Study of Variables That Affect Results in the ASTM D2274 Accelerated Stability Test. Part 1. Laboratory, Operator, and Process Variable Effects

摘要

Poor reproducibility among laboratories that use the ASTM D2274 test for the storage stability of distillate fuels has long been a problem. Different operators who use the same equipment obtained different average results even within a single laboratory. A questionnaire relating to the method was sent to users to elicit information about variations in practice among laboratories and to gain insight into the causes. This Center began a task to identify the critical variables in the test procedure. We tested three fuels and concluded that there is negligible effect from variations in the bath temperature of less than 0.2 C (32.4 F), in oxygen flow rate of less than 0.3 L/hr, and of time-in-bath of less than 0.25 hr. However, each of these variables (especially the temperature) has a major impact if the limits are exceeded.