Technical Committee Fuel Oils
Development of a method for the characterization of the oxidation stability of domestic heating oil and domestic heating oil with alternative components using chemiluminescence
Modern burner systems for heating oils have a complex mixture preparation that is adapted
specifically to a fuel according to DIN 51603 – Part 1. The focus of the domestic heating
market lies – right after the introduction of heating oil low-sulphur – on the development of
liquid fuels regarding their substitution with alternative and biogenic components. The quality
and stability of the fuel has to be secured over long storage periods and represents a criterion
for the operation safety of heating oil burner systems. Under the influence of atmospheric
oxygen, temperature, light and further influencing factors a thermo-oxidative degradation of
fuels can occur during the storage of fuels in the tank units of heating oil burner systems. In
this case a formation of oil ageing products takes place and leads to changes of the chemical-
physical characteristics of the fuels. The oxidation stability represents a parameter that
serves to evaluate the stability of fuels. Several analysis methodologies exist for the determination
of the oxidation stability of mineral oil based products. These standardized testing
methodologies have been adapted to the respective application (lubricants, thermal oils, pure
mineral oil based products, etc.). In recent years several methodologies have been developed
in the fuel sector. Primarily they are applicable for the stability determination of pure
products (diesel, heating oil, biodiesel, vegetable oil). But none of these methodologies have
turned out to be suitable for blends of mineral oil based and biogenic, regenerative products
without restrictions yet. Therefore, the project’s aim was to develop a process that serves to
determine the oxidation stability of heating oil – FAME-/ heating oil – vegetable oil-blends
clearly. Due to a directed energy input by means of the process of chemiluminescence,
statements about the storage stability and the thermal stability of blends can be made. During
the process the ageing of blend components and of the heating oil are taken into consideration.
As a result, ageing processes and products of pure heating oil as well as biogenic
components can be determined. It was shown that the process is applicable to blends up to
an admixture of at least 20 %(V/V) of biogenic components, whereby blends with higher admixture
shares can be analyzed as well. According to DIN SPEC 51603 – 6 “Heating Oil Alternative”
the admixture of FAME is limited to 20 %(V/V) and the admixture of vegetable oil to
5 %(V/V) because of the distillation range. On the basis of these investigations it could be
shown how oxidation products influence the signal process of the chemiluminescence radiation
and how they can be correlated by a measurable physical value. Moreover, a new evaluation
criterion has been developed. By means of this criterion a good reproducibility – regarding
the determination of the oxidation stability according to the chemiluminescence
methodology for non-aged fuels – can be achieved. The fuel characteristic decrease in the
stability of the tested fuels can be represented only partially by the chemiluminescence process,
as the measured values are subject to fluctuations.
The IGF project (16342 N) of the Research Association for Petroleum, Natural Gas and Coal was funded by the Federal Ministry of Economics and Technology via the AiF within the framework of the programme for the promotion of joint industrial research and development (IGF) on the basis of a resolution of the German Bundestag.