Pot Gas Treatment at High Gas Temperatures

HF regeneration due to submicron fluoride particles trapped inside the filter cloth reacting with the humidity in the pot gas is one likely mechanism that explains why the HF emissions increase with gas temperature and humidity in the dry scrubbers. A significant temperature effect is observed and gas cooling is in many smelters today necessary to keep the emissions under control. The GE heat exchanger (HEX) technology is one of the technologies that are now built and operated in full scale several places in the world. Results from the first full scale GTC installation document the positive effect of the cooling for the Abart GTC technology installed. The HEX cools the temperature with more than 25 °C down to less than 110 °C and HF emissions in the range 0.2–0.3 mg/Nm³ are measured at ambient temperatures higher than 40 °C, and high humidity.