Experimental study of a blend of Diesel/Ethanol/n-Butanol with hydrogen additive on combustion and emission and exegetic evaluation

Abstract

The energy demand and consumption due to population growth, urbanization, and industrialization have been dramatically increasing day by day, therefore, researchers have devoted their efforts to figuring out renewable and clean energy sources because of the reduction of drawbacks of fossil fuel usage. Attention has been drawn to alcohols as a renewable biofuel due to their favorable biological production pathways in the recent decade. Therefore, the study aims to reveal information about ternary blend fuels with H2 additives. In the present study, a ternary blend fuel, labeled as D + A, containing diesel (80% v/v), ethanol (10% v/v), and n-butanol (10% v/v) was investigated with a direct injection compression ignition engine. The combustion, emission, and exergy analysis were performed at 1750 rpm from 0 to 100% loading conditions with a 25% interval. Furthermore, the effects of H2 additive with different three flow rates (5, 15, and 25 g/h) on performance of the test engine and emissions were examined under dual-fuel mode. The ternary blend fuel generally increased BSFC and decreased BTE compared to diesel (D). At the full load, BSFC of D + A increased by 7.2% and BTE of D + A decreased by 1.3% with respect to D as base case. However, H2 addition through the intake manifold improved both BTE and BSFC. BTEs of D + A @5H2 (5 g/h flow rate), D + A @15H2, and D + A @25H2 increased by 9.9, 6.1, and 5.7% improvement compared to D at the full load. Moreover, at the same load condition and base fuel, the highest drop of BSFC was observed to be 4.3% from D + A @5H2 that is followed by D + A @15H2, and D + A @25H2 by 2.2 and 1.7%, respectively. The exergy efficiency was recorded as ∼ 1.5% decrement and ∼ 10.2% increment for D + A and D + A @5H2, respectively according to D at the full load. For all tested fuels at the full load, D + A @5H2 had the highest exergy performance coefficient of 0.61 and the most sustainable fuel mixture was found to be D + A @5H2 with 1.45 of the sustainability index value. The thermoeconomic and the exergoeconomic parameters showed the same trend. In the emission aspect, D + A showed a better performance than D with respect to CO, HC, and NO emissions. Under dual-fuel mode for all flow rates, CO emission was lower than D while HC and NO were slightly higher.