Hybrid C2H2/dust/air explosion characteristics of CaC2 in the presence of water drops

The explosion characteristics and influential factors of suspended calcium carbide (CaC 2 ) dust were studied using a 20-L spherical vessel. Acetylene (C 2 H 2 ) and calcium hydroxide (Ca(OH) 2 ) are the reaction products of CaC 2 and water. Therefore, C 2 H 2 /Ca(OH) 2 mixture was used as the reference sample in the experiment. Experimental results showed that the water content in the environment (air relative humidity and external water drops) had significant impacts on CaC 2 dust explosion. The explosibility of CaC 2 dust enhanced with the increasing air relative humidity In the experiments, CaC 2 dust and dry water were equally proportioned when the value of stoichiometric ratio R was 1. When the concentration of hybrid CaC 2 /dry water increased, the value of P ex of CaC 2 /dry water explosion rose first and then stabilized at 0.74   MPa, and the value of (d P /dt) ex showed a trend of rising first and then declining after reaching the maximum value of 238.25   MPa   s −1 . P ex and (d P /dt) ex of pure C 2 H 2 explosion and C 2 H 2 /Ca(OH) 2 hybrid explosion increased at the early stage and then decreased for the increasing C 2 H 2 content. P ex and (d P /dt) ex of the three samples increased in the following order: hybrid CaC 2 /dry water   <   hybrid C 2 H 2 /Ca(OH) 2   <   pure C 2 H 2 . Dry CaC 2 dust did not explode, but its explosibility was significantly enhanced for the increasing water content in the environment, and the main reason was the existence of C 2 H 2 .