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  • Author: Zuzana Szabová x
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The Maximum Explosion Pressure of Lignite in Dependence on Particle Size

Abstract

Floating coal dusts are always produced during coal mining process in the underground mines. In a coal mine and other coal processing or utilizing industries, there are always some potential safety problems, such as coal dust explosion accidents.[1,2] During lignite mining and processing, flammable coal dust is produced. Fire properties of coal dust depend on the particle size. The article deals with the measurement of explosion characteristics of lignite in dependence of particle size at three various concentrations. The measurements were carried out according to EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds. Tests of the lignite dust clouds explosions showed that the maximum value of the pressure was reached at the concentrations of 500 g.m−3 and the particle size between 0 – 56 µm. At this concentration, the highest explosion pressure of 8.25 bar was reached.

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Study of Fire Characteristics of Industrial Dust

Abstract

The article deals with the determination of fire characteristics of industrial dust samples. Particle size granulometry and determination of explosion parameters according to EN 14034 (Lower Explosion Limit LEL, Pmax, Kst) are presented. The minimum ignition temperatures of the dust layer and dispersed dust from the hot surface according to EN ISO / IEC 80079-20-2: 2016 were measured. It was found that LEL is 60 g.m−3, Pmax is 8.61 bar, and Kst is 89 bar.s−1.m. The minimum ignition temperature (MIT) of dust layer is 280 ° C and the minimum ignition temperature of dispersed dust is 400 ° C.

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Study of Explosion Characteristics of the Wheat Flour Dust Clouds in Dependence of the Particle Size Distribution

Abstract

Fire protection is an important part of the industry where flammable and explosive dusts are found. Production, storage and transport of food powders such as flour can be very dangerous in terms of explosiveness. The article deals with the measurement of explosion characteristics of wheat flour dust. The measurements were carried out according to EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds and the maximum rate of explosion pressure rise according to EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds. A sample of wheat flour with a median particle size 84 μm exhibits the maximum explosion pressure 7.00 bar at the concentration of 600 g.m−3 and then explosion constant is 16.9 bar.s−1.m. A sample of wheat flour with a median particle size 50 μm exhibits the maximum explosion pressure 7.97 bar at the concentration of 1000 g.m−3 and the explosion constant 54.9 bar.s−1.m.Based on the results of the measurements, we found that the particle size distribution has a significant influence on the explosion parameters of the wheat flour samples.

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Timing Parameters of Pyrotechnic Igniter Based on Magnesium Powder

Abstract

Chemical igniters are used in the study of dispersed dusts. Energy released during their use is defined by EN 14034 at 2 x 5 kJ. The Standard does not define the exact composition of the pyrotechnic mixture. The condition of using the igniter is to release energy according to the Standard. This article is focused on pyrotechnic composition with magnesium powder. It deals with various ways of activating, preparing and sealing the pyrotechnic mixture in the igniter. These values are important for setting up a device for studying the explosive properties of dispersed dusts.

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Determination of Explosion Characteristics of Sugar Dust Clouds

Abstract

A dust explosion occurs when an airborne combustible dust cloud encounters an effective ignition source. The resulting pressure and temperature increase can severely injure people and damage surrounding equipment and buildings, and therefore needs to be prevented or controlled (Taveau, 2016). The article deals with the measurement of maximum explosion pressure and maximum rate of explosion pressure rise of sugar dust cloud. The measurements were carried out according to STN EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds, the maximum rate of explosion pressure rise according to STN EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds and Determination of explosion characteristics of dust clouds. Part 3: Determination of the lower explosion limit LEL of dust clouds. The sugar dust cloud in the chamber is achieved mechanically. The testing of explosions of sugar dust clouds showed that the maximum value of the pressure was reached at concentrations of 1000 g/m3 and its value is 6,89 bars.

Open access
Study of Explosion Characteristics of Wood Dust Clouds in Dependence of the Particle Size Distribution

Abstract

The article deals with the measurement of explosion characteristics of wood dust. The measurements were carried out according to STN EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds and the maximum rate of explosion pressure rise according to STN EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds. On the basis of measurements, we found that the distribution of the particles has a significant impact on the parameters of wood dust samples.

Open access
Determination Of The Maximum Explosion Pressure And The Maximum Rate Of Pressure Rise During Explosion Of Wood Dust Clouds

Abstract

The article deals with the measurement of maximum explosion pressure and the maximum rate of exposure pressure rise of wood dust cloud. The measurements were carried out according to STN EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds and the maximum rate of explosion pressure rise according to STN EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds. The wood dust cloud in the chamber is achieved mechanically. The testing of explosions of wood dust clouds showed that the maximum value of the pressure was reached at the concentrations of 450 g / m3 and its value is 7.95 bar. The fastest increase of pressure was observed at the concentrations of 450 g / m3 and its value was 68 bar / s.

Open access
Determination of Fire and Explosion Characteristics of Dust

Abstract

The aim of this paper is to approximate danger of dust clouds normally occur by determining their explosion characteristics. Nowadays, dusty environment is phenomenon in the industry. In general, about 70% of dust produced is explosive. Dust reduction in companies is the main purpose of the national and European legislative. Early identification and characterization of dust in companies may reduce the risk of explosion. It could be used to identify hazards in industrial production where an explosive dust is produced. For this purpose several standards for identification and characterization of explosion characteristics of industrial dust are being used.

Open access
Determination of the Explosion Characteristics of Wheat Flour

Abstract

The article deals with the measurement of explosion characteristics of wheat flour. The measurements were carried out according to STN EN 14034-1+A1:2011 Determination of explosion characteristics of dust clouds. Part 1: Determination of the maximum explosion pressure pmax of dust clouds, the maximum rate of explosion pressure rise according to STN EN 14034-2+A1:2012 Determination of explosion characteristics of dust clouds - Part 2: Determination of the maximum rate of explosion pressure rise (dp/dt)max of dust clouds and LEL according to STN EN 14034-3+A1:2011 Determination of explosion characteristics of dust clouds: Determination of the lower explosion limit LEL of dust clouds. The testing of explosions of wheat flour dust clouds showed that the maximum value of the pressure was reached at the concentrations of 600 g/m3 and its value is 8.32 bar/s. The fastest increase of pressure was observed at the concentration of 750 g/m3 and its value was 54.2 bar/s.

Open access
Analysis Of Deviation In The Measurement Of Vibrations

Abstract

In order to achieve relevant and exact value in measurement of vibrations, it is necessary to add the corresponding value of deviation to the result of measurement. As the topic of determining the deviation is too complex and the scope of article is limited, we focus on the characteristic features and mathematical description of the basic types of deviations and some partial deviations which should betaken into account in measurement.

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