Summary

A gas-phase explosion in a storage tower with semichemical pulp at a paper mill has possibly been caused by combustion of a mixture of hydrogen and air. The hydrogen was formed by microorganisms in the pulp. Ignition may be due to electric sparks in connection with an electric field in the mist above the pulp.

Accident Description

A gas-phase explosion took place in a 1,300 m3 storage tower for semichemical pulp at a paper mill. The storage tower was 21 m high and equipped with an agitator at the bottom. By a pumping arrangement, the pulp was circulated from the bottom to the top through external pipes connected with the mill (Fig. 1).

On a given day the production was stopped at a time when the storage tower was loaded with 1,000 m3 pulp at a view more

A hydrogen explosion occurred in an Uninterruptible Power Source (UPS) battery room. The explosion blew a 400 ft2 hole in the roof, collapsed numerous walls and ceilings throughout the building, and significantly damaged a large portion of the 50,000 ft2 building. Fortunately, the computer/data center was vacant at the time and there were no injuries.

The facility was formerly a large computer/data center with a battery room and emergency generators. The company vacated the building and moved out the computer equipment; however the battery back-up system was left behind. The ventilation for the battery room appeared to be tied into a hydrogen monitoring system. The hydrogen sensor was in alarm upon emergency responders arriving at the scene (post-explosion). 911 callers view more

Hydrogen was stored in a plant in a 42 ½ ft diameter sphere made of 3/16 inch steel. The sphere was partitioned into two hemispheres by a neoprene diaphragm attached around the equator. Hydrogen was stored under the diaphragm, while the upper hemisphere contained air. An explosion-proof fan was situated in the upper portion of the sphere in order to provide a slight positive pressure on the top of the diaphragm.

When the plant was shut down for a local holiday, the fan on top of the hydrogen sphere was also stopped. During plant startup two days later, a violent explosion occurred in the sphere. The sphere shell was torn into many sections by the explosion, and some of the sections were propelled as far as 1,200 ft. Some of these sections struck flammable liquid storage tanks view more