Evaluation of biofuel effect on performance & emissions of a 2-stroke marine diesel engine using on-board measurements

Abstract

The use of biofuels in the marine industry is attracting interest as a potential mid-term solution towards its decarbonization targets. To study the biofuels effect on engine performance, combustion mechanism and emissions an extended experimental investigation was conducted on a commercial vessel's electronically controlled slow-speed 2-stroke engine. The fuels used were a biofuel blend, B30, comprising 70% Very Low Sulfur Fuel Oil and 30% second generation biofuel, gas oil (MGO) and crude oil (HFO). The measurements were conducted according to the International Maritime Organization guidelines. Cylinder pressure measurements were performed and analyzed to derive power, fuel consumption and combustion rate and engine settings. This allowed to isolate the biofuel's effect on performance and emissions. B30 effect on performance and combustion was found minimal without effect on the injection system. Fuel efficiency was minorly impacted. NOx emissions were increased by 7% compared to MGO and 3.5% compared to HFO, remaining compliant to legislation. Use of B30 had minimal effect on CO2 emissions, thus actual benefit lies on the well-to-tank path. It is concluded that the 30% biofuel blend can be used on electronically controlled 2-stroke engines with minimal impact on engine performance, fuel consumption and only small increase of NOx emissions.