Table Of ContentSOOT IN
COMBUSTION
SYSTEMS
AND ITS TOXIC
PROPERTIES
NATO CONFERENCE SERIES
I Ecology
II Systems Science
III Human Factors
IV Marine Sciences
V Air-Sea InteractiollS
VI Materials Science
VI MATERIALS SCIENCE
Volume 1 Molecular Metals
Edited by William E. Hatfield
Volume 2 Materials for Advanced Batteries
Edited by D. W. Murphy, J. Broadhead, and B. C. H. Steele
Volume 3 Adhesion in Cellulosic and Wood-Based Composites
Edited by John F. Oliver
Volume 4 Adhesion Problems in the Recycling of Concrete
Edited by Pieter C. Kreijger
Volume 5 Atomistics of Fracture
Edited by R. M. Latanision and J. R. Pickens
Volume 6 Electronic Structure and Properties of Hydrogen in Metals
Edited by P. Jena and C. B. Satterthwaite
Volume 7 Soot in Combustion Systems and Its Toxic Properties
Edited by J. Lahaye and G. Prado
SOOT IN
COMBUSTION
SYSTEMS
AND ITS TOXIC
PROPERTIES
Edited by
J.
Lahaye
and
G. Prado
Center for Research on the
Physico-Chemistry of Solid Surfaces, C.N.R.S., and
University of Haute-Alsace
Mulhouse, France
Published in cooperation with NATO Scientific Affairs Division
PLENUM PRESS· NEW YORK AND LONDON
Library of Congress Cataloging in Publication Data
NATO Workshop on Soot in Combustion Systems 11981: Le Bischenberg, Obemai,
France)
Soot in combustion systems and its toxic properties.
(NATO conference series. VI, Malerials science; v. 7)
"Proceedings of a NATO Workshop on Soot in Combustion Systems, held August
31-September 3, 1981, in Le Bischenberg, Obernai, France"-T.p. verso.
Includes bibliographical references and index.
1. Combustion-Congresses. 2. Soot-Congresses. 3. Soot-Toxicology-Con-
gresses. I. Lahaye, J., 1937- . II. Prado, G. III. North Atlantic Treaty Organiza-
tion. Scientific Affairs Division. IV. Title. V. Series.
QD516.N32 1981 621.402'3 82·22552
ISBN 978-1-4684-4465-0 ISBN 978-1-4684-4463-6 (eBook)
001 10.1007/978-1-4684-4463-6
Proceedings of a NATO Workshop on Soot in Combustion Systems, held
August 31-8eptember 3,1981: Le Bischenberg,Obernai, France
© 1983 Plenum Press, New York
Softcover reprint of the hardcover 1st edition 1983
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
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recording, or otherwise, without written permission from the Publisher
PREFACE
Our interest in Mulhouse for carbon black and soot began
some 30 years ago when J.B. Donnet developed the concept of
surface chemistry of carbon and its involvement in interactions
with gas, liquid and solid phases. In the late sixties, we
began to study soot formation in pyrolytic systems and later on
in flames.
The idea of organ1z1ng a meeting on soot formation originated
some four or five years ago, through discussions among Professor
J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the
scientific community was becoming aware of the necessity to
strictly control soot formation and emission.
Being involved in the study of surface properties of carbon
black as well as of formation of soot, we realized that the
combustion community was not always fully aware of the progress
made by the physical-chemists on carbon black. Reciprocally,
the carbon specialists were often ignoring the research carried
out on soot in flames. One objective of this workshop was to
stimulate discussions between these two scientific communities.
During the preparation of the meeting, and especially during
the review process by the Material Science Committee of the
Scientific Affairs Division of N.A.T.O. the toxicological aspect
emerged as being an important component to be addressed during
the workshop.
To reflect these preoccupations we invited biologists, physical
chemists and engineers, all leaders in their field. The final
programme is a compromise of the different aspects of the subject
and was divided in five sessions.
The first session presents the reasons which make it necessary
to control soot and PAR (polyaromatic hydrocarbons) formation and
destruction: the toxicological aspect and the formation of
these materials in practical systems are examined.
v
vi PREFACE
The second one is concerned with the mechanisms of pAR and
soot formation and burnout. In this session three presentations
out of nine are referring to ionic effects in flames: it does
not mean that the scientific committee considers that ions are of
major importance in PAR and soot formation but it appears that the
understanding on that particular point is ambiguous and needs to
be clarified.
Aerodynamics of sooty flames is very important with regards
to emissions from practical systems. The third session is devoted
to this aspect and special thanks are due to the speakers who have
accepted to introduce this difficult subject to an audience for
the major part not familiar with it.
The fourth session describes optical diagnostics. In the
programme it appears as an appendix to the former parts of the
meeting, but we must realize that without the development of
these techniques, progress in the understanding of soot formation
would have been very limited.
The last part of the meeting is devoted to a synthesis of
the workshop, first in sub-committees, and finally in a plenary
session.
The questions, comments, and answers submitted ~n a written
form have been edited in the present volume.
Special thanks are addressed to the Scientific Committee, Drs.
A. D'Alessio, W. S. Blazowski, Profs. N. Chigier, R. Truhaut,
H. Gg. Wagner, and F. Weinberg, for their efficient collaboration
to the preparation of the meeting.
We are grateful to N. Bomo, A. Garro, B. Prado, S. Wagner
ar.d E. Wozniak, for their technical assistance before and during
the workshop.
J. Lahaye
G. Prado
November, 1981
CONTENTS
INTRODUCTION SESSION
Soot Components as Genetic Hazards...................................................... 1
W. G. Thilly
The Toxicology of Soot ............................................................................ 13
E. Boyland
A Comparative Study of Soot and Carbon Black .................................... 25
D. Rivin and A. I. Medalia
Polycyclic Aromatic Hydrocarbons and Soot From
Practical Combustion Systems ...................................................... 37
J. P. Longwell
MECHANISMS OF SOOT FORMATION AND BURNOUT
Structure of Sooting Flames, ... , .............................................................. 57
J. B. Howard and J. D. Bittner
Chemistry of Intermediate Species in the Rich Combustion
of Benzene ...................................................................................... 95
J. D. Bittner, J. B. Howard and H. B. Palmer
Radical Chemistry in Sooting Flames ................................................... 127
J. Warnatz
Soot Particle Nucleation and Agglomeration ...................................... 145
G. Prado, J. Lahaye and B. S. Haynes
Kinetic Aspects of Diesel Soot Coagulation ..................................... 163
G. W. Smith
Mass Growth of Soot ................................................................................ 171
H. G. Wagner
vii
viii CONTENTS
Ionic Mechanisms of Soot Formation .................................................... 197
H. F. Calcote
Charged Soot Particles in Unseeded and Seeded Flames .................... 217
K. H. Homann and E. Strofer
Electrical Intervention in the Sooting of Flames ........................... 243
F. J. Weinberg
Burnout of Soot Particles ...................................................................... 259
J.-B. Donnet and J. Lahaye
AERODYNAMICS OF SOOTY FLAMES
Aerothermochemistry of Diffusion Flames ............................................ 273
M. Barrere
Soot Formation and Burn-out in Turbulent Coal
Liquid Fuel Flames ....................................................................... 309
J. M. Be~r, M. Togam, W. Farmayan, M. T. Jacques
and G. Prado
OPTICAL DIAGNOSTICS
Theoretical Models for the Interpretation of
Light Scattering by Particles Present in
Combustion Systems ....................................................................... 327
A. D'Alessio, A. Cavalliere and P. Menna
Laser Light Scattering and Fluorescence in
Fuel Rich Flames: Techniques and Selected Results .............. 355
A. D'Alessio, F. Beretta, A. Cavalliere and P. Menna
The Status of the Art in Soots Diagnosis by Means of
Diffusion Broadening Spectroscopy. ........................................... 379
M. E. Weill, P. Flament and G. Gouesbet
The Quasi-Elastic Scattering of Light: A Lecture with
Emphasis on Particulate Diagnosis ........................................... 395
G. Gouesbet and G. Grehan
Synthesis and Recommendations for Future Work ................................ 413
INDEX, .......................................................................................................... 427
SOOT COMPONENTS AS GENETIC HAZARDS
William G. Thilly
Department of Nutrition and Food Science
Massachusetts Institute of Technology
Cambridge, Massachusetts 02139
The study of combustion effluents potential health effects
involves identifying the substances present and estimating the
probable health hazards of each. Unfortunately, there are no
methods which permit such estimates of health hazards. We are
presently using techniques for which we have no means of assessing
accuracy.
In our program at MIT, we have chosen genetic changes induced
in bacteria and human cells as an indication of the inherent
hazard associated with a chemical or complex mixtures. I will
not attempt to defend this choice here beyond pointing out that
humans do indeed suffer from a myriad of diseases of demonstrable
genetic origin; this is accompanied by an assumption that environ
mental chemicals cause an appreciable amount of these diseases ..
If the assumption is correct, it thus follows that human exposure
to chemicals which do, in fact, cause significant genetic damage
should be reduced. 1
Our approach to complex mixtures depends on the interaction
and cooperation of a number of scientists and engineers. In this
paper I will draw illustrative data from an ongoing study of
emissions from an ordinary home oil burner, which is the principle
means of horne heating in New England. Engineers studying combustion
(Dr. Gilles Prado, Prof. Jack Longwell) in the Department of
Chemical Engineering were responsible for setting up, operating
the burner under reproducible conditions and devising means to
assure collection of all the effluent material. Extraction and
preliminary chemical identifications w.ere followed by capillary
column gas chromatography separations and identifications by mass
spectrometry in the Department of Chemistry (Ms. Julie Leary,
2 W. G. THILLY
Prof. Klause Biemann). Bacterial mutation assays were performed i.n
the toxicology testing laboratory (MS. Barbara Andon) and, when
indicated, human cell studies in my laboratory.
Basically, our approach is very simple. We start with the
hypothesis that, at low concentrations, such as those to which
people are expected to be exposed, there will not be signiticant
interactions among the chemicals effecting the amount of genetic
damage induced by each. We have tested this hypothesis fairly
vigorously in the case of a turbulent diffusion flame with
kerosene as a fuel2 and found it to be useful in describing our
observations. Thus, our expectation for home oil burner emissions
was stated as
M = l: C. A.
ill
in which M was the fraction of bacterial cells mutated by a known
amount of the complex extracts under study, Ci was the concentra~
tion (molar) of each chemical present in the test mixture and Ai
was the specific mutagenic activity of each chemical (mutants x
liter/survivor x mole), at the concentration tested.
MATERIALS AND METHODS
The burner used in my example of work in progress was a
modern flame retention burner, a Beckett,Model A. The burner
was fitted with a Monarch nozzle delivering 1.0 gallon per hour.
The fue I used was a No.2 heating oi I containing about 30%
aromatics. (A complete description of the burners and fuel
characteris tics wi 11 be offered in a future publication by Profs.
Prado and Longwell).
The burne r was operated under condi tions of varying excess
air which effected the amount of particulate produced. Both
continuous burning and cyclic burning mimicking actual in-home
conditions are being studied.
The sampling system consisted of a filter to collect part
iculates, a cooled condensor followed by an XAD-2 resin trap and
finally a solvent-trap in an ice bath were used. No material was
detected in the iae bath. Our discussion relates to the materials
extracted from the filters and resin traps. Details are discussed
in the paper submitted by J.P. Longwell at this conference.
Extraction (Soxhlet) of both the filter and resin trap with
methylene chloride yielded the primary samples for chemical
analysis and biological assay. Attempts to reduce extraction
