Effect of fluorine-containing explosion suppressants on methane explosions

To investigate the suppression effect of fluorine-containing explosion suppressants (FESs) on methane (CH4) explosions and the corresponding suppression mechanism, a 20-L spherical explosion testing device was used to analyze and compare the effects of perfluorohexanone (C6F12O) and heptafluoropropane (C3F7H) on CH4 explosion parameters. The explosion limit and pressure were obtained before and after adding these FESs. CH4 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 C6F12O and C3F7H reduces the upper explosion limit (UEL) and lower explosion limit (LEL) of CH4, with increased concentrations of C6F12O and C3F7H causing faster decreases in the UEL than in the LEL. The explosion limit range of CH4 with C6F12O is smaller than that with C3F7H. When the concentration of CH4 is low, increases in the C6F12O and C3F7H 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 CH4 is high, the two FESs only inhibit the explosion pressure. Compared with C3F7H, C6F12O has a stronger inhibitory effect; C6F12O has a smaller CH4 explosion triangle area, higher critical oxygen concentration (18.27