Stability, Compatibility and Related Problems of Additives in Navy Distillate Fuels Derived from Lower Quality Feedstocks. An Interim Report

摘要

This report describes the initial phases of a study co-sponsored by DOE and the US Navy to determine which antioxidant additives are most effective in delaying fuel degradation in a variety of straight-run middle distillate/light cycle oil blends. In this study, straight-run middle distillate products were blended with catalytically cracked products at ratios of 85:15, 70:30; and 60:40, respectively. All of these blended fuels were immediately treated with 12 or 24 ppM of one of 12 commercially available, proprietary, non-generic additives. Stability testing and fuel characterizations performed at four different laboratories were used to evaluate the additives. Each laboratory used a different type of stability test. NIPER used its newly developed, small-scale Teflon cup test. Stability testing, as well as fuel characterization, is still in progress at all laboratories. Beacuse of the high degree of stability of the neat fuels, there was no way to differentiate between the additives. This was probably due to the special handling of the samples. They were saturated with argon at each step of sampling and were never exposed to oxygen until they were filtered for the aging process. One laboratory found that a 15-minute purge with air greatly increased sedimentation when compared to testing a fresh sample with the ASTM accelerated D 2274 test method modified to run 40 hours. Thus, a pre-aging step may provide for a more realistic evaluation of the efficacy of the additives. This work must be verified at the lower temperature tests at other laboratories. 5 figs., 18 tabs. (ERA citation 11:039699)