Düsseldorf, Germany
Düsseldorf, Germany

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Schliephake H.,Georgsmarienhutte GmbH | Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH | Memoli F.,Tenova Core | Simmons J.,Tenova Core
Iron and Steel Technology | Year: 2011

Georgsmarienhütte GmbH (GMH), Germany, operating at 140 t/h DC EAF initiated a project to replace the cooling system after almost 25 years of continuous operation, including the time it was used for the BOF. The steam production is the best operating practice for flexible heat recovery as the steam can be used for many purposes, relatively easy to transport, and water an inexpensive and non-toxic base. The technology used to turn waste gas energy into steam is Tenova iRecovery. An iRecovery waste gas duct is a tube-tube construction that looks very similar to a conventional cooling duct. An iRecovery system is designed for partial evaporation of the water, typically no more than 5-12% will be evaporated under normal operation conditions, which ensures that there is spare capacity in the cooling system. An iRecovery waste gas ducts work with radiation heat transfer, which is efficient down to approximately 600°C.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2011

A standard top charged EAF will app. have 180-220 kWh/tls offgas energy content, where offgas is the central element for heat recovery. Depending on the temperature at the low end and the control of dilution air between 50-85% of this energy content can be recovered. Contradictory to a wide spread opinion heat recovery from a batch mode furnace is not an issue with Tenova iRecovery steam buffering technology; still superheated steam is an issue. But the discussion showed that in almost any case it's possible to avoid the need for superheated steam and economically better to generate power with i.e. an ORC turbine instead of using external burners for superheating. The right point in time to plan an iRecovery system is always when there is a high process steam demand, otherwise iRecovery should be taken into consideration when an existing cooling system needs revamping or a new furnace is planned.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2011

Heat recovery is the order of the day. Increasing energy prices and constantly stricter environmental regulations turn energy efficiency into a central topic for each energy intense plant, and heat recovery is a central component of each energy efficiency increase. Technology is not the issue: Tenova iRecovery is a reliable and well approved tool for all furnace operators that think about heat recovery. Despite all complaints about high energy prices the main challenge for heat recovery is reaching a sensible amortization. And this depends in the very first place on the steam demand. Power generation is not the silver bullet as one might expect; in fact all other usage should be considered first and the remaining energy be used for power generation. All this can't be done without a proper concept; especially for integrated plants that have different waste heat sources and a combination of potential heat sinks an energy survey is unavoidable. Doing such kind of survey brings a lot of typical problems and challenges; data collection, load case combination, equipment sizing and time slice problems shouldn't be underestimated.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2012

Heat recovery is the biggest source for improving the energy efficiency of industrial furnaces in steel and alloy plants, and steam generation with Tenova iRecovery® offers approved technology for different furnaces. The best use for steam is process use, still in many particular projects power generation for a part or all of the recovered energy is the only feasible option. Due to technical reasons the standard way of a turbine working with superheated steam is not always available: It must be carefully checked whether superheated steam is available and how long furnace operation cycles are. It's been showed that in many cases a careful planning can get a project on the track to the steam turbine, still in other cases the problems remain significant, especially in small projects. For these projects a discussion of alternative ways of power generation has shown that using ORC turbine technology is a way that combines acceptable electrical efficiency with very easy operation. AIS Tech.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
MPT Metallurgical Plant and Technology International | Year: 2013

Potential benefits and challenges involved in heat recovery in EAF steel plants are discussed on the basis techniques developed by engineers from the Tenova group to address these issues. Tenova engineers have developed a different way to address these contradictory issues. Their technique involves the off-gas energy content to be determined from the energy input via a mass and energy balance. The process engineers of Tenova Re Energy have developed an advanced mass and energy balance based on the mathematical models of Tenova Goodfellow, which allows exact conclusions to be drawn regarding the off-gas energy content of different EAFs and different melts of the respective EAFs. The results from these efforts have been compared with measurements and reverse calculations. These results allow the classification of EAFs into off-gas energy content categories by size and operation scheme.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
Stahl und Eisen | Year: 2010

Approximately 30 % of the primary energy input of an electric arc furnace are lost in the off-gas, which is the biggest part of all energy losses. This article describes the iRecovery technology to recover this energy, especially targeting the reference project at Georgsmarienhütte in Germany. The result of this heat recovery is steam; it will be discussed why the question of steam usage is often more important and complex than the question of steam generation.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
MPT Metallurgical Plant and Technology International | Year: 2013

Tenova's iRecovery® steam generation technology is used in many industrial plants for energy optimization. With level 1, the off-gas can be cooled down to 600°C in a steam generating off- gas duct. Level 2 enables the off-gas to be cooled down to 200°C using a waste heat boiler. The mixture of steam and water is guided into a steam drum where the steam and water are separated. While the steam is taken out, the water returns to the circuit. The German steelmaker Georgsmarienhütte GmbH (GMH) had chosen a level 1 system. After the iRecovery® duct, a water quenching tower is installed. No downstream oxygen control system is installed. iRecovery level 2 waste heat boilers are designed in such a way that the residence time is not longer than in the formerly used system. Fast quenching does not depend on water injection. The benefits of this system includes less inner corrosion, lower water consumption, lower water volume and higher safety in different emergency situation.


Once a furnace is equipped with all modern technology for energy consumption reduction the next big step in energy efficiency is heat recovery. Depending on the furnace type either off-gas or cooling water is the biggest potential; the common point is steam generation. If steam cannot be sold or used for plant processes the remaining option is power generation. Given the characteristics for steel plant heat recovery there are some challenges that must be overcome. The typical steam turbine is not always the best choice.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2013

Energy optimization is currently in the focus of many activities in the steel plant. It's common knowledge that the EAF loses ∼ 30% of the brought in energy in the off gas, thus offering a huge potential for energy recovery. In 2009 Tenova's iRecovery® steam generation technology was applied to an EAF for the first time at the Georgsmarienhütte GmbH, Germany. This project found wide attention. Three years later the projects at the Feralpi plant in Riesa and Hyundai plant in Incheon extends the scope of technology with additional innovation. Georgsmarienhütte uses heat recovery down to 600°C off gas temperature, Feralpi heat recovery is designed down to 200°C with additional control of the downstream oxygen content, these features turning the Feralpi EAF in the probably most efficient EAF worldwide. The steam is partly used for power generation by an ORC turbine. The article describes the new innovative aspects, compares the development between the two projects and also describes the interesting concept for mixed steam usage.


Born C.,Tenova Re Energy GmbH | Granderath R.,Tenova Re Energy GmbH
MPT Metallurgical Plant and Technology International | Year: 2010

German steel producer Georgsmarienhütte GmbH (GMH) has replaced the exhaust gas cooling system of its EAF meltshop after 25 years of continuous operation. The new system was used after the cooling system deteriorated considerably and GMH wanted to substitute the steam from the gas fired boiler house with steam generated in the new ECS. The new system, including the first element of the waste gas duct, was completely designed as Tenova iRecovery system that is now producing 20 t/h of saturated steam of 13 to 20 bar pressure. The whole cooling circuit was designed slightly bigger than required for cooling purposes, therefore the additional amount of water has an excess stored energy capacity. With the new gas cooling system, the boiler house at GMH has reduced its consumption of natural gas for the vacuum degassing to almost zero, providing the economic effect expected by GMH.

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