IPCC methodology for direct reduced iron production - tiers 2/3



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.

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