The Use of Bio-Distillate Marine Fuel To Decarbonize Marine Operations - Sea-Trial Experiment on A Small-Scale Vessel

Abstract Biodiesel blend is one of the multiple solutions that will contribute reaching the Carbon Footprint Reduction ambitions of the marine activities. However, field experience has shown issues with the use of FAME due to its hydroscopic behavior, resulting in filter blocking, increase of maintenance, injectors fouling… These issues are mainly linked to microbiological contamination. The objective of this test is to mitigate the risk of using biodiesel blends in small-scale vessels, representative of fishing and Exploration & Production activities, i.e. with engines from 150kW to 7 MW. To demonstrate the possibility of using biodiesel blends on small-scale vessels, a sea-trial was performed on a rescue ship equipped with two twin engines, Iveco Cursor (346 kW). The fuel tanks were isolated to dedicate one tank to one engine. Tanks and piping were cleaned, and filters replaced before the sea trial. One tank contained DMA the other one DFA with 30% FAME. The engines were instrumented with lubricant and fuel sensors as well as emissions sensors. In parallel, DMA and DFA were submitted to an ageing in specific lab conditions to follow a microbiological growth if any. The rescue ship is running on DMA (marine distillate) and DFA (marine distillate containing FAME) since July 2023 without any issue. The NOx emissions sensors don't emphasize any significant difference when the engine is running on DMA or DFA whereas the particulates matter emissions are reduced up to 50% at full load on the engine fueled with the DFA containing 30% of FAME. The crew didn't observe any dysfunction nor maintenance increase. The FAME content was increased to 50% without any issue so far. The ageing study to follow the microbiological growth is performed on the first production of DMA and DFA. DMA and DFA were spiked with 1% of contaminated water and the DFA sample is considered without and with an additive package containing a bacteriostatic molecule. ASTM D7687 is performed on a monthly basis and ATP (Adenosine TriPhosphate) was not detected in any of the samples. The demonstration of the smooth use of biodiesel blends on a small-scale vessel, with no adverse effect on-board the ship or in terms of pollutants emissions, is the essential step before developing a reliable and cost-efficient supply chain of biodiesel blends for offshore activities to reduce its carbon footprint. This solution can be implemented without any modification except a careful pre-cleaning of the tanks, fuel piping and filters onboard.