(301f) Improved Combustible Dust Minimum Ignition Energy (MIE) Test Method and Prediction Using CFD Simulation
AIChE Annual Meeting
Tuesday, October 30, 2018 - 9:30am to 9:48am
The add-on device developed in this work ensures complete purging of the MIE apparatus with the desired gas concentration before experimentation. The same gas is then used to make the dust cloud dispersions for ignition testing. This approach results in a very uniform gas concentration which is essential for producing proper measurements. Therefore, an important finding of this work is that purging before partial inerting MIE testing results in a proper characterization of the relationship between the MIE and oxygen for the dust. This work has also explored the influence of purge time on partial inerting MIE measurements. Oxygen sensor measurements were used to determine the purge time required to achieve the desired composition. It was observed that the apparatus should be purged for > 40 seconds. Additionally, an ANSYS Fluent CFD model was developed that supports the experimentally determined purge time. The CFD model also revealed ways to further improve the initial add-on device. These findings demonstrate the need to amend existing or develop new standards for this type of dust testing.
The performance of the add-on device and validity of the techniques are demonstrated through the experimental determination of partial inerting curves for Niacin (CaRo15), Anthraquinone, Lycopodium clavatum and Calcium Stearate using the MIKE3 apparatus. A mathematical model for the MIE-O2 relationship was proposed and compared with the existing models in literature. The proposed model led to more accurate prediction of the MIE-O2 experimental relationship. Therefore, through both experimentation and modeling, this study aimed at providing a scientific foundation for a partial inerting MIE test method to supplement existing testing standards such as ASTM E2019-03.