H2O2. Analysis of variance was also carried out to assess the statistical significance of H(2)O(2 )on the responses and is seen that the maximum impact of H2O2 was positively influencing brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), hydrocarbon (HC), and NOx. Compared with the B20 blend, H(2)O(2)emulsified fuel with a concentration of 1.5% showed a substantial reduction of 53.7%, 28.6%, 14.2%, and 16.2% in the average emissions of CO, HC, smoke, and NOx respectively. Similarly, 7.9% and 7.1% improvement in the BTE and BSFC is obtained. However, more studies are required to ascertain the NO(x )reduction mechanism and address issues of fuel vaporization at higher concentrations of H2O2.

Automated summary

In this study, hydrogen peroxide was used as an emulsifier in waste cooking oil biodiesel blend and its impact on emissions and performance in a compression ignition engine was assessed. The results showed that the addition of hydrogen peroxide improved fuel properties and reduced NOx emissions. However, higher concentrations of hydrogen peroxide resulted in vapor lock in the fuel pump. Compared to the pure biodiesel blend, the emulsified fuel with a hydrogen peroxide concentration of 1.5% showed significant reductions in CO, HC, smoke, and NOx emissions, as well as improved thermal efficiency and fuel consumption.