Abstract: In order to improve explosion control effectiveness of powder coatings during electrostatic spraying process, an experimental platform with a size of 80 mm×80 mm for cross profile and 800 mm at height was designed, explosion propagation characteristics of coatings with organic and inorganic pigment additions were studied, and inerting and anti-explosion effects of flue gas were explored. The results show that flame propagation of powder coating can be accelerated significantly with organic pigments addition, causing its peak velocity to rise from 4.8 m/s to 7.5 m/s. Applying flue gas can suppress it for both powder coating/air mixtures with inorganic and organic pigments, but in a different way. For the former case, explosion intensity progressively attenuates along with increase of flue gas volume, while for the latter, there is only a delay in ignition time, and peak velocity of flame propagation exhibits no obvious reduction when oxygen content drops to 18%. However, when the content is 15%, ignition difficulty will increase sharply, and self-sustained flame propagation will disappear.

Key words: flue gas, powder coating, inerting effects, explosion flame propagation, curing by crosslinking, powder/air mixtures