Performance and emissions of neat crude palm oil and its emulsions as diesel engine fuel

Abstract

The depletion of petroleum diesel has prompted the use of biofuels and other alternative sources of energy. The direct use of neat crude palm oil (CPO) has mostly resulted in the increase of oxides of nitrogen (NOx). Emulsification has demonstrated the capability of reducing NOx emissions. An experiment is conducted to investigate the effect of increasing water content in CPO. Water-in-CPO emulsions with varying water contents by volume (5%, 10%, and 15%) with 1% SPAN 80 surfactant are labeled as W5CPO, W10CPO, and W15CPO. The fuels were tested on a single-cylinder diesel generator at 2900 and 3200 rpm with varying electrical load. For all load conditions at 3200 rpm, the smoke opacimeter reading is highest at 35% with W15CPO and the lowest smoke reading is 15% with W5CPO as fuel. The NOx of CPO was higher than ordinary diesel up to 29% at lower load. The NOx emissions of the CPO was reduced when the amount of water was increased. The maximum reduction in NOx of W15CPO was 66% whereas the minimum NOx reduction was 31%. At 3200 rpm and 4 kW, the CO emission of W5CPO was 21% lower in relation to CPO. The W5CPO showed a different trend in the exhaust emissions compared to Water-in-CPO emulsions with higher water content. Overall, emulsification has the potential to reduce NOx emissions in relation to neat CPO.