The European Union (EU) aims to phase out fossil fuels by 2050. Shipping involves transportation of passengers or merchandise. Shipping, one of the largest sources of greenhouse gas emissions, must transition to alternative fuels. Alternative fuels such as hydrogen, ammonia, methanol (MeOH), hydrotreated vegetable oil (HVO) and their blends are possible fuels for future maritime applications to replace fossil fuels.
The compatibility of alternative fuels and engine materials creates a challenge for maritime applications. Internal combustion engine (ICE) materials, like various metals, have different corrosion resistances. Corrosion resistance and the compatibility of materials can be studied using several methods. The fuel passes through the ICE from the tank through the entire fuel system. Anywhere fuel flows the material compatibility of alternative fuels must be ensured.
The first objective of this study was to improve the University of Vaasa’s Fuel laboratory’s immersion test initial setting. The improvement of the immersion test was developed in sectors: the metal sample size, the method of attaching the metal sample to the sample container, the preparation of the fuel blend, the effect of temperature and scanning electron microscope (SEM) images. The second objective of this thesis was to implement the improved immersion test and examine the compatibility of various fuels with carbon steel (CS). The test was performed at two different temperatures of 23 ᵒC and 40 ᵒC, for over 300 hours, to examine the effect of temperature on the formation of corrosion. The studied fuels were Renewable Diesel (RD) and light fuel oil (LFO), both without additives, MeOH, and the blend of RD, and MeOH, stabilized with 1-octanol (later blend), containing 8 % of MeOH based on the energy ratio. The possible corrosion was studied by analyzing the fuels’ trace metals concentrations before and after the test and analyzing the CS samples visually and by SEM. In addition, the properties of the studied fuels were analyzed before and after the immersion test.
As a result of this thesis the improvement of the immersion test enables more detailed research results. According to the trace metal concentration analyses results, no contamination caused by the CS plates was found in any of the studied fuels. SEM images and visual observation of the samples support this result as no signs of corrosion were detected on the CS samples. The temperature did not affect fuel contamination and corrosion. The measured results of kinematic viscosity and density for RD, blend and LFO met the requirements of the standards. According to the distillation results, RD and LFO met the requirements of the standards. Neither the temperature change nor the immersion of the CS samples on the fuels changed the fuel properties.
