For a medium with a pH of 4.5, what is an appropriate corrosion margin?
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This post was last edited by yakui on 2009-7-21 09:00. The mixing container has a design pressure of 0.15 MPa and a design temperature of 80 degrees; it operates at atmospheric pressure and normal temperature. The medium used is pharmaceutical water with a pH value of 4.5. The shell is made of 0Cr18Ni10Ti material, and I have chosen a corrosion margin of 4 mm. I’m not sure if this choice is appropriate; I would appreciate the advice of the experts here.
Personally, I think 4 is a bit high. In acidic media, there are two types of corrosion: chemical corrosion and electrical corrosion. If chemical corrosion is present, I believe it indicates a problem with the material chosen. For values below 200, most materials have strong resistance to H-corrosion. From a safety perspective, I think 3 would be more than sufficient
This post was last edited by SHISHOUHUA on 2009-7-24 at 16:40. PH=4.5, which classifies it as a weak acid; the temperature is 80 degrees, the operating pressure is at atmospheric pressure, and the operating temperature is room temperature. The material used is 0Cr18Ni10Ti. A normal corrosion margin of 0 is sufficient, and there is no need for a design temperature of 80 degrees either. There are three principles guiding the design of the equipment: 1. Safety and reliability ； 2. Economically reasonable ； 3. Beautiful and elegant. Designing beyond the scope constitutes a loss of quality and a waste of resources.
I agree with your approach, but I disagree with your three principles: 1. Safety and reliability； 2. Economically reasonable ； 3. Beautiful and elegant ； My three points are: 1. Meet the process requirements ； 2. Safe and reliable ； 3. Economically reasonable. 3# SHISHOUHUA
If the right material is selected, the corrosion margin should be set to 0.
Reply to 4# yuqinglin876: Safety always comes first.........