Investigation of the physical and chemical effects of fire suppression powder NaHCO3 addition on methane-air flames

Fan, Rujia; Jiang, Yong; Li, Wei; Xiong, Caiyi; Qiu, Rong

doi:10.1016/j.fuel.2019.116048

Cited by 36 publications

(12 citation statements)

References 31 publications

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“…Surface modification such as a coating can do likewise. As a result, the extinguishing powder allows for more effective neutralization of free radicals and inhibition of the combustion process [ 1 , 7 , 9 , 10 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

et al. 2022

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This article analyzes the possibility of the modification of BC powder (a mixture of sodium bicarbonate and calcium carbonate) with magnesium hydroxide (Mg(OH)2). Extinguishing efficiency as well as the influence of this additive on other physicochemical properties were determined by performing a 13B fire test, rheological measurements of the powders, thermal tests (thermogravimetry (TG) and differential scanning calorimetry (DSC) in combination with quadrupole mass spectrometry (QMS)) and microscopic observations of the powders’ surface (scanning electron microscope (SEM) with energy dispersive X-ray analysis (EDS)). It was found that the increase of the Mg(OH)2 content causes deterioration of the rheological properties by increasing the slope angle of the flow curve in relation to the normal stress (the tangent of the flow curve slope varying from 0.258 for 5% of Mg(OH)2 up to 0.330 for 20% of Mg(OH)2). However, at the same time, the increased content of Mg(OH)2 increases the total energy of the chemical decomposition reaction (from −47.27 J/g for 5% of Mg(OH)2 up to −213.6 J/g for 20% of Mg(OH)2) resulting in the desirable higher level of heat removal from the fire. The initial extinguishing effect of the fire becomes more effective as the hydroxide content increases (within the first 2 s), but at a later stage (from t = 63 s), the temperature is no longer sufficient (it is below 350 °C) for thermal decomposition of Mg(OH)2. As such, the optimal content of Mg(OH)2 is 10–15%. The obtained results allowed for the assessment of the impact of individual powder components on its extinguishing effect and will contribute to the development of science in the field of developing new types of extinguishing powders.

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Section: Introductionmentioning

confidence: 99%

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

et al. 2022

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“… 2 − 4 The chemical process means that the powder directly participates in after gasification or produces new substances after pyrolysis to participate in the methane oxidation reaction, which interferes with the chain reaction. 4 − 11 At the beginning, researchers compared the flame suppression effect of NaHCO 3 and other various sodium salts 6 , 7 and believed that the flame suppression mechanism of sodium salt was consistent and Na could inhibit the production of OH • . With further studies, the gaseous NaOH produced after the pyrolysis of NaHCO 3 is considered to be the main substance for extinguishing the fire.…”

Section: Introductionmentioning

confidence: 99%

“…With further studies, the gaseous NaOH produced after the pyrolysis of NaHCO 3 is considered to be the main substance for extinguishing the fire. 4 , 10 − 12 NaOH inhibits the chain transfer and chain branching process by consuming a large amount of OH radicals. 13 , 14 In comparison, the chemical process plays a more important role in suppressing combustion.…”

Section: Introductionmentioning

confidence: 99%

“…The flame suppression effects of NaHCO 3 are produced by both physical and chemical processes. − The chemical process means that the powder directly participates in after gasification or produces new substances after pyrolysis to participate in the methane oxidation reaction, which interferes with the chain reaction. − At the beginning, researchers compared the flame suppression effect of NaHCO 3 and other various sodium salts , and believed that the flame suppression mechanism of sodium salt was consistent and Na could inhibit the production of OH • . With further studies, the gaseous NaOH produced after the pyrolysis of NaHCO 3 is considered to be the main substance for extinguishing the fire. ,− NaOH inhibits the chain transfer and chain branching process by consuming a large amount of OH radicals. , In comparison, the chemical process plays a more important role in suppressing combustion. At least 50% of the fire extinguishing efficiency depends on chemical processes, , which is why reducing the powder particle size can improve the efficiency of fire extinguishing.…”

Section: Introductionmentioning

confidence: 99%

“…Thereby, the chemical suppression is enhanced . For micron-level NaHCO 3 powder, when the particle size of the powder is reduced to 20 μm, the fire suppression and explosion suppression performance can be improved by about 8–10 times. , The experimental and simulation studies of Fan et al showed that when the particle size of the powder is large, the physical endothermic effect plays a major role in inhibition. On the contrary, the chemical process plays a leading role.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Coupling Analysis of Chemiluminescence and Pressure Changes in CH₄/Air Explosion Suppressed by NaHCO₃ Powder

Cui¹,

Li²,

Yang³

2020

ACS Omega

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This paper presents the coupling relationship between the flame emission spectrum and explosion characteristics of CH 4 /air mixtures with NaHCO 3 powder added. Due to the test of different concentrations of suppression powder in 20 L spherical-explosion-test devices, the flame emission spectrum and explosion pressure data were collected. In this experiment, four kinds of excited radicals, including CN*, HCHO*, CO*, and OH*, have a higher probability of being detected, and the changes of their existence duration and spectral intensity show strong regularity. Results reveal that for suppressant concentration in the range of 0–50 mg/L, together with the improvement of a suppression effect, the existence duration and spectral intensity of CN*, CO*, and OH* decrease, which is opposite to that of HCHO*. Besides, the spectral intensity of OH* and CO* shows a good linear relationship with the change of the maximum explosion pressure. Controlling the content of CN*, CO*, OH*, and HCHO* is of great significance in suppressing the explosion.

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Inhibition characteristics of coal dust explosion at the gasification atmosphere

Liang

Dai

Yin

et al. 2021

Advanced Powder Technology

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Investigation of the physical and chemical effects of fire suppression powder NaHCO3 addition on methane-air flames

Cited by 36 publications

References 31 publications

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

Coupling Analysis of Chemiluminescence and Pressure Changes in CH₄/Air Explosion Suppressed by NaHCO₃ Powder

Inhibition characteristics of coal dust explosion at the gasification atmosphere

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Investigation of the physical and chemical effects of fire suppression powder NaHCO3 addition on methane-air flames

Cited by 36 publications

References 31 publications

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

The Effect of Magnesium Hydroxide Addition on the Extinguishing Efficiency of Sodium Bicarbonate Powders

Coupling Analysis of Chemiluminescence and Pressure Changes in CH4/Air Explosion Suppressed by NaHCO3 Powder

Inhibition characteristics of coal dust explosion at the gasification atmosphere

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Product

Resources

About

Coupling Analysis of Chemiluminescence and Pressure Changes in CH₄/Air Explosion Suppressed by NaHCO₃ Powder