Engine Oil Life Increased at Biogas Plant

News Home » Engine Oil Life Increased at Biogas Plant 16 Jul 19

We are working with a local farmer to increase engine oil life in a Biogas M.A.N Generator. The 160kW engine is fed by one digester and the second digester used for stock piling. Energy created at the plant powers the farm. The balance of energy is fed into the UK National Grid. This is a key source of income and the health of the MAN engine is critical.

Oil Analysis

Before we can think about engine oil life our first step was to look at the condition of the engine oil at 400 hours. Doing this allows us to establish not only the condition of the engine, but also gives us an insight to the quality of the gas and how effectively the engine uses the gas. The first sample which was analysed by SYNLAB demonstrated that the engine, gas and oil are in good shape. One of the more common causes for oil life to shorten is the high presence of Silicon. Silicon gets into the engine oil through a chemical reaction process during combustion. Fortunately Silicon was not an issue and we were able to move forwards to testing again after another 400 hours. The second laboratory oil analysis was very similar to the first, essentially giving us the go ahead to select a product that would enable an engine oil life improvement.

Safe to continue with engine oil life extension

With two good oil analyses in hand we equipped the engine with a 1 micron oil filter system. This is an essential component to improving the oil life because oil life shortens as a result of contamination. The standard engine filters are only rated to filter debris to around 40 microns. This is key because most engine damage occurs when debris between 5 microns and 20 microns are present in the oil.

After 800 hours a sample of oil was tested and SYNLAB reported that the oil could be used further. However, after talking this through with the farmer we agreed that doubling the oil life was more than enough.

Financial Savings & Payback Period

They are using Fuchs Ganymet Ultra oil and pay around £2.20 per litre, with a 70 litre sump. The engine runs all year round unless essential maintenance is required. This equates to 22 oil services per year on the old 400 hour regime. A spend of around £3400 per year.

On the new 800 hour oil service interval the yearly spend is reduced to £1700.

A saving of £1700 per year & product payback in just 4 months

At some point in the future we should also be able to factor the savings in:

Oil and filter disposal costs
Reduced requirement to de-coke the engine
Decreased requirement to rebuild the engine. We have a track history of increasing engine life
Improved spark plug life