Effect of fluorine-containing explosion suppressants on methane explosions

To investigate the suppression effect of fluorine-containing explosion suppressants (FESs) on methane (CH 4 ) explosions and the corresponding suppression mechanism, a 20-L spherical explosion testing device was used to analyze and compare the effects of perfluorohexanone (C 6 F 12 O) and heptafluoropropane (C 3 F 7 H) on CH 4 explosion parameters. The explosion limit and pressure were obtained before and after adding these FESs. CH 4 explosion triangles under the action of the FESs were drawn, and the explosion hazard degree ( F ) was determined. The results reveal that the addition of C 6 F 12 O and C 3 F 7 H reduces the upper explosion limit (UEL) and lower explosion limit (LEL) of CH 4 , with increased concentrations of C 6 F 12 O and C 3 F 7 H causing faster decreases in the UEL than in the LEL. The explosion limit range of CH 4 with C 6 F 12 O is smaller than that with C 3 F 7 H. When the concentration of CH 4 is low, increases in the C 6 F 12 O and C 3 F 7 H concentrations first cause an increase and then a decrease in the explosion pressure, and the rise rate of explosion pressure increases. After adding the aforementioned FESs, F first increases and then decreases. When the concentration of CH 4 is high, the two FESs only inhibit the explosion pressure. Compared with C 3 F 7 H, C 6 F 12 O has a stronger inhibitory effect; C 6 F 12 O has a smaller CH 4 explosion triangle area, higher critical oxygen concentration (18.27% vs. 17.70%), and lower F value. Both FESs have promotion and inhibition effects on CH 4 explosion because of the comprehensive physical and chemical effects on CH 4 explosions; however, the performance of C 6 F 12 O is superior to C 3 F 7 H.