For 98% sulfuric acid storage tanks, is it necessary to use a fluorine-lined lining?

Some say plain carbon steel will do, while others suggest carbon steel lined with PE

Some say plain carbon steel will do, while others suggest carbon steel lined with PE

Carbon steel for industrial sulfuric acid； Refined sulfuric acid steel lining F4

If it is for a storage tank, simply choosing Q345R or Q245R is sufficient; there is no need to line it with F4.

98% concentrated sulfuric acid is available in industrial grade and reagent grade; due to the different storage requirements for these two grades, the materials used for storing concentrated sulfuric acid tanks also vary； The storage requirements for industrial-grade concentrated sulfuric acid are not stringent; it is sufficient to simply clean the tank, and industrial concentrated sulfuric acid can be stored in tanks made of carbon steel ； Since carbon steel can form a passivation film in concentrations of concentrated sulfuric acid above 95%, the concentrated sulfuric acid oxidizes the surface of the steel, creating an oxide layer ； Since concentrated sulfuric acid contains very little water and thus no free ions are present, the oxide layer is not subject to further oxidation or corrosion. As a result, carbon steel tanks can be used as materials for manufacturing equipment used for storing and transporting 80%–100% concentrated sulfuric acid under conditions of normal temperature, without flow, erosion, or inflation, and in a sealed environment. No additional anti-corrosion treatment is required for the inner wall, while the outer wall only needs to undergo ordinary treatments to resist mild corrosion and weathering, with enough margin built in to account for potential corrosion.

Reagent-grade sulfuric acid is divided into reagent-grade concentrated sulfuric acid, battery-grade sulfuric acid, analytically pure sulfuric acid, and high-purity sulfuric acid; the materials used vary depending on the purity requirements for storing concentrated sulfuric acid. To store reagent-grade concentrated sulfuric acid, the storage tank must be thoroughly cleaned; if water cleaning is insufficient, concentrated sulfuric acid should be used as a cleaning agent. Because even a small amount of organic matter in the storage tank can cause the color of the concentrated sulfuric acid solution to turn yellow or black. For storage tanks used to hold concentrated sulfuric acid, it is recommended to use steel-lined PE storage tanks, as they offer safety, hygiene, and good cost-effectiveness. The use of such tanks not only ensures the cleanliness of the concentrated sulfuric acid but also addresses the corrosion issues associated with carbon steel tanks in practical use. Moreover, they serve as a substitute for expensive materials such as polytetrafluoroethylene and special stainless steels.

At room temperature, a PTFE lining is not necessary, but insulation is required to prevent high temperatures in summer.

Industrial applications at room temperature do not require PTFE lining