Experimental study of thickening effectiveness of two herders for in-situ burning of crude oils on water

The thickening effectiveness of two commercially available herding agents (OP40 and TS6535) was investigated parametrically in small-scale laboratory experiments with two different crude oils (ANS - Alaska North Slope and Grane). Both fresh and emulsified in cold water conditions were used in order to provide further information for in-situ burning operations in an Arctic context. Two application procedures for the herder, as well as variations in the duration of the tests, were other variations in the study. Both herding agents demonstrated the ability to obtain the minimum oil slick thickness (1-5 mm) required for successful in-situ burning. OP40 was more efficient for short periods than TS6535, whereas TS6535 remained active for long periods (up to 400 h). Both herders were more efficient in pre-spill application than post-spill application of the herder. The herder monolayer was not affected during burning and was still active once the burning ceased. Nonetheless, some contradictory results were found over a range of parameters, but are still in line with previously reported findings. Further systematic studies study based on physical/chemical characteristics of the oils and herders are required to fully establish the physical dependencies.