Development of ASTM D2274 Reference Fuels Based on 1,2,5 Trimethylpyrrole in n-Dodecane. Interim Report: Effect of Preparation Procedures and Trimethylpyrrole Aging

摘要

Solutions of 1,2,5-trimethylpyrrole (TMP) in n-dodecane were evaluated for use asreference fuels to produce known amounts of sediment. Tests were run in accordance with ASTM D2274, Test Method for Oxidation Stability of Distillate Fuel Oil (Accelerated Method). Each of four test operators determined the amount of sediment formed as a function of TMP concentration (0 to 150 milligrams per 100 milliliters) and of D2274 stress time (4 to 96 hours). Results from the four operators were not in good agreement, probably due to the following factors. Some operators used TMP from freshly opened bottles; others used TMP from bottles that had been opened and refrigerated for a considerable length of time. Also, there were differences in the techniques used to prepare the TMP solutions, in the filter media used, and in operator precision. Gas chromatographic analysis of selected prestressed fuel samples indicated that the stated concentrations were not always accurate. Further tests to obtain a better definition of the usefulness of solutions of TMP in n-dodecane as reference fuel should concentrate on (1) stricter control of procedural and material factors (e.g., fuel preparation and TMP age) and (2) the range of D2274 insolubles of most interest to MIL-F-16884 users, namely 0 to 3 milligrams per 100 milliliters (i.e., initial TMP concentrations of <50 milligrams per 100 milliliters).