Kinetics and mechanisms of elementary chemical processes of importance in combustion

European Commission Directorate-General For The Information Society And Media Directorate-General For Research And Innovation

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Energy research

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• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 6 Mo

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Commission of the European Communities
energy
Kinetics and mechanisms of
elementary chemical processes
of importance in combustion
Report
EUR 12772 EN Commission of the European Communities
energy
Kinetics and mechanisms of
elementary chemical processes
of importance in combustion
Coordinated by:
R. A. Cox
Engineering Science Division,
Harwell Laboratory
Didcot, Oxfordshire 0X11 ORA
United Kingdom
Contract No EN3E-0096(1)-UK(h)
Final report
For the period 1 April 1986 to 30 June 1989
Prepared by: T. P. Murrels
Research financed by the Commission of the European Communities
within the frame of the non-nuclear energy R&D programme
Energy conservation
Directorate-General
Science, Research and Development
1990 EUR 12772 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
L-2920 Luxembourg
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting
on behalf of then is responsible for the use which might be made of
the following information
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1990
ISBN 92-826-1430-1 Catalogue number: CD-NA-12772-EN-C
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1990
Printed in Belgium TABLE OF CONTENTS
Page
SUMMARY VII
1. OBJECTIVE 1
2. INTRODUCTION - CO-ORDINATOR
1. Evaluation work
2. Experimental studies of rate constants and mechanisms 1
3. Scope of the report 2
CONCLUSIONS
1. Evaluation and modelling work
1.1. Task group activities
1.2. Modelling work 3
1.2.1. The H2/02/C0 System
1.2.2. Sensitivity tests in flame modelling 3
1.2.3. Autoignition in Butane/air mixtures 4
1.2.4. Summary 4
2. Experimental work
2.1. Unsaturated hydrocarbons
2.1.1. High temperature pyrolysis
2.1.2. Unsaturated radical reactions 6
2.1.3.d molecule + radical reactions
2.2. Soot formation 7
2.3. NOn 8
2.4. Oxfdation of CH-, radicals
4. SYMBOLS 10
5. DESCRIPTION OF ACTIVITIES - CO-ORDINATOR 11
1. Research activities of the individual projects 1
2. Co-ordination work
2.1. Reporting
III -2.2. Meetings 11
2.2.1. Technical discussion symposia 1
2.2.2. Data evaluation group meetings2
2.2.3.l advisory groups
6. RESULTS AND DISCUSSION
7. ECONOMIC ASSESSMENT 12
8. FUTURE WORK3
REFERENCES4
APPENDICES5
Appendix 1 - Diagram showing plan of co-ordination 17
Appendix 2 - Individual members of the CEC kinetics data
evaluation group 4
Appendix 3 - Summary of recommended rate coefficients 49
Appendix 4 - Research activities and reports of the
individual projects 51
Project Al - M. Braun-Unkhoff, P. Frank 53
DFVLR Stuttgart
A2 - R.W. Walker 65
University of Hull
A3 - H. Hippier, C. Reihs, J. Troe, W. Müller-Markgraf 7
University of Göttingen
Project - H. Gg. Wagner 9Bl
University of Göttingen
B2 - A. D'Alessio 107
University of Naples
Project CI - R. Weller, J. WoIfrum 123
University of Heidelberg
C2 - P.J. Van Tiggelen, J. Vandooren 137
University of Louvain
Project Dl - R. Zellner 165
University of Göttingen
- IV D2 - M.J. Pilling 179
University of Oxford
D3 - R. Lesclaux, P.D. Lightfoot, B. Veyret 18
University of Bordeaux
D4 - P. Pagsberg, E. Ratajczak, A. Sillesen 19
Risø National Laboratory
Project El - D.L. Baulch 213
University of Leeds
E2 - J. Warnatz 221
Universities of Heidelberg and Stuttgart
E3 - R.A. Cox 24
Harwel1 Laboratory
V -SUMMARY
This is the final report of the CEC Combustion Research Programme "Kinetics and
Mechanisms of Elementary Chemical Processes of Importance in Combustion" which
extended over the period from April 1986 to June 1989. The report summarises the detailed
descriptions of the research project which have been given in five 6-monthly Period
Reports. Emphasis has therefore been given to the main achievements and key results of the
research.
The programme was a collaboration involving most of Europe's leading experts in the field
of combustion chemistry and was co-ordinated at UKAEA Harwell Laboratory by
Dr. R.A. Cox. The principal scientists involved were:
Dr. P. Frank, DFVLR Stuttgart - DE
Dr. R.W. Walker, University of Hull - GB
Professor J. Troe,y of Göttingen - DE r H.G. Wagner, University of Göttingen - DE
Professor J. Wolfram,y of Heidelberg - DE r P.J. Van Tiggelen, University of Louvain - B
Professor A. D'Alessio, University of Naples - IT r R. Zellner,y of Göttingen - DE
Dr. M.J. Pilling, University of Oxford - GB
Dr. R. Lesclaux,y of Bordeaux - FR
Dr. P. Pagsberg, RisjoNational Laboratory - DK
Dr. D.L. Baulch, University of Leeds - GB
Professor J. Warnatz, Universities of Stuttgart and Heidelberg - DE r Th. Just, DFVLR Stuttgart - DE
Dr. J.A. Kerr, University of Birmingham - GB
Dr. R.A. Cox, Harwell Laboratory - GB
During the Programme, a critical evaluation of available kinetic data for 250 elementary
reactions has been performed. A kinetics data base, suitable for combustion modellers,
consisting of recommended rate parameters for 210 of these reactions has been compiled. The
Kinetics Data Evaluation Group have prepared data sheets summarising experimental data on all
the reactions evaluated and a summary table of the recommended rate data. In addition,
excellent progress was made on the formulation and testing of reaction mechanisms. This has
been supported by an extremely fruitful experimental programme which has produced new and
improved kinetic and mechanistic data on elementary processes in several areas of practical
VII -importance in combustion. The experimental programme was divided into four main
topics:
- Unsaturated Hydrocarbons
Soot Formation
- NOx Formation
- Oxidation of CH3 Radicals
The experimental activities have provided important new data on the reactions pertinent
to the combustion of alkenes and aromatic hydrocarbons. This will help towards the
development of detailed models for combustion of BTX fuels and PAH formation. Kinetic data
on unsaturated radicals indicate that these radicals are unreactive with 02 and hydrocarbons
and emphasise the importance of radical-radical reactions in the combustion of alkenes and
aromatics. Chemical anlaysis and optical measurements in sooting QIL/air flames have
provided information on the chemical structure of soot particles and the factors, such as
temperature and C/O ratio, which influence soot growth and the H/C ratio of soot. The work
has provided an insight into the mechanism for soot formation and clearly implicates the
involvement of large aromatic molecules. A technique has also been devised for monitoring
chemical change in fuel droplets in spray flames.
Rate coefficients have been determined over a wide temperature range for several
elementary reactions of the CN radical, providing reliable kinetic input data for modelling NO
formation via the prompt-NO and fuel-nitrogen cycles. The temperature dependence of the
rate coefficients and of the branching ratio for the OH-producing channel have been
determined for the NH2 + NO reaction which will be of great importance for modelling the
Thermal DeNO process.
Rate coefficients and branching ratios measured for the elementary steps in the CH3/O2
system together provide a complete kinetic description of this system over the temperature
range 300-1600K within which there is an important change in mechanism for the CH3 + 02
reaction. These data will considerably improve current models for CH4 combustion and for
ignition and quenching in hydrocarbon oxidation.
VIII -