Internal gear Pump Material for acids ( corrosive, toxic)
Internal gear Pump Material for acids ( corrosive, toxic)
(OP)
For acid such as sulfuric acid what is the suitable casing construction material ?
Is Ss316 or ss316 L could have corrosive resistant
Is alloy 20 is more superiour in term corrosive resistant compare to stainless steel ?
What kind of failure of pump usually when it react with acid ?
Is Ss316 or ss316 L could have corrosive resistant
Is alloy 20 is more superiour in term corrosive resistant compare to stainless steel ?
What kind of failure of pump usually when it react with acid ?





RE: Internal gear Pump Material for acids ( corrosive, toxic)
RE: Internal gear Pump Material for acids ( corrosive, toxic)
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Internal gear Pump Material for acids ( corrosive, toxic)
RE: Internal gear Pump Material for acids ( corrosive, toxic)
That said, if the expected service life of the system is short, such as for an experimental or demonstration application, then these greater costs are likely to not be justified. If there are system requirements for fluid purity, then the corrosion of the pump and piping system could introduce unacceptable trace contamination into the pumped fluid. Careful attention to acid concentration, temperature, and the potential for localized variation in concentration can play a major role in determining whether an all non-metallic system may be justified even for a relatively short service life system.
The corrosive attack rates can vary dramatically with differing concentrations. This is particularly evident with sulfuric acid where the corrosion rate for commercially pure sulfuric acid on carbon steel is very modest but very severe for lower concentrations.
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Internal gear Pump Material for acids ( corrosive, toxic)
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Internal gear Pump Material for acids ( corrosive, toxic)
Any advise using alloy c for pump construction to handle sulfuric ?
RE: Internal gear Pump Material for acids ( corrosive, toxic)
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Internal gear Pump Material for acids ( corrosive, toxic)
It really depends on the concentration and temperature of the sulfuric acid that you want to pump. For example, carbon steel would be a fine material of construction for sulfuric acid piping if the sulfuric acid is 94%-98% concentration and <100°F as sulfuric acid within that range isn't very corrosive to steel. However, I wouldn't recommend this material for a pump, even if your acid is within that range. The reason being is that sulfuric acid likes to act a little strange when higher velocities/higher turbulence is involved. The corrosion rate of steel by sulfuric acid is greatly increased in high velocity/turbulent regions, especially at higher temperatures. And I'm not talking about erosion due to the higher velocities/turbulence, the corrosion of the metal in a high velocity/turbulent region is notably more prominent than the 94%-98% sulfuric acid in a lower velocity/less turbulent region.
I have a system that circulates ~100°F 94%-98% sulfuric acid through carbon steel pipes. Recently we started having issues of leaks forming in the pipe elbows. Ultrasonic thickness readings of the pipe showed the pipe to be in good condition, but visual inspection of the elbows showed that they were seeing a significantly higher corrosion rate (again corrosion, not erosion) than the rest of the piping system. Upon further research I came across the studies that showed how velocity/turbulence affected the corrosion rate of sulfuric acid on steel.
So, in conclusion, the wet end of a centrifugal pump is a very turbulent region, so that become important when selecting a material of construction for sulfuric acid. I have had success with both Alloy 20 and Hast. C in turbulent 94%-98% sulfuric acid service (~100°F). As for 316L (CF3M when cast) I have no experience with it in said service, but it is possible, that it may see issues with high velocity/turbulent sulfuric acid, when typically it would not any other time.
I have also attached a link to a PDF version of the NorFalco Sulfuric Acid Handbook that may be of use to you, either now or possibly in the future. However, it does not mention the velocity effect on corrosion rate, so keep that in mind when reading their corrosion charts, additional research may still be needed.
And finally to ccfowler's point, non-metallic pumps/systems should also be considered, as they could result in a cost savings. Also, make sure to consider how you plan on sealing the pump, you may want to consider a mag-drive pump in this service as well, but understand there are pros and cons to everything and there is usually never a "perfect" solution to every problem.
I hope sharing my experience has helped. Good luck.