Pumps for Sulfuric Acid (H2SO4)
Why sulfuric acid is hard on pumps
Sulfuric acid punishes assumptions. Its aggressiveness does not scale simply with concentration: a material that survives dilute acid can fail in concentrated acid, and the reverse is just as true, so there is no single sulfuric acid pump. Temperature moves the line again, and diluting the acid generates its own heat. Strong acid is also noticeably denser and more viscous than water, which the hydraulic selection has to respect. Spent and contaminated acid streams, common in semiconductor and metal processing, add impurities that change the corrosion picture yet again. Every one of these variables has ruined a pump that was selected off a general chart.
Approaches that get specified
Engineered thermoplastic pumps cover a wide span of sulfuric acid duties with no metal in the wetted path: horizontal centrifugal pumps for transfer, vertical sump pumps for containment and drainage. Sealless and magnetically driven designs remove the mechanical seal leak path on a fluid nobody wants escaping. Metering pumps feed acid for pH control at high turndown. Where regulations govern the run, double containment piping keeps a primary line failure contained, an approach a central Texas semiconductor plant used for its spent acid handling. Alloy pumps hold a place at certain concentrations, which is precisely why the material call has to come from the actual duty, not the label on the tank.
How RE Merrill confirms the selection
Sulfuric acid selections live or die on concentration and temperature, so we start there. We confirm wetted materials against curated compatibility data and factory guidance before we quote, and unusual streams go to the factory for review. Send the duty: concentration, temperature, flow, head, whether the acid is fresh or spent, and whether the service is transfer, feed, or sump, and we return a confirmed selection.
Related lines
Related reading
- Code-Compliant Spent Sulfuric Acid Handling with Double-Containment Piping: A Simtech Case
- Thermoplastic vs. Metal Pumps: Which Should You Specify?
- Thermoplastic Pump Materials Guide: PVC, CPVC, PP, PVDF, ECTFE, and PTFE Compared