Experimental investigation of the inerting effect of CO₂ on explosion characteristics of micron-size Acrylate Copolymer dust

To investigate the inerting effect of CO₂ on micron-size Acrylate Copolymer (ACR) dust explosion, a standard 20-L spherical chamber, with a modified 1.2-L Hartmann tube and a Godbert-Greenwald furnace was adopted to determine the explosion severity and the ignition sensitivity of ACR dust under various CO₂ concentrations (ϕ). The results indicated that the explosion severity and the ignition sensitivity of ACR dust decreased gradually as ϕ increased. When ϕ increased to 40 vol%, decay rates of maximum explosion pressure (P_max) and dust explosibility index (K_st) were 48.1% and 58.4%, respectively. Moreover, when ϕ increased to 30 and 40 vol%, the minimum ignition energy (MIE) of ACR dust cloud increased respectively from 10 mJ to 207 and 267 mJ, where ACR dust had low sensitivity to ignition. Furthermore, the minimum ignition temperature (MIT) of ACR dust cloud was 460 °C. The MIT of ACR dust cloud increased as ϕ increased. The MIT increased by 50 °C when ϕ increased to 40 vol%. The inerting mechanism of CO₂ was that the chain reaction was interrupted or decelerated by CO₂. Besides, the carbon layer formed by carbon residues prevented the heat from transferring to the internal of ACR particles.