scholarly journals Comparative study of the explosion pressure characteristics of micro- and nano-sized coal dust and methane–coal dust mixtures in a pipe

2020 ◽  
Vol 7 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Bo Tan ◽  
Huilin Liu ◽  
Bin Xu ◽  
Tian Wang
Keyword(s):  
Coal Dust ◽  
Pressure Rise ◽  
Dust Explosion ◽  
Nano Particle ◽  
Explosion Pressure ◽  
Deflagration Index ◽  
Pressure Maximum ◽  
Explosion Accidents ◽  
The Impact ◽  
Pressure Characteristics

AbstractCoal dust explosion accidents often cause substantial property damage and casualties and frequently involve nano-sized coal dust. In order to study the impact of nano-sized coal on coal dust and methane–coal dust explosions, a pipe test apparatus was used to analyze the explosion pressure characteristics of five types of micro-nano particle dusts (800 nm, 1200 nm, 45 μm, 60 μm, and 75 μm) at five concentrations (100 g/m3, 250 g/m3, 500 g/m3, 750 g/m3, and 1000 g/m3). The explosion pressure characteristics were closely related to the coal dust particle size and concentration. The maximum explosion pressure, maximum rate of pressure rise, and deflagration index for nano-sized coal dust were larger than for its micro-sized counterpart, indicating that a nano-sized coal dust explosion is more dangerous. The highest deflagration index Kst for coal dust was 13.97 MPa/(m·s), indicating weak explosibility. When 7% methane was added to the air, the maximum deflagration index Kst for methane–coal dust was 42.62  MPa/(m·s), indicating very strong explosibility. This indicates that adding methane to the coal dust mixture substantially increased the hazard grade.

scholarly journals Explosion Characteristics of Propanol Isomer–Air Mixtures

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1574 ◽  
Author(s):  
Jan Skřínský ◽  
Tadeáš Ochodek
Keyword(s):  
Maximum Rate ◽  
Pressure Rise ◽  
Spherical Vessel ◽  
Explosion Pressure ◽  
Pressure Time ◽  
Vessel Volume ◽  
Deflagration Index ◽  
Pressure Maximum ◽  
Series Of Experiments ◽  
Effects Of Temperature

This paper describes a series of experiments performed to study the explosion characteristics of propanol isomer (1-propanol and 2-propanol)–air binary mixtures. The experiments were conducted in two different experimental arrangements—a 0.02 m3 oil-heated spherical vessel and a 1.00 m3 electro-heated spherical vessel—for different equivalence ratios between 0.3 and 1.7, and initial temperatures of 50, 100, and 150 °C. More than 150 pressure–time curves were recorded. The effects of temperature and test vessel volume on various explosion characteristics, such as the maximum explosion pressure, maximum rate of pressure rise, deflagration index, and the lower and upper explosion limits were investigated and the results were further compared with the results available in literature for other alcohols, namely methanol, ethanol, 1-butanol, and 1-pentanol. The most important results from evaluated experiments are the values of deflagration index 89–98 bar·m/s for 2-propanol and 105–108 bar·m/s for 1-propanol/2-propanol–air mixtures. These values are used to describe the effect of isomer blends on a deflagration process and to rate the effects of an explosion.

scholarly journals Explosion prevention and mitigation in plants which process, generate and store combustible dusts

2022 ◽  
Vol 354 ◽  
pp. 00041
Author(s):  
Adrian Marius Jurca ◽  
Mihaela Părăian ◽  
Niculina Vătavu
Keyword(s):  
Pressure Rise ◽  
Process Equipment ◽  
Process Industries ◽  
Explosion Pressure ◽  
Dust Clouds ◽  
Large Numbers ◽  
Burning Rates ◽  
Explosion Protection ◽  
Pressure Maximum ◽  
Protective Systems

Combustible dusts which are present in workplaces are a significant hazard which cannot be ignored by the plant owners, managers and workers. Combustible dust deflagrations and explosions have caused large numbers of deaths and catastrophic property damages in various industries, ranging from pharmaceutical plants to sugar factories. One may say that dust explosions in process industries always start inside process equipment such as mills, dryers, filters. Such events may occur in any process in which a combustible dust is handled, produced or stored, and can be triggered by any energy source, including static electricity, friction and hot surfaces. For any combustible dust type, several important parameters have to be taken into account when designing and using protective systems: i.e. the ease with which dust clouds ignite and their burning rates, maximum explosion pressure, maximum rate of explosion pressure rise. These parameters vary considerably depending on the dust type, their knowledge being a first step for carrying out a proper explosion risk assessment in installations which circulate combustible dusts. The paper presents the main aspects concerning explosion protection which have to be taken into account when designing protective systems intended to be used in explosive atmospheres generated by combustible dusts and the importance of selecting the proper explosion protection technique.

Research on Gas Temperature Affect on Pharmacy Dust Explosion Pressure in Transport Pipeline

2013 ◽  
Vol 634-638 ◽  
pp. 3618-3621
Author(s):  
Xiao Liang Zhang
Keyword(s):  
Combustion Velocity ◽  
Pressure Change ◽  
Velocity Model ◽  
Dust Explosion ◽  
Gas Temperature ◽  
Explosion Pressure ◽  
Pressure Pipeline ◽  
Pressure Maximum ◽  
Potassium Clavulanate ◽  
Explosion Experiment

This document has firstly been established explosion combustion velocity model in trasport pipeline, analysis on gas temperature effect on dust explosion strength. Gas temperature at 40 °C~ 60°C on the potassium clavulanate mixed dust explosion experiment are studied in the pipeline. The experiment indicates that dust explosion pressure change as gas temperature at 40°C, 46.3°C, 50.5 °C, 54.1°C, 55.8°C, 59.7°C, The studies show that gas temperature rise causes dust explosion pressure pipeline center development,bring piston wave phenomenon.Dust explosion pressure maximum value is get up to 375kPa and negative pressure value is 875kPa.

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 Influence of acetylene on methane–air explosion characteristics in a confined chamber

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinzhang Jia ◽  
Jinchao Zhu ◽  
Wenxing Niu ◽  
Jing Zhang
Keyword(s):  
Free Radicals ◽  
Volume Fraction ◽  
Pressure Rise ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Maximum Pressure ◽  
Mixed Gas ◽  
Explosion Pressure ◽  
Combustion Modes ◽  
The Impact

AbstractTo study the impact of acetylene on methane explosions, the safe operation of coal mines should be ensured. In this paper, a 20 L spherical tank was used to study the explosive characteristics of acetylene–methane–air mixture. In addition, the GRI-Mech3.0 mechanism was used to study the chemical kinetic mechanism for the mixed gas, and the effect of adding acetylene on the sensitivity of methane and the yield of free radicals was analysed. The results show that acetylene can expand the scope for methane explosion, lower the lower explosion limit, and increase the risk of explosion. Acetylene increases the maximum explosion pressure, laminar combustion rate and maximum pressure rise rate for the methane–air mixture while shortening the combustion time. Three combustion modes for the acetylene–methane–air mixture were determined: methane-dominated, transitional and acetylene-dominated combustion modes. Chemical kinetic analysis for the mixed gas shows that as the volume fraction of acetylene increases, the generation rate for key free radicals (H*, O* and OH*) gradually increases, thereby increasing the intensity of the explosive reaction. The results from this research will help formulate measures to prevent coal mine explosion accidents.

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.

Experimental Study of Explosion Pressure Characteristics of Methane under High Temperature Conditions

2014 ◽  
Vol 687-691 ◽  
pp. 148-152 ◽  
Author(s):  
Run Zhi Li ◽  
Rong Jun Si ◽  
Yan Song Zhang
Keyword(s):  
Environmental Temperature ◽  
Pressure Rise ◽  
Test System ◽  
Coal Bed ◽  
Maximum Pressure ◽  
Explosion Pressure ◽  
Pressure Rise Rate ◽  
Maximum Explosion Pressure ◽  
Rise Rate ◽  
Pressure Characteristics

Methane explosion pressure characteristics under the condition of different temperatures (25°C-200 °C) were studied by the special environment 20L explosion characteristics test system. By the experimental results, in the case of other conditions unchanged, with the increase of environmental temperature, the maximum explosion pressure of the optimum explosion concentration decrease, the maximum explosion pressure and the reciprocal of environmental temperature show linear attenuation law, the maximum pressure rise rate is not influenced by environmental temperature basically; Outside the scope of explosion limits at normal temperature and pressure, with the increase of environmental temperature, no explosion methane-air mixture are explosive gradually, the maximum explosion pressure and maximum pressure rise rate are in the relationship of different exponential growth with the increase of ambient temperature. The conclusions provide an important theoretical basis for prevent mine gas explosion accidents and coal bed methane safely use.

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 The effect of selected inhibitors on the characteristics of wood dust explosion

2018 ◽  
Vol 247 ◽  
pp. 00056
Author(s):  
Łukasz Zubek ◽  
Mirosław Sobolewski
Keyword(s):  
Pressure Rise ◽  
Magnesium Carbonate ◽  
Wood Dust ◽  
Dust Explosion ◽  
Dry Powders ◽  
Explosion Pressure ◽  
Pressure Time ◽  
Fire And Explosion ◽  
Derivatives Of ◽  
Rock Dust

The mass concentration of four inhibitors which is required to suppress pine dust explosion were measured in laboratory-scale system. Measurements were conducted using four commercially available additives commonly used to decrease the fire and explosion hazards, three extinguishing powders: BC FOREX C, ABC Favorit X90, BC 101K and rock dust powder consisting calcium carbonate CaCO3 and magnesium carbonate MgCO3. The inhibition effect was investigated by measuring explosion pressure of various dust/powder mixtures using a 20 dm3 sphere by PN-EN 14034. On the basis of pressure-time curves the derivatives of pressure with respect to time (dp/dt), maximum explosion pressure pmax and maximum rate of explosion pressure rise (dp/dt)max were determined. It was found that inhibiting dust explosions with additives of various dry powders is a very effective way to decrease explosion effects. The experimental results have also shown that inhibiting effectiveness is strictly related to chemical composition of the powder. The order of effectiveness was monoammonium phosphate, sodium bicarbonate, potassium bicarbonate and rock dust.

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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