All chemicals stored in polyethylene tanks require some form of venting in order to keep them safely stored. However, in some cases, the harmful fumes emitted from the chemicals cannot be released directly into the atmosphere. Fuming chemicals require special considerations to reduce harmful vapors before they are evacuated. There are many important things to consider when managing harmful chemical fumes and controlling air pollution.
What Causes Chemical Fumes?
Some chemicals naturally create their own fumes and may be accelerated as a result of the airflow in a storage tank. Many storage tanks are pneumatically loaded via a tanker truck which uses an an air system to push the chemical through the fill line into the tank. This causes more cubic air per minute flowing through into the tank with the chemical. Regardless of whether chemicals produce fumes naturally or with the presence of airflow, the chemicals that produce the most fumes are the ones that require extra precautions in storage.
High Fuming Chemicals
Three very common chemicals known for fuming are:
- Hydrochloric Acid: This chemical needs to be stored with a fume-tight lid in order to comply with federal regulations; a very corrosive chemical with similarly corrosive fumes, it can endanger employees and pose a threat to the integrity of the equipment.
- Acetic Acid: This chemical emits very pungent fumes that plant operators usually want to control; it's used to make vinegar and creates an unpleasant smell.
- Hydrofluoric Acid: This chemical also creates very toxic gas; the fumes can actually etch the glass in a building and attack the metals of equipment surrounding it.
The fumes from all of these chemicals, especially HCL, are aggressive and can even damage the polyethylene tanks themselves if not vented properly.
Properly Venting Chemical Fumes
It's crucial to make sure chemical storage tanks are properly vented. You want to make sure the pressure in the tank is less than 10 inches of water column in order to protect it from overpressurization and potential failures. You can also implement some or all of the following items to ensure adequate ventilation:
- Fume-tight manway covers: These lids help to keep fumes from seeping out of the tank and into the air. They can also be retrofitted to a tank if you decide to use them after you've already constructed the tank system.
- Scrubbers: Certain toxic or high-fuming chemicals require a scrubber for proper venting. Scrubbers are also helpful for chemicals like acetic acid, to ensure that the fumes are released into an atmosphere where they won't be in contact with people.
- OR-1000: OR-1000 is the #1 system for oxidizing chemical environments. It was designed to address the effects of highly oxidizing chemicals by adding an additional chemical barrier of antioxidant resin to the surface of the tank.
Managing harmful chemical fumes is an important aspect of safely storing chemicals at your facility.
For more information about chemical storage venting, contact one of our chemical storage experts.