The Inhibition Effect of Gas–Solid Two-Phase Inhibitors on Methane Explosion

Abstract

In order to study the inhibition effect of gas-solid two-phase inhibitors on a methane explosion, the influence of these parameters was investigated and compared with that of single-phase inhibitors. The results show that the inhibition effect of gas-solid two-phase inhibitors on a methane explosion is better than the added effect of two single-phase inhibitors, indicating that a synergistic effect can be obtained by gas-solid two-phase inhibitors. The two-phase inhibitors which are composed of NaHCO 3 (BC) powders and inert gas have a better suppressing property than those composed of NH 4 H 2 PO 4 (ABC) powders and inert gas. The two-phase inhibitors composed of CO 2 and powders have a better suppressing property than those composed of N 2 and powders. The 9.5% premixed methane-air mixture can be completely inhibited by 0.10 g/L BC powders mixed with 8% CO 2 . The suppression mechanisms of the gas-solid two-phase inhibitors on the methane explosion were discussed.Energies 2019, 12, 398 2 of 10 Chemical powders, such as carbonate, phosphate, halide etc., have widely been used as extinguishing agents on methane explosions and dust explosions, due to their physical and chemical inhibition effects. The inhibition effects of various chemical powders (such as SiO 2 , CaCO 3 , ABC, BC, zeolite, red mud, Al(OH) 3 , composite powders, etc.) on methane explosions have been studied [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. The experimental results presented that different powders showed different suppression performances on methane explosions.Recently, more attentions have been paid to gas-solid two-phase inhibitors [27][28][29]. Deng [30] studied the influence of a two-phase inhibitor Mg(OH) 2 /CO 2 on methane explosion, and observed that the actual superposition effect was inferior to the theoretical superposition effect. The research by Luo [31] showed that the ABC/CO 2 two-phase inhibitor had a cooperative synergism, which gave a good suppression performance on methane explosion. Jiang [32] researched the suppression effect of ultrafine ABC powders and N 2 mixture on methane explosions. The results showed that the maximum decreasing amplitudes of the overpressure and the flame speed were 76.8% and 100%, respectively. According to the research, it is clear that the suppression effect of gas-solid two-phase inhibitors was better than the single-phase gases or powders. However, there are few studies comparing the actual suppression effect of gas-solid two-phase inhibitors with the theoretical addition effect suppressed by single-phase gas and powders, respectively. It is not clear whether there is a cooperative effect between inert gas and powders.In this paper, the influence of ABC powders (NH 4 H 2 PO 4 ), BC powders (NaHCO 3 ), N 2 , CO 2 and gas-solid two-phase inhibitors on the 9.5% premixed methane-air explosion parameters, including the max-pressure, the time to max-pressure and the maximum rate of pressure rise, was experimentally researched using a 20 L spherical vessel. The actual suppre...

Numerical Investigation of the Required Quantity of Inert Gas Agents in Fire Suppression Systems

“…Equation (10) gives an expression to calculate oxygen mass fraction as a function of ventilation mass rate, discharge mass rate, and discharge time.…”

“…Some research [9] has been carried out to investigate the application of inert gas agents in some typical buildings for disabled persons, elderly in nursing homes, and other citizens with reduced cognitive function, etc. Inert gas agents also have great potential as inhibitors of gas explosions by reducing or possibly eliminating the risk of explosions [10][11][12].…”

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

“…A 20 L explosion vessel is commonly used to study the explosibility of dust or combustible gases [26][27][28]. Figure 6 shows the explosion pressure history of coal dust measured at a concentration of 250 g/m 3 , and indicates two parameters used to evaluate the explosibility of dust: P max and (dP/dt) max .…”

Experimental Study on Two-Phase Explosion Suppression of Gas/Pulverized Coal by Explosion Suppressant

“…The results showed that the injection of nitrogen and ABC powder has an obvious inhibitory effect on the explosion overpressure and flame propagation velocity. Wang et al 22 studied the effect of a gas–solid two-phase inhibitor on gas explosion. The results showed that an inhibitor composed of NaHCO 3 (BC) powder/inert gas had better inhibition performance in comparison to an inhibitor composed of NH 4 H 2 PO 4 (ABC) powder/inert gas.…”