iRecovery® System
Process optimization and energy efficiency to reduce emissions are ever more important for all steel producers. In the past 10 years, TENOVA in the frame of environmental sustainability developed the iRecovery® system for recovering of the thermal power available in the EAF waste gas and valorize it.
Overview
iRecovery® technology results in effective recovery of EAF off-gas thermal energy. This energy is the biggest fraction of the primary energy input in the EAF process typically wasted away. The iRecovery® system consists in a Heat Recovery for Steam Generation (HRSG) with a radiant, Evaporative Cooled System (ECS), and convective section, the Waste Heat Boiler (WHB), which can completely process the waste gas from approx. 1700°C to 200°C. Pressurized water at boiling point feeds the ECS + WHB where it is converted into steam through the heat exchanged with the waste gas. Saturated steam the energy carrier to the different users.
iRecovery® was firstly developed for standard 100% scrap EAF basket charging processwhere the energy in the waste is almost 25% of the primary input in a standard process using about 380 kWh of electrical energy per ton of liquid steel. The iRecovery® performance is based on 180-200 Kg/tls of steam.
The well-known Tenova EAF Consteel process for continuous charging and charge pre-heating, [2], is one of the main technologies for recovering and re-using the waste gas thermal power directly in the melting process. Tenova coupled the Consteel and iRecovery® in order to improve the effectiveness of its technologies: while the high temperature thermal power contained in the waste gases, up to 800°C, is first used in scrap preheating by Consteel, the WHB is recovering the residual waste gas energy. This combination can produce about 90-140 kg/tls of steam.”
Technical data
Total energy lost into the EAF primary off-gas is typically ranging between 20÷30% of total energy input (140÷260 kWh/tls).
iRecovery system can recover up to 200 kWh/tls counting with 13 worldwide operating plant is the most reliable technology to recover waste heat from EAF waste gases.
iRecovery recovers heat in the ECS duct (by radiation) and/or in the WHB (by convection) ensuring a rapid cooling of the EAF off-gasses below 200°C
Innovation
Heat recovery through steam as vector carrier:
- iRecovery system is a state of the art EAF waste gas primary line in terms of pollution control and treatment
- Minimum risk of dew point problems because surface in contact with hot-gases > 150°C
- Less thermal stress on steel part in contact with hot-gases because constant temperature during operations
- Lower water volume flow due to higher heat transfer, latent heat instead of heat capacity, will drive to lower power consumption for water pumping system
- Possibility to recover waste gas energy from approx. 1500°C to 200°C
Safety & Automation
Fully automated control system in order to run boiler system without direct monitoring for 72h according to EN standard
Complete on-line data system for performance monitoring in order to planning production and maintenance actions
Equipment supply according the boiler code of the relevant country where the iRecovery system is installed
Digital
Machine learning technology for the prediction of thermal power available in the EAF waste gas through the correlation of the input features in EAF process
Integrated energy management system with requirements of utility providers for electrical power pricing optimization.
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