Bunkering Testing Breakthrough

Octel Petroleum Specialties, the UK fuel additive manufacturer, has made a significant breakthrough in the science of predicting the stability of heavy fuel oils. The development could lead to greater efficiency in critical applications such as estimating the oil quality before bunkering and evaluating the benefit of additives for upgrading Bunker “C” fuel oils.

Bunker "C" oil is currently produced by blending the oil remaining after the refining process with lighter oil. The main destination for Bunker “C” is ships using diesel engines for propulsion. Traditionally, predicting the stability of Bunker "C" is fraught with difficulty, largely because stability is ill defined and also because previous methods have been somewhat subjective. This, however, is about to change.

Octel's innovative new method, which has been granted ASTM approval (ASTM-method No. D 7061-04 "Standard Test Method for Measuring n-Heptane Induced Phase Separation of Asphaltene-Containing Heavy Fuel Oils as Separability Number by an Optical Scanning Device"), involves the unprecedented use of a Turbiscan instrument for measuring the stability reserve of fuels. The Turbiscan can also be used to check additive performance. Scientific instrument specialist Formulaction, who have recently signed a co-operation agreement with Octel, manufactures Turbiscan.

In the Octel test method, oil is diluted with toluene and heptane is added in order to provoke destabilisation of the oil. The phase separation rate is measured by Turbiscan, which uses a pulsed near infrared light source to scan the sample and thereby quickly indicate the stability behaviour of the oil. Once the stability reserve of the oil is determined, this method is a quick and easy-to-use tool to quickly find counter-measures by additive treatment in cases of oils with a low stability reserve.

"The innovation is in the development of the use of the equipment, said Octel Research and Technology Section Head Jenny-Ann Östlund. "It is not only a very effective way of predicting the stability of fuels, but it is very easy to use, portable and quick. Instead of taking days of lab analysis to find out about the stability reserve, we can now achieve this in 15 minutes, which makes the Octel test method extremely valuable to the industry.”

Octel pioneered the new method during an exhaustive R&D programme to improve their test method. ASTM International, originally known as the American Society for Testing and Materials (ASTM), officially approved the Octel method earlier this month