REDIFUEL – Determination of the flash point

Newsletter offers overview of interim results

6 February 2020 –

Flash point measuring device OptiFlash: Determination of the flash point according to the Pensky-Martens method with closed cup. Photo: OWI

In the EU project REDIFUEL the production of a renewable diesel biofuel is being researched, which is compatible (drop-in capable) with conventional fuels in any mixture ratio. After more than a year of research work, the current REDIFUEL newsletter offers an overview of the initial results. One of the numerous intermediate steps on the way to a drop-in capable product was the design of a distillation process to set a standard flash point of the REDIFUEL. The desired fuel must meet the quality requirements of standard EN 590 for diesel fuels with a flash point of at least 55 °C. To achieve this, an intermediate product must be distilled. This intermediate product contains, among other things, long-chain paraffins which lower the flash point and must therefore be separated in a distillation process. This process must be designed to avoid the separation of short-chain alcohols, which have a similar boiling range as long-chain paraffins, in order to maximize product yield.

The aim is to adjust the flash point of the hydroformulated intermediate by distillation to comply with the EN 590 standard with minimum product loss. Hydroformylation is the process of converting paraffins (straight chain alkanes or hydrocarbons with the molecular formula CnH2n+2) and olefins (straight chain alkanes or hydrocarbons with the molecular formula CnH2n) into a product rich in alcohols.

Research: In order to determine the best operating point, four different operating points of a distillation column were simulated at the Max Planck Institute for Chemical Energy Conversion. This is an apparatus for the thermal separation of mixtures according to the boiling points of their components. The simulation results were four different product compositions. These product compositions were then prepared as samples at the Oel-Waerme-Institut and their flash points were measured.

The result: In order to meet the EN 590 flash point requirement, it is not necessary to completely remove the paraffins from the hydroformylation product by distillation.

What is it used for? The results are used to design a distillation process for REDIFUEL production.

Impact: A reduction of unwanted losses of short chain alcohols can be realized by only a partial removal of the paraffins during the distillation process. This helps to make the whole REDIFUEL production process more efficient and cost effective.

In further steps, OWI will investigate chemical-physical properties of the REDIUFEL, such as density, viscosity and oxidation stability, as well as storage stability and possible interactions with engine oil among other things.

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