Can you please let me know the type of corrosion that could occur in an oxidation reactor in a PTA (pure terephthalic acid) plant. The process to produce purified terephthalic acid is by the catalytic liquid phase oxidation of paraxylene in acetic acid, in the presence of air. The process uses manganese or cobalt acetate as a catalyst. What are the possible types of corrosion that could be observed both externally and internally to the vessel? And what are the possible mechanisms to avoid it? The temperature is 250 degrees C and the pressure is 26 kg/cm2. The reactor shell is SA 516 GR 70 + Ti GR 1 Clad Thickness: 62+2(ti clad) and the head is SA 516 GR 70 + Ti GR 1 Clad Thickness: 65.5+ 2(ti clad). The agitator shaft and impeller are made of Ti-Gr 3.
Topic: What are the possible types of corrosion that could occur in an oxidation reactor?4 April 2012
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Brian Dalder Forum Moderator 171 Posts
Re: What are the possible types of corrosion that could occur in an oxidation reactor?4 April 2012 at 1:29pmI am not familiar with these types of chemistries so I cannot offer much in the way of guidance. It sounds like the materials of construction exposed to your reaction conditions are titanium grades 1 and 3. Titanium is generally resistant to oxidizing acids and conditions that permit the protective oxide layer to be maintained. The presence of halides may be cause for concern. Previous experience with certain MOCs at production, pilot, or lab scale might offer some insight.