EPA EAF iron and steel production

The category at business/processes/production/ironandsteel/epa/eaf provides a methodology for calculating greenhouse gas emissions associated with Electron Arc Furnace (EAF) steel facilities. This methodology accounts for the CO₂ emissions due to carbonate flux and the use of carbon electrodes. Any emissions from coke and/or coal consumption should be calculated using a methodology for stationary combustion. The methodology is sourced from the guidelines published by the Climate Leaders industry-government initiative for reporting and reducing greenhouse gas emissions.

To use this category, simply create a profile item - there are no drill choices.

The calculation takes into account emissions from both the carbonate flux and carbon electrodes used. Users must specify data relating to each.

Carbonate flux emissions

To set the quantity of the carbonate flux used, set the fluxQuantity profile item value. The calculation of emissions assumes that the quantity specified represents 100% calcium carbonate (limestone). The calculation uses a default value for CO₂ emissions per unit of calcium carbonate, based on the known stoichiometric relationship between the two.

Users can override these assumptions if appropriate, for a more accurate calculation. The purity (i.e. percent carbonate) of the flux can be specified using the fluxPurity profile item value. If a type of carbonate other than calcium carbonate is used, users can directly specify the weight fraction of carbon using the fluxCarbon profile item value. In both cases, these should be expressed as decimal fractions, i.e. between 0-1.

Carbon electrode emissions

Users of this methodology have two options for calculating the emissions due to carbon electrodes based on either: (1) the quantity and carbon content of electrodes used; and (2) the quantity of steel produced.

To calculate using the electrode-based methodology, simply specify the quantity and carbon content of electrodes using the electrodeQuantity and electrodeCarbon profile item values. There is no default value provide for electrode carbon content in the Climate Leaders methodology.

If these electrode data are not available, users can alternatively calculate the emissions due to electrode consumption by using a generic carbon factor based on the the quantity of steel produced. In this case, users must specify the quantity of steel using the steelQuantity profile item value. The quantity of electrode carbon consumed is calculated using a default factor according to Climate Leaders methodology.

Final calculation

Each of the aforementioned steps establish the absolute quantity of carbon oxidised during the EAF steel manufacturing process. The final step is to convert this quantity into a quantity of CO₂ emitted. This is done by multiplying by the stoichiometric ratio of atomic C to CO₂.