Many different types of explosions may occur in waste incineration processes

INERIS has had to investigate several accidental explosions which occurred in domestic waste incineration processes. From the circumstances of the explosions and from damages observed, it has been possible to reveal that the mechanism of each explosion was either based on physical or chemical phenomena of various types. In studied "physical explosion" the released energy was initially stored in a physical way. It corresponds to the rapid vaporisation of overheated water, or the burst of a pressurised vessel, whereas in studied chemical explosions, the released energy results from a chemical reaction that involves either the explosive decomposition of a thermally unstable product or the explosion of a gaseous explosive atmosphere (ATEX). Each type of explosion is detailed with help of an example. It is pointed out that lack of process control due to the somehow unexpected nature of wastes and equipment failure are common causes of these explosions. They usually induce equipment damages. Finally, the present review illustrates the need for this process to deserves a better attention from designers and end-users in order to better control explosions