EPA primary iron and steel production

The category at business/processes/production/ironandsteel/epa/primary provides a methodology for calculating greenhouse gas emissions associated with the production of primary iron and steel. This methodology accounts for the CO₂ emissions due to carbonate calcination and adjusts stationary combustion emissions by accounting for carbon which remains contained within process products or by-products. 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.

Next, set the quantity of the carbonate flux used by setting the fluxQuantity profile item value. The returned amount represents CO₂ emissions associated with this quantity of flux, assuming 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.

Products and by-products

The quantity of process products and by-products, together with their carbon contents can also be specified. The carbon retained within these products is subtracted from the basic calculation of carbonate flux-associated emissions. Use the following profile item values to specify these quantities where appropriate:

• Iron: ironQuantity (mass-based quantity)

• Steel: steelQuantity (mass-based quantity)

• Coke: cokeQuantity (mass-based quantity)

• Residual oil: oilQuantity (liquid volume-based quantity)

• Tar: tarQuantity (liquid volume-based quantity)

• Coke oven gas: cokeOvenGasQuantity (gaseous volume-based quantity)

• Blast furnace gas: blastFurnaceGasQuantity (gaseous volume-based quantity)

These quantities should only be included when representing transfers offsite, i.e. quantities sold.

The Climate Leaders documentation provides default carbon content values for iron and steel products as well as several common by-products. Users can specify quantities of each of these and override the default carbon content factors if facility-specific data are available. Use the following profile item values to specify these quantities where appropriate:

• Iron: ironCarbon

• Steel: steelCarbon

• Coke: cokeCarbon

• Residual oil: oilCarbon

• Tar: tarCarbon

• Coke oven gas: cokeOvenGasCarbon

• Blast furnace gas: blastFurnaceGasCarbon

Each of these should be specified as a decimal fraction, i.e. 0-1, representing the proportion by weight of carbon within the product/by-product.

Note: the default carbon content factors for coke oven gas and blast furnace gas have been converted from kg per 1000 ft''3'' used in the original documentation into kg per ft''3'', using a factor of 1/1000.