• Raw coal is fed into the coal inlet, dried and ground to a fine dust on the grinding table. Hot air (inert gas) is used to pneumatically carry the coal dust upward through the classifier and into the transport pipe.
Coal Pulverizer Explosion History:
• Loss history for the past ten years due to dust explosions from FM Global Data Sheet 7-76:
• Six in ball/hammer mills for a loss of $2,012,000.
• Ten in Pulverizer/Fragmentizers for a loss of $1,643,000.
Coal Pulverizer Sources of Ignition:
• Tramp metal, i.e. railroad spikes, and pyrites are a typical source for ignition.
• A loss history evaluation for a recent twelve year period indicates that a loss of inerting or not following inerting
procedures was a factor in all explosion incidents.
• Many explosion incidents resulted when proper isolation, clearing, or shutdown procedures were not followed.
• Half of all explosions occurred during a hot restart.
• Hot furnace gases backing up into the pulverizer system was responsible for several explosions.
Coal Pulverizer Solution:
• Explosion Venting of the pulverizer is not allowed per NFPA 8503 or FM 6-24/13-21, so this equipment is best
protected by either containment (tested to 200 psi), or an Explosion Suppression System. Chemical Isolation should be used on the inlet and outlet to prevent flame propagation to other equipment.
Archives
Recent Posts
Categories
Calendar
Meta
EXPLOSION PROTECTION COAL PULVERIZER
Coal Pulverizer Functionality:
• Raw coal is fed into the coal inlet, dried and ground to a fine dust on the grinding table. Hot air (inert gas) is used to pneumatically carry the coal dust upward through the classifier and into the transport pipe.
Coal Pulverizer Explosion History:
• Loss history for the past ten years due to dust explosions from FM Global Data Sheet 7-76:
• Six in ball/hammer mills for a loss of $2,012,000.
• Ten in Pulverizer/Fragmentizers for a loss of $1,643,000.
Coal Pulverizer Sources of Ignition:
• Tramp metal, i.e. railroad spikes, and pyrites are a typical source for ignition.
• A loss history evaluation for a recent twelve year period indicates that a loss of inerting or not following inerting
procedures was a factor in all explosion incidents.
• Many explosion incidents resulted when proper isolation, clearing, or shutdown procedures were not followed.
• Half of all explosions occurred during a hot restart.
• Hot furnace gases backing up into the pulverizer system was responsible for several explosions.
Coal Pulverizer Solution:
• Explosion Venting of the pulverizer is not allowed per NFPA 8503 or FM 6-24/13-21, so this equipment is best
protected by either containment (tested to 200 psi), or an Explosion Suppression System. Chemical Isolation should be used on the inlet and outlet to prevent flame propagation to other equipment.