Table Of ContentAl-FARABI KAZAKH NATIONAL UNIVERSITY
М. Nazhipkyzy
MODERN PROBLEMS
OF PROCESSES BURNING,
DETONATION, EXPLOSION
Educational manual
Almaty
«Qazaq university»
2017
1
UDC 662 (075.8)
LBC 35.51 я 73
N 32
Recommended for publication by the decision
of the Academic Council
of the Faculty of Chemistry and Chemical Technology,
Editorial and Publishing Council of Al-Farabi Kazakh National University
(Protocol №5 dated 11.07.2017);
Educational and methodical association on groups of specialties
«Natural sciences», «Engineering and technology»
of Republican educational-methodical council on basis
Al-Farabi Kazakh National University
(Protocol №2 dated 29.06.2017)
Reviewers:
Doctor of chemical sciences, Professor R.A. Kazova
Doctor of chemical sciences, Professor I.S. Irgibaeva
Doctor of chemical sciences, Professor M.K. Aldabergenov
Nazhipkyzy М.
N 32 Modern problems of processes burning, detonation,
explosion: educational manual / М. Nazhipkyzy. – Almaty:
Qazaq university, 2017. – 134 p.
ISBN 978-601-04-2795-2
The educational manual is devoted to the problems of soot formation and
fullerenes in the flame of hydrocarbons. The results on the synthesis of
superhydrophobic soot in the combustion of hydrocarbons and the production of
waterproofing materials based on it are presented, and materials on the use of soot as a
waterproof combustible additive in ammonia-nitrate explosives are also presented.
The educational manual can be recommended not only to PhD doctoral students
of the speciality 6D073400 – Chemical Technology of Explosives and Pyrotechnics,
but also to undergraduates, PhD doctoral students of other training profiles, in
addition, specialists mastering this field.
Published in authorial release.
UDC 662 (075.8)
LBC 35.51 я 73
ISBN 978-601-04-2795-2 © Nazhipkyzy M., 2017
© Al-Farabi KazNU, 2017
2
CONTENT
FOREWORD ............................................................................................. 4
INTRODUCTION ..................................................................................... 5
1. FORMATION OF FULLERENES C IN HYDROCARBON
60
FLAMES ................................................................................................... 7
1.1. The main allotropic modifications of carbon ...................................... 7
1.2. The mechanism of formation of soot particles and fullerenes
particles in a flame ..................................................................................... 10
1.3. The methods of synthesis of fullerenes in flames ............................... 19
1.4. The influence of external local impact on the processes
of formation of combustion products ......................................................... 25
1.5. The influence rendered by a local effect of external acetylene –
oxygen flame on temperature profile benzene – oxygen flame. ................. 31
1.6. The effect of local action of external acetylene – oxygen flame
on the mass yield of fullerene C during combustion of benzene –
60
oxygen mixture. ......................................................................................... 34
1.7. The influence of an external impact on the processes of
formation of fullerenes nuclei .................................................................... 44
2. FORMATION OF THE SUPERHYDROPHOBIC SOOTY
SURFACE IN THE FLAME ..................................................................... 56
2.1. Hydrophobic and hydrophilic properties of materials ......................... 56
2.2. Modeling of the wetting angle for liquid which is in contact
with a rough surface. .................................................................................. 74
2.3. Synthesis of hydrophobic soot in a flame ........................................... 80
2.4. Synthesis of hydrophobic soot in a flame under the effect
of an electric field ...................................................................................... 91
2.5. Electron microscopic studies of hydrophobic soot samples
obtained in the flame ................................................................................. 98
2.6. Investigations on the interaction of surface-active substances
with the obtained hydrophobic soot surface ............................................... 102
2.7. Application of hydrophobic soot in textiles ........................................ 105
2.8. Application of hydrophobic soot in the construction industry ............ 109
2.9 The use of nanoparticles in power sysmems of exlusive ...................... 115
2.10. The use of hydrophobic soot in the ammonia-saltpeter
explosive .................................................................................................... 118
BIBLIOGRAPHIC LIST ........................................................................... 124
References ................................................................................................. 124
3
FOREWORD
Recently, at the intersection of chemistry and physics of
combustion processes, all over again much attention have been paid
to the intensive development of investigations related to the study of
soot formation processes in hydrocarbon flames. The use of
hydrocarbon flames for synthesis of various nanomaterials is
promising. In a flame, changing the modes of combustion and the
design of torches, that is, varying conditions, it is possible to achieve
a directed synthesis of the required materials. Soot formation in
combustion processes is one of the multifaceted, inter-disciplinary
phenomena the study of which is important both from the point of
view of ecology and for formation of various nanomaterials which is
rapidly developing in recent years. Despite numerous researches,
there is no clear understanding of the mechanism of conversion of
initial fuel to final products – soot, fullerenes. Changing
experimental conditions (pressure, a ratio fuel/oxidizer, application
of electric field, introduction of different additives), it is possible to
obtain carbon materials of different properties.
This educational manual deals with the mechanisms of
formation of soot particles and fullerenes in a flame, influence of
external local impact on the processes of formation of combustion
products, influence of external impact on the process of formation of
fullerene germs. The results on synthesis of hydrophobic soot with
and without the influence of electric field are presented. Also,
materials on the use of superhydrophobic soot as waterproof
combustible additive in an ammoniac-saltpetre explosives are
presented. The educational manual presents the data on the use of the
obtained superhydrophobic soot as a modifying additive for creation
of waterproof nanostructured materials. The data on investigation of
interaction of surface active substances with the obtained
hydrophobic soot surface are presented.
4
INTRODUCTION
The combustion process as the technological reactor has long
been used for production of soot with specified properties, which is
widely used in different field of industry.
Being an important technological raw material, soot is produced
on a commercial scale by different methods. To produce soot, the
method of thermal decomposition is mainly used, when burning up
liquid and gaseous hydrocarbons with the lack of oxygen at the
temperatures of ~1500 ° C followed by rapid cooling of the decom-
position products. Such soot consists of separate closed particles,
wherein the primary globules are spherical with a diameter of 9 to
600 nm, which are able to chemically bind with each other to form a
secondary structure aggregating in the form of linear branching
chains, spirals, bunches, so-called fractal clusters. The size of soot
particles, the specific surface and the degree of structurization (i.e.,
branching of soot chains) depend on the conditions of its formation
[1-2]. The shape of most types of soot particles is close to spherical.
However, microcrystallites in the soot particle are not ordered and
come onto the surface at different angles, so that the soot surface is
quite non-uniform. There may be free valence bonds of carbon
atoms, side chains of both saturated and unsaturated hydrocarbons
and compounds containing oxygen.
Investigations on the methods of controlling the combustion
process to produce products with the specified initial properties (soot
particles, fullerenes) is an important aspect in the study of soot
formation process. The methods of exerting an influence on the
flame electric, magnetic and high-frequency electromagnetic fields
are being intensively investigated. The flame has electrical
properties, and this fact has been known for a long time.
However, only in the twentieth century when the molecular and
kinetic theory of substance was formulated, it became clear that
electric properties of a flame are conditioned by the existence in
them of charged particles – ions and electrons.
The presence of charged particles in the flame allows influen-
cing the processes taking place in the flame, when applying an
5
electric field. Specificity of electrical phenomena and the nature of
the structure of the flame front during combustion is such that even a
weak external electric field exerts an effect on all the processes
occurring in the flame [3].
Currently, there already exist facilities for production of fulle-
renes in hydrocarbon flames, but problems remain. In particular, it is
an expensive cost for their preparation and the lack of large-scale
production. Therefore, the research of the conditions allowing inten-
sifying the process of obtaining fullerenes with smaller costs and
with the possibility of organizing their commercial production is an
actual task. One of the methods allowing to create such conditions is
a method of external energy impact on a flame.
In some cases, for reliable functioning of products it is necessary
to provide high water and oil repelling properties of their surfaces
(for example, glasses of cars, planes, protective suits, walls of
reservoirs for storage of liquids, building constructions, etc.).
Therefore, production of hydrophobic substances for water
resistant and waterproof properties to various materials is an actual
task. Soot can have hydrophobic properties and be used as additives
of materials of such profile. The process of producing hydrophobic
soot in a flame has its own specifics being continuous technological
and controllable. Development and research of the controllable
synthesis of hydrophobic soot in flames is an important and actual task.
It is of interest to use additives of nanocarbon materials in explosive
materials for improvement of operational characteristics [4, 5].
Widely spread and at the same time the cheapest and safe
explosives are compounds based on ammonium nitrate (ammonium
saltpeter explosives - ASE) in which nitrate is an oxidizing agent and
impurity is a fuel. The impurities can be both explosive and non-
explosive (wood flour, cake, pitch).
The data on the use of superhydrophobic soot as additive to
ammonium saltpeter explosives are presented. A modified explosive
in the composition of ammonium nitrate soot without liquid com-
bustible additives is obtained. Explosive Granulite N (Nano) is
highly water resistant in comparison with other granular ammonium
saltpeter explosives. Field testing of the explosive with addition of
superhydrophobic soot for the completeness of detonation showed
improved performance.
6
1
FORMATION OF FULLERENES C
60
IN HYDROCARBON FLAMES
1.1. The main allotropic modifications of carbon
Carbon is quite a widespread element. Until recently, it was
known that carbon forms three allotropic forms – diamond, graphite,
carbyne. Allotropy, from the Greek «allos» – different, «tropos» –
turn, the property, the existence of one and the same element in the
form of various structures differing in properties and structure. Now
the fourth allotropic form of carbon, the so-called fullerene
(polyatomic molecules of carbon C ) is known.
n
Graphite has a layered structure and is found in the form of two
crystalline modifications – hexagonal and rhombohedral. Each layer
consists of carbon atoms covalently linked to each other in regular
hexagons with strong chemical bonds (Figure 1).
The distance between the layers (0.334 nm) is much larger than the
interatomic distances within the layer (0.142 nm), and the link between
the layers is provided by van der Waals interactions, so they can easily
slide over one another. A simple pencil can serve as an example: if you
draw a graphite rod on paper, the layers gradually get «peeled off» from
one another, leaving a trail.
Diamond has a three-dimensional tetrahedral structure. The
structure of diamond is presented in Figure 2.
Each carbon atom is linked with the four others in a covalent union.
All the atoms in the crystal lattice are arranged at the same distance
(0.1544 nm) from one another. Each of them is linked with the others
with a direct covalent bond to form in the crystal, no matter what size it
is, one giant macromolecule. Due to the high energy of covalent C-C
bonds, diamond has the highest strength and is used not only as a
precious stone, but also as a feedstock for the production of cutting and
grinding tools.
7
Figurre 1. The structure ofgraphite Figure 2. The struccture of diamond
Successful syntheesis of the third aallotropic form of carbon was
execcuted by Yu. P. KKudryavtsev, A. MM. Sladkov, V. I. Kasatochkin
and V. V. Korshak in 1960. The neew form was nammed carbine.
A poossible synthesis route was found when investigatiing the follo-
wingg oxidation polymmerization reactionn:
As acetylene cann be considered ass a molecule conssisting of two
C-H fragments, it has been assumed that such reaction is possible for
it, tooo. Really, the reseearch of this oppoortunity as a result has come to
the eend with opening of the third allotroopic form of carboon.
The discovery off fullerenes – a neww form of existennce of carbon,
is reecognized as one of the most amaazing and the moost important
discooveries in the scieence of the XX cenntury.
Fullerenes are called closed molecules off the type
C ,С ,С ,С , in which all the atomms are arranged aat the vertices
60 70 76 84
of reegular hexagons oor pentagons coveering the surface oof a sphere or
spheeroid. The origin of the term «fulllerene» is associaated with the
namee of the Americcan architect andd mathematician Buckminster
8
Fuller, who designed hemispherical architectural constructions
consisting of hexagons and pentagons. As an architect, he proposed
constructions in the form of multi-faceted spheroids intended for
covering a large area of the premises, and as a mathematician he
used a systematic approach to the analysis of structures of different
origin and showed that the structure is a self-stabilizing system.
The most studied structure and properties of fullerene C a
60
stable isomer of which is composed of 20 hexagonal and 12 penta-
gonal cycles. Compound C has a spherical shape similar to a soccer
60
ball (Figure 3). The molecule contains 90 ribs.
The radius of C molecule is 0.3512 nm, the length of a short
60
C-C bond (common in pentagons and hexagons) is 0.1391 nm, the
length of the other C-C bond (common in hexagons) is 0.1455 nm.
Pentagons do not articulate with each other.
Fullerene C («rugby ball«, «melon«) is the next after C
70 60
fullerene (Figure 3), one of 8149 of isomers which corresponds to the
rule of isolated pentagons. It contains 25 hexagonal and the same
12 pentagonal cycles.
a b c
Figure 3. Fullerene molecules: a) C , b) C , c) a forecast of a fullerene molecule
60 70
containing more than 100 carbon atoms [6-7]
There are varieties of fullerene compounds: endofullerenes,
heterofullerene and exofullerenes, shown in Figure 4.
Endofullerenes М @C are fullerene molecules in which m
m n
atoms of other chemical elements (M) are located within the
fullerene molecule (C ), where m1 (Figure 4a.). Heterofullerenes
n
М C are fullerene molecules in which m carbon atoms are
m n-m
substituted for the atoms of other elements (Figure 4b).
9
a b cc
Figure 4. The structure of the moleccules of endofullerenee (a),
heteerofullerene (b) and exxofullerene (c)
Exofullerenes М C are fullerene molecules, in whhich m atoms
mm n
of oother elements arre attached to thhe fullerene moleecule outside
(Figuure 4 c). When obtaining exofulllerenes, soluble in water the
moleecules have a morre complex structuure.
1.2. The mechannism of formationn of soot particlees
and fullerennes particles in a flame
Up to the presentt time, the mechannism of soot formmation has not
beenn studied well. Thiis is explained byy the fact that formmation of soot
partiicles takes place inn a very short timme, fractions of a ssecond [8, 9].
The study of the meechanism of formmation of soot paarticles in the
flamme and the structture of soot flammes provides impportant infor-
mation on the physicaal and chemical processes that occuur before and
durinng soot formationn.
Investigation of tthe processes takiing place in the course of soot
formmation is still impportant and actuaal. This is determmined by the
folloowing reasons: fiirst, soot is produuced on a large scale and is
wideely used as an acttive filler of rubbber, ink componennts; secondly,
soot is a carcinogenicc pollutant of thee environment duee to combus-
tion of hydrocarbon fuuel in power plantts [11, 12].
Thus far, polycycclic aromatic hydrrocarbons are connsidered to be
the mmain intermediatee compounds in the processes of formation of
combbustion products aand act as nuclei oof soot particles aand fullerenes
beingg formed [12, 13]].
10
