Effects of antioxidant additives on pollutant formation from the combustion of palm oil methyl ester blends with diesel in a non-pressurised burner

Abstract

In order to alleviate escalating worldwide crises of oil reserves exhaustion and global warming, an alternative fuel that is sustainable, economically feasible and environmental friendly must be developed for large-scale adoption. Biodiesel has emerged as the leading alternative fuel of choice due to its cost, availability of current production technology and compatibility with existing infrastructure of petroleum diesel. Although considerable in-roads have been made to understand combustion and tailpipe emissions of various biodiesel fuels in compression-ignited engines, research efforts dedicated to examining these and the associated impacts of additives for non-transportation usage have been scarce. This work aims to establish the effects of antioxidants addition on pollutant emissions from the combustion of palm oil methyl ester blends with No. 2 diesel in a non-pressurised, water-cooled combustion chamber. Antioxidant additives butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) were individually dissolved at varying concentrations in B10 and B20 fuel blends for testing. Both BHA and TBHQ were effective in lowering the nitric oxide (NO) emission produced, where their concentrations in the fuel blends were shown to scale proportionately to NO levels in the flue gas. Addition of BHT to both fuel blends, however, increased the generation of NO during combustion. BHA was found to decrease the carbon monoxide (CO) levels when added to B10 and B20, while both BHT and TBHQ were observed to raise CO formation at all test points. With the proper selection of additives type and quantity for application to specific biodiesel blends, this simple measure has been shown to be an effective pollutants control strategy which is more economical than other existing technologies.