Publications

We share our knowledge.

WS is at the forefront of new technical developments. And not only that, we share our advances with the community. Only together we can achieve what is needed to make the energy revolution a reality. 

We deliberately try not only to write our publications for the scientific community, but also to formulate them as close to the application as possible. Because only what is actually implemented makes a real contribution to progress. 

Technical Books

 

The handbook of Burner Technology for Industrial Furnaces can be purchased through all major book stores as well as directly from Vulkan-Verlag.

 

The current edition contains updated information on recent developments in industrial burner technology.

The book "Praxiswissen Industriebrenner" is available directly from Vulkan-Verlag.


The book gives a good overview of current industrial burner technology by summarizing relevant articles from GWI journals.

Papers

Title: Defossilization of thermoprocessing technology

published in: Steel, No. 3-4/2021, pages 62-63, Vulkan Publishing House

Recordings of the presentations of the online conference:

"Biogas becomes hydrogen" by Joachim Wünning: Record

"Study: hydrogen from biogas" by Maximilian Schleupen: Record

2nd Aachen Furnace Construction and Thermal Process Colloquium

October 10 and 11, 2019 in Aachen

 

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Author: M. Schönfelder, S. Mickey, J.G. Wünning

Journal: Industrial Heating

Date: June 12th, 2017

 

In many locations throughout North America, nitrogen oxide (NOx) emissions of gas-heated furnaces are limited by law or code. This is typically the case in urban areas or in places where special topographical characteristics intensify the negative local and regional effects of NOx emissions.

 

Link to the article 

Title: Scale growth of copper and steel in direct firing with excess fuel.


Summary:
An article published in issue 3/2016 of the journal Gas Heat International The method presented here for heating semi-finished metal products in direct-fired plants uses the process of combustion with excess fuel. Laboratory tests show that under these conditions, significantly smaller amounts of scale result for useful material made of copper and a hot-working steel compared with heating with excess air. On copper, scale is already no longer formed at an air number of 0.96, and on steel the metal loss is reduced by approx. 50 % at an air number of 0.95.

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 ...


Article (english)

Presentation (english) 

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 to the article

Author: J.G. Wünning
Journal: Gas Heat International
Issue: 1/2013

 

Fuel gases are in most cases the most economical and environmentally friendly energy source for heating industrial furnaces. However, further increases in efficiency and reductions in pollutants are possible. The introduction of new burner technology requires close cooperation with plant manufacturers and operators so that new developments can be successfully implemented.

Author: J.G. Wünning
Publication: Gas Heat International
Year: 4 / 2012

 

Combustion is the central process for converting fuel energy into heat. The goal of low-pollution and efficient combustion can be achieved by flameless oxidation in many processes. The heating of high-temperature processes, the possibilities for increasing the efficiency of low-temperature processes, the provision of heating energy and the generation of electricity in power plants are considered.

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.

 

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Author: J.G. Wünning
Journal: Gas Heat International
Year: 2010

 

Computer simulation of flow, heat and mass transfer (CFD - computational fluid dynamcis) is used in universities and increasingly also in industry. The greatest weaknesses are still considered to be the often dubious reliability of the results and the long calculation times. In the present article, it is to be shown how combustion processes of flameless oxidation can be calculated very quickly by suitable selection of the boundary conditions. The goal here is calculation times of a few minutes. The short calculation times allow extensive testing of the calculation models and permit a wide range of parameter variations.

Author: J.G. Wünning
Journal: Gas Heat International
Year: 2010

An approximation formula for estimating the exhaust gas losses is proposed which can also be used at higher temperatures.

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 calculations could be performed as an alternative or addition to existing calculations.

 

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Author: J.G. Wünning
Publication: Gas Heat International
Year: 2009

 

Reducing exhaust gas losses is in many cases the most effective and economical solution for increasing the energy efficiency of industrial furnaces. In the following article, two new burner designs are presented with which the exhaust gas losses can be almost halved compared to finned tube recuperator burners. With the regenerator burner, the highest efficiencies are achieved, but a certain amount of effort for cyclic switching and exhaust gas extraction must be accepted. Particularly in the case of low-power burners and small furnace systems, this expense is not always justified at current energy prices. With the new split-flow recuperative burner, high efficiencies are achieved with a recuperative system. Both burner types use flameless oxidation, which achieves very low nitrogen oxide values.

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

 

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 to the Article 

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

 

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 great 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.

 

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Authors:
A. Georgiev, J.G. Wünning, U. Bonnet
Publication: Heat Processing
Year: 2008

 

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

 

In recent years flameless combustion technology has been developed in order to reduce NOx emissions in combustion processes. 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 twice 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.

 

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Author:
Joachim G. Wünning
Conference: 7th HTACG 08
Location: Phuket, Thailand
Year: 2008

 

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.

 

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Author: J.G. Wünning
Conference : AFRC - JFRC
Location: Hawaii, USA
Year: 2007

 

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 great 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.

 

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Authors: A. Georgiev, J.G. Wünning, U. Bonnet
Journal: Gas Heat International
Year: 2007

 

The article describes the use of compact regenerative burners in double-P radiant heating tubes of a hot-dip galvanizing line. After a brief description of the overall system and the annealing furnace, the operation of the regenerative burner is described. The regenerative burner contributes decisively to energy savings by very high air preheating temperatures and at the same time reduces NOx emissions by applying flameless oxidation.

 

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Authors: J.A. Wünning, J.G. Wünning
Conference: German Flame Day
Place: Berlin, Germany
Year: 2007

 

Radiant tubes are used for the indirect heating of thermoprocessing equipment, mainly in the field of heat treatment of steel. The state of the art are recuperative burners, in which the burner and the recuperative air preheater form a single unit. In the wake of rising energy prices, increased efforts are being made to further improve the efficiency of air preheating and thus the firing efficiency. Higher air preheat temperatures can be achieved with a regenerative air preheater, which offers potential savings over a recuperative burner of 15-25%. To date, however, regenerator burners have been used primarily for open heating and at higher burner capacities. The paper describes the development and initial applications of compact regenerator burners that are compatible with recuperator burners. In combustion technology, the formation of thermal nitrogen oxides must be prevented above all. With the help of flameless oxidation, it is possible to achieve low NOx values despite the extremely high air preheating temperatures in conjunction with the confined flow conditions in the radiant tube. Another challenge is the accommodation of the regenerative heat exchanger in a very compact construction volume.

Authors: A. Schuster, M. Zieba, G. Scheffknecht, J.G. Wünning
Conference: 15th European Biomass Conference
Location, Berlin, Germany
Year: 2007

 

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

 

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 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.

 

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Author: J.G. Wünning
Conference: Thermprocess Symposium
Location: Düsseldorf, Germany
Year: 2007

 

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 too complex and expensive for heating small and medium size heat treating furnaces.

 

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Author: J.G. Wünning
Journal: Industrial Heating
Year: 2007

 

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 too complex and expensive for heating small and medium size heat treating furnaces.

Authors:
R. Berger, A. Schuster, J.G. Wünning
Journal: Gas Heat International
Year: 2006

 

The bio-refinery concept counters simple wood combustion with an integrated material and energy use of biomass resources. Similar to the concept of Verbund sites in large-scale chemistry, this requires the effective use of by-products and waste. For these purposes, the company WS-Wärmeprozesstechnik GmbH and the University of Stuttgart are developing new burner systems based on the proven principle of Flameless Oxidation (FLOX®). This development has meanwhile led to the foundation of the company e-flox GmbH, which is dedicated to the marketing of these new technologies. This paper describes lean gas burners that are directly coupled with pre-gasifiers to utilize solid residues. The 800-900 °C hot gases are converted in a FLOX® burner. With CO emissions of < 30 mg/m3 at O2 contents of 4%, it was thus possible to reduce CO emissions by a factor of 4 and flue gas losses by around 25 % compared with the state of the art. The burner tested operates stably at oxygen contents of 3 to 9% in the exhaust gas. It succeeds in avoiding thermal nitrogen oxide formation, as expected for FLOX® burners, but fuel-nitrogen based NOx emissions cannot be reduced in this operating range. For this reason, the burner concept was further developed into a staged FLOX® burner. This is to be tested on an industrial pre-gasification plant in the fall.

 

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Authors: U. Bonnet, H. Kaczor, J. Wünning
Journal: Millenium Steel
Year: 2006

 

Heating of forging ingots in bogie hearth furnaces can be greatly improved by a specially
designed ceramic nozzle burner that distributes heat in a more uniform pattern while minimising
scale formation, energy consumption and NOx emissions, and maximizing productivity.

 

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Authors: E. Beck, R. Schönenberg, S. Zeizinger, J. Wuenning
Conference: Galvanizers Meeting
Location: Columbus, Ohiol
Year: 2006

 

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

 

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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

 

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.

Authors: H. Kaczor, U.Bonnet
Journal: Gas Heat International
Year: 2005

 

The successful use of recuperator burners in a bogie hearth furnace for heating forging ingots is reported. The special distribution of the flame by a ceramic burner head makes this application very economical with simultaneous uniformity of through-heating.

 

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Authors: Tim McCrea, G. Gabbert, R. Patil
Journal: Millenium Steel
Year: 2005

 

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.

Author: J.G. Wünning
Conference: HTACG05
Location: Essen, Germany
Year: 2005

 

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

 

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

 

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.

 

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Author:
J.G. Wünning
Journal: Heat Treating Progress
Year: 2005

 

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

 

Abstracts:

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

 

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Author: J.G. Wünning
Conference: Galvanizers
Location: Charleston, USA
Year: 2004

 

After an 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.

 

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Authors:
W. Roth, L.A. Ruiter, K.-H. Kirchhoff
Journal: Heat Processing
Year: 2004

 

The furnace of a continuous annealing and pickling line for stainless steel strip usually is directly 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.

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

Journal: GasWärme Int.
Year: 2004

 

Continuous annealing furnaces as part of an annealing and pickling line for stainless steel strip are usually directly heated. Due to the bright surfaces of the stainless steel strip, high zone temperatures are necessary to achieve a reasonable heating performance in the furnace. In order to minimize exhaust gas losses, either a long unheated preheating zone in conjunction with a central heat exchanger for the combustion air must be provided or regenerative burners must be used.

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

 

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 ionization 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.

 

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Author:
V. Burkhardt, W. Roth, H. Tibbenham, J.Wuenning
Publication: Millenium Steel
Year: 2004

 

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.

 

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

 

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
Journal: Industrial Heating Magazine
Year: 2004

 

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

 

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 easier operating conditions.

Author: J.G. Wünning
Publication: Heat Processing
Year: 2003

 

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 cost 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.

 

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Author: J.G. Wünning
Conference: AISE
Location: Pitsburgh, PA
Year: 2003

 

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
Conference: German Flame Day
Year: 2003

 

As part of a joint project sponsored by the German Federation of Industrial Research Associations (AiF), the Gaswärme-Institut e.V. Essen (GWI) and the Chair of Energy Systems and Energy Process Technology (LEAT) at the Ruhr University Bochum, new firing systems are being investigated with the aim of developing a burner concept that ensures the energy-efficient and environmentally friendly combustion of lean gases with a CH4 content < 30 vol. -% and thus contributes to the decentralized generation of electricity from lean-calorific gases in micro gas turbines. Based on detailed investigation results under atmospheric conditions at GWI, the optimal burner configurations are established by means of numerical simulations and scale-up criteria for the pressure tests on the LEAT pressure combustor based on these results. In this paper, the results of the atmospheric investigations are presented and the status of the pressure tests is explained.

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

 

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 cost 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.

 

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Author: J.G. Wünning
Conference: Thermprocess Symposium
Location: Düsseldorf, Germany
Year: 2003

 

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 ionization 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.

 

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Authors: Domschke Th., Becker C., Wünning J.

VDI Reports 45, Flame Day 1997

 

Low nitrogen oxide combustion of N-containing streams - A combination of catalytic cracking and combustion.

 

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Author: J.G. Wünning

 

Student research project at RWTH Aachen University entitled "Hydrogen for process heat generation".

 

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