Autor: J.G. Wünning

Veranstaltung: Galvanizers, GA2014

Jahr: 10/2014

 

A good durability of radiant tubes is essential for a profitable operation of a strip line. There are several factors influencing the radiant tube life ........

Vortrag (Englisch)
Präsentation (Englisch)

Autor: J.G. Wünning

Publication: Industrial Heating

January 2014

 
Energy costs usually represent a large fraction of operating cost for an industrial furnace. Most of these furnaces use natural gas as an energy source for heating.

link zum Artikel

Autor: J.G. Wünning

Publikation: Gaswärme International

Jahr: 1/2013

 

Brenngase sind in den meisten Fällen der wirtschaftlichste und umweltfreundlichste Energieträger zum Beheizen von Industrieöfen. Eine weitere Steigerung der Effizienz und Absenkung der Schadstoffe ist aber möglich. Die Einführung neuer Brennertechnik erfordert eine enge Zusammenarbeit mit Anlagenherstellern und -betreibern, damit Neuentwicklungen erfolgreich eingesetzt werden können.

Autor: J.G. Wünning

Publikation: Gaswärme International

Jahr: 4 / 2012

 

Die Verbrennung ist das zentrale Verfahren zur Umwandlung von Brennstoffenergie in Wärme. Das Ziel einer schadstoffarmen und effizienten Verbrennung kann durch die flammlose Oxidation bei vielen Prozessen erreicht werden. Betrachtet werden die Beheizung von Hochtemperaturprozessen, die Möglichkeiten zur Effizienzsteigerung von Niedertemperaturprozessen, die Bereitstellung von Heizwärme und die Stromerzeugung in Kraftwerken.

Autor: E. Cresci, A. Milani, J.G. Wünning

Conference: IFRF Member conference

Ort / Jahr: Maffliers Frankreich / 2012

 

The scope of the present publication is to illustrate how the application of flameless oxidation can actually represent a significant contribution to the achievement of the climate goals addressed by the European energy strategy for the future decades. The benefits and opportunities related to the utilization of the flameless oxidation technology still have large potential not only on the industrial field, but also in the private and domestic energy sector as well as in power generation plants. Basically, two methods can be addressed for the achievement of the goals set by the Energy 2020 strategy: on one hand the CO2-free power generation, on the other hand the energy conservation through higher efficiency. It can be shown how the implementation of these latter measures implies much more contained economical efforts.
Artikel als pdf

Autor: J.G. Wünning

Publikation: Gaswärme International

Jahr: 2010

 

In Hochschulen und zunehmend auch in der Industrie wird die Computersimulation von Strömung, Wärme- und Stoffübertragung (CFD – computational fluid dynamcis) eingesetzt. Als größte Schwachpunkte werden noch immer die oftmals zweifelhafte Zuverlässigkeit der Ergebnisse sowie die langen Berechnungszeiten angesehen. Im vorliegenden Artikel soll gezeigt werden, wie Verbrennungsvorgänge der flammlosen Oxidation durch geeignete Wahl der Randbedingungen sehr schnell berechnet werden können. Das Ziel sind dabei Berechnungszeiten von wenigen Minuten. Die kurzen Berechnungszeiten ermöglichen ausgiebige Überprüfung der Berechnungsmodelle und erlauben vielfältige Parametervariationen.

Autor: J.G. Wünning

Publikation: Gaswärme International

Jahr: 2010

 

Eine Näherungsformel zur Abschätzung der Abgasverluste wird vorgeschlagen die auch bei höheren Temperaturen angewendet werden kann.

Author: J.G. Wünning
Conference: HTACG2010
Location: Poznan, Poland

 

Abstract: This article should stimulate a discussion about the role of CFD simulations for flameless oxidation with the goal to increase trustworthiness of the results of CFD. It is proposed to drastically reduce the complexity of the cases to achieve results in less than 5 minutes. These calculation could be performed as an alternative or addition to existing calculations.

(pdf - full article)

Autor: J.G. Wünning
Publikation: Gaswärme International
Jahr: 2009

Zusammenfassung:

Die Verringerung der Abgasverluste ist in vielen Fällen die wirksamste und wirtschaftlichste Lösung zur Steigerung der Energieeffizienz von Industrieöfen. Im folgenden Beitrag werden zwei neue Brennerbauarten vorgestellt, mit denen die Abgasverluste gegenüber Rippenrohr-Rekuperatorbrennern nahezu halbiert werden können. Mit dem Regeneratorbrenner werden höchste Wirkungsgrade erzielt, es muss jedoch ein gewisser Aufwand für das zyklische Umschalten und die Abgasabsaugung in Kauf genommen werden. Besonders bei Brennern geringer Leistung und bei kleinen Ofenanlagen ist dieser Aufwand bei derzeitigen Energiepreisen nicht immer gerechtfertigt. Mit dem neuen Spaltstrom - Rekuperatorbrenner werden hohe Wirkungsgrade mit einem rekuperativen System erzielt. Bei beiden Brennertypen kommt die flammlose Oxidation zum Einsatz, womit sehr niedrige Stickoxidwerte erreicht werden.

Authors: S. Ogonek, L. Rabe, S. Dixon
Publication: Industrial Heating
Year: 2009

Abstract:

Betts Spring, an OEM producer of coiled springs for automotive and other uses, was established in 1868 in the San Francisco Bay area of California. They have been in business longer than most companies because they are successfully dealing with (among other things) cost increases – both production costs and the cost of living for associates. To provide a better quality of life for their employees and to control costs for the company, the management team made the decision to move their spring production operation to a new location.
(link zum Artikel)

Author: J.G. Wünning
Conference: 8th INFUB
Location: Portugal
Year: 2008

Abstract:

Regenerative combustion air preheating became increasingly popular due to rising energy costs. Advances in the abatement of NOx-formation made it possible to lower emissions in new installation despite high air preheating temperatures. Now, there are many regenerative fired furnaces in the steel industry, many of them in the large reheating furnaces. But there is still are large potential in energy savings. Besides the large firing capacities in reheating furnaces, there are many heat treating furnaces with smaller capacaity burners and also radiant tube heated furnaces. Small capacity regenerative burner systems require different concepts which will be discussed in the presentation.
(pdf-full article)

Authors:
A. Georgiew, J.G. Wünning, U. Bonnet

Publication: Heat Processing
Year: 2008

Abstract:

This article will describe the application of a new self regenerative burner in a continuous galvanizing line. After a brief introduction of the process line, the self regenerative burner will be described. Very high air preheat temperatures enable considerable energy savings and flameless oxidation suppresses the formation of NOx.

Authors:
Dragisa Ristic1, Maik Schneider, Anja Schuster, Prof. Dr. techn. Günter Scheffknecht, Dr. Joachim G. Wünning

Conference: 7th HTACG 08
Location: Phuket, Thailand
Year: 2008

Abstract:
In recent years flameless combustion technology has been developed in order to reduce NOx emissions in combustion proceses. Within this work a significant reduction of NOx emissions was achieved by developing a novel coal flameless burner design. The objective of this paper is to examine mechanisms forming NOx in the pulverised coal air staging combustion. Within this research, determination of the fuel-NO portion out of total-NO concentrations has been done by evaluating the flue gas measurements and using Ar/O2 mixture instead of combustion air in flameless and flame mode. Nitrogen-containing species such as HCN and NH3 and gaseous species used for calibration have been recorded using a high resolution FTIR spectrophotometer in flameless and flame mode. The effect of stoichiometry in the fuel-rich zone and the effect of furnace wall temperature were examined in flameless mode. The results show strong influence of volatile matter content in coal on NOx emission. The thermal-NO could be reduced double within flameless mode. Within flameless mode in primary combustion zone under fuel-rich conditions reducing components HCN and NH3 are dominant volatile nitrogenous species. Amount of yielded total fuel volatile nitrogen within primary combustion zone under fuel-rich condition depend on local stoichiometry. Increasing furnace wall temperature decreases fuel-NO.
(pdf-full article)

Author:
Dr. Joachim G. Wünning

Conference: 7th HTACG 08
Location: Phuket, Thailand
Year: 2008

Abstract:

Air preheating became increasingly popular due to rising energy costs. Advances in the abatement of NOx-formation made it possible to lower emissions in new installation despite high air preheating temperatures. Besides the large firing capacities in reheating furnaces, there are many heat treating furnaces with smaller capacity burners and also radiant tube heated furnaces. Small capacity recuperative and regenerative burner systems require different concepts which will be discussed in this paper.
(pdf-full article)

Author: J.G. Wünning

Conference : AFRC - JFRC
Location: Hawaii, USA
Year: 2007

Abstract:

Regenerative combustion air preheating became increasingly popular due to rising energy costs. Advances in the abatement of NOx-formation made it possible to lower emissions in new installation despite high air preheating temperatures. Now, there are many regenerative fired furnaces in the steel industry, many of them in the large reheating furnaces. But there is still are large potential in energy savings. Besides the large firing capacities in reheating furnaces, there are many heat treating furnaces with smaller capacity burners and also radiant tube heated furnaces. Small capacity regenerative burner systems require different concepts which will be discussed in the presentation.
(pdf-full article)

Autoren: A. Georgiew, J.G. Wünning, U. Bonnet

Publikation: GasWärmeInternational
Jahr: 2007

Zusammenfassung:

Im Beitrag wird der Einsatz kompakter Regenerativbrenner in Doppel-P-Strahlheizrohren einer Feuerverzinkungslinie beschrieben. Nach einer kurzen Darstellung der Gesamtanlage und des Glühofens wird die Arbeitsweise des Regenerativbrenners beschrieben. Der Regenerativbrenner trägt durch sehr hohe Luftvorwärmtemperaturen entscheidend zur Energieeinsparung bei und reduziert gleichzeitig durch Anwendung der flammlosen Oxidation die NOx Emissionen.
(pdf-Artikel)

Autoren: J.A. Wünning, J.G. Wünning

Konferenz: Dt. Flammentag
Ort: Berlin, Deutschland
Jahr: 2007

Abstract:

Strahlheizrohre werden für die indirekte Beheizung von Thermoprozessanlagen, vorwiegend auf dem Gebiet der Wärmebehandlung von Stahl, eingesetzt. Stand der Technik sind Rekuperatorbrenner, bei denen der Brenner und der rekuperative Luftvorwärmer eine Baueinheit bilden. Im Zuge der steigenden Energiepreise werden verstärkte Anstrengungen unternommen, die Effizienz der Luftvorwärmung und damit den feuerungstechnischen Wirkungsgrad noch weiter zu steigern. Höhere Luftvorwärmtemperaturen können mit einem regenerativen Luftvorwärmer erreicht werden, der ein Einsparpotential gegenüber einem Rekuperatorbrenner von 15-25% bietet. Bislang werden Regeneratorbrenner aber im wesentlichen für offene Beheizung und bei höheren Brennerleistungen eingesetzt. Im Beitrag wird die Entwicklung sowie erste Anwendungen von kompakten Regeneratorbrennern beschrieben, die kompatibel mit Rekuperatorbrennern sind. Bei der Verbrennungstechnik muss vor allem die Bildung der thermischen Stickoxide verhindert werden. Mit Hilfe der flammlosen Oxidation gelingt es, trotz der extrem hohen Luftvorwärmtemperaturen in Verbindung mit den beengten Strömungsverhältnissen im Strahlrohr niedrige NOx-Werte zu erreichen. Eine weitere Herausforderung ist die Unterbringung des regenerativen Wärmetauschers in einem sehr kompakten Bauvolumen.

Authors: A. Schuster, M. Zieba, G. Scheffknecht, J.G. Wünning

Conference: 15th European Biomass Conference
Location, Berlin, Germany
Year: 2007

Abstract:

The demand on biomass for heat and power production has intensively increased within the last years due to the rising gas and oil prices. Up to now mostly high-quality biomass (e.g. wood pellets, untreated wood) is used for heat production but also low-grade biomass becomes more and more of interest. For utilization of low-grade biomass an advanced combustion technology is required due to its high content on inert components, e.g. nitrogen. Gasification of solid bio-residues to generate low calorific value (LCV) gases and their subsequent combustion is one of the possible conversion pathways. Within the presented work a multi-nozzle burner for LCV gases applying flameless oxidation (FLOX®) was developed that has several advantages compared to conventional flame burners. The FLOX®-burner was integrated in an existing dual-chamber furnace and four different residues from biorefinery processes were tested. Besides a more stable combustion with an improved burnout and thus a broader range of operation also a better performance due to the operation at lower excess oxygen were achieved. Furthermore the high power density of a FLOX®-burner reduces the volume of the combustion chamber by about 75 %. However, the investigations have also shown that the FLOX®-burner can only reduce thermal NO emissions but NO emissions related to fuel-bond nitrogen (e.g. in high contents in agricultural residues) are still on a high level or even increased by the flameless combustion.

Authors: A. Schuster, M. Zieba and G. Scheffknecht, J.G. Wünning

Conference: IFRF Member Conf.
Location: Pisa, Italy
Year: 2007

Abstract:

The utilisation of low-grade biomass requires an appropriate technology that meets the increased demands regarding emission reduction (e.g. NOx). Within this work a new burner for low calorific value (LCV) gas applying flameless oxidation (FLOX®) will be presented that replaces the conventional flame burner of a dual-chamber furnace. The integration of an adapted FLOX®-burner has shown several benefits. Different bio-residues were tested and a more stable combustion with enhanced burnout was achieved for all tested fuels. Furthermore, the burner can be operated in broader range of operation and closer to stoichiometric conditions. Due to the high power density of a FLOX®-burner the complete facility could be downsized in the future. Still, the tests have shown that the NOx reduction potential of a FLOX®-burner is limited for LCV gas combustion since the most NO emissions are related to fuel-bond nitrogen. In the LCV gases generated from wheat pellets and rape cake pellets high concentrations of NO-precursors (NH3 and HCN) are measured that are subsequently be oxidized to NO in the FLOX®-burner. Therefore, an air-staged burner for N-rich LCV gases based on flameless combustion is proposed where NO-precursors can be reduced to N2 in a first substoichiometric region. CFD simulations were applied to investigate an appropriate design of an air-staged FLOX®-burner. Special emphasis is placed on the creation of a sufficient internal recirculation of flue gases required for flameless combustion. First results of CFD simulations are presented.
(pdf-full article)

Author: J.G. Wünning

Conference: Thermprocess Symposium
Location: Düsseldorf, Germany
Year: 2007

Abstract:

Energy efficiency has become a top priority for many companies in the steel and heat treating business. Since hot exhaust gases represent the largest source for losses in most industrial furnaces, preheating the combustion air provides the highest potential for energy savings. Different strategies will be discussed in this paper in respect to their advantages but also regardings things which have to be considered. A new type of regenerative burner for radiant tube heating will also be presented. Regenerative air preheating is accepted as the most effective way to increase energy efficiency for high temperature process heating but was seen in the past as to complex and expensive for heating small and medium size heat treating furnaces.
(pdf-full article)

Author: J.G. Wünning

Publication: Industrial Heating
Year: 2007

Abstract:

Gas fired radiant tubes are widely used to heat industrial furnaces. Energy efficiency has become a top priority for many companies in the heat treating business. This paper will discuss the available options and will present a new type of regenerative burner for radiant tube heating. Regenerative air preheating is accepted as the most effective way to increase energy efficiency for high temperature process heating but was seen as to complex and expensive for heating small and medium size heat treating furnaces.

Autoren:
R. Berger, A. Schuster, J.G. Wünning

Puplikation: GasWärmeInternational
Jahr: 2006

Abstract:

Das Konzept der Bio-Raffinerie setzt der simplen Holzverbrennung eine integrierte stoffliche und energetische Nutzung von Biomasseressourcen entgegen. Ähnlich wie bei dem Konzept der Verbundstandorte in der Großchemie erfordert dies die effektive Nutzung von Nebenprodukten und Abfällen. Für diese Zwecke entwickeln die Firma WS-Wärmeprozesstechnik GmbH und die Universität Stuttgart neue Brennersysteme auf Basis des bewährten Prinzips der Flammenlosen Oxidation (FLOX®). Diese Entwicklung hat inzwischen zur Gründung der Firma e-flox GmbH geführt, die sich der Vermarktung dieser neuen Technologien widmet. In diesem Beitrag werden Schwachgasbrenner beschrieben, die direkt mit Vorvergasern gekoppelt werden, um feste Reststoffe zu nutzen. Die 800–900 °C heißen Gase werden in einem FLOX-Brenner umgesetzt. Mit CO-Emissionen von < 30 mg/m3 bei O2-Gehalten von 4% gelang es damit die CO-Emissionen gegenüber dem Stand der Technik um den Faktor 4 und die Abgasverluste um rund 25 % zu senken. Der getestete Brenner arbeitet stabil bei Sauerstoffgehalten von 3 bis 9% im Abgas. Es gelingt zwar, wie für FLOX-Brenner erwartet thermische Stickstoffoxidbildung zu vermeiden, aber die auf Brennstoff-Stickstoff basierenden NOX-Emissionen können in diesem Betriebsbereich nicht reduziert werden. Aus diesem Grund wurde das Brennerkonzept zu einem gestuften FLOX-Brenner weiterentwickelt. Dieser soll im Herbst an einer industriellen Vorvergasungsanlage getestet werden.
(pdf-Artikel)

Authors: U. Bonnet, H. Kaczor, J. Wünning

Millenium Steel

Year: 2006

Authors: E. Beck, R. Schönenberg, S. Zeizinger, J. Wuenning

Conference: Galvanizers Meeting
Location: Columbus, Ohiol
Year: 2006

Abstract:

Thyssen Krupp Steel started up a new 450,000 t/year (500,000 tons/year) galvanizing line in the fall of 2001 at their Dortmund, Germany plant. The vertical annealing furnace is equipped with a total of 189 double-P-radiant tubes. This is the first time that a vertical annealing furnace was completely furnished with the new radiant tube design. The main motive to install new radiant tube technology was to improve tube life, due to better temperature uniformity of the tube. The presentation will describe the technology and will give a status report after five years of operation with special focus on:
- tube life
- energy efficiency
- reliability
- maintenance and
- emissions
(pdf-full article)

Author: A. Schuster, R. Berger, G. Scheffknecht, J.G. Wünning, M. Hiltunen, T. Eriksson, M. Schmid, C. Gaegauf

Conference: Biogas05
Location: Paris, France
Year: 2005

Abstract:

The utilisation of low grade biofuels suffers from the lack of advanced technology. Within the European Project BIO-PRO new burner systems are developed to exploit the unused sources of gaseous, liquid and solid bio-residues. Two innovative burner technologies like flameless oxidation (FLOX®) and continuous air staging (COSTAIR) will be applied and adapted to low calorific value (LCV) gas combustion. The project objectives and the general approach for the development of two burner systems, one for gases and liquids and one for solids, are described. Results of the FLOX-burner development and a first industrial test of a prototype burner are presented in detail. LCV gases with a minimum calorific value of 2.5 MJ/Nm3 can be burned stably in a bench-scale FLOX-burner. The utilisation of liquid biofuels (rapeseed oil) is successfully tested. First investigations on the fuel-NO reduction potential of the burner system show promising results. A first prototype FLOX-burner demonstrated its fuel flexibility in a 176 hours industrial test run. The current results of the gas/liquid burner development will now be applied to a burner that can be directly integrated in gasifiers.

Autoren: H. Kaczor, U.Bonnet

GasWärme International
Vulkan Verlag
Year: 2005

Zusammenfassung:

Es wird über den erfolgreichen Einsatz von Rekuperator-Brennern in einem Herdwagenofen für die Erwärmung von Schmiedeblöcken berichtet. Die besondere Verteilung der Flamme durch einen keramischen Brennerkopf macht diese Anwendung sehr wirtschaftlich bei gleichzeitiger Vergleichmäßigung der Durchwärmung.
(pdf-Artikel)

Authors: Tim McCrea, G. Gabbert, R. Patil

Millenium Steel
Year: 2005

Abstract:

Retrofitting ceramic single-end recuperative burners in a continuous galvanising line has provided improved availability, energy efficiency and heat flux, and reduced emissions compared to the pre-existing alloy tube system. This solution has eliminated the source of tube failures and extends the life of the tubes from 3.5 years to potentially over 10 years.
(pdf-full article)

Author: J.G. Wünning

Conference: HTACG05
Location: Essen, Germany
Year: 2005

Abstract:

Flameless Combustion was first developed to suppress thermal NOx formation in burners for heating industrial furnaces using preheated combustion air. While this technique is applied in large numbers now, there are a number of other applications emerging. The presentation will give an introduction into flameless combustion and then show industrial applications and applications which are at a research stage.

- heat treating and heating furnaces in the steel industry
- gas turbines - bio gas burners
- burners for hydrogen reformers
- burners for CHP units
- and others
(pdf-full article)

Author:
U. Bonnet, K. Telger, J.G. Wünning
Conference: HTACG05
Location: Essen, Germany
Year: 2005

Abstract:

A new design of a preheating unit for electrical steel strip has been developed and installed in front of a continuous radiant tube furnace. The unit uses self recuperative FLOX® burners arranged in a “nozzle field” and is designed to preheat the strip up to 400 °C. The required heating length is reduced to one fourth of a comparable radiant tube furnace section. This implies a large reduction in specific furnace length and therefore in lay-out and investment costs. The present article describes the new fast heating unit, the feedback from industrial tests and the conclusions derived from the successful installation on the continuous annealing line.
(pdf-full article)

Author:
J.G. Wünning

Publication: Heat Treating Progress
Year: 2005

Abstract:

Natural gas prices, after an extended period of stability, have become extremely volatile in the last few years. This is only one of the challenges that companies operating heat treating furnaces are now facing. Worldwide competition is forcing companies to produce more product with fewer people. There is pressure to increase furnace uptime, while furnace operators and maintenance staff are reduced. In addition, there are tightening emission requirements and as yet unknown future carbon dioxide tariffs. These challenges are related to radiant tube heating systems. Heat treating furnaces with outdated technology will not be competitive in the future. However, much effort has been put into the development of new radiant tube designs, and there is also new technology on the market that can be adapted for heat treating furnaces.

Author:
J.G. Wünning
Conference: IGT05
Location: Orlando, Florida
Year: 2005

Abstract:

Flameless Combustion was first developed to suppress thermal NOx formation in burners for heating industrial furnaces using preheated combustion air. While this technique is applied in large numbers now, there are a number of other applications emerging. The presentation will give an introduction into flameless combustion and then show industrial applications and applications which are at a research stage.
- heat treating and heating furnaces in the steel industry
- gas turbines
- bio gas burners
- burners for hydrogen reformers
- burners for CHP units
- and others
(pdf-full article)

Author:
J.G. Wünning

Conference: Galvanizers
Location: Charleston, USA
Year: 2004

Abstract:

After a extended period of low and stable natural gas prices, the prices have become extremely volatile in the last years. This is only one of the challenges, the operating companies of galvanizing lines are facing right now. Worldwide competition is forcing companies to produce more and more tons of strip with fewer and fewer people. Uptime of the lines must increase while the number of furnace operators and maintenance staff is reduced. In addition there are tightening emission requirements and yet unknown future carbon dioxide tariffs. All of these challenges are also related to the radiant tube heating systems of the strip line furnaces. Strip lines with outdated technology will not be competitive in the future. On the other hand, a lot of effort was put into the development of new radiant tube designs, and there is also new technology out on the market which can be adapted for strip line furnaces.
(pdf-full article)

Authors:
w. Roth, L.A. Ruiter, K.-H. Kirchhoff

Publication: Heat Processing
Year: 2004

Abstract:

The furnace of a continuous annealing and pickling line for stainless steel strip usually is direct fired. Due to the bright surface of stainless steel strip, high zone temperatures are required to achieve good heating rates. The flue gas losses can be reduced with long unheated preheat zones in combination with a central heat exchanger or by using self regenerative burners.

Autoren:
W. Roth, L.A. Ruiter, K.-H. Kirchhoff

Fachzeitschrift: GasWärme Int.
Year: 2004

Zusammenfassung:

Kontinuierliche Glühöfen als Teil einer Glüh- und Beizlinie für Edelstahlband werden in der Regel direkt beheizt. Aufgrund der blanken Oberflächen des Edelstahlbandes sind hohe Zonentemperaturen notwendig um eine vertretbare Aufheizleistung im Ofen zu erreichen. Damit die Abgasverluste dabei minimiert werden, ist entweder eine lange unbeheizte Vorheizzone in Verbindung mit einem zentralen Wärmetauscher für die Verbrennungsluft vorzusehen oder aber der Einsatz von Regenerativbrennern.

Author: J.G. Wünning

Conference: IFRF Member Conf.
Location: Noordwijkerhout, Netherlands
Year: 2004

Abstract:

If a combustible mixture of fuel and air is ignited, a flame can develop. In the reaction zone, called flame front, the temperature rises quickly to temperatures close to the adiabatic temperature. The flame can be stabilized within or close to the burner, so that the combustion goes stable and controlled. The different methods for flame stabilization play an important role in the field of burner development. Examples are baffle and swirl stabilization. For the required flame supervision, optical and electrical effects of flames are used. Modern burner designs use UV or ionisation detectors for automatic flame safety systems. In the absence of a flame signal, the burner is shut off. Therefore it can be said, that flames fullfill two important functions: flame stabilisation guarantees a constant and controlled reaction and a stable flame provides a steady reliable signal for flame safety systems. The question is why to five up the proven concept of flames and what are the advantages of flameless oxidation. The main important answer to this question is that flameless oxidation can suppress thermal NO-formation even when highly preheated air is used. The presentation will provide an overview of the activities around flameless oxidation from the last decade and it will also give an outlook on future potentials.
(pdf-full article)

Author:
V. Burkhardt, W. Roth, H. Tibbenham, J.Wuenning

Publication: Millenium
Year: 2004

Abstract:

Continuous annealing and pickling lines (A&P) for stainless steel strip are large plants where the strip is annealed in free-flame furnaces at high temperature (1250 °C max) and where uniform heating and oxidation is important for surface quality. The coils are cold rolled, then annealed in a downstream A&P line where the quality requirements are very stringent. Energy saving, NOx emissions from combustion of natural gas and from pickling, productivity and good performance (uniformity, ease of operation and control) are major issues, as they directly affect product quality and costs. Flameless technology has been developed to make possible extremely high air preheating together with low NOx in high temperature process furnaces
(pdf-full article)

Author:
A. Milani, J.G. Wünning
Conference: IFRF Member Conf.
Location: Noordwijkerhout, Netherlands Year: 2004

Abstract:

The following report reviews modern technology of radiant tubes with emphasis on heat recovery and low-NOx combustion techniques, including flameless combustion. Performance of radiant tubes is of basic consequence in large strip line furnaces; combustion pattern inside the tube, as well as connection of many tubes to the furnace, play a crucial role. The paper assesses features related to this topic, from main design concepts to materials available for radiant tubes, from energy saving measures to abatement of NOx emissions and flame/plant control. Significant applications to large industrial plants are reported, as well as on-going development of new products. Industrial practice and field feed-back point out that additional investment costs for an efficient and reliable radiant tube system can be recovered in a few years and provide better quality and operating conditions.

Author: J.G. Wünning

Publication: Industrial Heating Magazin
Year: 2004

Abstract:

Performance of the combustion equipement is a major issue in modern annealing and pickling lines for stainless steel strip, not only for energy savings and low NOx emissions, but also for product quality and reliable operation. A compact regenerative burner for this purpose has been designed, extensively tested and sucessfully installed on industrial furnaces in different countries. Recently, an A&P line at Columbus Stainless Ltd. in South Africa was upgraded, using regenerative burners.

Author:
A. Milani, J.G. Wünning
Conference: IFRF Totem
Location: Stockholm, Sweden
Year: 2003

Abstract:

The following report reviews modern technology of regenerative burners with emphasis on heat recovery and flameless combustion techniques for high temperature processes. Performance of the combustion equipment are most important in large, strip line furnaces not only for energy saving and NOx abatement, but also for reliable, trouble free operation. The paper describes a modern, compact regenerative burner that has been extensively installed and tested on industrial furnaces and assesses related features. Significant and successful applications to large Annealing and Pickling lines for stainless steel strip are reported. Industrial practice and field feed-back point out that a modern, efficient and more reliable combustion system may be competitive and that possible additional investment costs can be recovered in a short time, while providing better quality and easy operating conditions.

Author: J.G. Wünning

Conference: ASM
Location: Indianapolis, Indiana
Year: 2003

Abstract:

Author: J.G. Wünning

Publication: Heat Processing
Year: 2003

Abstract:

Natural gas is the most widely used fuel for heating strip in furnaces due to its availability and clean combustion and is enabling much lower energy costs, compared to electrical heating systems, provided that an efficient system is used. Besides energy costs issues, heating systems play an important role for the performance of a furnace, especially regarding temperature uniformity / product quality, net heat input / productivity, energy efficiency / operating costs, maintenance / operating costs, tube life / operating costs, flue gas emissions / pollution, furnace downtime, ease of operation and investment costs. The following reports shows that all these aspects have to be considered to make a decision for a new heat treating furnace or a retrofit project. (pdf-full article)

Author: J.G. Wünning

Conference: AISE
Location: Pitsburgh, PA
Year: 2003

Abstract:

Many strip processing lines include furnaces operating under a protective atmosphere. Most of them are heated using gas fired radiant tubes. The performance of the radiant tubes is vital for: productivity strip quality operating (energy) costs availability and required maintenance. The strip lines often have production rates in a range of 50 to 100 t/hr of strip and all unscheduled line stops create major trouble. Strip quality is essential to meet high customer standards. Process lines with a low fuel efficiency carry the risk of not being competitive, especially in times of high fluctuations of natural gas prices and global markets. Maintenance, especially unscheduled one, must be reduced since the process lines are operated with less and less personnel.

Author:
A. Al-Halbouni; A. Giese; M. Flamme, B. Michalski; V. Scherer, J. G. Wünning

Konferenz: Dt. Flammentag
Year: 2003

Zusammenfassung:

Im Rahmen eines von der Arbeitsgemeinschaft industrieller Forschungsvereinigung AiF geförderten Gemeinschaftsprojekts werden in Zusammenarbeit zwischen dem Gaswärme-Institut e.V. Essen (GWI) und dem Lehrstuhl für Energieanlagen und Energieprozesstechnik (LEAT) der Ruhr-Universität Bochum neue Feuerungssysteme mit dem Ziel untersucht, ein Brennerkonzept zu entwickeln, das zur energieeffizienten und umweltschonenden Verbrennung von Schwachgasen mit einem CH4-Anteil < 30 Vol. -% gewährleistet und somit zur dezentralen Verstromung schwachkaloriger Gase in Mikrogasturbinen beiträgt. Basierend auf detailierten Untersuchungsergebnissen unter atmosphärischen Bedingungen am GWI werden die optimalen Brennerkonfigurationen mittels numerischer Simulationen und scale-up-Kriterien für die darauf aufbauenden Druckversuche an der LEAT-Druckbrennkammer aufgestellt. In diesem Beitrag werden die Ergebnisse der atmosphärischen Untersuchungen vorgestellt und der Status der Druckversuche erläutert.

Author:
C. Fielenbach, Th. Holfeld, C. von Petery, U. Renz, J.G. Wünning
Conference: Coal
Location: Pitsburgh, PA
Year: 2003

Abstract:

Natural gas is the most widely used fuel for heating strip in furnaces due to its availability and clean combustion and is enabling much lower energy costs, compared to electrical heating systems, provided that an efficient system is used. Besides energy costs issues, heating systems play an important role for the performance of a furnace, especially regarding temperature uniformity / product quality, net heat input / productivity, energy efficiency / operating costs, maintenance / operating costs, tube life / operating costs, flue gas emissions / pollution, furnace downtime, ease of operation and investment costs. The following reports shows that all these aspects have to be considered to make a decision for a new heat treating furnace or a retrofit project. (pdf-full article)

Author: J.G. Wünning

Conference: Thermprocess Symposium
Location: Düsseldorf, Germany
Year: 2003

Abstract:

If a combustible mixture of fuel and air is ignited, a flame can develop. In the reaction zone, called flame front, the temperature rises quickly to temperatures close to the adiabatic temperature. The flame can be stabilized within or close to the burner, so that the combustion goes stable and controlled. The different methods for flame stabilization play an important role in the field of burner development. Examples are baffle and swirl stabilization. For the required flame supervision, optical and electrical effects of flames are used. Modern burner designs use UV or ionisation detectors for automatic flame safety systems. In the absence of a flame signal, the burner is shut off. Therefore it can be said, that flames fullfill two important functions:
· flame stabilisation guarantees a constant and controlled reaction
· and a stable flame provides a steady reliable signal for flame safety systems.
The question is why to give up the proven concept of flames and what are the advantages of flameless oxidation. The main important answer to this question is that flameless oxidation can suppress thermal NO-formation even when highly preheated air is used. The presentation will provide an overview of the activities around flameless oxidation from the last decade and it will also give an outlook on future potentials. (pdf-full article)