In the marine sector, oil can now speak even more clearly! OELCHECK deciphers the message of oil – and along with the all important lubricant itself, accurate conclusions can be drawn about the state of individual cylinders in 2-stroke engines through a new, clear evaluation of the analysis results. The "OELCHECK system", with tailor-made and thus more cost-effective analytical sets for almost every issue, is unique. OELCHECK now offers a significantly expanded and, of course, globally usable analysis service for the "Scrape-Down Oil Analysis" (SDA) of slow-speed 2-stroke diesel engines in which, after a short period, the cylinder oil is exhausted and is lost.
The 2-stroke marine diesel in particular, with an output of over 100,000 HP, is a hard worker with plenty of stamina. These are mostly operated with HFO (heavy fuel oil). Its quality not only varies constantly but it is also contaminated, above all, with sulphur. Then there are also impurities, such as water, salt, nickel, vanadium and cat-fines. These fine-grained aluminium and silicone compounds have an abrasive effect like that of sand. They originate from the treatment of the HFO with a catalyst which is called cat-fines.
HFO fuel and its fluctuating feed rates that depend on its quality pose a constant challenge for engines and their lubrication. The volume of lubricant, which is provided for each cylinder with an individually set dosing pump, needs to be continuously adjusted for the fuel and the operating conditions of the engine. The more sulphur the fuel contains, the higher the concentration of additives needs to be to neutralise the sulphuric acid and the combustion residues.
In order to determine how heavily contaminated the lubricating oil is and whether more or less should be fed in, the cylinder oil running down from the liner is analysed with rapid test equipment, often on board the ship itself.
At times when engines are only operating at partial load due to slow steaming, condensation occurs in the engine, causing corrosion which will deteriorate further if insufficient lubricant is supplied, but will not improve by adding too much engine oil.
Sampling point for SDA oil tests
To ensure that the main engine of a ship works reliably and efficiently over several years and for well over one hundred thousand hours of operation, even under extremely unfavourable operating conditions, it requires excellent maintenance and effective control mechanisms. If the injection of the heavy fuel oil can also be optimised as part of the engine management, along with optimised feed rates for cylinder oil, the immense operating costs can be significantly reduced.
After all, a large, slow-speed 2-stroke diesel engine requires up to 25 tonnes of HFO fuel per cylinder per day. Moreover, large ship engines consume up to 2,000 litres of cylinder oil per day with their 12 or even 14 cylinders.