i prefer tfe lined pipe for small applications especially if it is in an area that i may need to service frequently. the cleaning, flushing and commissioning of this pipe can result in significant corrosion. also, the velocity issue is eliminated.
Concentrated sulfuric acid has a tendency to cause "hydrogen grooving" in carbon steel piping systems of moderate velocities. You must consider both the material and velocity in piping materials selection.
Many companies use CS for tankage and SS for nozzles and piping.
If you can assure that the concentration will not go below 96%, carbon steel works well. For small diameter piping, a cast alloy called Duriron (high silicon) also works, but cannot be bent or welded. Carpenter 20 (20Cb-3) also can hold up pretty well, but care has to be made heat treating or welding it as the wrong welding process & PWHT can really gebooger it up. If, on the other hand, you are going to run into moisture problems, where the concentration can drop, or if you are running this into a mixing system to make weaker sulfuric acid, then carbon steel is not a good selection at all.
SMF1964 has a very valid point: H2SO4 is a very aggressive dessicant and it will grab the moisture from the air. If you have the acid in a tank it can become locally diluted at the surface. H2SO4 magically becomes MORE corrosive when it is diluted to 93% or less. Moral of the story: Store it in a Nitrogen-blanketed tank or let the tank breathe through a dessicant dryer. Or use all resistant materials: Glass or Polymer lined, or exotic alloy.
JimCasey makes a good point about the dilute level of acid that will be generated in an improperly vented H2SO4 storage tank. For many years several companies have produced dessicant dryers designed specifically for concentrated H2SO4 storage tanks.
Addtionally, API has publications and inspection recommendations(including pictures)on how this dilute acid layer will corrode just a section of the tank shell.
