Research, development and implementation of simultaneous low Nox/CO combustion technology for gaseous fuel firing in the iron and steel industry

Directorate-General For Research And Innovation European Commission

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• Publié par: DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION-EUROPEAN-COMMISSION
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• Langue: English
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ISSN 1018-5593
* *
European Commission
technical steel research
Mechanical working (rolling)
Research, development and implementation
of simultaneous low Nox/CO combustion
technology for gaseous fuel firing
in the iron and steel industry
STEEL RESEARCH EUROPEAN COMMISSION
Edith CRESSON, Member of the Commission
responsible for research, innovation, education, training and youth
DG XII/C.2 — RTD actions. Industrial and materials technologies —
Materials and steel
Contact: MrJ.-L. Martin
Address: European Commission, me de la Loi 200 (MO 75 1/10),
B-1049 Brussels — Tel. [phone]; fax [phone] European Commission
technical steel research
Mechanical working (rolling)
Research, development and implementation
of simultaneous low Nox/CO combustion
technology for gaseous fuel firing
in the iron and steel industry
E. Unzalu, P. Cuesta, J. Anza, E. Schaeidt, G. Aurtenetxe,
V. Ayala, J. Mugica, M. Troyano, J. Domínguez, A. Gomez
Labein
Cuesta de Olabeaga 16
Apartado 1234
E-48013 Bilbao
Contract No 7210-CB/933
1 April 1991 to 30 September 1994
Final report
Directorate-General
Science, Research and Development
1998 EUR 17917 EN LEGAL NOTICE
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Luxembourg: Office for Official Publications of the European Communities, 1998
ISBN 92-828-3130-2
© European Communities, 1998
Reproduction is authorised provided the source is acknowledged.
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PRINTED ON WHITE CHLORINE-FREE PAPER ABSTRACT
Research, Development and Implementation of Simultaneous
Low NOx/CO Combustion Technology for Gaseous Fuel Firing
in the Iron and Steel Industry. STELFLAM Project Group 1
E. UNZALU1, P. CUESTA1, J.J.ANZA2, E. SCHAEIDT2, G. AURTENETXE2 ,
V. AYALA1, J. MUGICA1, M. TROYANO2, J. DOMÍNGUEZ1 and A. GOMEZ1
LABEIN. TECHNOLOGICAL RESEARCH CENTER.
Cuesta de Olabeaga/Olabeagako Aidapa 16. 48013 Bilbao , Spain
1 Environment & Chemistry Dpt. 2 Analysis & Design Dpt.
One of the main anthropogenic sources of the atmospheric pollution originated by
NOx and CO emissions comes from high temperature combustions such as the ones
produced in the reheating furnaces in Iron and Steel Industry. The works carried out
along the STELFLAM Project have been performed to reach the reduction of those
emissions including the following main objectives: 1) extension of the current
knowlegde on formation mechanisms of the NOx and CO in combustion processes for
variable conditions of furnace performance; 2) use of mathematical models for the
improvement of predictions of NOx and CO emissions in mixed gas type burners; 3)
retrofitting current burners to achieve lower NOx and CO emissions without any
decrease of thermal efficiency.
Measurement campaigns have been carried out in ENSIDESA Plate Mill Reheating
Pusher Furnace No. 1 Zone 2 and 4 about the current NOx/CO emission levels related
with the furnace operation. These results were used as a comparison basis with the
optimized refitting design selected in base of the hot semi-industrial trials performed
in a laboratory. Different geometries of a scaledl burner, supported by
previous modelling and representing feasible alternatives of retrofitting current
burners, have been tested. At the end of the project the Demonstration Tests have
been carried out on the ENSIDESA's Furnace as on-site validation of the refitted
burner.
Specific techniques have been applied for the accurate solution of problems taking into
account a selection criteria in order to avoid any major alterations in the furnace
burners. Severala have been stated in order to achieve enough
interchangeability with the current industrial gas (mixed COG and BFG) and the test
gas (15,7% propane in air) and to compare the industrial burner's behaviour against
the semi-industrial test burner due to differences in geometrical scale.
The results obtained throughout this module of the STELFLAM Project confirm that
the objetives concerning three main points have been reached :
- Abatement of NOx emissions.
- Maintaining of the furnace performance.
- Minor modifications needed for burner retrofitting. On the other hand, and focussing on the mathematical modelling tasks carried out by
LABEIN, five main points can be summarized : 1) starting and training period, which
has contributed to an improvement in general burner and combustion knowledge and
to the familiarization with FLUENT code, FLUENT/BFC preprocessor, mesh
generation techniques and convergence acceleration methods; 2) predictions of the
current ENSIDESA burner performance, which has helped to obtain better results; 3)
modelling of two flames common to all partners of the Project, favouring a close and
positive cooperation beetween the different partners, as well as a tunning in models,
methods and presentation of results; 4) simulating proposed burner modifications at
the semi-industrial scale, helping the experimentalists in decision making about the
best refitting design and, optimizing the number of performance tests required; 5)
validation of numerical results against the experimental data. LIST OF CONTENTS
1. Objetives 7
8 2. Introduction
10 3. Description of activities
20 4. Results and discussion
29 5. Conclusions
31 6. Table of symbols
32 7. List of references
33 8. Key words
35 9. Tables and Figures
10. Appendices
APPENDIX A LABEIN/ENSIDESA Global Programme 51
APPENDE* Β Industrial furnace: Data Base 53 * C Semi-industrial scale trials: Data Base 89
APPENDIX D Considered modifications for ENSEDESA's burner 111 X E Simulation results: Current ENSIDESAr zone 2 123
(three-dimensional 3-D model)
APPENDE* F: Design of Experiments 127 * G: The swirling coke-oven gas flame 3 and 4 of the NFA 3-1 179
investigation: Input Data and Results
LIST OF TABLES
Table 1. Simulated geometries
Table 2. Phase main magnitudes
Table 3. Semi-industrial burner tests
Table 3.1. Burners Geometries Nomenclature Key
Table 4. Comparison between predicted and measured values
Table 5. Design of Experiments. Summary LIST OF FIGURES
Fig. 1. Current industrial burner.
Fig. 2. Testing furnace
Fig. 3. Cross section
Fig. 4. Probe transverse position
Fig. 5. Flame Temperature. Access N° 1 (Ml)
Fig. 6. NO Concentration in flame. Access N° 7 (M7)
Fig. 7. NO Concentration. Geometries SM-01A.1 / SM-01A.2
Fig. 8.O.s SM-01B.1 / SM-02B.1
Fig. 9. NO.s SM-01A.1 / SM-03A.1-45
Fig. 10. Retrofitted industrial burner
Fig. 11. NO-02 Concentrations. Current vs. Retrofitted Industrial Burner
Fig. 12. NO-CO.t vs. RetrofFitedlr 1. OBJETIVES OF THE R&D PROTECT
One of the main anthropogenic sources of the atmospheric pollution originated by
NOx and CO emissions comes from combustions at high temperature like the ones
produced in the reheating furnaces in Iron and Steel Industry. Thus, it is expected
that more stringent environmental regulations will appear in a near future in the E.U.
In accordance with these global objectives embodied in the STELFLAM Program and
interrelationated to other cooperative R+D projects in this domain of Combustion
Technology applied to Steel Mill Plants, the project entitled "Pollution control from
reheating furnace burners fired with both mixed gas and heavy fuel oil with
normal excess air" is focussed to decrease the emissions of Plate Mill Reheating
Pusher Furnace and specifically oriented to the facilities of ENSIDESA (Spain).
The specific research goals of this project, performed in co-operation between
LABEIN and ENSIDESA are:
Improve the current knowlegde on the formation mechanisms of the ΝΟχ and
CO in combustion processes for variable conditions of furnace performance.
Development of basic mathematical models for the improvement of predictions
of NOx and CO emissions in mixed type burners
Retrofitting of current burners to achieve lower NOx and CO emissions
without any decrease of thermal efficiency. 2. INTRODUCTION
The work carried out during the active period of the STELFLAM project has been
performed as scheduled for the tasks in the Global Work Plan wich is included in
Appendix A. and mainly covers the following:
Industrial trials
The first two measurement campaigns in site, performed at ENSIDESA Plate Mill
Reheating Pusher Furnace No. 1, have been carried out in Zone 2 measuring the
current NOx/CO emission levels related with the furnace operation. Later on and due
to the difficulties to install the retrofitted burners in Zone 2 with the furnace in
operation, in 1994 it was performed a new measurement campaign in Zone 4 furnace
lateral wall.
The results are to be used as comparison basis with the final solution obtained in base
of the hot semi-industrial trials and implemented the optimized industrial scaled
retroffited b