Selection of suitable surrogate fuel for initial screening (May 2019 – Month 8/36)

Intermediate result from partners T4F, OWI, MPI-CEC

Result has been achieved on 9 May 2019 in month 8 of the project.

To enable the initial screening of REDIFUEL at early project stages, surrogate fuels must be selected due to the limited availability of the final product at the beginning of the project. Max-Planck-Institute (MPI) provided a sample of the target alcohol mixture (TAM) for analytics. The TAM contains both linear chain and branched alcohols. As a surrogate replacement for TAM, a mixture of individual linear chain alcohols (surrogate alcohol mixture, SAM) has been selected and its suitability to represent the TAM has to be proven. With the available portion of the TAM, most of the important properties such as density and viscosity are compared with the surrogate mixture. In this process, also the compliance of TAM (blended with GtL and Diesel) to the EN 590 standard is checked. The measurements contribute to a selection of a suitable fuel matrix to conduct further investigations using the surrogate mixture.

  • Objective: To select suitable surrogate fuels for TAM considering, among others, density and viscosity.
    To check the compatibility of the fuel with current technology and compliance to EN590 standard.
  • Research: For initial screening of the fuel, a surrogate alcohol mixture (SAM) has been tested and compared to the target alcohol mixture (TAM) in properties such as density and viscosity, oxidation stability. Further it has been tested in which blend ratios the fuel meets the EN590 standards.
  • Result: The surrogate and TAM show similar density and viscosities over a range of temperatures from 15 °C to 125 °C (Figure 1 and Figure 2). At 15 °C the TAM and the SAM show densities of 830.69 kg/m3 and 828.13 kg/m3 respectively. The viscosities at 40 °C of the TAM and the SAM are 5.3902 mm2/s and 5.6650 mm2/s respectively.
    The blend ratios of the alcohol mixture and the paraffinic fuel with standard diesel fuel to fulfill EN 590 requirements concerning density and viscosity have been determined.
  • What will it be used for: After a sequence of tests, including the density and viscosity investigations, the SAM was selected as a suitable surrogate of the TAM. Finally, based on the investigations of blends a fuel matrix for further investigations has been determined.
  • Impact: The selection of suitable surrogate fuels and the determination of a fuel matrix enable the investigation of fuel properties, the impact of fuel on various materials of a fuel system, effects on lubricity and ageing characteristics as well as performance in the engine already at an early stage of the project.

Figure 1: Density of Target Alcohol Mixture and Surrogate Alcohol Mixture (OWI)

Figure 2: Viscosity of Target Alcohol Mixture and Surrogate Alcohol Mixture (OWI)