@article{GENERAL,
      recid = {11193},
      author = {La Colla, E and van Biert, L and Grenko, B and Loeff, G},
      title = {Experimental and modelling studies on HVO-methanol  mixtures separation for superyachts applications},
      journal = {Conference Proceedings of INEC},
      address = {2024-11-07},
      number = {GENERAL},
      abstract = {A growing concern is associated to the greenhouse gases  emissions of superyachts, consequently alternative fuels  are introduced to the market.
For the yachting  decarbonisation, this work focuses on hydrotreated  vegetable oil (HVO) and methanol. Nevertheless, the  uncertain global availability of these fuels can undermine  the operations of ocean-crossing superyachts. Thus, a  multi-fuel system is installed allowing for fuels  switchover and built-in flexibility. Moreover,  non-dedicated tanks are installed for the alternative  storage of HVO and methanol to make optimal use of the  tanks’ capacity. However, the alternative storage of HVO  and methanol causes mutual fuels’ contamination. The lack  of standards and research on accepted fuels impurity makes  full fuels’ separation relevant to be explored. In this  work, to avoid degradation of dual-fuel engines or fuel  cells, gravity-settling tanks and disc-bowl centrifuges  were studied to separate HVO-methanol mixtures. Shake tests  were conducted on HVO-methanol mixtures to quantify the  separation time and relative concentrations to obtain  complete gravity separation. The gravity tests revealed  methanol traces in HVO for all the tested mixtures within  the 1 hour-3 days observation time, due to the low-density  difference between the fuels. This makes the use of  gravity-settling tanks impractical onboard for  quasi-instantaneous fuels supply to the converters. A  mathematical model was developed for disc-bowl centrifuges  to assess the separator performance and separation time.  Furthermore, the centrifuge was sized by providing the  separator working conditions for varying engine modes.  Moreover, spin tests were conducted to validate the  mathematical model. The model showed that full separation  is achievable with a larger centrifuge compared to existing  designs. The larger design is due to the low-density  difference between the fuels. The maximum separation time  ranges from 5-10 minutes. Nevertheless, all the tested  mixtures with the spin tests failed at achieving a state of  full separation due to the dilution of a certain residual  volume in the continuous liquid. The discrepancy between  the mathematical model and the spin test results can lie in  the neglected diluted phase of the dispersed fuel in the  continuous liquid in the mathematical model. However, the  mathematical model is a good tool to simulate the dynamic  behaviour of the dispersed droplets. Consequently, the  onboard use of a centrifuge for separating HVO-methanol  mixtures should be evaluated by quantifying the  concentration of the fuels’ mixture entering the separator  tailored per yacht. Furthermore, tests on dual-fuel engines  or fuel cells are recommended to establish tolerable limits  of fuel’s contamination.},
      url = {http://library.imarest.org/record/11193},
      doi = {https://doi.org/10.24868/11193},
}