scholarly journals Variation and Prediction Methods of the Explosion Characteristic Parameters of Coal Dust/Gas Mixtures

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 264
Author(s):  
Yingquan Qi ◽  
Xiangyang Gan ◽  
Zhong Li ◽  
Lu Li ◽  
Yan Wang ◽  
...  
Keyword(s):  
Coal Dust ◽  
Dust Cloud ◽  
Prediction Method ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Characteristic Parameters ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Spherical Explosion ◽  
Explosion Limit

In order to investigate the change law of the explosion characteristic parameters of hybrid mixture of coal dust and gas, and then establish an effective prediction method of these parameters, the maximum explosion pressure, explosion index, and lower explosion limit of coal dust and gas mixtures were measured in a standard 20 L spherical explosion system. Four different kinds of hybrid mixture were selected in this study and they are composed of coal dust with different components and gas respectively. According to the measured results, the change law of the explosion characteristic parameters of hybrid mixture of coal dust and gas was analyzed, and the prediction method of these parameters was discussed. The results show that the addition of gas to a coal dust cloud can obviously increase its maximum explosion pressure and explosion index and notably reduce its minimum explosion concentration. On increasing the gas equivalent ratio, the maximum explosion pressure of coal dust and gas mixture increases linearly and the explosion index increases quadratically, while the decrease curve of the lower explosion limit is nonlinear. Based on these change laws, the methods for predicting the maximum explosion pressure and the explosion index of hybrid mixture of coal dust and gas were established respectively. The applicability of the existing methods for predicting the lower explosion limit of hybrid mixture to coal dust and gas mixture was demonstrated.

scholarly journals Determination of Explosion Characteristics of Sugar Dust Clouds

2018 ◽  
Vol 13 (1) ◽  
pp. 15-20
Author(s):  
Richard Kuracina ◽  
Zuzana Szabová ◽  
Matej Menčík
Keyword(s):  
Maximum Rate ◽  
Dust Cloud ◽  
Pressure Rise ◽  
Dust Explosion ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Dust Clouds ◽  
Maximum Value ◽  
Explosion Limit

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.

scholarly journals Determination of the Explosion Characteristics of Wheat Flour

2017 ◽  
Vol 25 (40) ◽  
pp. 9-16
Author(s):  
Richard Kuracina ◽  
Zuzana Szabová ◽  
Denisa Pangrácová ◽  
Karol Balog
Keyword(s):  
Wheat Flour ◽  
Maximum Rate ◽  
Pressure Rise ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Dust Clouds ◽  
Maximum Value ◽  
Flour Dust ◽  
Explosion Limit

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.

A New Method to Evaluate the Suitability of Ignitor Strength Used in the Tests of Dust Explosions

2013 ◽  
Vol 448-453 ◽  
pp. 3916-3922
Author(s):  
Jing Jie Yuan ◽  
Wei Xing Huang ◽  
Bing Du ◽  
Nian Sheng Kuai ◽  
Jing Yi Tan
Keyword(s):  
Bituminous Coal ◽  
Coal Dust ◽  
Dust Cloud ◽  
Pressure Rise ◽  
Ignition Process ◽  
Dimensionless Time ◽  
Test Results ◽  
Flame Kernel ◽  
Explosion Pressure ◽  
Action Time

Based on systematic experiments in the 20-L Siwek sphere, the explosion behaviors of bituminous coal dust were investigated by changing the strength of pyrotechnic ignitor. The effect on the maximum explosion pressure (Pex) and maximum rate of pressure rise ((dp/dt)ex) of the ignitor strength is analyzed. Due to the under-or over-driven phenomena, the overly low or high ignitor strength may result in unrealisticPexand (dp/dt)ex, especially for lower dust concentration. To evaluate the suitability of ignitor strength, the time scales (i.e. the effective action time,teff, and the induction time,ti,) of the ignitor combustion and flame kernel development are introduced by analyzing the ignition process of dust cloud. It can be found that theteffsignificantly heightens and thetigradually decreases with the rise of ignitor strength. Moreover, when theteffis much lower than theti, the under-driven phenomenon will occur, which leads to the underestimatedPexand (dp/dt)ex. Conversely, when theteffis much higher than theti, the explosion tests may be over-driven to cause the overestimatedPexand (dp/dt)ex. For ideal ignitor strength, theteffwould be comparable to theti. Based on these facts, the under-and over-driven phenomena can be effectively verified by comparing theteffand theti. As a result, when the dimensionless time ratioteff/tiis 0.52 or 1.42, the explosion tests in the 20-L sphere would be, respectively, under-driven or over-driven. To obtain the realistic test results in the 20-L sphere, it is suggested that theteff/tivalue should be in the range of 0.8~1.2 as much as possible.

scholarly journals The Maximum Explosion Pressure of Lignite in Dependence on Particle Size

2019 ◽  
Vol 27 (44) ◽  
pp. 57-64
Author(s):  
Richard Kuracina ◽  
Zuzana Szabová
Keyword(s):  
Particle Size ◽  
Coal Dust ◽  
Underground Mines ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Dust Clouds ◽  
Potential Safety ◽  
Fire Properties ◽  
Explosion Accidents

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.

scholarly journals Principal component analysis of the effect of coal quality indexes on the maximum explosion pressure of coal dust

2021 ◽  
pp. 104-104
Author(s):  
Tao Ban ◽  
Wen-Ling Li ◽  
Guo-Xun Jing ◽  
Lei Cheng ◽  
Chuang Liu ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Coal Dust ◽  
Principal Component ◽  
Calorific Value ◽  
Component Analysis ◽  
Multivariate Statistical ◽  
Coal Quality ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Quality Indexes

It is well-known that the calorific value and heat transfer speed of coal are closely related to the coal quality index, and affect the explosion intensity and the maximum explosion pressure of coal dust explosion. In this paper, the pressure for different coal quality indexes is studied experimentally, and the main parameters affecting the pressure are elucidated by the principal component analysis of multivariate statistical analysis.

scholarly journals Determination Of The Maximum Explosion Pressure And The Maximum Rate Of Pressure Rise During Explosion Of Wood Dust Clouds

2015 ◽  
Vol 23 (36) ◽  
pp. 49-56 ◽  
Author(s):  
Richard Kuracina ◽  
Zuzana Szabová ◽  
Pavol Čekan
Keyword(s):  
Maximum Rate ◽  
Dust Cloud ◽  
Pressure Rise ◽  
Wood Dust ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Dust Clouds ◽  
Maximum Value

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.

scholarly journals Experimental Investigations of the Ignitability of Several Coal Dust Qualities

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6323
Author(s):  
Reyhane Youssefi ◽  
Tom Segers ◽  
Frederik Norman ◽  
Jörg Maier ◽  
Günter Scheffknecht
Keyword(s):  
Moisture Content ◽  
Coal Dust ◽  
Characteristic Number ◽  
Ash Content ◽  
Hard Coal ◽  
Volatile Content ◽  
Explosion Pressure ◽  
Maximum Explosion Pressure ◽  
Deflagration Index ◽  
Ignition Characteristics

The ignition characteristics of coal dust is of high importance for the flame stability in coal-fired power plants. We investigate the ignitability of six lignite dust qualities and one hard coal using dust explosion tests and an ignitability characteristic number. The paper aims to identify the degree of impact of the properties of coals, such as the moisture content, the ash content etc., on the ignition characteristics and ultimately to compare the identified relevant ignition parameters to the ignition performance of the dust qualities in an industrially relevant environment. The minimum cloud ignition temperature (MCIT), the maximum rate of pressure rise ((dp/dt)max), the maximum explosion pressure (pmax), the deflagration index (Kst-value) and the modified ignitability characteristic number (ZWZmod.) were determined and were attributed to the moisture content, the ash content and the median particle size. The MCIT was largely influenced by the volatile content, whereas the variations of moisture and ash contents within the range of 10% to 20% did not have a significant impact on the MCIT. The maximum explosion pressure did not differ considerably and stayed in a narrow range among the tested dust qualities. The deflagration index showed a higher sensitivity to the dust properties. The deflagration index and the modified ignitability characteristics number dropped as the moisture content increased and the volatile content reduced. The Kst and ZWZmod. values showed the highest susceptibility to the coal dust properties. Hence, they were used as representative parameters for further comparison with the ignition performance of coal dust in a pilot-scale testing. The results showed that both parameters predicted the ignition performance relatively well and can be used as indicators for the prediction of the ignition performance.

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