International Symposium on Safety Science and Engineering in China, 2012 (ISSSE-2012) An Extensive Discussion on Experimental Test of Dust Minimum Explosible Concentration

TLDR: In this article, an extensive investigation on experimental test of dust minimum explosible concentration (MEC) was carried out by using the Siwek 20 L vessel, and the results reported in this work provide t he experimental basis and data guidance for the prevention and evaluation of dust explosion risk.

Abstract: An extensive investigation on experimental test of dust minimum explosible concentration (MEC) was carried out by using the Siwek 20 L vessel. Systematic data were reported on the MEC of various dusts and the influences of ignition energy, dust calorific value, moisture content and particle size were taken into account. It is found that the overly low or high ignition energy will result in unrealistic MEC results. To reliably measure MEC, the experimental tests should be preformed under the condition that the test result is independent of ignition energy. For the Siwek 20 L vessel, the 4-6 kJ is the most appropriate energy ranges to determine the MEC of various dusts. The more incombustible component contained in lower calorific value dust acts as a thermal sink in the ignition and heating process of dust cloud, and therefore, the higher MEC can be found in the MEC measurement of lower calorific value dust. Mo reover, due to the notable dust agglomeration, to validly measure MEC, the moisture content of test dust should not exceed 10 wt %. When the moisture content is lower than 10wt %, the MEC smoothly increases with the rise of moisture content. With the decrease of particle size, the measured MEC becomes lower, and the MEC has an approximate linear relation with particle size. The results reported in this work provide t he experimental basis and data guidance for the prevention and evaluation of dust explosion risk.