How do you choose the right materials for a chemical storage tank?

If you’re not a professional engineer that specializes in this area, then you should consult with one for this. In Canada, only professionals licensed to professionally apply science can properly do this, and in all other situations where the application of natural sciences is required. The application of science (deduction), is not the same as science (induction). Anyone can practice science. Only professionals licensed by a professional engineering association can professionally apply science.

Selecting the proper materials for a chemical storage tank involves considering factors such as chemical compatibility, temperature, pressure, and tank design. Identify the specific chemicals to be stored and consult chemical resistance charts to ensure the chosen material can withstand them. Evaluate the temperature and pressure conditions to determine the material's mechanical properties. Choose corrosion-resistant materials for durability. Assess the tank's design requirements, such as structural integrity and potential for expansion. Consult with materials engineers and adhere to industry standards to make informed decisions, ensuring the selected materials provide optimal safety, longevity, and functionality.

Fore tanks manufactured from plastic materials the density and temperature of the liquid has a big impact on the construction requirements. Density can limit the volume of tank that can actually be manufactured due to the upper limits of the manufacturing capabilities. For example an 80m3 Vertical Tank for 96% Sulphuric Acid may need a wall thickness at the base in excess of 100mm. If the temperature of the liquid is elevated this also must be factored into the calculation. For plastic tanks, low temperatures and mechanical impacts can bring a risk of catastrophic failure where the material has become embrittled. The effect is not the same across all plastic materials, it different for GRP vs Thermoplastics and between thermoplastics.

During operations, we will need to inspect the tank. Make allowance for this and allow access space and design internals that we can easily access and inspect during shutdowns. Although we are talking about tanks it is worthwhile looking at HOIS-RP-103, HOIS Recommended Practice for Non-Intrusive Inspection of Pressure Vessels, HOIS-RP-103,

Tanks must be manufactured to recognised standard and within that standard there will be a design life such as 5, 10, 20 years... . Design life is based on a period of time and the expected conditions in which the tank will be operating. Factors such as : Density, Volume, Corrosivity, Number of Fill Cycles, Other Chemical Factors that may contribute to Stress Cracking, Ambient Temperature, Operating Temperature and more will all feed into this.

For thermoplastic tanks, the liquid density can limit the volume of tank that can actually be manufactured, due to the upper limits of the manufacturing capabilities. For example an 80m3 Vertical Tank for 96% Sulphuric Acid may need a wall thickness at the base in excess of 100mm. If the temperature of the liquid is elevated this also must be factored into the calculation and can result in a thickness that is not achievable.

I remember working in Dublin and one of our clients calculated that it would be more economical not to paint a bank of carbon steel filters. The thought process was if we add to the corrosion allowance the initial cost of the metal would outweigh the cost of painting and subsequent maintenance. So, it was decided not to paint but to let them rust slowly. Financially it may have made sense but in terms of aesthetics, it was a disaster. Especially, as these filters were visible to the public from an adjacent road. The corroded shells looked awful. So, after this, I always think of how things will look when finished.