Dust explosions pose a serious safety risk to the processing and manufacturing industries where fine particles of various materials are used or produced. This includes the wood and metal processing and metalworking industries, the pharmaceutical industry, the coal industry, the food industry and many others. The formation, development and consequences of a dust explosion are influenced by many factors. To manage the risk of dust explosions, we need to understand the cause and the factors that
influence its progression. The key information for evaluating the consequences of a dust explosion is the minimum ignition energy, with the help of which we can assess the possibility of a dust explosion and introduce appropriate explosion protection. The diploma thesis will present both the chemical and morphological properties of zinc and iron dust and their influence on the minimum ignition energy and consequently, on the formation on a dust explosion.
The thesis examines the properties of zinc and iron powder. Results are given for a commercially available sample and a sieved sample containing size fractions less than 56 μm. The samples were determined by particle size and size distribution, specific surface area by BET method and thermal properties using thermal analysis. The explosion parameter determined was the minimum ignition energy.
Based on the results, I found that size fractions smaller than 56 μm predominate in the commercially available sampels of zinc and iron dust. Iron dust poses a greater risk of ignition and dust explosion, as it has smaller particles on average, and the range of MIE when measuring was 100 mJ <MVE <300 mJ. According to the literature, the iron dust MVE is 150 mJ and belongs to the MVE range determined experimentally. For zinc dust, the minimum ignition energy was determined to be higher than 1000 mJ. The literature value of MVE for zinc dust at 200 mJ thus differs significantly from the
experimentally determined value. No particle size information is given. I conclude that data from the zinc powder literature were obtained using significantly smaller particles than in our case. The thesis provides a more detailed overview of how smaller particle fractions can affect the minimum ignition energy compared to a wider range of iron and zinc dust particle sizes.
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