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Results showed furnace extraction has been increased by 41%, blockage was eliminated from furnace offtake ducts, hood temperatures were been reduced and stack emissions were below 5 mg/Nm3.

Extraction at the furnace has increased above the design. The main fan damper is partially closed to control the extraction at the furnace. Tapping fume has been added into the same baghouse. The smelt house environment is much cooler, and it led to a decrease in maintenance of the electrode system and mechanical stokers.

System optimization and installation of GORE filter bags resulted in improvements to the baghouse and overall production process. Emissions from all the filters are well below 10 mg/Nm, maintenance on the filters has been significantly reduce, and extraction volumes from the furnaces have been significantly increased, leading to lower stack temperatures.

With the new high temperature membrane filter media, required dilution air from the canopy hood is reduced and furnace suction pressure is consistently maintained, reducing furnace fugitive emissions.

Bag failures stopped since the GORE ePTFE membrane and the fiberglass backing material are not subject to hydrolysis and resist spark damage. The bags have not required tensioning since start up. Furnace suction and shop evacuation have improved due to the more consistent operation of the baghouse.

Eliminated the need for sonic horns and dramatically decreased baghouse pressure drop. Gas flow increased significantly, even with fewer filter bags than had originally been used in the non membrane sytem.

By removing the U Tube cooler pressure loss the plant was able to open the canopy hood dampers more. This allowed increased secondary flow from the shop. With less flow resistance through the DEC system the primary evacuation has also increased with better fume capture at the furnace.

The system now runs with a consistent airflow of 41,000 acfm and compartment pressure drops of 4.5 - 6.5" H2O. The customer is able to run two ladles simultaneously, increasing metal throughput.

Original set of GORE® membrane filter bags were in service for more than three years and were removed during a planned maintenance shutdown. Emission levels measured less than required by standards/regulations during this operational period.

After the GORE Filter Bags were installed, bag life increased from one year to five years. Production downtime caused by the need to replace bags prematurely was virtually eliminated.