Inhibition Effect of KHCO₃ and KH₂PO₄ on Ethylene Explosion

The explosion risk of ethylene (C₂H₄) seriously hinders safe development of its production and processing. To reduce the harm caused by C₂H₄ explosion, an experimental study was conducted to assess the explosion inhibition characteristics of KHCO₃ and KH₂PO₄ powders. The experiments were conducted based on the explosion overpressure and flame propagation of the 6.5% C₂H₄-air mixture in a 5 L semi-closed explosion duct. Both the physical and chemical inhibition characteristics of the inhibitors were mechanistically assessed. The results showed that the 6.5% C₂H₄ explosion pressure (P _ex) decreases by increasing the concentration of KHCO₃ or KH₂PO₄ powder. The inhibition effect of KHCO₃ powder on the C₂H₄ system explosion pressure was better than that of the KH₂PO₄ powder under similar concentration conditions. Both powders significantly affected the flame propagation of the C₂H₄ explosion. Compared with KH₂PO₄ powder, KHCO₃ powder had a better inhibition effect on the flame propagation speed, but its ability to reduce the flame luminance was less than KH₂PO₄ powder. Finally, the inhibition mechanism(s) of KHCO₃ and KH₂PO₄ powders were revealed based on the powders' thermal characteristics and gas-phase reaction.