Hydrochloric acid (HCl) and chemical storage tanks

For hydrochloric acid, including HCl 30%, we most often weld tanks from PE100 or PP-H. There is no rule that fits every case: the choice depends on concentration, working and peak temperature, contact time and whatever else ends up in the tank. We have delivered, for example, a 12,000 L acid tank in PE100 and, for a plant in Câmpia Turzii, Romania, 25 m³ double-wall HCl tanks.

Wall thickness is never guessed. We calculate it to DVS 2205 from the volume, dimensions, liquid density and the material producer's data sheets. Welded thermoplastic tanks follow EN 12573, and the welding is done by DVS-certified staff. Hydrochloric acid is denser than water, so a tank designed for water is not automatically fit for acid. Where the chemistry calls for it, we also discuss PVDF.

Spilled acid attacks concrete, rebar and any metal nearby, so leak protection is settled at quotation stage. A double-wall tank has the inner vessel enclosed in a second welded shell. It takes little floor space, suits a tank standing on its own, and the interstitial space can be checked visually or fitted with a leak sensor. That is how we built the 25 m³ HCl tanks for Câmpia Turzii.

With a bund, one or more tanks stand in a welded containment tray made from the same material. It works well when you have several tanks or want direct access to the bottom valves. The bund volume is set by your designer, based on your environmental permit. The HCl 30% tank we delivered in 2025 and our 7,000 L acid tanks were both built with a bund. Acids and alkalis, such as HCl and NaOH, never share a bund.

Concentrated hydrochloric acid gives off corrosive fumes, especially during filling, when the air inside is pushed out. That is why an HCl tank should not vent freely into the building. We size the vent nozzle for the filling and emptying flow and place it so it can be piped to the scrubber or gas washing column in your plant.

If your plant has no fume treatment yet, tell us early. We have already delivered a welded exhaust gas treatment system with a ventilation filter. The overflow, discharging into the bund, and a sealed manway for inspection are agreed at the same stage.

Level can be read on an external transparent sight tube, a mechanical float indicator, or a sensor wired to your control system. Nozzles are welded in the shop, flanged or socketed, where your drawing shows them: fill, bottom drain, pump suction, vent, overflow, level and recirculation. PVC-U, PP-H and PVDF valves and fittings are available from the Weldplast catalogue. If the tank is filled from a road tanker, ask for a high-level alarm that can be seen or heard from the unloading point.

For road tanker unloading, we agree the height and size of the fill nozzle, the coupling used by your acid delivery and the pipe route in advance. A fill pipe running down towards the tank bottom reduces splashing and fumes during filling.

Nearly half of our customers send a drawing or a specification with their enquiry. That is the fastest route to an accurate quote, but a hand sketch with the main dimensions and nozzle positions is a perfectly good starting point.

Along with the drawing, we need the substance and concentration with its safety data sheet, the normal and maximum temperature, the working volume and the available space, including door sizes and building height. Tell us whether the tank stands indoors or outdoors, whether you want a double wall or a bund, how it will be filled, and whether you need transport and installation.

We build tanks up to about 35 m³ each. For larger volumes we propose several tanks or talk the project through in detail.