An explosion occurred within the hydrogen processing system of a chemical plant that produces sodium chlorate for bleaching pulp and paper. The chemical process utilizes electrolytic cells and is pH-dependent. Hydrogen is produced as a byproduct and is utilized as a fuel.

At the time of the incident, the plant was at an abnormal operating level of 25% capacity. A non-routine maintenance operation to repair high-pH liquid piping was in progress. To assist, operations personnel rerouted the high-pH liquid stream to the plant sump. However, in doing this, the liquid eventually made its way back into the electrolytic process by design. Ultimately this created the root cause of the explosive condition in that the pH of the electrolytic process increased faster than the computer- view more