Class and Home Problems. Modeling an Explosion: The Devil Is in the Details

Within the past 15 years, three North American pulp mills experienced catastrophic equipment failures while using 50 wt% hydrogen peroxide. In two cases, explosions occurred when normal pulp flow was interrupted due to other process problems. To understand the accidents, a kinetic model of alkali-catalyzed decomposition of peroxide was developed. Modeling a normal start-up condition where peroxide and sodium hydroxide flow to a mixer in a stoichiometric ratio does not show a significant pressure rise, but a scenario in which peroxide enters the pump in advance of the sodium hydroxide displays a rapid pressure rise that greatly exceeds the rated pressure for the pumps.