EAF waste-heat
recovery plants
Thermal energy generated by steelmaking processes can be captured and converted into electric power or steam to serve plant utilities or district heating systems, and carbon credits can make these investments even more attractive.
The waste heat contained in the EAF primary fumes can be recovered by the CHR - Clean Heat Recovery system and transformed into electric energy.
In the CHR, the thermal energy contained in the EAF primary fumes is used to generate pressurized hot water that is then sent to an ORC - Organic Rankine Cycle system. There, a hot organic fluid that works in a closed circuit feeds an ORC turbine used for electric energy generation.
Clean Heat Recovery installations feature hot-water accumulator and temperature stabilizer. They are able to treat 30%-50% of fumes enthalpy and produce electricity with savings up to 20 kWh/t of crude steel.
Danieli CHR is a completely automatic system that has no influence on the steelmaking process and requires only minimal maintenance activities –basically only periodic controls that are done during the standard scheduled plant shutdowns. According to the different necessities of each plant and layout constraints, it’s possible to implement different configurations, aiming to maximize energy recovery and optimize CapEx. ORC turbines are particularly suitable for EAF applications thanks to high flexibility in working conditions that match with the variable process of the EAF.
ORC systems inside CHR convert thermal energy contained in the pressurized hot water into electric energy thanks to the ORC turbines. Such turbines are particularly suitable for EAF applications thanks to high flexibility in working conditions that match with the variable process of the EAF.
Danieli Q-Steam makes it possible to recover thermal energy from EAF primary fumes and produce saturated steam for various uses, such as VD vacuum pumps, district heating and power generation, making it possible to reduce natural gas consumption, with a consequent, very attractive return of investment.
This technology can be applied in any new or existing EAF steelmaking plant, and is a further opportunity for technology transitions from converter to electric melting in pursuit of CO2 emission reduction.
Typically, ironmaking plants already have a steam network –as they generate steam from converter cooling stacks– so installing a waste-heat recovery system for steam generation on the EAF primary fumes line is a simple step from the previous technology to the new one.
Furthermore, secondary fumes emitted by the EAF, mainly during charging/tapping phases, are captured by the Danieli canopy hoods, whilst patented Acou-Stacks for fume-treatment plants ensure low noise levels to cope with recent, low sound-pressure regulations. Danieli-designed primary fume suction lines contribute to reduced electrical energy and water consumption.
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