What materials are used for pumps that can operate in sulfuric acid media? In particular, what material should be used under high-temperature conditions (such as 140°C)? ）

In sulfuric acid media, especially under high-temperature conditions, the material choice for pumps is crucial, as it directly affects the equipment’s lifespan and the safe operation of the plant. In short, there is no \"universal\" material that can handle sulfuric acid at all concentrations and temperatures. The choice of material depends entirely on the concentration of sulfuric acid, temperature, the presence of impurities (such as chloride ions), and the operating conditions of the pump (such as flow rate, whether it is running idle). Next, I will explain in detail different scenarios, with a focus on the choices under high-temperature conditions. Core principle: The corrosive properties of sulfuric acid. The corrosiveness of sulfuric acid is quite unique: dilute sulfuric acid has strong reducing properties, while concentrated sulfuric acid has strong oxidizing properties. This leads to an interesting phenomenon: some materials resistant to dilute sulfuric acid are not resistant to concentrated sulfuric acid, and vice versa. For every 10°C increase in temperature, the corrosion rate roughly doubles; therefore, material selection requirements at high temperatures are extremely stringent. I. Room temperature or moderate-low temperatures (90%): Carbon steel, cast iron, 316L stainless steel – cost-effective; corrosion resistance relies on a passivation film. High temperatures (~140°C): Dilute sulfuric acid – Hastelloy B-3, Zirconium 702, high-quality PFA lining – top performance at a high price. High temperatures (~140°C): Concentrated sulfuric acid – Zirconium 702, Hastelloy B-3, 316L (requires verification); it is necessary to refer strictly to corrosion charts. High-temperature sulfuric acid with chloride ions: Hastelloy C-276, titanium-palladium alloy. B-3 alloy is not resistant to chloride ions and is therefore an inappropriate choice for such conditions. Final decision-making process: Determine the exact operating conditions: concentration, temperature, chloride ion content, presence of particles (abrasion), pH value, and operation mode (continuous/intermittent) – these are all prerequisites for selecting the appropriate material. Consulting the Iso-Corrosion Chart: This is the most scientific tool. Material suppliers such as those of Hastelloy and zirconium provide corrosion charts in sulfuric acid (corrosion rates of 0.1 mm/year and 0.5 mm/year), which allow for the quick identification of the appropriate material based on your concentration and temperature conditions. Consult professional suppliers: Provide detailed operating conditions to experienced pump manufacturers or material experts, who can offer the most reliable advice and even supply test samples for corrosion testing. Consider cost and lifespan: strike a balance between initial investment (CAPEX) and maintenance costs (OPEX). For example, although Hastelloy pumps are expensive, if they can be used for many years without needing to be replaced, their total cost may be lower than that of cheaper pumps that require frequent maintenance or replacement. For the high-temperature operating condition of 140°C you mentioned, Hastelloy B-3 and Zirconium 702 are the most reliable and commonly used choices. If the budget is limited, the possibility of using high-quality PFA-lined pumps or alloy 20 pumps can be explored, but strict operational testing is required. 3602169[/attachimg