On board a vessel, a good way to measure the compatibility of marine fuels, including residual and distillate fuels, is the ASTM D4740 spot test. The ideal percentage mix is 50/50 as this is the worst case scenario.
A drop of the blend is put on a test paper and heated to 100°C. After 1 hour, the test paper is removed from the oven and the resultant spot is examined for evidence of precipitation and rated for compatibility against D4740 reference spots.
AD Systems has developed a portable / on-site / on-board fully automated instrument for cleanliness and compatibility testing of heavy fuel oil. This portable device is a complete automation of the ASTM D4740 method.
This method is very simple and practical for the test but it had the serious handicap to rely on the know-how and subjectivity of the operator.
We have grouped all the phases of the test in a suitcase, the conditioning of the samples, and the preparation of the spot, its drying and the automatic rating by camera and associated software.
The only phases under the load of the operator are the sampling and the deposition of the drop with the aid of a micropipette supplied with the equipment.
As a result, the apparatus can be used anywhere by untrained persons for this test whenever power is available.
The apparatus is provided with a database for storing the results. The image of the spot is memorized at the time the spot is rated and we therefore ensure perfect traceability of the test.