The effect of coolant additives on the vapour explosion behaviour in melt droplet impingement experiments

Abstract

Vapour explosions are a known hazard with potentially devastating consequences in several industries. They might occur when a hot liquid comes into direct contact with a cold and volatile liquid. Eutectic PbS-Cu2S droplet impingement experiments were performed to investigate the effect of the coolant composition on the vapour explosion behaviour. The composition was varied between water with systematic additions of NaCl, MEG, or a combination of both. The experiments were monitored with a hydrophone and a high-speed camera. Also, the resulting debris was sieved for further analysis. The investigation considered the trigger probability and explosion intensity. The latter was quantified via the size of the explosion, the height of the hydrophone signal, and the debris particle size. NaCl additions were found to increase both the trigger probability and the explosion intensity, whereas MEG additions were found to decrease the trigger probability and explosion intensity. However, combined additions of MEG and NaCl resulted in a decreasing trigger probability, while having an unclear effect on the explosion intensity.