Research on flame propagation and explosion overpressure of oil shale dust explosion suppression by NaHCO3

The explosion-suppression effects of NSSs on overpressures, flame propagation and flame tip velocities were explored under the initial pressures of 0.2 MPa, 0.3 MPa and 0.4 MPa. All experiments tested in a constant volume combustion bomb (CVCB). Explosion reaction of premixed propane–air gas in a new designed CVCB filled with nonmetallic spherical spacers (NSSs) was analyzed. The results showed that overpressures decreased under the different initial pressures. With the increase of filling density, the overpressure decreased, the time to reach explosion overpressure decreased, and the decay rate of explosion overpressure increased. It was also found that the explosion-suppression effects of NSSs on pressures. Flame front could be captured by high-speed schlieren photography. Combustion phenomena were captured including flame propagation, corrugated laminar flame, jet flame, corrugated turbulent flame as well as tulip flame under different initial pressures. Flame tip velocities also were captured. The results demonstrate that flame tip velocities decreased with the increase of filling densities. However, compared with unfilled CVCB, flame tip velocities increased after filling NSSs in CVCB under different initial pressures. NSSs suppressed the explosion overpressure in the cylinder, and promoted the flame propagation. In both cases, NSSs played a dual role. The suppression effect of NSSs was affected by both its suppression and promotion effect on the explosion. This work provides a scientific basis for the effective prevention of explosion accidents with propane–air premixtures and the development of explosion-suppression products.

Download Full-text

Suppression of Aluminum Dust Explosion by Ca(H2PO4)2/RM Composite Powder with Core–Shell Structure: Effect and Mechanism

Processes ◽

10.3390/pr7100761 ◽

2019 ◽

Vol 7 (10) ◽

pp. 761 ◽

Cited By ~ 4

Author(s):

Junfeng Wang ◽

Xiangbao Meng ◽

Ke Yan ◽

Jinshe Chen

Keyword(s):

Flame Propagation ◽

Shell Structure ◽

Composite Powder ◽

Glass Tube ◽

Dust Explosion ◽

Core Shell ◽

Explosion Overpressure ◽

Core Shell Structure ◽

Dust Flame ◽

The One

A Ca(H2PO4)2/RM composite powder suppressant with core–shell structure was prepared with modified red mud (RM) as the carrier and Ca(H2PO4)2 as the loaded particles, using a solvent–antisolvent process, in an attempt to suppress aluminum dust explosion more effectively. The suppression effects of the Ca(H2PO4)2/RM composite powder suppressant for aluminum dust flame propagation and for explosion overpressure were tested in a vertical glass tube test apparatus and a 20 L explosion vessel. The results show that the Ca(H2PO4)2/RM composite powder suppressant was more effective in suppressing aluminum dust flame propagation and explosion overpressure than either Ca(H2PO4)2 or RM powder alone. Finally, the suppression mechanism of the Ca(H2PO4)2/RM composite powder suppressant was analyzed. On the one hand, a large amount of burning heat was absorbed through the decomposition of Ca(H2PO4)2 and the melting phase transformation of the decomposition product; on the other hand, the strong isolation provided by the RM helped limit flame propagation. The strong adsorptivity of RM allowed this material to adsorb the radicals from the explosion reaction perfectly.

Download Full-text

Effect of Pristine Palygorskite Powders on Explosion Characteristics of Methane-Air Premixed Gas

Energies ◽

10.3390/en11102496 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2496 ◽

Cited By ~ 4

Author(s):

Yimin Zhang ◽

Yan Wang ◽

Ligang Zheng ◽

Tao Yang ◽

Jianliang Gao ◽

...

Keyword(s):

Flame Propagation ◽

Low Cost ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Flame Propagation Velocity ◽

Explosion Pressure ◽

Pyrolysis Characteristics ◽

Explosion Suppression ◽

Adsorption Desorption ◽

Methane Explosion

In this study, pristine palygorskite powders were used as the inhibition materials to suppress the explosion of methane-air premixed gas for the first time. The composition, porosity and pyrolysis characteristics of the powders were tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), N2 adsorption-desorption and Thermogravimetry-differential scanning calorimetry (TG-DSC) techniques. The effects of pristine palygorskite powders concentration on the explosion pressure and the average velocity of flame propagation of the 9.5% methane-air premixed gas were tested by a 20 L spherical explosion system and a 5 L pipeline explosion system. The results indicated the pristine palygorskite powders possess a considerable suppression property on methane explosion. When the mass concentration of pristine palygorskite powders was 0.20 g·L−1, the max-pressure of methane explosion was decreased by 23.9%. The methane explosion flame propagation velocity was inhibited obviously. Owing to the excellent inhibitory performance and the advantage of low-cost and environmental harmlessness, pristine palygorskite powders are potential new materials for the application on gas explosion suppression.

Download Full-text

Experimental analysis on post-explosion residues for evaluating coal dust explosion severity and flame propagation behaviors

Fuel ◽

10.1016/j.fuel.2017.11.093 ◽

2018 ◽

Vol 215 ◽

pp. 417-428 ◽

Cited By ~ 36

Author(s):

Qingzhao Li ◽

Chuangchuang Yuan ◽

Qinglin Tao ◽

Yuannan Zheng ◽

Yang Zhao

Keyword(s):

Flame Propagation ◽

Experimental Analysis ◽

Coal Dust ◽

Dust Explosion

Download Full-text

Pressure and flow propagation rule beyond original premixed area of methane-air in tunnel

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-08-2013-0259 ◽

2014 ◽

Vol 24 (8) ◽

pp. 1626-1635 ◽

Cited By ~ 3

Author(s):

Qi Zhang ◽

Qiuju Ma

Keyword(s):

Numerical Simulation ◽

Flame Propagation ◽

Volume Fraction ◽

Ignition Point ◽

Content Type ◽

Explosion Overpressure ◽

Air Explosion ◽

Propagation Rule ◽

Flow Propagation ◽

Propagation Rules

Purpose – Whether a fire can be initiated in an explosion accident depends on the explosion and deflagration process. In the methane-air explosion in a tunnel, the flame accelerates from the ignition point. However, where it begins to decelerate is not clear. The purpose of this paper is to examine the explosion overpressure, flow and flame propagation beyond the premixed area of methane-air in a tunnel. Design/methodology/approach – The numerical simulation was used to study the explosion processes of methane-air mixtures in a tunnel. Based on the numerical simulation and its analysis, the explosion overpressure, flow and flame propagation rules beyond the premixed area were demonstrated for a methane-air explosion. Findings – The peak overpressure of methane-air mixture explosion was observed to reach its maximum beyond the original premixed area of methane-air. The hazardous effects beyond the premixed area may be stronger than those within the premixed area for a methane-air explosion in a tunnel. Under the conditions of this study, the ratio between the length of combustion area (40 m) and that of original premixed area (28 m) reaches 1.43. Originality/value – Little attention has been devoted to investigating the explosion overpressure, flow and flam propagations beyond the original premixed area of methane-air in a tunnel. Based on the numerical simulation and the analysis, the propagation rule of overpressure wave and flow inside and outside the space occupied by methane/air mixture at the volume fraction of 9.5 percent in a tunnel were obtained in this work.

Download Full-text

Dust explosion of oil shale and olive cake solid fuels: a comparison study

International Journal of Energy Research ◽

10.1002/er.1055 ◽

2005 ◽

Vol 29 (10) ◽

pp. 871-878 ◽

Cited By ~ 6

Author(s):

M. A. Hamdan ◽

A. Sakhrieh

Keyword(s):

Oil Shale ◽

Solid Fuels ◽

Dust Explosion ◽

Comparison Study ◽

Olive Cake

Download Full-text

Flame propagation and flow field measurements in a Hartmann dust explosion tube

Powder Technology ◽

10.1016/j.powtec.2017.10.001 ◽

2018 ◽

Vol 323 ◽

pp. 346-356 ◽

Cited By ~ 5

Author(s):

Sepideh Hosseinzadeh ◽

Maarten Vanierschot ◽

Frederik Norman ◽

Filip Verplaetsen ◽

Jan Berghmans

Keyword(s):

Flow Field ◽

Flame Propagation ◽

Field Measurements ◽

Dust Explosion

Download Full-text

Efficiency of triggered barriers in dust explosion suppression in galleries

Journal of Loss Prevention in the Process Industries ◽

10.1016/s0950-4230(01)00056-0 ◽

2001 ◽

Vol 14 (6) ◽

pp. 489-494 ◽

Cited By ~ 7

Author(s):

K Lebecki ◽

J Śliż ◽

K Cybulski ◽

Z Dyduch

Keyword(s):

Dust Explosion ◽

Explosion Suppression

Download Full-text

Explosion Characteristics and Flame Propagation Behavior of Mixed Dust Cloud of Coal Dust and Oil Shale Dust

Energies ◽

10.3390/en12203807 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3807 ◽

Cited By ~ 3

Author(s):

Junfeng Wang ◽

Yansong Zhang ◽

Huifeng Su ◽

Jinshe Chen ◽

Bo Liu ◽

...

Keyword(s):

Gas Phase ◽

Flame Propagation ◽

Oil Shale ◽

Coal Dust ◽

Dust Cloud ◽

Pressure Rise ◽

Volatile Matter ◽

Experimental Device ◽

Dust Particles ◽

Propagation Behavior

Coal and oil shale are often mined and utilized together, and mixed dust is easily formed in these processes. In order to ensure safe production in these processes, the explosion characteristics of mixed dust were studied. Using a Godbert-Greenwold (G-G) Furnace experimental device, Hartmann tube experimental device, and 20 L explosion vessel, the oil shale and coal mixed dust ignition sensitivity experiment, flame propagation experiment, and explosion characteristics experiment were carried out. The minimum ignition temperature (MIT), minimum ignition energy (MIE), maximum explosion pressure (Pmax), maximum rate of pressure rise ((dp/dt)max), and explosibility index (KSt) parameters and the flame propagation behavior of the mixed dust were analyzed in detail. A scanning electron microscope (SEM) analysis of the coal and oil shale dust before and after the explosion was carried out to study the changes in the microscopic morphology of the dust particles. The results show that due to the oil shale having a high volatile content and low moisture content, in the mixture, the greater the percentage of oil shale, the more likely the dust cloud is to be ignited and the faster the explosion flame is propagated; the greater the percentage of oil shale, the greater the (dP/dt)max and KSt will be and, under a high dust concentration, a greater Pmax will be produced. During explosion, coal dust will experience particle pyrolysis and the gas phase combustion of the volatile matter, followed by solid phase combustion of coal char, whereas oil shale dust will only experience particle pyrolysis and the gas phase combustion of the volatile matter.

Download Full-text