Iron and Steel DRI

Summary

This methodology represents carbon dioxide (CO₂) and methane (CH₄) emissions associated with the production of direct reduced iron. The data and calculation methodology is sourced from the Greenhouse Gas Protocol (GHGP) worksheet tool CO2 emissions from the production of iron and steel, version 2.0, which is ultimately based on the methodologies described in Volume 3, Chapter 4 - Metal Industry Emissions of their 2006 IPCC Guidelines for National Greenhouse Gas Inventories.

The methodology

Emissions model

Direct reduced iron (DRI) is produced from the direct reduction of iron ores in solid form (at temperatures of <1000 °C) by reducing gases typically produced from natural gas or coal. The eventual oxidation of the carbon-bearing feedstocks (gas, coal) produces CO₂ and CH₄.

This methodology enables the calculation of DRI-associated CO₂ emissions based upon a mass balance approach that accounts for the carbon inputs and outputs to the reduction process. All carbon which enters the process is assumed to be completely oxidised, adn therefore by considering the quantities and carbon contents of natural gas, coke breeze and metallurgical coke consumed, the quantity of CO₂ emitted can be estimated.

CH₄ emissions are based on an emissions factor which describes the rate at which CH₄ is emitted per unit quantity of DRI produced.

This methodology represents the IPCC Tier 2 approach where default carbon content data is used for carbon-bearing feedstocks and products, but Tier 3 where these are based on facility-specfic data.

Model data

This methodology is based on a mass-balance of process inputs and outputs, and depends upon quantities and carbon concentrations for each. Default carbon content data is provided for natural gas for cases where facility-specific data is not available. CH₄ emissions also require the quantity of DRI produced to be specified. A default emissions factor for CH₄ is available but can be specified if facility- or country-specific data is available.

Activity data required

CO₂ emissions require quantities and carbon concentrations of feedstock in order to calculate. CH₄ emissions require the quantity of DRI produced to be specified, and a facility- or country-specific emissions factor for CH₄ can be provided if available.

Calculation and results

CO₂ emissions are calculated by the mass-balance of the specified input/output activity data. CH₄ emissions are calculated by multiplying the quantity of DRI specified by the specified emissions factor. CO₂e emissions are also calculated by converting absolute emissions using the appropriate global warming potentials.

Related methodologies

If feedstock and by-product data is unavailable, a simpler methodology based solely on quantities of DRI produced is also available.

IPCC methodologies for other iron and steel-associated process emissions are also available, including tier 1 and tier 2/3 methodologies for iron and steel production, sinter and coke production.