Synfuel Stability: Degradation Mechanisms and Actual Findings

Storage stability of synfuels from oil shale. 2. Effects of nitrogen compound type and the influence of other nonhydrocarbons on sediment formation in model fuel systems

“…It is likely that the thiols are acting as antioxidants (Nixon, 1962;Kennedy and Paterson, 1955). The elemental analyses of sediments from DMP plus thiophenol are similar to those obtained in the absence of sulfur (Frankenfeld and Taylor, 1981). This indicates that the sulfur compounds are affecting only the rate of reaction and not the characteristics of the sediment.…”

“…As shown in previous studies (Frankenfeld et al, 1983a;Frankenfeld and Taylor, 1981) the structure of the nitrogen compound being tested has a large effect on the amount of sediment produced under accelerated storage conditions. Some compounds react nearly quantitatively in 4-6 months while others show little or no tendency to form sediment even after prolonged storage at elevated temperatures.…”

“…A variety of sulfur and oxygen compounds are known to be present in shale liquids (Frankenfeld and Taylor, 1981). Some of these, especially the sulfur compounds, have been shown to be unstable in thermal stability studies (Taylor, 1976;Taylor and Wallace, 1968).…”

“…In the present study, a large number of interactions were discovered. The occurrence of an interaction was identified by means of a 2X2 factorial experiment (Brinkman, et al, 1981; Bennett and Franklin, 1954) and their significance was verified by use of Student's test (Davies, 1958). A summary of some of the more important interactions between pairs of nitrogen compounds is given in Table IV.…”

“…A major cause of sediment formation is the high nitrogen content of synfuels as compared with comparable fuels derived from petroleum (Frankenfeld and Taylor, 1981;Dineen and Bickel, 1951). In part 1 of this series (Frankenfeld et al, 1983a) the general features of nitrogeneous sediment formation were discussed.…”