Comparison of the yields and structure of fuels derived from freshwater algae (torbanite) and marine algae (El-Lajjun oil shale)

► A high-sulfur Jordanian oil shale is much more reactive than a low-sulfur algal coal, torbanite. ► The reactivity of the materials is similar with either hydrogen or nitrogen as the reaction medium. ► The asphaltene from the Jordanian oil shale is readily converted to oil in the relatively low temperature range, 350–390°C. ► The oils and asphaltenes from both materials have a highH/C atomic ratio. Reactions of a Jordanian El-Lajjun oil shale under N2 or H2 for 1h results in almost complete conversion of the organic material to liquid products at 355°C or 390°C. In contrast, reactions for 1h of the algal coal, torbanite, give minimal conversion at 390°C, but almost total conversion if the reaction time is extended to 5h. At 355°C reactions of torbanite are minimal at 1 and 5h reaction times, however at 425°C for 1h almost complete conversion is observed. In addition, the oil to asphaltene ratio for the products from the Jordanian oil shale increases in the temperature range 355–390°C, whereas the oil to asphaltene ratio for the products from torbanite strongly favours oil at all temperatures. The oil from both materials is highly aliphatic. The torbanite oil is mainly long chain, saturated hydrocarbons with few aromatic compounds. The oil from the Jordanian shale also has a high aliphatic content but a much wider range of aromatics. In addition, significant amounts of sulfur-containing compounds are present.