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Pilot plant for Steel Giant

April 4, 2025

BHS-Sonthofen is supplying a candle filter pilot plant for an international steel producer at its site in Avilés, Spain. In addition to new and improved products, the Group's corporate goals include CO2-neutral steel production by 2050. The BHS system will be used for research and development in the field of solid-liquid separation.

High-efficiency filtration under extreme conditions

BHS-Sonthofen supplies a candle filter system for iron oxides in highly alkaline media (pH-value 16). A diaphragm pump feeds the suspension into the filter vessel at a constant flow rate. The solid particles are retained by the filter candle, while the clean filtrate passes through. Once the maximum permissible differential pressure between the filtrate outlet and the vessel's internal pressure is reached, the tank is emptied. The unfiltered suspension is then returned to the supplied agitator tank. The moist filter cake is dewatered by a gas flow, blown off from the back of the filter candle, and discharged from the system – after which the next filtration cycle begins.

Compact and flexible solution for low throughput

Due to the very low required throughput of approx. 150 l/h, BHS has eveloped a customized solution with only one filter candle (CF 12-001) and a total filter area of about 0.3 m². To prevent heavy solid particles from settling at the bottom of the filter vessel, a bypass at the top of the filter ensures a homogeneous suspension, forming a uniform cake thickness on the candle. To achieve a uniform solids content of approx. 20 wt.-%, the filter is fed from an agitator tank, which has been supplied by BHS´ long term Spanish partner Caperva.

Mobile and user-friendly

The customer's requirement was to install the entire system on a mobile base unit so that the pilot filter could be used at different locations. The candle filter system, including agitator tank and control unit, is located on a frame measuring just 2.3 x 1.8m and can be easily moved using a pallet truck.

The process can be run fully automatically via the integrated control system or manually, when new products are tested on the filtration system for the first time. The entire process is visualized on an HMI and can be conveniently controlled via a touch panel.