How to Select a Pump for Hydrochloric Acid

Hydrochloric acid is the liquid that ends the 'just make it stainless' habit. HCl attacks SS 316 aggressively at almost any concentration — the chromium-oxide film that protects stainless steel simply cannot survive chloride acid attack. Every reliable HCl pump is non-metallic.

The material decision

Polypropylene (PP) handles HCl across normal concentrations up to about 70 °C and is the economical standard. PVDF extends temperature capability toward 110 °C and adds margin for fuming grades and oxidising contaminants. Both eliminate corrosion of the wetted end entirely — there is no metal to attack.

The sealing decision

For dilute, cold transfer duty, a PP/PVDF centrifugal pump with a properly specified mechanical seal is entirely serviceable. For concentrated or fuming acid — where a leaking seal means hazardous vapour — the seal-less magnetic drive construction is the professional answer: no dynamic seal, no leak path, nothing to report to the safety officer.

The duty questions that change the selection

Concentration first: 5% pickling rinse and 36% fuming acid are different pumps. Temperature second, measured at the pump, including cleaning cycles. Specific gravity third — 36% HCl runs around SG 1.18, which raises motor power roughly proportionally. Finally the suction arrangement: tanker unloading and below-grade tanks change the construction choice entirely.

The installation details

Use PP/PVDF or lined suction piping — a plastic pump on a corroding steel suction line just relocates the failure. Provide a strainer during commissioning. And plan the drain: an acid pump that cannot be emptied safely is a maintenance hazard.

Send the concentration, temperature, flow, head and suction layout — we return a confirmed selection with the material stated in writing, backed by a Material Test Certificate on delivery.