Insulated Outdoor Tank Storing Sodium Hydroxide

Fusion designed and manufactured a 20,000L HDPE storage tank for 50% sodium hydroxide (caustic soda). The tank was fabricated from HDPE sheet and designed for outdoor installation, with insulation and electric trace heating to prevent the chemical from crystallising in cold conditions.

The tank was designed to store 20,000 litres of 50% sodium hydroxide at atmospheric pressure, with an average operating temperature of 40°C and a maximum ambient temperature of 60°C.

One of the main considerations was maintaining the temperature of the chemical. At 50% concentration, sodium hydroxide begins to crystallise at approximately 12°C. If the temperature drops too low, crystallisation can interfere with chemical transfer and potentially block outlets and associated pipework.

The tank therefore required insulation and heating to maintain the chemical above its crystallisation temperature during colder weather.

Fusion designed the tank in accordance with DVS 2205, using a liquid design density of 1.5 and a chemical reduction factor of 1.0.

The tank was fabricated from HDPE sheet, with all butt welds carried out in accordance with DVS 2207-1. Extrusion weld sizes and welding parameters were specified in accordance with DVS 2205 and DVS 2207-4.

To limit heat loss, the tank was insulated with 50 mm of polyurethane foam. An elastomeric protective coating was applied over the insulation to protect it from outdoor exposure.

An electric trace heating system was installed at the base of the tank and encapsulated within the insulation system. This provides heat to help maintain the sodium hydroxide above its crystallisation temperature.

The completed 20,000L tank combines HDPE sheet fabrication, thermal insulation and electric trace heating in a single chemical storage unit.

The project was designed and manufactured by Fusion, including the tank fabrication and integration of the insulation and heating system.