Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Siemens offers solution for generating steam from off-gases of electric arc furnaces

15.11.2013
- Steam can be used directly or used to generate electrical energy
- Reduces conversion costs and consumption of fossil fuels
- Modular structure facilitates modernization of existing plants

Siemens Metals Technologies has developed a system for recovering heat from the hot off-gases of electric arc furnaces. The thermal energy that was previously discharged unused to the environment is now used to generate steam.


Heat recovery system from Siemens: The thermal energy recovered from the hot exhaust gases of electric arc furnaces is used to generate steam.

The steam can be put to good use in other processes in the steel works or in the generation of electricity. The system has a modular structure and can be dimensioned for the amount of heat to be recovered and integrated into the existing exhaust gas cooling system. To maximize the amount of steam obtained, it can substitute the complete conventional off-gas cooling system in the electric steel plant.

A possible saving of 22.5 kilowatt hours per metric ton of steel in the specific use of energy was proven in a Turkish steel mill. If the generated steam is used to preheat the feed water in the plant's in-house power station, the annual savings potential amounts to 45,000 metric tons of coal.

In order to cut running costs or to fulfill environmental regulations, more and more operators of electric steel mills are banking on improving the energy efficiency of their plants. Although the electric steel production route based on scrap recycling has a much lower specific energy requirement than steel production from iron ore, it is nevertheless an energy-intensive process.

Depending on the method of operation, up to one-third of the energy used by an electric arc furnace is lost through off-gases. The sensible heat of the exhaust gases is usually discharged unused to the environment through the water and air cooling systems.

Temperatures of up to 1,800 °C prevail in the exhaust gas stream. To make these considerable amounts of energy suitable for use, Siemens has developed a steam generation system that can be integrated into the existing off-gas cooling system of the arc furnace or can replace it entirely. The system consists of a boiler including steam drum, piping, water tanks, pump groups for feed and boiler water, and the associated sensors.

A group of feed water pumps supplies the boiler with the necessary water and ensures the required pressure. To increase its recovery performance, the system can be equipped with a feed water preheating process called an "economizer". This economizer heats the water almost to the boiling point before feeding it into the steam drum on the boiler.

To separate the heat from the off-gas of the electric arc furnace as efficiently as possible, the new Siemens system has diverse nested radiation and convection heating surfaces. The water is fed to the heating surfaces through distribution pipes with the aid of recirculation pump groups. The amount of water fed depends on the different pipe geometries and the heat load of the respective sections.

A correspondingly adapted recirculation ratio ensures safe, reliable and cost-effective operation of the boiler system. A certain amount of the boiler water evaporates during every circulation cycle between the steam drum and the heated surfaces. The resulting steam bubbles are then separated from the water inside the steam drum. A buffer storage can be optionally installed to balance out steam production, which is uneven due to the production process.

The heat recovery system from Siemens was specially conceived for the tough ambient conditions in the steel mill. Large amounts of dust and corrosive components in the exhaust gas must be dealt with as well as changing temperatures and amounts of the off-gas. Moreover, the system is equipped with the required safety facilities to comply with the Pressure Equipment Directive. It has a modular structure and can be adapted to differing requirements in each plant, thus facilitating the modernization of existing systems. Plant operators can choose between using the energy recovered in the form of steam directly or, for example, to generate electrical energy in steam turbines.

Installation of an energy recovery system in the exhaust gas system of an electric arc furnace with a tapping weight of 190 metric tons was analyzed within the scope of a feasibility study in a Turkish steel mill. The system was conceived for feed water preheating in the plant's own coal-fired power station. The continuous 50 bar(a) high-pressure steam production enables an annual saving of about 45,000 metric tons of coal in the power station. A power output of five megawatts (electrical) could be achieved if the steam were used directly to generate electricity. This corresponds to a reduction in the specific energy requirement of 22.5 kilowatt hours per metric ton of liquid steel.

Further information on solutions for steel works, rolling mills and processing lines can be found at www.siemens.com/metals.

Follow us on Twitter: www.twitter.com/siemens_press

The Siemens Industry Sector (Erlangen, Germany) is the world's leading supplier of innovative and environmentally friendly products and solutions for industrial customers. With end-to-end automation technology and industrial software, solid vertical-market expertise, and technology-based services, the Sector enhances its customers' productivity, efficiency, and flexibility. With a global workforce of more than 100,000 employees, the Industry Sector comprises the Divisions Industry Automation, Drive Technologies and Customer Services as well as the Business Unit Metals Technologies. For more information, visit http://www.siemens.com/industry

The Metals Technologies Business Unit (Linz, Austria), part of the Siemens Industry Sector, is one of the world's leading life-cycle partners for the metals industry. The Business Unit offers a comprehensive technology, modernization, product and service portfolio as well as integrated automation and environmental solutions covering the entire life cycle of plants. For more information, visit http://www.siemens.com/metals

Reference Number: IMT201311534e

Contact
Mr. Rainer Schulze
Metals Technologies
Siemens AG
Turmstr. 44
4031 Linz
Austria
Tel: +49 (9131) 7-44544
rainer.schulze​@siemens.com

Rainer Schulze | Siemens Industry
Further information:
http://www.siemens.com/industry

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>