Integrated Direct Reduction Electric Arc Furnace (with and without CCS)

Contents

Overview | Asset Structure | Flow Equations | Input File (Standard Format) | Types - Asset Structure | Constructors | Examples

Overview

In Macro, the Integrated Direct Reduction–Electric Arc Furnace (DR-EAF) pathway represents integrated steelmaking facilities that combine direct reduction units with electric arc furnaces. In this configuration, iron ore is first reduced in a direct reduction reactor using natural gas or hydrogen as the reductant to produce hot direct reduced iron (hDRI), which is then melted in electric arc furnaces to produce crude steel. These assets are specified via input files in JSON or CSV format, located in the assets directory, and are typically named with descriptive identifiers such as integrated_hydrogen_direct_reduction_electric_arc_furnace.json or integrated_naturalgas_direct_reduction_electric_arc_furnace_ccs.csv.

Asset Structure

A DR-EAF plant (with and without CCS) is made of the following components:

• 1 Transformation component, representing the DR-EAF (with and without CCS).
• 8 Edge components:
  • 1 incoming IronOre Edge, representing the iron ore supply in the form of the IronOreDR subcommodity. (Macro distinguishes between two iron ore sub-commodities: IronOreBF, a blast-furnace-grade ore with approximately 65% iron content, and IronOreDR, a higher-purity ore (above ~67% iron) suitable for use in direct-reduction furnaces.)
  • 1 incoming Reductant Edge, representing reductant supply, which can be natural gas or hydrogen.
  • 1 incoming Electricity Edge, representing electricity supply.
  • 1 incoming CarbonSource Edge, representing the carbon source supply. (Applicable only when hydrogen is used as the reductant and not relevant for natural gas variants. The resulting DRI is carbon-free, and a carbon source—such as metallurgical coal, charcoal, or other carbon materials—is added to adjust the steel’s carbon content, minimize iron oxide losses, and supply additional chemical energy.).
  • 1 outgoing CrudeSteel Edge, representing the crude steel production.
  • 1 outgoing CO2 Edge, representing the CO2 that is emitted.
  • 1 outgoing CO2Captured Edge, representing the CO2 that is captured (only if CCS is present).

Here is a graphical representation of a natural gas-based DR-EAF asset without CCS:

Flow Equations

The integrated DR-EAF asset follows these stoichiometric relationships:

\[\begin{aligned} \phi_{ironore} &= \phi_{crudesteel} \cdot \epsilon_{ironore\_consumption} \\ \phi_{fuel} &= \phi_{crudesteel} \cdot \epsilon_{fuel\_consumption} \\ \phi_{elec} &= \phi_{crudesteel} \cdot \epsilon_{elec\_consumption} \\ \phi_{carbonsource} &= \phi_{crudesteel} \cdot \epsilon_{carbonsource\_consumption} \quad \text{(non-zero when hydrogen is the reductant, not relevant for natural gas variants)} \\ \phi_{co2} &= \phi_{crudesteel} \cdot \epsilon_{emission\_rate} \\ \phi_{co2\_captured} &= \phi_{crudesteel} \cdot \epsilon_{co2\_capture\_rate} \quad \text{(if CCS)} \\ \end{aligned}\]

Where:

• $\phi$ represents the flow of each commodity.
• $\epsilon$ represents the stoichiometric coefficients defined in the Conversion Process Parameters section.

Input File (Standard Format)

The easiest way to include an integrated DirectReductionElectricArcFurnace asset in a model is to create a new file (either JSON or CSV) and place it in the assets directory together with the other assets.

your_case/
├── assets/
│   ├── integrated_naturalgas_direct_reduction_electric_arc_furnace.json    # or integrated_naturalgas_direct_reduction_electric_arc_furnace.csv
│   ├── other_assets.json
│   └── ...
├── system/
├── settings/
└── ...

This file can either be created manually or using the template_asset function, as shown in the Adding an Asset to a System section of the User Guide. The file will be automatically loaded when you run your Macro model. An example of an input JSON file is shown in the Examples section.

The following tables outline the attributes that can be set for a DirectReductionElectricArcFurnace.

Transform Attributes

Essential Attributes

Conversion Process Parameters

General Attributes

Investment Parameters

Economic Parameters

Constraints Configuration

DirectReductionElectricArcFurnace assets can have different constraints applied to them, and the user can configure them using the following fields:

For example, if the user wants to apply the BalanceConstraint to the transformation component and the MaxCapacityConstraint to the output edge, the constraints fields should be set as follows:

{
    "transform_constraints": {
        "BalanceConstraint": true
    },
    "edges":{
        "crudesteel_edge": {
            "constraints": {
                "MaxCapacityConstraint": true
            }
        }
}

Users can refer to the Adding Asset Constraints to a System section of the User Guide for a list of all the constraints that can be applied to the different components of a DirectReductionElectricArcFurnace asset.

Default constraints

To simplify the input file and the asset configuration, the following constraints are applied to the DrEaf asset by default:

• Balance constraint (applied to the transformation component)
• Capacity constraint (applied to the output crude steel edge)
• MustRun constraint (applied to the output crude steel edge)

Types - Asset Structure

The DirectReductionElectricArcFurnace asset is defined as follows:

struct DirectReductionElectricArcFurnace{T1 <: Commodity,T2 <: Commodity} <: AbstractAsset
    id::AssetId
    dreaf_transform::Transformation
    crudesteel_edge::Edge{CrudeSteel}
    reductant_edge::Edge{T1} # natural gas or hydrogen
    elec_edge::Edge{Electricity}
    carbonsource_edge::Edge{T2} # coal, charcoal, etc. 
    ironore_edge::Edge{<:IronOre}
    co2_edge::Edge{CO2}
end

Here, two of the asset edges are parameterized. T1 denotes the reductant, which may be either natural gas or hydrogen, while T2 denotes the carbon source, which may be coal, charcoal, or other carbon materials.

Constructors

Factory constructor

make(asset_type::Type{DirectReductionElectricArcFurnace}, data::AbstractDict{Symbol,Any}, system::System)

Stochiometry balance data

dreaf_transform.balance_data = Dict(
    :ironore_consumption=> Dict(
        crudesteel_edge.id => get(transform_data, :ironore_consumption, 0.0),
        ironore_edge.id => 1.0
    ),
    :electricity_consumption => Dict(
        crudesteel_edge.id => get(transform_data, :electricity_consumption, 0.0),
        elec_edge.id => 1.0
    ),
    :reductant_consumption => Dict(
        crudesteel_edge.id => get(transform_data, :reductant_consumption, 0.0),
        reductant_edge.id => 1.0
    ),
    :carbonsource_consumption => Dict(
        crudesteel_edge.id => get(transform_data, :carbonsource_consumption, 0.0),
        carbonsource_edge.id => 1.0
    ),
    :emissions => Dict(
        crudesteel_edge.id => get(transform_data, :emission_rate, 0.0),
        co2_edge.id => -1.0, 
    ),
)

Examples

This example illustrates a basic DirectReductionElectricArcFurnace configuration using natural gas as a reductant and metallurgical coal as a carbon source in JSON format, featuring standard parameters in a three-zone case.

{
    "IntegratedNaturalGasDirectReductionElectricArcFurnace": [
        {
            "type": "DirectReductionElectricArcFurnace",
            "global_data":{
                "nodes": {},
                "transforms": {
                    "timedata": "NaturalGas",
                    "constraints": {
                            "BalanceConstraint": true
                    }
                },
                "edges":{
                    "crudesteel_edge": {
                        "commodity": "CrudeSteel",
                        "unidirectional": true,
                        "has_capacity": true,
                        "can_retire": true,
                        "can_expand": true,
                        "constraints": {
                            "CapacityConstraint": true
                        }
                    },
                    "reductant_edge": {
                        "commodity": "NaturalGas",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "ironore_edge":{
                        "commodity": "IronOreDR",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "elec_edge":{
                        "commodity": "Electricity",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "carbonsource_edge": {
                        "commodity": "MetCoal",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_edge": {
                        "commodity": "CO2",
                        "unidirectional": true,
                        "has_capacity": false,
                        "end_vertex": "co2_sink_steel"
                    }
                }
            },
            "instance_data":[
                {
                    "id": "SE_natural_gas_dr_eaf",
                    "transforms":{
                        "ironore_consumption": 1.59,
                        "reductant_consumption": 3.89,
                        "electricity_consumption": 0.6,
                        "emission_rate": 0.85
                    },
                    "edges":{
                            "crudesteel_edge": {
                                "end_vertex": "crudesteel_SE",
                                "existing_capacity": 0.0,
                                "investment_cost": 6973921,
                                "fixed_om_cost": 139478,
                                "variable_om_cost": 135
                            },
                            "reductant_edge": {
                                "start_vertex": "natgas_SE"
                            },
                            "elec_edge":{
                                "start_vertex": "elec_SE"
                            },
                            "ironore_edge":{
                                "start_vertex": "ironoredr_source"
                            },
                            "carbonsource_edge": {
                                "start_vertex": "metcoal_source"
                            }
                        }
                },
                {
                    "id": "MIDAT_natural_gas_dr_eaf",
                    "transforms":{
                        "ironore_consumption": 1.59,
                        "reductant_consumption": 3.89,
                        "electricity_consumption": 0.6,
                        "emission_rate": 0.85
                    },
                    "edges":{
                            "crudesteel_edge": {
                                "end_vertex": "crudesteel_MIDAT",
                                "existing_capacity": 0.0,
                                "investment_cost": 6973921,
                                "fixed_om_cost": 139478,
                                "variable_om_cost": 135
                            },
                            "reductant_edge": {
                                "start_vertex": "natgas_MIDAT"
                            },
                            "elec_edge":{
                                "start_vertex": "elec_MIDAT"
                            },
                            "ironore_edge":{
                                "start_vertex": "ironoredr_source"
                            },
                            "carbonsource_edge": {
                                "start_vertex": "metcoal_source"
                            }
                        }
                },
                {
                    "id": "NE_natural_gas_dr_eaf",
                    "transforms":{
                        "ironore_consumption": 1.59,
                        "reductant_consumption": 3.89,
                        "electricity_consumption": 0.6,
                        "emission_rate": 0.85
                    },
                    "edges":{
                            "crudesteel_edge": {
                                "end_vertex": "crudesteel_NE",
                                "existing_capacity": 0.0,
                                "investment_cost": 6973921,
                                "fixed_om_cost": 139478,
                                "variable_om_cost": 135
                            },
                            "reductant_edge": {
                                "start_vertex": "natgas_NE"
                            },
                            "elec_edge":{
                                "start_vertex": "elec_NE"
                            },
                            "ironore_edge":{
                                "start_vertex": "ironoredr_source"
                            },
                            "carbonsource_edge": {
                                "start_vertex": "metcoal_source"
                            }
                        }
                }

            ]
        }
    ]
}

See Also

• Edges - Components that connect Vertices and carry flows
• Transformations - Processes that transform flows of several Commodities
• Nodes - Network nodes that allow for import and export of commodities
• Vertices - Network nodes that edges connect
• Assets - Higher-level components made from edges, nodes, storage, and transformations
• Commodities - Types of resources stored by Commodities
• Time Data - Temporal modeling framework
• Constraints - Additional constraints for Storage and other components