Evacuation of a Shaft Furnace for Secondary Copper Production in Austria

Application

Evacuation of a shaft furnace for secondary copper production in Austria. Scheuch pulse-jet baghouse installed downstream of the heat recovery system. Flue gas flow 27,000 m³/h, air-to-cloth ration 59 m/h.

Optimization Potential

While using copper scrap, the furnace produces high amounts of dioxins and furans, that have to be limited to a maximum emission of 0.4 ng/m³. The customer did not want to use carbon injection for dioxin removal because the baghouse filter is operating at a temperature range of 90 to 125ºC. Active carbon tends to self ignite at higher temperatures.

Solution

GORE® membrane filter media have the capability to efficiently capture the extremely fine particles (which mainly adsorb dioxins and furans). Removal efficiency for particles as fine as 0.1µm is higher than 97%.

Results

Comparison tests and measurements of different filter media showed that with GORE® membrane filter bags versus conventional bags significantly lower dioxin emissions have been achieved. The plant meets the required emission limits without injecting active carbon. In addition the GORE® membrane filter bags have a longer, effective life and a more stable baghouse filter operation than the conventional acrylic felts used before. The GORE® membrane filter bags operated from 1995 to 1998 for three years with no failure. Afterwards the baghouse temperature was increased and GORE® membrane/TEFLON® B fiberglass fabric filters have been installed.