Manufacturing and process plants collect the emissions from process units, tanks, vessels and other odor or emission locations in their facilities. These fumes can be mainly air or a combination of air and nitrogen with organic material from the tanks or reactors. The fumes are typically treated in an Thermal Oxidizer (TO), RTO (Regenerative Thermal Oxidizer), RCO (Recuperative Thermal Oxidizer), Catalytic Oxidizer, incinerator, boiler or used to supply air or heat in process equipment. The high temperature of the treatment equipment will destroy most of the organic material to meet EPA and State emissions standards. The required destruction level is set by the local regulators.
The fume line collection system must be designed to prevent explosions and fires. The amount of organic material and the oxygen concentration are very important design parameters. If the oxygen or organic concentration reaches a level where fire can be sustained, a fire or explosion may happen. The Lower Flammability Limit (LFL) or Lower Explosive Limit (LEL) must be determined for the fume lines for all operational conditions.
Flame arresters and explosive limit detectors are utilized to protect parts of the fume collection systems from fire and explosion. The LEL monitors continuously check the conditions in the fume collection line. Flame arresters are installed within the ducting, at specific locations, to prevent any flame that has begun in the ducting from moving through the duct. But it is most important to prevent the flame from starting in the duct system. Careful review of the operational conditions must be performed to minimize the potential of the fire or explosion. Periodic inspection is mandatory to prevent build up of material on the flame arrester element.
When a fire does occur, there is always a potential for an explosion. The operational conditions that can lead to the explosion must be carefully reviewed during the initial design or when the process is modified. Therm-A-Cor has evaluated fires and explosions in fume lines.
For litigation or engineering support on fume collection system problems, contact DonCorwin@Therm-A-Cor.com