Selection of materials for nitric acid vent valves and gaskets
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Our factory has a nitric acid storage tank that holds 10 M3 of 97% nitric acid. Every time material is added to the tank, yellow smoke comes out of the vent valve located at the drainage point; the condensed liquid drips onto the tank and corrodes its surface, which is a very unsightly sight. The body of the breather valve is made of carbon steel, lined with polytetrafluoroethylene, and the gasket is also made of polytetrafluoroethylene; as a result, it doesn’t seal properly. I would like to ask everyone if there are any better options for the material of the breathing valve and the gasket
Based on your description, the breathing valve is functioning properly; it’s not a problem with the valve not sealing tightly. During feeding, the breather valve functions properly to release nitric acid gases, which combine with moisture in the air to form nitric acid that drips onto the nitric acid tank and corrodes its walls. Solution: Install a nitrogen sealing system to reduce nitric acid gas emissions