Study to evaluate test methods to assess the stability and compatibility of marine fuels in view of the IMO PARPOL Annex VI Regulation 14.1.3 for 2020 Sulphur requirements

Report no. 11/19: This report describes work sponsored and coordinated by Concawe and conducted by ISO/ TC28/ SC4/ WG6in view of the variety of fuel blend formulations expected to enter into the market as a result of tightening sulphur limits for marine fuels as of 1 January 2020.The objective was to explore whether the test methodologies of ASTM D7157, D7112 andD7060 can be applied to residual marine fuels to obtain additional insight into their stability with respect to precipitation of asphaltenes and whether these methods can be used to predict the compatibility between fuels, without blending the fuels together.

The study was conducted on a limited number of fuel samples as 0.50% max. sulphur fuels were not widely available at that time. The study shows that ASTM D7157, D7112 and D7060 can be used to obtain information on the degree of compatibility, though in some cases inconsistencies have been observed. Where possible, testing for compatibility of fuels to be coming led is recommended. Good practices to minimise the risk of incompatibility of fuels should be maintained and more data collected on commercially available samples.