Technical Committee Fuel Oils

Correlations between the Composition of Light Fuel Oil and the Corrosion of Flame Tubes by Metal Dusting

In order to investigate fuel-related influence factors on the occurrence of the high temperature corrosion phenomenon known as metal dusting, numerous test series are conducted at close-to-reality and idealised test rigs.

Out of a multitude of fuel-related parameters the sulphur content provides as a good indicator for a increased probability of the occurrence of Metal Dusting at critical burners. Sulphur contents in the interval 20 ppm < S < 300 ppm are identified as potentially critical. A maximum of the carburization is found in the interval 100 ppm < S < 200 ppm. < S < 300 ppm. A maximum of the carburization rate is observed at sulphur contents in the interval 100 ppm < S < 200 ppm detected.

Concerning further fuel-related parameters examined in the tests (nitrogen content, content of mono-, di- and polyaromatic compounds, boiling range, final boiling point (simulated distillation), thermal stability, content on of bio components (FAME), etc.) no distinct correlation to the probability of the occurrence of Metal Dusting can be determined.

With an idealised test rig it can be shown that the high carburizing rates, which are observed at systems critical to the occurrence of Metal Dusting, are not caused by carbon separation from the gaseous phase.

An impairment of the system can only occur, when additionally to the usage of a potentially critical fuel, the combustion system and the material of the flame tube are susceptible to metal dusting.