Improving the usage of vegetable oils in generator sets used for off-grid power generation by hydrogen addition

Abstract

This study experimentally investigates the effects on the performance and combustion process of a diesel generator set operating with blends of 20 and 50% of vegetable oil (V20 and V50) in B7 (volumetric mixture of 7% biodiesel with 93% diesel fuel) and with addition of hydrogen in the air intake. Hydrogen was injected continuously into the plenum at various volumetric flow rates (2.7, 6.5, 7.7, 8.5, 11.4, and 14.3 l/min). Results showed an improvement in the engine performance when increasing the hydrogen addition, reducing the specific fuel consumption, and decreasing its effective thermal efficiency. In the same way, the CO2, CO and HC emissions concentration decreased proportionally as the hydrogen concentration was increased. On the other hand, the levels of nitrogen oxides (NOx) increased due to the higher in-cylinder average temperature. In the combustion process, the maximum pressure peak and the rate of heat release inside the cylinder increased in, since the ignition delay for both mixtures (V20 and V50) reduced, also reduces the combustion duration due to the increasing on hydrogen addition.