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In earlier post "FAYF - Acid Solution Storage", Carbon Steel (CS) may be used for concentrated Sulfuric acid (H2SO4) at ambient temperature. However, diluted H2SO4 may severely corrodes CS. Non-metal material (PVC, PFA, FEP, PTFE) may be used for concentrated and diluted H2SO4 solution. Nevertheless, these materials lose it strength at high temperature and high pressure operation. Using non-metal material may not be cost effective at high temperature and high pressure design.
Thus for high temperature and high pressure operation, exotic material Zirconium and its alloy may be considered.
Zirconium has excellent corrosion resistance in all concentrations of sulfuric acid up to 70% and well above boiling.
Zirconium Limitation and its work-around...
H2SO4 concentration exceeded 55%, there will be preferential corrosion attack at weld. WIth H2SO4 concentration exceeded 65%, there may be Sulfide Stress Corrosion Cracking (SSCC) in Zirconium. Thus, stress-relief anneal (heat treatment) should be conducted to avoid above mentioned preferential corrosion and SSCC. However, In the presence of fluoride ions, Zirconium should not be used with sulfuric acid.
For H2SO4 concentration exceeded 70%, other material such as Tantalum may be considered. Tantalum can take any H2SO4 concentration with temperature upto 200 degC.
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RELATED POST
Subscribe FREE - Plant Services
In earlier post "FAYF - Acid Solution Storage", Carbon Steel (CS) may be used for concentrated Sulfuric acid (H2SO4) at ambient temperature. However, diluted H2SO4 may severely corrodes CS. Non-metal material (PVC, PFA, FEP, PTFE) may be used for concentrated and diluted H2SO4 solution. Nevertheless, these materials lose it strength at high temperature and high pressure operation. Using non-metal material may not be cost effective at high temperature and high pressure design.Thus for high temperature and high pressure operation, exotic material Zirconium and its alloy may be considered.
Zirconium has excellent corrosion resistance in all concentrations of sulfuric acid up to 70% and well above boiling.
Zirconium Limitation and its work-around...
H2SO4 concentration exceeded 55%, there will be preferential corrosion attack at weld. WIth H2SO4 concentration exceeded 65%, there may be Sulfide Stress Corrosion Cracking (SSCC) in Zirconium. Thus, stress-relief anneal (heat treatment) should be conducted to avoid above mentioned preferential corrosion and SSCC. However, In the presence of fluoride ions, Zirconium should not be used with sulfuric acid.For H2SO4 concentration exceeded 70%, other material such as Tantalum may be considered. Tantalum can take any H2SO4 concentration with temperature upto 200 degC.
Read more details explanation in
Note :
*This article is only available FREE to Chemical Engineering Magazine registered user.
Login required. Registration FREE (Click HERE).
** Download immediately as article available FREE within short period (JUNE 2008 only)
*** Found lost link or unable to download, may contact me...
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