Hazardous substances that are produced and stored in industrial plants can cause fires and explosions under certain conditions. Catastrophic consequences can affect the entire plant and its surroundings and cause human losses or serious injuries. The Master's thesis examines both gas and dust explosions and explains the differences between them.
The parameters for a gas explosion are easier to determine than those for a dust explosion, and therefore, as part of the experimental work, physical, chemical and explosion parameters were determined for five combustible dust samples (corn cationic starch, oxidised corn starch, wheat starch, paper and wood dust). The moisture, carbon and hydrogen content of the samples were measured and the bulk and compacted densities were determined. Specific surface area was measured by BET analysis and particle size and size distribution was determined using a laser particle size analyser. Thermal analysis was used to determine the mass and thermal changes, and the volatile components released from the sample at elevated temperature. The minimum ignition energy (MVE) was measured for all samples. The minimum explosive concentration (MEC), the maximum explosive pressure (pmax) and the maximum rate of pressure rise (Δp/Δt)max) were determined in the explosion chamber. Finally, the deflagration index (Kst) of the dust was calculated.
Explosion parameters were were performed on all samples, except for the wood dust sample, for which we could not be determined due to the thin composition of the particle structure. We found that all samples were capable of producing a weak explosion. A slightly higher energy is required to ignite powders with a spark and they show a lower sensitivity to the formation of a dust explosion. In the event of an explosion, all dusts can cause fatalities as the pmax of all dusts is higher than 4,5 bar, therefore explosion hazard studies should be carried out for these combustible dusts and risk mitigation measures should be identified.
As part of gas explosions, we considered four energy sources: natural gas, biogas, diesel fuel and gasoline. All the mentioned substances are found in a company that produces cardboard. Each substance presents a different explosion risk. Physico-chemical properties and explosive characteristics for each substance are presented, as well as the risks of creating an explosive atmosphere. The Master's thesis also covers risk analysis and the measures that must be taken into account. The attachment contains a form that must be filled out before entering the explosion zone, as well as general instructions for working in explosion zones.
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