When designing your chemical storage tank, it’s vital to consider the chemical you’re storing before any other factor. This information allows the manufacturer to determine what material to use, what types of fittings and accessories are needed, and whether or not the tank needs an antioxidant system or other special considerations.
It’s equally important to have an upfront understanding of what processing temperatures are needed for the chemical. This information also helps the manufacturer to design the best tank for your chemical storage application.
Let’s examine the issues that revolve around proper tank design for the right chemical temperatures.
How Chemical Temperature Affects Polyethylene
Cross-linked polyethylene (XLPE) chemical storage tanks expand and contract as chemical and environmental temperatures fluctuate. The tanks must be designed with consideration for the chemical and the temperature that the chemical must be stored at.
The weight, maximum temperature (the highest temperature of the chemical in the tank), and ambient temperature (the resting temperature) of the chemical dictate the thickness of the tank. If a heavier chemical or a warmer chemical is stored in a tank not designed for those metrics, the tank can expand until it exceeds allowable hoop stress. This can result in tank failure.
Not all chemical storage tanks are made equal, because not all chemicals are equal in their properties.
Why Chemical Temperature Can Vary
Some chemicals must be stored at specific temperatures because of their chemical properties. Once a chemical like sodium hydroxide falls below a certain temperature, it will crystalize or freeze. Others, like alum, ferric and polymer, are often delivered warm and later cool down to their ambient temperature.
In certain mixing tank situations, a higher concentrated chemical can be delivered in bulk when a lower concentration is what is eventually needed. In this case, the highly concentrated chemical must be diluted. If it’s a chemical like sodium hydroxide, dilution causes an exothermic chemical reaction, which elevates the temperatures within the tank.
A tank that is properly designed and manufactured to meet the particular needs of your chemical and application will perform reliably for many years.
The Benefits of a Properly Designed and Manufactured Tank
It is possible to buy a standard tank that meets general ASTM specifications, which is prepped for a maximum of 73 degrees. However, by using a tank that merely meets ASTM standards, a chemical temperature above 73.4 downgrades the maximum allowable hoop stress. This, results in a compromised tank that can fail unexpectedly.
A thicker tank is needed for a heavier chemical’s specific gravity. In most cases, chemicals with higher ambient temperatures require robust cross-linked polyethylene rather than linear polyethylene.
Consult An Expert
Poly Processing’s XLPE tanks are designed for 100°F chemical storage but can withstand even higher temperatures. If you need a chemical storage solution for higher temperatures, consult with our engineers to ensure that your tank is properly and expertly designed.