Heat recovery and district heating integration in EAF steelmaking via iRecovery® and Heat Leap systems
The iRecovery® technology, developed by Tenova, recovers thermal energy from EAF off-gases and cooling circuits, converting it into steam for internal use or for power generation. The integration of Heat Leap - a high-performance heat pump also developed by Tenova - further enhances this concept by upgrading low-grade heat from the EAF cooling water to supply district heating networks. This has been successfully integrated with a Consteel® EAF in the ORI Martin EAF plant (Brescia, Italy).
TECHNICAL DESCRIPTION
The iRecovery® system operates through an evaporative cooling system (ECS) and a Waste Heat Boiler (WHB). Off-gases exiting the EAF at temperatures up to 1 500–1 800°C are cooled to approximately 750°C in the ECS and then to around 200°C before entering the WHB. This process generates saturated steam, which is collected in a steam drum and stabilised via a steam accumulator to manage fluctuations in EAF operation. This technology enables the recovery of EAF off-gas thermal energy which in many installations around the world is not recovered and treated in inefficient water quenching systems.
The iRecovery® technology was firstly developed for standard 100% scrap EAF basket charging process where the energy in the waste is almost 25% of the primary input in a standard process using about 380 kWh of electrical energy per tonne of liquid steel. The iRecovery® system can typically produce about 180-200 kg steam / tonne of liquid steel.
This technology has also been successfully integrated with a Consteel® EAF. This was demonstrated in the ORI Martin EAF plant (Brescia, Italy) where the system benefits from continuous scrap charging, ensuring stable off-gas flow and maximising heat recovery efficiency.
Heat Leap complements iRecovery® by using the EAF cooling water circuit as a heat source. With a Coefficient of Performance (COP) of 7–9, the heat pump upgrades low-temperature heat to deliver up to 12 MWt of hot water for district heating in winter mode. The combined system achieves global efficiency of about 1.0 in winter and 0.5 in summer, supplying steam, hot water, and electricity flexibly according to seasonal demand.
DEGREE OF MATURITY
The iRecovery® technology has reached TRL 9 and is commercially proven, with 15 successful installations worldwide, including Feralpi Riesa (Germany), Arvedi Cremona (Italy), Aichi (Japan), and ORI Martin (Italy). Heat Leap has been demonstrated at ORI Martin, providing additional heat to district heating networks and showcasing the potential for industrial-urban energy symbiosis. Consequently, both iRecovery® associated with Heat Leap technology have reached TRL 9.
CROSS-MEDIA EFFECTS
The main trade-off is the additional electricity consumption for operating the heat pump (approximately 0.5 MWt). However, this is offset by the significant energy recovery and CO₂ savings.
Basic information about the technique
Reference documents related to the innovative technique
Download
heat-recovery-and-district-heating-integration-in-eaf-steelmaking-incite-10022026.pdf
Participant Companies
Technology provider
- Tenova
Operational
Achieved
TRL
9+
TRL above 9 (e.g. candidate BAT)
- Environmental purpose of the innovative technique
- Decarbonisation
- Energy efficiency
- Water efficiency
- Circular economy (e.g. recovery/reuse/recycling of residues, industrial symbiosis)
- Relevant industrial sector
- Iron and Steel
- IED activity
- 2.2 Production of pig iron or steel (primary or secondary fusion) exceeding 2,5 tonnes per hour
Locations
ORI Martin S.p.A
Environmental benefits
As compared to: The iRecovery® technology enables the recovery of EAF off-gas thermal energy which in many installations around the world is not recovered and treated in inefficient water quenching systems.
GHG Emission
GHG emissions reduction:
Up to 50 kg CO₂ per ton of liquid steel, considering direct steam use (up to 8% of global emission Melt Shops + Rolling Mills), while up to 20 kg CO₂ per ton of liquid steel considering the use of steam for power generation (up to 3% of global emission Melt Shops + Rolling Mills). For example, in ORI Martin, the saving is equal to 13.5 kg CO₂ per ton via power generation.
At ORI Martin, the integration of iRecovery® with Consteel® and an ORC turbine enables recovery of up to 40 GWht/year, saving approximately 8,700 tons of CO₂ annually.
Energy efficiency
Energy recovery: 20–30% of EAF energy input (160–250 kWh/ton). Electricity consumption for off-gas filtration fans: Reduction by 20–30%.
Water consumption
Water savings: 40–90 m³/h compared to conventional quenching towers.
Industrial Symbiosis
Industrial Symbiosis
Supports circular economy by supplying heat to district heating and reducing fossil fuel dependency.
Heat Leap has been demonstrated at ORI Martin, providing additional heat to district heating networks and showcasing the potential for industrial-urban energy symbiosis.
Economics
The investment for an iRecovery® system varies depending on its configuration. Considering direct steam use, the capital expenditure is approximately 700 € per thermal kilowatt of capacity. The economic return is very attractive. Typically, this technology achieves a payback period of two to five years, depending on the average electricity price and the CO2 emission prices. When equipped with an Orgabic Rankine Cycle or Steam Rankine Cycle turbine for power generation, the capital expenditure is approximately €4,500 per kilowatt of electrical capacity. The economic return is also attractive for power generation that typically achieves a payback period of two to ten years, depending on the average daily electricity price and the CO2 emission prices. The ORI Martin EAF plant successfully reached a three-year payback by combining steam utilisation, electricity production, and integration with district heating,