Using Biofuel in Oil-Fired Systems

Danfoss Burner Components plays an active role in the implementation of both national and international climate change targets. Protection of our natural resources and reduction of greenhouse gas emission can be achieved by reducing the use of fossil fuel.

Basic considerations

The latest technology in efficient heating technologies, such as oil-fired condensing boilers, is often combined with renewable energies such as solar systems or/and bio fuels. Oil-fired condensing boiler recovers the heat from the waste gases to pre-heat the circulating water.

Normally, low-sulfur heating oil (S<50ppm) is used and can be mixed with a certain percentage of biodiesel (FAME =Fatty Acid Methyl Ester) to produce such bio fuel. The bio proportion is produced from rape or soy seed, which undergoes a chemical process to make it look like normal heating oil. Using bio fuel is not problem-free and can place certain demands in the materials used from oil tank to oil nozzle. First, the burner itself must be suitable for bio fuel and the pipes, filters and hoses need to be adapted and last but not least, oil pump, oil preheater and oil nozzle should be suitable for use with bio fuel.

Danfoss has carried out extensive studies in order to offer components fit for this new oil. Since early 2010, Danfoss has offered the service components suitable for B10 and in February 2011 all new oil burner components from Danfoss were released for use with B10. B10 is the term for bio mixtures containing up to 10.9% bio diesel (according EN 14214, which is equivalent to ASTM D6751). This is rated according to the German standard DIN SPEC 51603-6. On the German market a bio fuel B10 is already available and therefore it is necessary that the oil burner components can cope with this percentage.

What about existing oil burners?

In Europe there are around 12 million oil burners in operation and a large proportion of these use Danfoss Burner Components. The vast majority of these burners have been in operation for many years and have three important components to take into consideration when switching to bio fuel. The Danfoss nozzle is exchanged regularly and thus will not cause any difficulties. The Danfoss preheater has a long life and will not be worn. The materials used for the preheater have always been appropriate for use with B10, as it happens to be the same

materials that are suited for higher temperatures which are also suited for bio fuel. This means that the Danfoss nozzle and preheater can be used with the new bio fuel B10 completely unchanged.

The situation is quite different when it comes to the Danfoss oil pump. The materials previously used for this product can only handle a B5 mixture, i.e. 5% share of bio fuel in the heating oil (equivalent to ASTM D396). As a result of the previously mentioned studies, Danfoss has chosen to equip all its pumps with FKM (Viton ) seals. This means that you can upgrade your oil burner by replacing the oil pump with a new BFP service pump. By using FKM seals Danfoss isn’t only living up to the future demand for lower C02 emissions coming from bio fuel but also taking responsible attitude towards eliminating the risk of leaking seals and thereby a risk of contaminating the ground water

Which type of oil can the user then put in the tank?

Initially you should ask the supplier of the burner system if it can run with bio fuel. Then you must ensure that the entire system is suitable for this new oil, i.e. the tank pre-filter, pipes and hoses should be bio ready. The burner manufacturer or the installer may be helpful in determining whether the installation is suitable for switching to bio fuel. Since bio fuel has some unfortunate characteristics, e.g. easily absorbing water which over time will cause the oil to oxidize, this may produce a varnish-like precipitation in the pump, preheater and nozzle. If the bio fuel does not completely follow the regulations it may lead to a shutdown of the oil burner. This kind of downtime is obviously outside of the product warranties which Danfoss can provide.

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