Influence of the Pyrotechnic Igniter Composition Aging on Explosion Parameters of Dispersed Dusts

A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a Standards to study the explosiveness of dispersed dusts. Its pyrotechnic composition consists of 1.2 g of zirconium (40% wt.), barium peroxide (30% wt.) and barium nitrate (30% wt.). The energy released during the combustion of that amount of composition is 5 kJ. The article investigates the influence of aging of the pyrotechnic composition in the igniter on its initiation parameters. In the study, igniters of different years from date of manufacture were used: Igniter 1, manufactured in 2021 (less than 1 year from date of manufacture), and Igniter 2 (more than 2 years from date of manufacture). The study was performed in the KV 150M2 explosion chamber with a volume of 365 L and the 20 L sphere chamber with a volume of 20 L. A standard sample of Lycopodium clavatum was used in the KV 150M2 explosion chamber. Magnesium and benzoic acid were used as the samples in the 20 L sphere explosion chamber. The experiment showed that the explosion pressure Pmax of the igniter with more than 2 years from date of manufacture decreased by up to 10%, while the value of the explosion constant Kst decreased by up to 40%. The attained results proved that aging of igniters affects their explosion parameters and measurement accuracy.

Influence of Explosion Chamber Shape on Timing Parameters of Disperser

A standardized device with a volume of 1 m3 or 20 L is used to determine explosion parameters. An explosion chamber where explosion takes place is of a spherical or cylindrical shape that suits the shape of a cubic container. In the case of a cylindrical vessel, the diameter and depth of the vessel are 1: 1. In this case, it is a spherical vessel with a volume of 365 liters. Time parameters of the disperser in the spherical vessel are compared with those of a truncated spherical vessel with a volume of 291 liters. Comparison of the measurement results showed that the optimal delay time of the explosion chamber with a volume of 291 liters is 290 ms, while the delay time of the explosion chamber with a volume of 365 liters is 350 ms.

CREATION OF MATHEMATICAL AND COMPUTER MODELS OF THE DYNAMICS OF FLAME PROPAGATION OF AIR-SUSPENDED SOLIDS IN VARIOUS ROCKS USING MATLAB ENVIRONMENT

The propagation of transient, air-suspended solids in a vented explosion chamber is numerically investigated by a dynamic formulation for the Concentration Limit of Flame Propagation (CLFP) with the GUI MATLAB environment. The geomechanics is modeled by a one-step overall reaction, which simulates the reaction of a stoichiometric propane– air-suspended solids. The CLFP modeling in the reaction rate model is numerically employed with mathematical models on basis Antoine's equation. This is based on an empirical correlation of the velocity fluctuations and implemented as interface with input-output data with graphic realization. The computer modeling show that the dynamic CLFP models provide superior results as general implementation of physical process of flame propagation and could be used for different rocks (f.e. granite, limestone, sandstone etc).

Effect of Particle Breakage on Explosibility of Coal/Rock Dust Mixtures due to Dispersion in 20-L Chambers

Research has shown that particle size has a significant impact on the explosibility of coal dust/rock dust mixtures. Previous explosion studies conducted using the U.S. Bureau of Mines’ (BOM) 20-L explosion chamber tend to show a difference in the amount of inerting material needed to prevent an explosion when compared to the 20-L Siwek chamber. To reconcile these differences, samples were comparatively tested in the historic BOM 20-L chamber and the new NIOSH 20-L Siwek chamber with an emphasis on particle breakage. Rock dust and coal dust samples were dispersed in the chambers without ignitors and their specific surface areas were compared to the undispersed specific surface areas in order to quantify the breakage. Then, rock dust and coal dust mixtures were prepared, dispersed using the Siwek chamber, collected and tested for explosibility in the BOM 20-L chamber to see if the severe particle breakage in the Siwek chamber would influence the inerting limits of the BOM chamber. Results indicate that the particle breakage of friable brittle materials during explosion testing should be considered when evaluating the explosion risks in the process industries.

Design of Dust Dispersion System for Explosion Chamber KV-150 M2

Dust explosions are a major hazard in many industrial processes. In operations such as crushing and grinding, conveying, classifying and storage, an explosion may occur in the presence of combustible dusts or powders. Such explosions can result in loss of production, process equipment and quite possibly human life. This paper is oriented on design of dust dispersion system for explosion chamber KV-150 M2. The explosion chamber KV-150 M2 is designed to measure the explosion parameters of dispersed dusts.