PROTOCOL FOR MEASUREMENT OF TETRAFLUOROMETHANE AND HEXAFLUOROETHANE FROM PRIMARY ALUMINUM PRODUCTION

Two perfluorinated compounds (PFCs), tetrafluoromethane (CF4) and hexafluoroethane (C2F6), are produced periodically during primary aluminum production by the Hall-Héroult process. The measurement of PFCs is required to assist with developing the most accurate greenhouse gas emissions inventories. These inventories can be used to support company benchmarking and process improvement activities, to facilitate reporting under the United Nations Framework Convention on Climate Change, and to assist with the implementation of Kyoto Protocol mechanisms such as emissions trading and the Clean Development Mechanism (CDM). This paper describes a measurement protocol to assist with developing accurate PFC inventories based on the Intergovernmental Panel on Climate Change (IPCC) Tier 3b method. The protocol has been produced with an aim to foster consistency in smelter-specific sampling programs. The procedure described here provides a method for making accurate measurements of CF4 and C2F6 emissions and relating those measurements to anode effect process data. A methodology is presented for summarizing the collected data and calculating IPCC Tier 3b emission factors, which provide for the most accurate calculation of long-term PFC emissions from aluminum production. The protocol provides the necessary guidance to allow individual facilities to develop detailed plans for sampling and analysis based on plant specific technology, anode effect data, and chosen measurement instrumentation