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Electrostatic Precipitator Sparks Cement Plant Explosion

Insurance Claim, North America

April 1, 2016

A large cement production plant experienced an explosion that caused significant damage to the facility’s electrostatic precipitator (ESP), which is designed to remove dust particles from the plant’s flue gas before it is released through an exhaust stack.  The heart of a typical cement plant is the kiln—a large refractory-lined pipe that slowly rotates and is downward sloping so that the cement materials can travel by gravity down the pipe towards the kiln’s fuel burners.  The kiln’s operating temperatures (in excess of 2,600°F) cause the cement materials to react and form the final product – Portland cement.     

Flue gases from the kiln’s burners pass through the ESP, which uses high voltage electrical wires to impart a negative charge to the dust particles which are then attracted to positive (grounded) plates.  The accumulated dust particles fall by gravity into collection bins at the precipitator’s base.  ESPs are common air pollution control devices used across a wide range of industries, such as refineries and power plants.

Baker & O’Brien was engaged to investigate the cause and origin of the explosion.  We concluded that it was caused by a “flameout” at the kiln’s burners that went unnoticed for almost 20 minutes.  A flameout is the sudden extinguishing of the burner flame.  In this case, unburned hydrocarbon-rich gases continued to pass through the kiln’s burners until they were ignited by sparks in the ESP.

 

Because ESPs use high voltage electricity, there is always a potential for sparking, which makes it imperative that the flue gas entering the ESP not contain any combustible gases.  The facility remained down for an extended period of time following the explosion until repairs could be completed.  Baker & O’Brien consultants provided a report on our findings to the owner and its insurer to support decisions regarding coverage and potential subrogation.