Method Development to Estimate Total Low Voltage and High Voltage PFC Emissions

Perfluorocarbons (PFC) emissions must be reported as accurate as possible. The aluminum industry is using a consistent method to estimate high voltage PFC emissions. However, a new or improved method is needed to account for low voltage PFC emissions. Thus, equipment sensitivity and time frequency must be revised to estimate both high and low voltage emissions, during not only anode effects above 8 volts, but also during pot disturbances that affect pot noise and therefore can make the contribution of low voltage emissions significant higher. Preliminary results showing the variability of low voltage and estimation of total PFC emissions is presented from recent PFC measurement campaigns at two Alcoa smelters.