Bulk stored chemicals can become contaminated from two major sources: debris and moisture. As the product is emptied from the chemical storage tank, dirty air and moisture can be drawn into the tank. Temperature fluctuations can also cause the tank to expand and contract, so that it “breathes” contaminants in and out.
Maintaining chemical purity is essential in many industrial chemical applications, such as computer chip manufacturing, food processing, clean in place, and pharmaceutical manufacturing. Contaminated chemicals can become less effective, and more hazardous to your storage equipment.
To prevent contamination, Poly Processing often recommends installing special accessories. Tank vent dryers and desiccant filters may be your best choice for keeping moisture out of the chemical storage tank.
Tank vent dryers can be especially valuable if you’re storing sulfuric acid. Because concentrated sulfuric acid is hygroscopic, any moisture entering the tank will be quickly absorbed into the chemical. If your supply of sulfuric acid isn’t frequently replenished, the top layer of acid will become more diluted, and more corrosive. As the contents continue to sit in the tank, the top layer of weak acid will corrode a ring around the inner tank wall.
Let’s take a closer look at the role of tank vent dryers and desiccant filters.
What Is a Tank Vent Dryer?
A tank vent dryer is a small accessory that is placed inline with the vent. When the tank breathes air in, the desiccant material in the dryer filters out contaminants, preventing moisture and debris from entering the tank space.
This decreases the corrosiveness of stored products in the storage tank, so that chemicals can be stored and drained with a higher level of purity.
In addition to preventing contaminants from entering the tank, the life of the chemical is extended. Clean up, repairs, and maintenance of the tank are reduced by filtering out these harmful contaminants.
The average tank vent dryer needs replenished desiccant only once or twice per year. It’s practically a maintenance-free system, making it an ideal solution for many storage tank systems.
Tank Vent Dryer Design Considerations
Desiccant dryers are the most common way of keeping moisture out of a tank. The size of the dryer is determined by the amount of air and the rate at which the air enters the storage tank. Generally, this is the pump-out rate, although a large tank that is nearly empty can have an air intake that’s faster than the pump-out rate.
The desiccant that is used in the dryer should be sized to last from one to six months per charge of desiccant.
Poly Processing works with a number of tank vent manufacturers to offer you the best options to meet your specific challenges. Typically, our customers coordinate the vent design with the vent manufacturer. However, we can help coordinate with the vent manufacturer and make sure the vent design meets our tank warranty requirements.
Let us help you maintain proper air flow, venting, and filtering to prevent chemical contamination with a specialized vent design.