In the past, flue gases were usually not utilized, so the energy they carried was lost. The system consists of steam boilers, pipes, water tanks, and pumps and can be directly integrated into the existing flue gas cooling system. Theoretically, the system could entirely replace conventional cooling.
A feasibility study carried out at a steel mill in Turkey revealed potential savings of 44.5 kilowatt hours of electricity per ton of steel produced. That corresponds to around ten percent of the electrical energy that is normally required. If the steam were used to preheat the feed water for the steel mill's power plant, for example, the mill would save 45,000 tons of coal per year.
Electric arc furnaces melt steel scrap under arcs heated to a temperature of about 3,500 °C using high-voltage electricity. Depending on the specific furnace operation, up to one third of the energy used escapes in the flue gases. Normally these flue gases - which can be as hot as 1,800 °C - are extracted from the furnace through water-cooled pipes. Because this cooling water circulates within a closed system, it cannot be permitted to form steam. Cooling towers dissipate the excess heat.
This is where the solution developed by the experts at Siemens Metals Technologies comes in. The hot flue gas is diverted into a steam generator, where it flows around pipes filled with water. The heat from the gas turns the water into steam. A sophisticated system of nested heating surfaces ensures that heat is transferred from the flue gas as efficiently as possible.
Special recirculation pumps ensure that the steam boiler is adequately cooled. The system can handle fluctuations in flue gas temperature and volume, and it is specially designed to deal with the high levels of dust, some of which is corrosive, in the flue gas. Continuous steam production, such as that required for generating electricity, can be achieved through the installation of optional storage buffers known as "steam accumulators."
The heat from the flue gas can be recovered even more efficiently if the gas is directed through an "economizer" after it leaves the steam boiler. In the "economizer" the gas flows around a second system of pipes, where the remainder of its heat is used to preheat the feed water for the steam boiler.
The steam generation system has a modular construction and can be easily adapted to the specific requirements of each plant. This makes it especially easy to modernize existing steel mills.
Dr. Norbert Aschenbrenner | Siemens InnovationNews
Making magnets flip like cats at room temperature
21.07.2016 | Johannes Gutenberg-Universität Mainz
NASA eyes first-ever carbon-nanotube mirrors for CubeSat telescope
13.07.2016 | NASA/Goddard Space Flight Center
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis
A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...
Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.
In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...
Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.
Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
22.07.2016 | Information Technology
22.07.2016 | Physics and Astronomy
22.07.2016 | Life Sciences