The fundamentally new methods of hydrocarbons combustion by means of chemically active additives (including hydrocarbons) processes control have been proposed; chemical mechanisms of the additives action have been suggested.
The present research includes both action of additives on hydrocarbons combustion and usage of hydrocarbons as active additives to suppress flame propagation and combustion.
It has been detected that small additives (~ 10-1 %) of chromium hex carbonyl and molybdenum hex carbonyl promote combustion of stoichiometric mixture of H2 + O2 resulting in the decrease of the lower limit of initiated ignition and increase of the visible velocity of flame propagation. As this takes place, the inhibition of hydrocarbons oxidation by example of propylene by the additives is observed. It means that the kinetic mechanism of metal organic substances action on hydrocarbons combustion based on hydrogen atoms termination reported in literature is to be revised. Excited Cr atoms have been observed in H2+O2 flame in the presence of chromium hex carbonyl, their concentration in hydrocarbon – O2 flame was found to be ~ 10 times lower. It means that hydrogen atoms may prevent metal oxidation due to their reducing ability, therefore non-oxidized metal particles in H2 + O2 reaction exhibit a promoting action.
The results obtained indicate that hydrogen atoms are not of primary importance in chain branching in oxidation of hydrocarbons. (N.M.Rubtsov, G.I.Tsvetkov, V.I.Chernysh, B.S.Seplyarsky, Effect of the Vapors of Organometallic Compounds on the Processes of Ignition and Combustion of Hydrogen, Propylene, and Natural Gas Theoretical Foundations of Chemical Engineering, 2009, Vol. 43, No. 2, pp. 175–181© Pleiades Publishing, Ltd., 200.
It has been found that normal flame velocities in rich H2 + air mixtures in the presence of propene or isobutene fall smoothly with increase in the concentration of an active additive to a limiting value of the velocity. An approximate analytical method of calculation of flame velocity and flame propagation limits in the presence of small active hydrocarbon additive has been suggested for the first time by the example of combustion of rich H2 + air mixtures. The method can be used for effective rate constants estimation of inhibition of hydrocarbons and hydrogen combustion with chemical additives and calculation of flame propagation limits in the presence of the additives. The method is based on the model of a narrow reaction zone and takes into account the peculiarities of the branched chain mechanism of H2 oxidation. It is shown that occurrence of flame propagation limits with the inhibitor amount increase is caused by a positive feedback between flame velocity and the amount of active centres of combustion, being terminated via an inhibitor. According to the feedback the influence of an inhibitor leads to combustion temperature and flame velocity decrease. Theoretical analysis allows qualitative description of experimentally observed regularities, namely the occurrence of the flame propagation limit in the presence of small amounts of an inhibitor when heat losses into the wall are missing, a decrease in flame velocity at the limit more than that of a factor √е (е = 2.718…) as well as the dependence of the limit on the chemical nature of an inhibitor.
The results obtained give requirements to effective flame inhibitors: both high value of the pre-exponential factor and low activation energy of the elementary reaction of H atoms and inhibitor, as well as the necessity of the regeneration of the inhibitor in the combustion process used (N.M. Rubtsov, B.S. Seplyarskii, G.I. Tsvetkov, V.I. Chernysh, 2008, Effect of Added Reactive Agents on the Flame Propagation Velocity in Rich Hydrogen–Air Mixtures, Theoretical Foundations of Chemical Engineering, 2008, Vol. 42, No. 6, pp. 884–893. © Pleiades Publishing, Ltd., 200.
New unexpected scientific results have been obtained for controlling practically important methane combustion. It was shown that the particles of coals of different types deposited on the hot surface of a quartz reactor can completely suppress self-ignition of CH4 + O2 stoichiometric mixture. For instance an induction period of 73 Torr of the CH4 + O2 mixture over HF treated quartz surface makes up 48±2 s at 685С. However the CH4 + O2 mixture does not self-ignite even at 740C both over high volatile steam coal coating and over anthracite coating. It was also shown that the ability of deposited coal particles to suppress self-ignition of CH4 + O2 stoichiometric mixture markedly decreases after thermal treatment over several hours under vacuum, in this case the rate of the decrease depends strongly on the type of coal. The investigations performed allow inferring that under thermal treatment coal powder evolves chemical substances, which suppress combustion of methane in O2.
The results obtained can form the basis of new unique methods of methane-air mixtures explosions prevention in mines and in other processes using methane combustion (Nikolai M. Rubtsov, Boris S. Seplyarskii, Georgii I. Tsvetkov and Victor I. Chernysh, Thermal ignition of coal–gas suspensions containing natural gas and oxygen, Mendeleev Commun., Ed. RAS, Univ.Col.London UK, 2008, 18, 340–341).
The modern means of common fuels combustion control (hydrocarbons and hydrogen) consist in usage of small chemically active additives (inhibitors) due to branched chain nature of combustion processes. In this connection the revealing of main parameters of combustion critical conditions and flame propagation in the presence of additives is a highly urgent problem. Seemingly the vast majority of calculations of flame velocities especially for hydrocarbons combustion taking into account mechanisms including hundreds of elementary steps show formal agreement with experimental data. However the agreement is achieved even if the mechanism of the action of additives is unable to explain important experimental phenomena.
For example in e.g. the action of metal organic additives on hydrocarbons oxidation is related to H atoms termination via an additive. However as we showed (see below) these additives promote H2 oxidation, though in this reaction the role of H atoms is most pronounced, i.e. the model proposed in the literature cannot explain that result. It means that the calculations of combustion features should be referred to with care. In addition the analysis of hundreds of reactions does not provide reliability of its results, because the majority of the values of rate constants and activation energies are not accurate enough to make plausible conclusions on the basis of calculations with such errors.
It means that our knowledge of mechanisms of hydrocarbons oxidation as well as of the action of active additives is quite unsatisfactory. Therefore there are both the certain lack of experimental data and the lack of understanding of the features of combustion; these do not allow adequate solving such a problem as hydrocarbons combustion controlling. The other urgent problem is providing safe conditions of production, transport and “mobile” storage of H2, because usage of hydrogen as fuel in engines and other power devices instead of hydrocarbons holds the great promise for decrease of pollution.
This raises the question of whether both understanding of regularities of combustion and revealing of main parameters responsible for critical conditions of combustion and flame propagation could be achieved without use of numerical calculations. The analysis could be based on the approaches developed in theory of thermal flame propagation, which is adequately worked out in [2,3]; the grounds of the description of flame propagation in branched-chain process are given in . The analysis of flame propagation can be performed analytically if the mechanism of BCP is known as for model reaction Н2 + О2. In the reaction with linear mechanism of chain branching the only feedback factor responsible for the occurrence of stationary propagating flame is warming-up, therefore mathematical tools of thermal theory apply.
In the work both the action of additives on hydrocarbons combustion and the usage of hydrocarbons as active additives to suppress flame propagation have been investigated.
The first part of the work includes complex experimental and theoretical investigation performed to establish the nature of concentration limit of flame propagation (flame propagation limit) of rich hydrogen-air mixtures in the presence of small hydrocarbons (isobutene (iso- С4Н and propene (С3Н6)) additives. The experiments were carried out under static conditions at 293 K and total atmospheric pressure. A stainless steel cylindrical reactor (10 cm in diameter, 16 cm length) was equipped with inlets for gas evacuation and optical windows as well as a pressure transducer. Ignition was provided with a spark (0.45 and 0.91 J) at the centre of the reactor. The reactor was evacuated to 10-3 Torr before each experiment. The mixtures of 40%H2 + air + (0-2.3%) С3Н6 and 40%H2 + air + (0-1.6%) iso- С4Н8 were used in experiments. An additive was initially allowed to bleed into the evacuated reactor up to the necessary pressure. Then the combustible mixture was admitted up to 1 atm. Values of normal flame velocity were calculated using initial parts of the curves of the pressure increase .
It was shown that normal velocities at [iso-С4Н8]/[O2]= 12.4% и [С3Н6]/[O2]= 16% correspond to flame propagation limits. It was also experimentally shown that the values of flame propagation limits and normal velocities at flame propagation limits do not depend on spark power.
Approximate calculations of the normal velocities of flame propagation in the presence of an inhibitor were performed on the basis of  using the simple mechanism of branched chain process of hydrogen oxidation for rich mixtures. The mechanism included (as compared to ) the termination of H atoms via an inhibitor. The amount of an inhibitor is small enough (In0< 2%) to ignore its consumption in reaction of termination Н + In →products (k5). Neglecting of the reaction Н+О2+М → НО2+М (k6) causes some overestimation of the normal velocity of flame propagation.
We restricted our attention to analysis of the single limiting case of practical importance: the temperature in branching zone Т1 is close to combustion temperature Tb, i.e. Tb-T1 =Θ << Tb – T0 (Tb is adiabatic combustion temperature, T0 is initial temperature). This is called in  the case of strong recombination. It is the case when all O atoms and OH radicals enter into reactions of chain development. We obtain for the normal velocity of inhibited flame (Tf is adiabatic combustion temperature in the presence of an inhibitor):
vf2ρ2 = 4DH k20exp(-E/RTf) √k11(M+Z) k20exp(-E/RTf) Tf6R3 /[ k11(M+Z)E3(Tf-T0)3] (1)
here ρ is density, Е is activation energy of chain branching, k20 is its predexponent, k5 is the rate constant of H + In termination, Нm is maximal concentration of H atoms, DH –diffusivity of H atoms, Z = k5In0/k11Hm. In the absence of an inhibitor (Z = 0) (1) we have equation for vf2ρ2 coincident with the one obtained in .
On the basis of the method of narrow reaction zone the influence of heat losses along with termination via an inhibitor on the velocity and limits of propagation of stationary combustion wave has been analyzed. The following equation has been obtained for the normal velocity and the values of governing parameters:
F(ζ) = ζ √ 1 + Z/M exp (β/ζ) = 1 (2)
Here ζ=vf2/v2, β=¼√λδ(Tb-T0)(3E+4RTb)/(Cp2v2ρ2RTb2), λ-thermal conductivity,δ -coefficient of the rate of heat losses , Cp is heat capacity at constant pressure.
Equation (2) is coincident with classical one if In0 = Z =0. The analysis of eq. (2) shows that if such a value of parameter β is chosen that flame propagation occurs in the absence of an inhibitor (Z =0) i.e. eq. (2) has two solutions at Z =0 then with increasing Z (which corresponds to an increase in the amount of an inhibitor in the mixture flame propagation limit) will be attained.
However, in our conditions the flame propagation limit is observed when a spherical flame front does not touch reactor walls i.e. heat losses into the wall are missing. Therefore the flame propagation limit observed is caused by the termination of active centres of combustion via an inhibitor.
Let us consider the action of an inhibitor on the processes of chemical transformation in preheating zone, namely termination of H atoms via an inhibitor. The termination is possible due to low activation energy of the reaction Н+In products, which makes up < 3 kcal/mole for both iso-С4Н8 and С3Н6. It has been shown that qualitatively the termination of H atoms via an inhibitor influences on the velocity of the flame front similar to heat losses. This allowed obtaining the equation coincident in appearance with (2):
F1(ζ) = ζ√1+Z/M exp (β/ζ)=1 (3)
However in (3) the value of β is governed by termination via an inhibitor and makes up λQ k5O20In0(3E+4 RTb)/(N Cp2v2ρ2 RTb2).
The solution of equation (3) with the values of governing parameters substituted was found graphically. The flame propagation limit is attained when with increasing In0 the curve F1(ζ) is tangent to horizontal straight line y = 1.
In accordance with eq.(3) the occurrence of the flame propagation limit as the concentration of active additive (inhibitor) increases is related to the positive feedback between the combustion temperature and amount of the active centers of combustion, which are terminated in the reaction with an inhibitor. As it was shown in the work for the first time, the consideration of narrow branching zone model  with taking into account for chain termination via an inhibitor by the example of model reaction of H2 oxidation (its kinetic mechanism as distinct from hydrocarbon oxidation is well-understood) in the presence of an additive allows qualitative description of experimentally observed regularities, namely: a) occurrence of the flame propagation limit in the presence of small amounts of an inhibitor, b) a decrease in flame velocity at the flame propagation limit more than by a factor of √е, c) the dependence of the flame propagation limit on the chemical nature of an inhibitor. It was shown that the action of the inhibitor is due to its reaction with H atoms in preheating zone. The inhibiting action of active additive causes decrease in both combustion temperature and normal flame velocity. Though due to oxidation of an inhibitor the heat releases, this heat is several times less than it could be released in the absence of the reaction of termination of active centers (H atoms) via an inhibitor. That is why the reaction of termination of active centers (H atoms) via an inhibitor might be formally considered as heat losses. On the basis of the results obtained the following requirements to effective inhibitors important for practical use are given: high value of elementary step and low activation energy of reaction of H atoms and inhibitor, the necessity of the regeneration of the inhibitor in the combustion process.
As distinct from this part of the work where hydrocarbons were used as active additives to suppress flame propagation, in the following the action of additives on hydrocarbons combustion is considered.
It is well known that the production of the effective and widely used fire suppressant CF3Br (Halon 1301) and other related compounds has been banned due to their contribution to ozone depletion . Therefore the attention was attracted to the search for alternative compounds. It is well established that some phosphor organic and metal organic  compounds (among them metal carbonyls) are very powerful hydrocarbons lame inhibitors being of about ~ 100 times more efficient than CF3Br [1,5], but those are flammable and highly toxic. The compounds may find use as fire suppressants only in unoccupied areas. Notice that the mechanism of the action of metal organic compounds has not been proved experimentally . In any event understanding inhibition mechanism of metal organic compounds could provide insight into the behavior of other highly effective agents and aid in the development of new non-toxic agents.
The influence of metal organic compounds has been investigated by the example of solid inflammable carbonyls on the hydrogen and hydrocarbons (methane, propylene) combustion; their vapor pressure is quite small (0.17 Torr) to provide marked toxic effect. The experiments were carried out under static conditions at 293K and total pressures in the range of 25 — 300 Torr. Two quartz cylindrical reactors (4 cm in diameter, 25 cm and 120 cm long) had inlets for gas evacuation as well as optical windows. The ignition was provided with a spark (0.91 J) at the butt-end of the reactor. The spark was also used for the start-up of recording. The reactors were evacuated to 10-3 Torr before each experiment. The mixtures of 2H2+O2 (stoichiometric), C3H6+O2 and CH4+O2 were prepared prior to experiment. Metal carbonyl vapor was initially allowed to bleed into evacuated reactor up to necessary pressure (0.05 – 0.17 Torr). Then the combustible mixture was admitted up to necessary total pressure. The mixture containing metal carbonyl was kept in the reactor for 10 min for better mixing. Chemiluminescence was recorded with photo multipliers (spectral sensitivity 200-600 nm) equipped with interference filter 306±10 nm (OH А2 –X2 emission). The visible velocity of flame propagation was recorded by means of photo multipliers equipped with three light guides placed 15 cm apart. It should be noted that it was not necessary to measure normal velocities due to qualitative character of the investigation. The output signal was recorded by means of a digital oscilloscope and stored in computer memory. Emission spectra of initiated ignition were recorded with an optical spectra analyzer OSA-500 (Germany) sensitive over the range 200-900 nm with the resolution ~ 0.2 nm per channel. The required number of scans (1 scan = 500 channels per 32 ms) was also stored in computer memory.
The inhibition of propylene oxidation by the additives (~ 10-1 %) of chromium hex carbonyl and molybdenum hex carbonyl was observed. However it has been shown that the small additives promoted combustion of stoichiometric mixture of H2 + O2 resulting in the decrease of the lower limit of initiated ignition and increase of the visible velocity of flame propagation. It means that hydrogen atoms are not of primary importance in chain branching in oxidation of hydrocarbons. It means also that the kinetic mechanism of inhibition by carbonyls based on hydrogen atoms termination reported in literature is to be revised.
Excited Cr atoms have been observed in H2+O2 flame in the presence of chromium hex carbonyl, their concentration in hydrocarbon – O2 flame was found to be ~ 10 times lower. The phenomena revealed are additional immediate evidence that hydrogen atoms do not in essence take part in chain branching in hydrocarbons oxidation contrary to certain of the contemporary notions. In our opinion, dimensional effect, implying that chemical properties of nanoparticles markedly differ from those of bulk material, plays governing role in the observed promotion of H2 + O2 and inhibition of propylene oxidation with metal organic substances. Whereas the rate of termination of hydrogen atoms on the bulk metal oxide surface is high , nanoparticles, containing metal atoms react in another way with chain carriers of H2 + O2 reaction, this way is somewhat similar to the promoting action of bulk platinum on this reaction . In addition, hydrogen atoms may prevent metal oxidation due to their reducing ability, therefore non-oxidized metal particles in H2 + O2 reaction exhibit a promoting action; on the other side metal oxide exhibits inhibiting action in the case of oxidation of hydrocarbons, where the role of hydrogen atoms is insignificant as it was mentioned above.
New unexpected scientific results have been obtained for controlling practically important methane combustion. It is well known that dust explosions are an actual danger for many fields of processing and mining industries, when performance of some technological processes is accompanied by formation of suspensions of combustible particles in the gas containing an oxidant. Experimental investigations showed that the danger of the dust explosion occurrence became much higher if even minor amounts of a combustible reactant were contained in the gas . Thus, the minimum energy of ignition of a gaseous mixture of coal powder could be decreased by 20-30 times with addition of small amounts of methane (2-3%) . These conditions are typical for coalmines, where both combustible components, coal powder and methane, are present simultaneously. This may bring even greater hazard in closed volumes, e.g., mines, within which the explosion aftereffects are particularly destructive and may result in fatalities. Therefore establishment of the regularities of combustion of coal gas mixtures, containing natural gas and oxygen both at room and higher temperatures is a very urgent problem.
The influence of coal powder obtained by grinding of coals of different types on the flammability of the mixture of methane and oxygen in self-ignition area has been experimentally determined. In the experiments reactor inner surface was coated with coal powder. Experimentally determined value of the induction period of self-ignition in quartz reactor was the measure of flammability. Pure oxygen was chosen as oxidizer to make the phenomenology of the process more pronounced.
Experiments were carried out at the total pressure 73 Torr in the temperature range from 685 to 855C in a heated quartz cylinder 3.6 cm in diameter and 25 cm in length. The reactor was pumped to 10-2 Torr. The temperature of the reactor was controlled accurate to ± 0.5 К. Stoichiometric mixture (33% of methane in oxygen) was used. Emission of electronically excited OH radicals (A2+) at 306 nm during the self-ignition was recorded by means of the interference filter (Δλ = 25 nm) and a photo multiplier. Interference filter at 435 nm (Δλ = 15 nm) was used to record CH (A2 – X2) emission. The signal from the photomultiplier was directed to one of the inputs of a dual-trace memory oscilloscope operating in the leading mode. The synchronization input of the oscilloscope received the signal from the opt-coupler used to detect the instant the gas admission assembly let the combustible mixture into the pumped reactor. This enabled us to measure induction periods. Pure oxygen (99.9%) was used. In the experiments the following types of coals were used: high volatile steam coal (~ 38% volatiles), coking coal (~ 17% volatiles), and anthracite (~ 8% volatiles). Suspension of coal powder (0.3 g) in ethanol (2 ml) was placed in the reactor and rotated under pumping to remove the liquid.
For quantitative determination of the influence of the coating on self-ignition the induction period of the self-ignition of stoichiometric mixture of methane and oxygen over quartz surface at 73 Torr total pressure was measured. It made up 48±2 s at 685С in accordance with literature data.
However it was shown that over high volatile steam coal coating the mixture did not self-ignite at 740C. After thermal annealing of the reactor at 855C for 12 hours and lowering the temperature to 695C self-ignition of the stoichiometric mixture was observed; the induction period τ in this case made up≈280±20 s.
It was shown that the 33% methane + O2 stoichiometric mixture did not self-ignite at 740C over coking coal coating and anthracite coating. Self-ignition of the methane + O2 mixture was observed only after thermal treatment at 855C for 3.5 hours (coking coal coating) and 2 hours (anthracite coating). For these surfaces the values of τ made up 0.5 s and 0.2 s correspondingly. The self-ignition was accompanied by initiation of many bright sparks in the reactor.
By this means the establishment of regularities of coal coating combustion in pure O2 was of direct interest. It was found that 73 Torr of oxygen over thermally treated (855C, 5 hours) high volatile coal coating gave a blue flash immediately after bleeding-in at 695C. The intensive emission of CH radicals (A1 – X2) at 431 nm was observed in the spectrum of the blue flash. The detection of the emission spectrum shows that the volatile substances evolving from coal powder burn in oxygen yielding exited CH radicals. The only volatiles evolving from heated coal powder can provide the inhibiting effect on combustion of methane; the volatiles are evidently hydrocarbons, probably polycyclic aromatic hydrocarbons. Both the lower and upper concentration limits of the higher hydrocarbons are considerably low. This explains the experimental fact of the occurrence of a blue flash (CH radicals (A1– X2)) in reaction of pure O2 with a coal coating. According to low values of concentration limits the vapor of the higher hydrocarbons self ignites in pure O2 but does not ignite in the mixture of methane and oxygen where fuel content exceeds an upper concentration limit at given temperature.
By this means in accordance with aforesaid at higher temperatures the coal coating self-ignition in oxygen can precede the combustion of methane and initiate the ignition of methane. It means also that under certain conditions coal powder can ignite methane-oxygen mixtures, though it is commonly accepted that the two processes go in the reverse order namely the explosion of methane-air mixtures in mines causes the combustion and detonation of coal powder.
The investigations performed allow inferring that under thermal treatment coal powder evolves chemical substances, which inhibit combustion of methane in O2. In addition, thermal treatment of the coal powders of coking coal and anthracite provides self-ignition of coal powder in O2. This can initiate ignition of methane in oxygen. The results obtained offer unique possibilities of suppression of ignition of methane-air and coal-methane-air mixtures.
The above resuls may be summed up as follows:
It has been detected that small additives (~ 10-1 %) of chromium hex carbonyl and molybdenum hex carbonyl promote combustion of H2 + O2 stoichiometric mixture resulting in the decrease of the lower limit of initiated ignition and increase of the visible velocity of flame propagation. As this takes place, the inhibition of propylene oxidation by the additives is observed. It means that hydrogen atoms are not of primary importance in chain branching in oxidation of hydrocarbons. It means also that the kinetic mechanism of inhibition by carbonyls based on hydrogen atoms termination reported in literature is to be revised.
An approximate analytical approach to the estimation of the influence of inhibitor additives on flame velocity and flame propagation limits has been suggested by the example of combustion of rich H2 + air mixtures; the approach is based on the model of the narrow reaction zone as well as on the branched chain mechanism of transformation of initial substances into products. The method can be used for estimation of effective rate constants of inhibition of hydrocarbons and hydrogen combustion with chemical additives and ab initio calculation of flame propagation limits in the presence of the additives.
It has been shown that the gases evolving during heat treatment of coal powder have a strong inhibiting effect on combustion of methane. The phenomenon detected can form the basis of new unique methods of prevention of explosions of methane-air mixtures in mines and in other processes using methane combustion.
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The research can be divided into three interrelated parts which have been worked out for the first time:
— An approximate analytical method of calculation of flame velocity and flame propagation limits in the presence of small active hydrocarbon additive has been suggested. The method can be used for estimation of effective rate constants of inhibition of combustion with chemical additives and ab initio calculation of flame propagation limits in the presence of the additives.
— It has been shown that the small additives of metal carbonyls promote combustion of hydroden but suppress hydrocarbon oxidation. It means that hydrogen atoms do not play noticeable role in oxidation of hydrocarbons. It means also that the mechanism of inhibition by carbonyls based on hydrogen atoms termination reported in literature is to be revised.
— New unexpected scientific results have been obtained for controlling practically important methane combustion. It was shown that the particles of coals of different types deposited on the hot surface of a quartz reactor can completely suppress self-ignition of methane-oxygen mixtures. The result can lead to development of new unique methods of prevention of explosions of methane-air mixtures in mines and in other processes using methane combustion.
The results obtained allow getting over the difficulties due to the lack of understanding of combustion regularities of fundamental importance. That was the reason to propose my candidature.
This work was supported by the Russian Foundation for Basic Research, project no. 02-03-32993, 07-08-12241, 08-03-01034, 09-03-00622 ; US Civilian Research and Development Foundation (CRDF), project no. RUE1-2686-MO-5; and International Association for the Promotion of Cooperation with Scientists from the Independent States of the Former Soviet Union (INTAS), project no. 05-1000005-7664
1. N.M.Rubtsov, G.I.Tsvetkov, V.I.Chernysh, B.S.Seplyarsky, Effect of the Vapors of
Organometallic Compounds on the Processes of Ignition and Combustion of Hydrogen,
Propylene, and Natural Gas Theoretical Foundations of Chemical Engineering, 2009, Vol.
43, No. 2, pp. 175–181© Pleiades Publishing, Ltd., 2008.
2. N.M. Rubtsov, B.S. Seplyarskii, G.I. Tsvetkov, V.I. Chernysh, 2008, Effect of Added
Reactive Agents on the Flame Propagation Velocity in Rich Hydrogen–Air Mixtures,
Theoretical Foundations of Chemical Engineering, 2008, Vol. 42, No. 6, pp. 884–893. ©
Pleiades Publishing, Ltd., 2008.
3 Nikolai M. Rubtsov, Boris S. Seplyarskii, Georgii I. Tsvetkov and Victor I. Chernysh
Thermal ignition of coal–gas suspensions containing natural gas and oxygen, Mendeleev
Commun., Ed. RAS, Univ.Col.London UK, 2008, 18, 340–341.