Study of the Radical Chain Mechanism of Hydrocarbon Oxidation … · 2019. 7. 30. · Study of the...

Research ArticleStudy of the Radical Chain Mechanism of HydrocarbonOxidation for In Situ Combustion Process

Alexandra Ushakova1 Vladislav Zatsepin2 Mikhail Varfolomeev1 and Dmitry Emelyanov1

1Department of Physical Chemistry Kazan Federal University Kremlevskaya Str 18 420008 Kazan Russia2Institute of Geology and Petroleum Technologies Kazan Federal University Kremlevskaya Str 18 420008 Kazan Russia

Correspondence should be addressed to Alexandra Ushakova paravoz-syandexru

Received 16 September 2016 Revised 25 December 2016 Accepted 9 January 2017 Published 6 March 2017

Academic Editor Tran X Phuoc

Copyright copy 2017 Alexandra Ushakova et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Despite the abundance of in situ combustionmodels of oil oxidationmany of the effects are still beyond consideration For exampleuntil now initial stages of oxidation were not considered from a position of radical chain process This is a serious difficulty for thesimulation of oil recovery process that involves air injection To investigate the initial stages of oxidation the paper considers thesequence of chemical reactions including intermediate short-living compounds and radicals We have attempted to correlate themain stages of the reaction with areas of heat release observed in the experiments The system of differential equations based onthe equations of oxidation reactions was solved Time dependence of peroxides formation and start of heat release is analyticallyderived for the initial stages We have considered the inhibition of initial oxidation stages by aromatic oil compounds and havestudied the induction time in dependence on temperature Chain ignition criteria for paraffins and crude oil in presence of coresamples were obtained The calculation results are compared with the stages of oxidation that arise by high-pressure differentialscanning calorimetry According to experimental observations we have determined which reactions are important for the processand which can be omitted or combined into one as insignificant

1 Introduction

Air injection is a promising enhanced oil recovery methodin which compressed air is injected into oil reservoir withthe expectation that oil oxidation will lead to the high-temperature combustion front formation and oil effectivedisplacement [1] It has already been applied in numeroustypes of reservoirs of light and heavy oil as well The mosttechnically and economically successfully field implementa-tions are going on from twenty to forty years [2]

The air injection EOR method is based on oil in situoxidationwhen it contactswith compressed oxygen in porousmediaThe reservoir conditions and oil properties determinethe rate of oxidation which leads to the combustion frontformation The efficiency and safety of air injection dependon the combustion front stability

In general oxidation of crude oil can be divided intolow-temperature and high-temperature oxidation (LTO andHTO reactions) [1] The intensity of oxidation and the

transition fromLTO toHTOmainly depends on the reservoirtemperature and pressure

Usually for heavy oil reservoirs pressure is from 1ndash5MPaand temperature from 20ndash50∘C In such case that oxidationof crude oil on contact with atmospheric oxygen may occurvery slowly the process cannot go into the combustion stage(HTO) and end as the LTO stage and transformation of crudeoil into oxidized high-molecular compounds The transitionfrom LTO to HTO reactions needs additional heating orartificial ignition

For light oil and high-pressure reservoirs (15ndash30MPa) theinitial temperature is higher 80ndash95∘C For this kind of oilsignition usually occurred without the artificial initiation ofcombustion Delhi - 57∘b 40∘API [3] Buffalo - 93∘b 32∘API[4] and Gnedintsy 48∘b 32∘API [5]

There are also some heavy oil deposits where oil is activeenough to occur spontaneous combustion Pavlova Gora28∘b 18∘API [6] and California oilfields about 37∘b 15∘API[7] In the history of field development with the help of air

HindawiJournal of CombustionVolume 2017 Article ID 2526596 11 pageshttpsdoiorg10115520172526596

2 Journal of Combustion

injection there are cases where self-ignition of low-viscositylight oil did not occur such as Arlankovsky field 24∘C 30∘API[8] There was no ignition of the oil from Salymsky oilfield82∘b 40∘API during the experiments in the ARC [9]

Thus one can see that spontaneous ignition has nonob-vious dependence on the reservoir temperature and oilgravity The main conclusions on the impact of the differentcharacteristics of the oil reservoir to initiate combustionare the following the higher the temperature and pressurein the formation the greater the risk of ignition light oilignites faster than heavy oil but there are enough exceptionsmentioned above

There are numerous types of models of crude oil oxida-tion which demonstrate the stable combustion process gasoutput the amount of fuel for combustion and temperaturerise

On the basis of field experience it may be noted thatsome regularities of various factors influence on the initiationof combustion were identified empirically without definingtheir mutual influence Also the mechanism of crude oil self-ignition in reservoir conditions allowing building a reliablemodel of the process is not identified

2 The Mechanism of Low-Temperature andHigh-Temperature Oxidation

According to the literature the rate-limiting step of theoxidation process is the accumulation of hydroperoxides[10] The formation of hydroperoxide is a key stage of theprocess at first oxygen penetrates into the oil chains (thisstage takes place at any temperature) and forms free radicalsand radicals are passed from one molecule to another (chaingrowth) until they form hydroperoxide Hydroperoxides candecompose into a pair of radicals this is a branching chainreaction Such reactions rarely occur in hydrocarbons (chainbranching factor is small so the oxidation of hydrocarbons iscalled the oxidation with degenerate chain branching)

Next is the destruction of free radicals with the formationof oxidation products Products are oxidized compoundsacid aldehydes ketones or CO CO2 and water The processof low-temperature and then the high-temperature oxidationbegins with consumption of peroxides Another variantof oxidation is a high-temperature oxidation where chainmechanism takes place but it is not the main one Athigh temperatures peroxide decomposes without radicalmechanism [10]

Thus the initial stages have the same mechanism regard-less of the temperature a radical chainmechanism and high-temperature oxidation can occur by two different mecha-nisms Nonradical peroxide decomposition takes place athigh temperature above 250∘C and radical decompositionmay also occur at a low temperature (lower that 50∘C) andmay stay unfinished

For the first time in a theoretical paper [11] an attemptto describe the oxidation kinetics of in situ combustionwithin the idea of the radical chain mechanism of aliphatichydrocarbon oxidation reactions was made

There are several interesting conclusions in the paperassuming these conclusions we are building our model ofoxidation

(i) It is shown that oil oxidation occurs with the for-mation of intermediates hydroperoxides At insuffi-ciently high temperatures oxidation ends at this stage

(ii) Isomerization and decomposition reactions occur athigher temperatures CO2 and CO can be releasedat this stage Decomposition reaction dominates attemperatures above 500∘C resulting in completecombustion with formation of b2 and X2

(iii) Crude oil contains aromatic compounds which act asinhibitors of the initial stages of oxidation Inhibitorsbecome inactive at temperatures of 180ndash220∘C Aro-matic oxidized compounds are not decomposed aslong as the temperature does not rise to the HTO(350∘C) Below this temperature only these com-pounds continue to be oxidized forming oxidizedheavy residue which is a fuel for high-temperaturecombustion

(iv) There is an area of the negative temperature gradientOxidation in the gas phase through this area occursbefore the liquid phaseThenegative temperature gra-dient arises due to overlapping of peroxides formationeffects and their decompositionwith the release of gasand the formation of oxidized heavy residue

(v) Complexity of the heavy oil reservoir ignition isexplained by overlaying of inhibition and stabiliza-tion of oxidized compounds in the area of negativegradient further oxidation of which is inhibited byinsufficient temperature

Further we analyze different types of reaction in orderto derive the most complete and common set of chemicalreactions

21 Initiation of theOxidation Studies of hydrocarbon oxida-tion with oxygen suggest that oxidation always proceeds witha separation of the C-H bond both in branched chain and inunbranched process [12] Liquid hydrocarbons are resistantto dissociation of the C-C bond up to 200∘C If oxidation isinitiated without specific molecular reaction initiator suchinitiation is called autoxidation of oil Bimolecular initiationreaction is as follows

Oil +O21198961997888rarr Rlowast +HOOlowast (11015840)

Rlowast is the alkyl radical Initiation rate depends on thefollowing concentrations V0 = 1198961119862Oil119862O2

Intramolecular initiation reaction can occur in case ofliquid phase oxidation Oil + O2 + Oil

11989610158400997888rarr 2Rlowast + H2O2

Then the reaction rate can be written as V10158400 = 119896101584001198622Oil119862O2 The activation energies of the first and second reactionsrespectively are 197 kJmol and 577 kJmol The probabilityof the first reaction is higher than the second one due to thegain in energy but it is possible to check the implementedmechanismwhen determining the order of initiation reactionby fuel

Journal of Combustion 3

22The Formation of Peroxides Free radicals again enter intothe chain propagation reactions which can be written as in[11]

Rlowast +O21198962997888rarr ROlowast2 (21015840)

Oil + ROlowast21198963997888rarr Rlowast + P (31015840)

ROlowast2 is the alkyl peroxyl radical P = ROOHndashhydroperoxide radicals react almost instantly after theformation as their activation energy is very small Accordingto [10] the rate constant of this reaction amounts to 105ndash108liter(mollowasts) Therefore the chain growth stage is regulatedby radical formation rate Then radicals form hydroperoxideHydroperoxides are major oxidation products at early stagesof the process They are formed from a wide variety ofoil compounds undergoing oxidation The bond strengthof O-Osim160ndash200 kJmol is inferior to bond strengths ofO-H (sim480 kJmol) and O-C (sim380 kJmol) thereforeperoxides are the most unstable from oxygen-containing oilcompounds

23 The Decomposition of Peroxides The hydrocarbonhydroperoxides can actively participate in the oxidationprocess Thermal decomposition of hydroperoxides canproceed by a monomolecular mechanism on two freeradicals by the following reaction

P1198964997888rarr ROlowast + lowastOH (41015840)

The kinetic equation of such decomposition is first orderHydroperoxides may accumulate in the system especially iftemperature is low (100ndash200∘C) andhydroperoxides can reactby [10] as P + P rarr ROlowast2 + ROlowast + H2O The kinetic equationof such decomposition is second order it goes slowly andis not included into the main set of reactions But on theother hand there are experiments that have shown waterexistence at the initial stages of oxidation The process ofwater appearance is sometimes called ldquowaste of hydrogenrdquo [1]that can be expressed in reaction [13]

P +Oil1198965997888rarr ROlowast + Rlowast +H2O (51015840)

According to EPR-spectroscopy experiments the con-centration of organic radicals got by the hydroperoxidesdecomposition increased twice with the temperature growth(from 45 lowast 106 sping at 60∘C to 84 lowast 106 sping at 170∘C)For grater temperatures the amount of free radicals reachesdynamic equilibrium

From temperature more than 200∘C hydroperoxides alsodecompose by nonradical mechanism with the release of COCO2 and water

P1198966997888rarr CO2 + CO +H2O (61015840)

Decomposition of hydroperoxide is a stage of oxidationin the process of which dependence of reaction rate onoxygen concentration is reduced therefore according to

the authors [11] it is confined to the negative temperaturegradient

Characteristics of hydroperoxide are determined withtheir hydrocarbon component Hydroperoxides of paraffinichydrocarbons actively decompose at temperatures of 180ndash200∘CThis process is called degenerate chain branching andleads to an acceleration of the oxidation process

24 The Formation of Alcohols Aldehydes and Ketones ROlowastradicals come into further interaction with oil and continuenew chains by the reaction

ROlowast +Oil1198967997888rarr Rlowast + RO-H (71015840)

This reaction is most likely to occur in the gas phase Aquadratic break of radicals with formation of alcohols andketones can occur by the following reactions Rlowast+Rlowast rarr R-RROlowast2 + Rlowast rarr RO-OR or ROlowast2 + ROlowast2 rarr RO-OR + O2 Suchreactions have low activation energy of about 4 kJmol andoccur almost immediately after the peroxide decompositionRadicals may also interact with alcohols and acids with therelease of CO2 The oxidation rate at this stage dependson the molecular structure of the hydrocarbon moietiesof alcohols aldehydes acids and radicals themselves Theoxidation of the hydrocarbon molecules sequentially intohydroperoxide alcohol and ketone preserves the originalhydrocarbon skeleton of the molecule because C-C bondbreaking has an energy of 377 kJmol [10] Activity of radicalsvaries in the process of oxidation as it depends on whichhydrocarbon molecule is subjected to oxidation with theformation of a radical If paraffin molecules are active thenaromatic compounds form phenols under the oxidationwhich start to inhibit further oxidation processes Oxidationinhibition effect begins when all the radicals have alreadycreated all possible oxidized compounds and energy of thesystem is insufficient to break formed bonds (C-O O-O C-H and C-C)

All processes mentioned above referred to a very smallheat release during the reaction as well as to the almostabsence of CO andCO2 in the reaction products At this stagethe following can be observed

(1) absorption of oxygen(2) formation of peroxide radicals(3) consumption of peroxide radicals(4) small release of CO and CO2(5) increase in density and viscosity of the oil aggregation

of oxidized compounds its adsorption on the rocksurface and deposition of insoluble residue (fuelformation for further process of oxidation)

These processes are known as partial oxidation (low-temperature oxidation) If high-temperature combustionfront is not formed as a result of these processes thenaccumulation of oxidation products (which are centers of freeradicalsrsquo destruction) in crude oil occurs Crude oil propertiesdeteriorate it becomes strongly connected with the rock andless mobile becomes capable of forming a rigid emulsion


Figure 1 Schematic representation of a chain reaction with therare chain branching (as hydrocarbon oxidation) and completelybranched reaction (as nuclear reactions) [14]

and loses its ability to self-ignition Depositions in the formof oxidized compounds are sometimes recovered at the fieldafter air injection from injection well

25 Influence of Crude Oil Group Composition on the Rate ofOxidation The formation of peroxides and oxidized prod-ucts occurs due to chain reactions (formation growth anddestruction of free radicals) through short-lived radicalsDeceleration and acceleration of radical reactions causedby small additions of catalysts or inhibitors are possible atthe stage of radical oxidation Crude oil can initially containthese compounds which can be formed during the initialstages of oxidation Most likely features of light and heavy oiloxidation are associated with the presence of substances thataffect the oxidation process at the stage of the chains growthby a radical mechanism

Oxidation of organic compounds proceeds as a chainreaction involving the Rlowast and ROlowast2 radicals at different stagesand ROlowast lowastOH radicals from decomposed peroxides Thedecomposition of peroxides greatly accelerates the oxidationas it leads to branching of chains formation of two radicals ata time reaction (41015840) (Figure 1)

Slowing down of oxidation occurs when scavengingradicals by inactivemolecule in the process of hydroperoxidedecomposition without formation of radicals or during theformation of inactive peroxide Well-known inhibitors (Ing)contained in oil are different aromatic compounds phenolderivatives and other substances having a benzole ring in itscomposition

ROlowast2 + Ing1198968997888rarr Inglowast (81015840)

The earlier the inhibitor is entered into the system thegreater is its effect on the deactivation of active centers ifthe crude oil contains the inhibitor initially it starts its effectimmediately and oxidation does not develop until the rateof radicals formation does not exceed the rate of inhibitionor until the whole inhibitor becomes oxidized and inactiveThis effect was observed in experiments on oil-hexadecanemixture oxidation in various concentrations (Figure 2) Thecontinuous addition of crude oil to C16 acts as inhibitor uponhexadecane oxidation

As the temperature rises above 180∘C some inhibitorsbecome less active and are not able to slow down theoxidation reaction

C16

minus10

10

30

50

70

90

130

110

0 100 150 200 250 300 350 40050T (∘C)

C16 + 05 oilC16 + 10 oilC16 + 20 oil

dQd

t(W

tg)

Figure 2 Heat output for hexadecane and hexadecane solutionswith oil of various concentrations oxidation (inhibition effect ofcrude oil)

26 Formation of Fuel and Related Changes in the SystemAccording to the current terminology all substances whichburn at the second peak of heat release (450ndash600∘C) arecalled ldquofuel for combustionrdquo Fuel often called ldquocokerdquo in theliterature is generated during the oxidation process fromaromatic cyclic and even saturated hydrocarbons

Therefore according to oil composition it can be saidthat resinous and aromatic fractions of crude oil provide fuelunder heating in addition to asphaltenes existing in the oil

This process is characterized by waste of hydrogen fromhydrocarbon molecules as it was obtained in TG experi-ments with crude oil oxidation TG and DTG curve wereobtained from the experiments with crude oil in dynamic airatmosphere (75mLmin) under 20Kmin heating rate usingthermogravimetry coupled with spectrometer Figure 3(a)demonstrates the weight loss during the oxidation (threeDTG peaks first corresponds to evaporation and second andthird are caused by oxidation) The hydrogen is taken awayduring the second weight loss peak (430ndash480∘C) which isconfirmed by Figure 3(b) where water CO and CO2 aremeasured Water is measured till 470∘C

It is necessary to mention that oil oxidation underatmospheric pressure is not the same as under 5ndash10MPabecause of the strong influence of evaporation which doesnot occur in reservoir conditionsThus Figure 3 demonstratesthe behavior of crude oil oxidation in temperature range400ndash600∘C For lower temperature the process is very muchdistorted due to evaporation which does not happen inpressurized DSC experiments

Oil begins to demix and lose uniformity on the stageof the fuel formation Precipitation of solids occurs in caseof rock presence that fact was studied in experiments onoil oxidation by pressurized differential scanning calorimetry(PDSC) [15] Increase of the acid number observed at the fieldalso indicates on oxidized but not burnt fractions whichpresent in the produced crude oil Emulsions obtained atthe field are also associated with the presence of oxidized


minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

1

DTG

(m

in)

0

20

40

60

80

100TG

()

200 300 400 500 600 700100Temperature (∘C)

Peak 19811∘C

Peak 46452∘C

Peak 31445∘C

Onset 15027∘C

Mass change minus681



Peak 57445∘CMass change minus1195


Residual mass 055 (80000∘C)

(a)

CO

200 300 400 500 600 700100Temperature (∘C)

0

02

04

06

08

10

12

14

Abs

orba

nce

H2O

CO2

Peak 36273∘C

Peak 56377∘C

Peak 30041∘C

Peak 42506∘C

Peak 57081∘C

(b)

Figure 3 Crude oil oxidation (a) TG and DTG of oil oxidation and (b) CO CO2 and water output into gaseous phase

fractions in crude oil these fractions have polar groups intheir composition and are able to form stable emulsions

It turns out that substances different in structure andproperties are combined into one group of componentswhich burn down on the second peak of heat release by thereaction Coke rarr CO2+CO+H2O In terms of the produced

set of equations this reaction is the continuation of reaction(81015840)2ROlowast2 + Ing

1198968997888rarr Inglowast (91015840)The heat release at each of the stages described below is

given in Table 1 [16 17]


Table 1 Heat release of oxidation reactions

Heat release of the peroxidation reaction 105ndash146 kJmolHeat release of the alcohol-formation reaction 293ndash377 kJmolIn the formation of CO aldehydes andketones 356ndash398 kJmol

In case of complete combustion and oxidationto b2 X2

440 kJmol

These values are important for the further ldquoconnectionrdquoof experimental data onheat release in theDSCwith reactionsdescribed below

3 Equation System of Radical ChainOxidation of Oil

Thus the set ofmain oxidation reactions ((11015840)ndash(91015840)) is formedInitiation rate is 1198961 chain transfer rates are 1198962 1198963 and 1198967chain branching rates are 1198964 and 1198965 (hydrocarbon oxidationis a chain mechanismwith degenerate branching) and 1198966 1198968and 1198969 are chain termination rates

At present the oxidation of paraffinic hydrocarbons isconsidered to be the most studied process Experiments onthe oxidation of crude oil paraffinic hydrocarbons and syn-thetic paraffins were carried out repeatedly on a differentialscanning calorimeter under pressure for studying of in situcombustion mechanisms [15]

Paraffinic hydrocarbons comprise 70ndash75 of the oil com-position the remaining 20 are aromatic compounds and 5ndash10 are resins and asphaltenes In [11] crude oil separates intothe main oxidizing components alkanes and their oxidationinhibitors aromatic compounds which then form the fuel

Then kinetic regularities of oxidation are studied usingreactions on example of paraffinic hydrocarbons oxidationand all other components without specifying their structureFor paraffinic hydrocarbons it is proved that hydroperoxidesare the only primary oxidation products

Crude oil oxidation mechanism can be written as schemecomprising main stages of paraffins oxidation intermediatecompounds Rlowast ROlowast ROlowast2 radicals peroxide P and a stageof free radical destruction on oxidation inhibitors Ing [11 17]The inhibitors are aromatic resin and asphaltene fractionsof oil they contain a number of compounds capable ofinhibiting the process of oil oxidation

Usually the following approximations are used to sim-plify the system of equations [11]

(1) Activity of any alkoxy ROlowast radicals is equal toactivity of the hydroxyl lowastOH radical which suggeststhat these particles are indistinguishable and rewrite

reaction (41015840) in the form P1198964997888rarr 2ROlowast

(2) HOlowast2 radicals are low-active and are not included inthe reaction scheme

(3) Stage (21015840) is instantaneous all alkyl Rlowast radicals areturning into ROlowast2 radicals The following approxi-mation is described in [10] for the same reason the

products of reaction (51015840) are similar to the productsof reaction (41015840) apart water output

(4) ROlowast radicals are muchmore active than ROlowast2 radicalsin the stage of the hydrogen atoms separation from thehydrocarbon molecules hydroperoxyl ROlowast2 radicalsare more stable in comparison with alkoxy radicals

Besides the chain branching hydroperoxides can undergotransformations at higher temperatures by nonradical mech-anism (61015840) with complete combustion to CO2 and water

Aromatic hydrocarbons act as inhibitors of the initialstages of oxidation [18] Such compounds are able to catchthe free radicals generated at the initiation stage whilealso transforming into highly stable radicals which are notable to continue further chain growth reaction (81015840) thisis an oxygenation reaction without further development ofcombustion which leads to high-molecular residue Finalreaction of the fuel combustion can be written as (91015840)

The reaction rates are expressed by the Arrhenius law

119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)

The system of differential equations for the reactionscheme (11015840)ndash(91015840) can be written as

120597120597119905 (119862O2) = minus1198961119862Oil119862O2 minus 1198962119862R119862O2 minus 1198969119862Inglowast119862O2 (2)

120597120597119905 (119862Oil) = minus1198961119862Oil119862O2 minus 1198963119862Oil119862RO2 minus 1198965119862Oil119862P

minus 1198967119862Oil119862RO

(3)

120597120597119905 (119862P) = 1198963119862Oil119862RO2 minus (1198964 + 1198966 + 1198965119862Oil) 119862P (4)

And for the radicals

120597120597119905 (119862R) = 1198961119862Oil119862O2 + 1198963119862Oil119862RO2 minus 1198962119862R119862O2

+ 1198965119862Oil119862P + 1198967119862Oil119862RO

120597120597119905 (119862RO) = 1198964119862P + 1198965119862P119862Oil minus 1198967119862Oil119862RO

120597120597119905 (119862RO2) = 1198962119862R119862O2 minus 1198963119862Oil119862RO2 minus 1198968119862Ing119862RO2

(5)

Bodensteinrsquos principle of quasi-stationary concentrationcan be applied to the equations with radicals (5) becausereaction rate of radical formation is much lower than the rateof radicalrsquos decay The bulk of the reaction occurs with theintermediate product under its constant concentration Theequations can be converted into algebraic form and solvedrelatively to concentration of peroxide

1198960119862Oil119862O2 + 1198962119862Oil119862RO2 minus 1198961119862R119862O2 + 1198964119862Oil119862RO = 01198963119862P minus 1198964119862Oil119862RO = 0

1198961119862R119862O2 minus 1198962119862Oil119862RO2 minus 11989651198622RO2 minus 1198967119862Ing119862RO2 = 0(6)


To solve (4) in an explicit form it is necessary to expressthe concentration of ROlowast2 radicals through the concentrationof peroxides

119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)

119862RO2 = 1198963119862Oil1198968119862Ing(1198961119862Oil119862O2 + 119862P (21198965119862Oil + 1198964)) (8)

The differential equation for the peroxide (4) can bewritten as120597120597119905 (119862P) = 1198963119862Oil1198968119862Ing

(1198961119862Oil119862O2 + 119862P (21198965119862Oil + 1198964))minus (1198964 + 1198966 + 1198965119862Oil) 119862P

(9)

Now in order to solve the equation explicitly we assume aconstant concentration of oil oxygen and inhibitor duringthe time of peroxides accumulation Let us denote 119891 =(1198963119862Oil1198968119862Ing)(21198965119862Oil + 1198964) where chain growth factor isdetermined by the rate of hydroperoxides formation andradical decomposition119892 = 1198964+1198966+1198965119862Oilwhere interruptionfactor is determined by all the decomposition types ofreactions and120593 = 119891minus119892where factor of degenerate branchingis determined according to Semenovrsquos theory [14]

120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)

The rate of initiation 1198961119862O2119862Oil = V0 is also assumed to beconstant for the considered period of time

Equation (10) can be integrated int119862P0

120597119862P(120593119862P + (1198963119862Oil1198968119862Ing)V0) = int1199050 120597119905After calculation of the integrals we obtain the time

dependence of hydroperoxides

ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)

from which the concentration of peroxide is expressed by theformula

120593119862P = 1198963119862Oil1198968119862IngV0 [exp (120593119905) minus 1] (12)

On the other hand the oxidation mechanism is such that allof the products are formed through the stage of peroxidestherefore we can write 120597120597119905 (119862CO2) = 1198961P119862P

120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)

Heat release is connected with the decomposition ofperoxide and thus start of paraffins heat release (in case

100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin

∘Cmin∘Cmin∘Cmin∘Cmin∘Cmin

dqd

t(W

tg)

Figure 4 Kinetic curves of oil paraffins oxidation in DSC at apressure of 5MPa and different heating rates 119887

when the inhibition rate exceeds the rate of nonradicaldecomposition of peroxides ignition chain case) must havean exponential dependence on time where the coefficient ofthe exponent 120593 in (12) is close to zero

Heat release is connected with the decomposition ofperoxide and thus start of paraffins heat release (in casewhen the inhibition rate exceeds the rate of nonradicaldecomposition of peroxides ignition chain case) must havean exponential dependence on time where the coefficient ofthe exponent 120593 factor is close to zero (12)

This dependence is observed experimentally for paraffins(Figure 4) and crude oil in presence of cuttings (Figure 5) inthe temperature range of 180ndash220∘C

119889119902119889119905 sim 119860119890120593119905120593sat = 0016 plusmn 0002119888minus1

(14)

Constant oil concentration and the inhibitor conditionare fulfilled (the degree of transformation in considered reac-tion site does not exceed 10) and the constancy of oxygenconcentration is provided by the experimental conditions onthe DSC

To prove the existence of a chain reaction mechanism onthe stage of the first peak of heat release (180ndash280∘C) experi-mental kinetic curves are shown as a function ln(119889119902119889119905) of thetime 119905 (Figure 6) which are characterized by fairly constantpositive slope of the initial straight section Exactly the samedependence shows integral curves and the time derivative ofthe kinetic curves


Table 2 The values of the exponent in Semenovrsquos formula foracceleration rate of oxidation reaction at the initial stage of theprocess

Heating rate ∘CminThe exponent in Semenovrsquos formula

For the oxidationrate

For the oxidationacceleration

5 001760 001710 001760 0019315 001710 0017820 001610 0016235 001200 0013140 001330 0011750 001210 0012660 001790 001870 001690 0016780 002000 002Avg value 00161 plusmn 00025 00162 plusmn 00027

200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)

∘Cmin∘Cmin∘Cmin∘Cmin∘Cmin∘Cmin

∘Cmin∘Cmin∘Cmin

Figure 5 Kinetic curves of light oil oxidation adsorbed on crushedcarbonate rocks in the DSC at a pressure of 5MPa

The values of the exponent in the Semenovrsquos formula (14)for acceleration rate of oxidation reaction at the initial stageof the process are given in Table 2

4 Identification of Chain Ignition Conditionsfrom Reaction Equation

Differential equation (10) was solved under the assump-tion that the 120593 coefficient is positive That is the

3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80∘Cmin∘Cmin∘Cmin∘Cmin

∘Cmin

∘Cmin∘Cmin ∘Cmin

∘Cmin

∘Cmin

Figure 6 Dependence of natural logarithm of oxidation reactionrate on time for paraffins

chain growth factor exceeds the interruption factor119891 = (1198963119862Oil1198968119862Ing)(21198965119862Oil + 1198964) gt 119892 = 1198964 + 1198966 + 1198965119862Oil119892 minus 119891 = 120593 gt 0 This is the requirement of chain ignitionIf chain termination factor exceeds chain growth factor

then the chains are spent on inhibitors due to formation ofperoxides steady-state concentration of inactive peroxides isachieved and ignition does not occur as it occurs by a differentmechanism Let us write the condition of the chain ignitionassuming that reactions (51015840) and (41015840) have similar rates at theinitial stages 1198964 asymp 1198965

Let us suppose that at the initial moment in time theamount of inhibitor is enough so condition (15) fails

11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)

Let us write the differential equation for the consumption ofthe inhibitor (120597120597119905)(119862Ing) = minus1198968119862Ing119862RO2 Substituting (8)and (12) into (16) we obtain

120597120597119905 (119862Ing) = minus1198963119862OilV0 (1+ 1198963119862Oil1205931198968119862Ing

(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)

As in the previous section we believe that before thebeginning of the intensive consumption of oxygen concen-trations of oil and oxygen are constant At 120593 factor close tozero the second term in formulae (16) also tends to zero

120597120597119905 (119862Ing) = minusV0 (17)


Linseed oilCrude oil

Oil paraffinsOil and core

R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)

Figure 7 Dependence of the natural logarithm of crude oil heating time from the reverse temperature of self-ignition obtained in PDSCexperiments of oxidation The yellow box is the data obtained from ARC experiment which agree with DSC data

Let us determine the inhibitor consumption time until themoment of ignition

int119862Inglowast119862Ing0

120597119862P = minusV0 int120591Ind0

120597119905Δ119862Ing = minus1198600119862O2119862Oil exp( 1198640RT) 120591Ind

(18)

Induction time depends on the temperature

Δ119862Ing1198600119862O2119862Oil= exp (minus 1198640

RT) 120591Ind

ln 120591Ind = lnΔ119862Ing1198600119862O2119862Oil

+ 1198640RT

(19)

Linear dependence of ignition time from reciprocaltemperature is observed experimentally during the oxidationof the oil in the PDSC (initial point is the moment when thetangent to a heat release curve on the DSC becomes inclinedFigures 4 and 5)The slope of the line describes the activationenergy for the initiation stage and the free term describesthe logarithm of the concentrations ratio of oxygen crude oiland inhibitor

Figure 7 shows the above relationships for crude oilparaffins and linseed oil The slope of the lines does notchange greatly and the value on the 119909-axis is moved Thegreater the proportion of the inhibitor is the greater theinduction period characterizing the time of binding theinhibitor to oxygen is Oil paraffins have a minimum fraction

of the inhibitor in its composition proportional to degree oftheir purification

Oil on the rock is characterized by smaller fraction of theinhibitor as compared with pure oil due to inhibitor adsorp-tion Paraffins have an even smaller fraction of inhibitor in itscomposition

Let us add another reaction to describe the second peakof heat release combustion of inhibitors which formed thefuel This reaction occurs at a temperature of 350ndash400∘C

120597120597119905 (119862lowastIng) = 119862lowastIng1198967 minus 119862O2119862lowastIng1198968119889 (119862lowastIng)119862lowastIng = (1198967 minus 119862O21198968) 119889119905

119862lowastIng = exp (1198967 minus 119862O21198968) 119905(20)

The analysis shows that the concentration of oxidizedinhibitor (fuel) increases until the formation rate exceeds theconsumption rate then fuel consumption goes up exponen-tially in time

5 Correlation of Radical Chain Oxidation ofCrude Oil Equations with Heat Release DataObtained by the PDSC

Reaction equations can be related to heat release of oilcombustion on the PDSC due to the accuracy and smallreactivity of the method of differential scanning calorimetry


Crude oil in the presence of cuttings oxidation

compounds throughout theentire process (mechanism is unknown)

of peroxides bynonradical mechanism

peroxides consumptiongrowth and branching

inhibitors by nonradical

initial stagesinhibition

accumulationof peroxides

300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim

(9998400) consumption of oxidized

of chains sim exp(t)

(3998400)-(4998400) and (3998400)-(5998400)

(6998400) consumption

(8998400) accumulation of oxidizeddqd

t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)

Figure 8 Distribution of examined oxidation processes according to heat release curve on the DSC

As it can be seen from Figures 4 and 5 the heat releasefrom the oil in presence of core samples and oil paraffinsoxidation has two peaks the first peak is divided on thetime and temperature components studied in [15] schematicseparation of the first peak in two separate peaks is shown inFigure 8

(1) The induction period occurs almost without heatgeneration and goes through a chain of reactions(11015840) rarr (21015840) rarr (81015840) until inhibitors will be spent atthe same time there is an accumulation of peroxidesby the reaction (11015840) rarr (21015840) rarr (31015840) The inductionperiod is associated with the rate of initiation rate ofinhibitor consumption and temperature (18)

(2) The first massive bond breaking after the inductionperiod is caused by the exponential increase of perox-ides concentration (12) when the condition of chainignition is fulfilled (14) and then also due to expo-nential growth of heat release from decomposition ofperoxides (31015840) rarr (41015840) and (31015840) rarr (51015840)

(3) Temperature rises in the process of exponentialgrowth of heat release in time so nonradical decom-position of peroxides becomes possible (61015840) Thisdecomposition is characterized by Arrhenius depen-dence in the temperature range of 250ndash300∘C It is

most likely a decomposition of linear peroxides andlinear tails of aromatics by nonradical mechanismCO CO2 and H2O are released during the process

(4) At higher temperatures (300ndash350∘C) there beginreactions of isomerization and cyclization with aseparation of linear molecules tailings separation ofhydrogen and oxidation of these tailings which turninto CO and CO2 respectively This stage is alsoaccompanied by the formation of coke and a negativetemperature gradient (81015840) And then at the secondcombustion peak occurs by the reaction (91015840)

This last stage the combustion of coke takes place duringthe oxidation of any crude oil containing aminimumquantityof initial stages inhibitors aromatics resins and asphaltenes

Thus the connection stage between LTO and the HTOis a generalized reaction (81015840) which depends on the initialamount of oil inhibitors (aromatics)This reaction takes placeduring the entire process of oxidation at any temperatureInitially this reaction inhibits initial steps of oxidationoxygen is absorbed in this reaction due to the appearanceof inactive radicals Then molecular weight of crude oilincreases with the rise of temperature and a transition ofthe resins into secondary asphaltenes occurs which alsocontributes to the formation of fuel The oxidized oil is


adsorbed onto the rock surface and then the combustion ofoxidized components takes place

6 Conclusions

The theory of radical chain oxidation of hydrocarbons is usedto describe the self-ignition of oil in the reservoir

It is shown that crude oil as a mixture of hydrocarbonsof various structures can be oxidized by a radical chainmechanism at low temperatures as well as by the nonradicaldecomposition Chain mechanism investigated using thetheory of Semenov is clearly evident at the initial stages ofoxidation It is shown that ignition is the result of free radicalsrsquoformation and destruction processes A chain reaction ofoxidation with heat release starts when the amount ofradicals produced per unit of time exceeds the number ofdecomposed ones Then this reaction turns into nonradicalcombustion reaction

Otherwise accumulated radicals do not initiate inflam-mation Destruction of free radicals occurs on inhibitors ofinitial stages of oxidation molecules resins and asphaltenesAromaticmolecules capturing the free radicals remove themfrom oxidation process up to temperatures of 300ndash350∘CThus in the process of combustion initiation (150ndash200∘C)and the low-temperature oxidation (250ndash300∘C) accumula-tion of fuel for high-temperature combustion occurs

We have proposed equation system for oxidation reac-tions including the radical chain mechanism Level of modeldetail allows obtaining analytically basic experimentallyobserved dependences and the types of reactions occurring

Competing Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The work has been performed according to the RussianGovernment Program of Competitive Growth of KazanFederal University

References

[1] P S Sarathi In-Situ Combustion HandbookmdashPrinciples andPractices BDM Petroleum Technologies 1999

[2] A T Turta S K Chattopadhyay R N Bhattacharya ACondrachi and W Hanson ldquoCurrent status of commercialin situ combustion projects worldwiderdquo Journal of CanadianPetroleum Technology vol 46 no 11 pp 8ndash14 2007

[3] H J Remy ldquoIn-situ combustionrdquo in Proceedings of the 8thWorldPetroleum Congress Discussion Symposium USSR MoscowRussia June 1971

[4] D Gutierrez R J Miller A R Taylor B P Thies and V KKumar ldquoBuffalo field high-pressure-air-injection projects tech-nical performance and operational challengesrdquo SPE ReservoirEvaluation and Engineering vol 12 no 4 pp 542ndash550 2009

[5] Y GMamedov andA A Bokserman ldquoApplication of improvedoil recovery in Sovet Unionrdquo in Proceedings of the Enhanced Oil

Recovery Symposium 24162-MS SPE Tulsa Okla USA April1992

[6] C Chu ldquoA study of fireflood field projects (includes associatedpaper 6504)rdquo Journal of Petroleum Technology vol 29 no 2 pp111ndash120 1977

[7] T M Counihan ldquoA successful in-situ combustion pilot in theMidway-Sunset Field Californiardquo in Proceedings of the SPECalifornia Regional Meeting SPE 6525 Bakersfield Calif USAApril 1977

[8] A N Shandrygin and A Lutfullin ldquoCurrent status of enhancedrecovery techniques in the fields of Russiardquo in Proceedings of theSPEAnnual Technical Conference andExhibition (ATCE rsquo08) pp1929ndash1946 Denver Colo USA September 2008

[9] D G Mallory I I Abu K Fraassen M G Ursenbach R GMoore and S A Mehta ldquoAccelerating Rate Calorimetry TestsWest Salym Oil amp Core in Contact with Airrdquo 2011

[10] E T Denisov Kinetics of Homogeneous Chemical ReactionsHigh School Moscow Russia 1973 (Russian)

[11] N P Freitag ldquoChemical-reaction mechanisms that governoxidation rates during in-situ combustion and high-pressure airinjectionrdquo SPE Reservoir Evaluation amp Engineering vol 19 no4 2016

[12] N M Emanuel ldquoPresent state of the theory of chain reactionsin the liquid phase oxidation of hydrocarbonsrdquo in Proceedingsof the 7thWorld PetroleumCongress Mexico City Mexico April1967

[13] KU Ingold ldquoOxidation of organic compoundsrdquo inOxidation ofOrganic Compounds vol 75 of Advances in Chemistry chapter23 pp 296ndash305 American Chemical Society 1968

[14] N Semenov ldquoAdvances of chemical kinetics in the SovietUnionrdquo Nature vol 151 no 3824 pp 185ndash187 1943

[15] V A Klinchev V V Zatsepin A S Ushakova and S VTelyshev ldquoLaboratory studies and implementation of in-situcombustion initiation technology for air injection process in theoil reservoirsrdquo Tech Rep SPE-171244 2014

[16] J G Burger and B C Sahuquet ldquoChemical aspects of in-situ combustionmdashheat of combustion and kineticsrdquo Society ofPetroleum Engineers Journal vol 12 no 5 pp 410ndash422 1972

[17] B Sequera R G Moore S A Mehta and M G Ursen-bach ldquoNumerical simulation of in-situ combustion experi-ments operated under low temperature conditionsrdquo Journal ofCanadian Petroleum Technology vol 49 no 1 pp 55ndash64 2010

[18] A E Shilov and G B Shulrsquopin Activation and CatalyticReactions of Saturated Hydrocarbons in the Presence of MetalComplexes Kluwer Academic Publishers London UK 2002

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpswwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



injection there are cases where self-ignition of low-viscositylight oil did not occur such as Arlankovsky field 24∘C 30∘API[8] There was no ignition of the oil from Salymsky oilfield82∘b 40∘API during the experiments in the ARC [9]

Thus one can see that spontaneous ignition has nonob-vious dependence on the reservoir temperature and oilgravity The main conclusions on the impact of the differentcharacteristics of the oil reservoir to initiate combustionare the following the higher the temperature and pressurein the formation the greater the risk of ignition light oilignites faster than heavy oil but there are enough exceptionsmentioned above

There are numerous types of models of crude oil oxida-tion which demonstrate the stable combustion process gasoutput the amount of fuel for combustion and temperaturerise

On the basis of field experience it may be noted thatsome regularities of various factors influence on the initiationof combustion were identified empirically without definingtheir mutual influence Also the mechanism of crude oil self-ignition in reservoir conditions allowing building a reliablemodel of the process is not identified

2 The Mechanism of Low-Temperature andHigh-Temperature Oxidation

According to the literature the rate-limiting step of theoxidation process is the accumulation of hydroperoxides[10] The formation of hydroperoxide is a key stage of theprocess at first oxygen penetrates into the oil chains (thisstage takes place at any temperature) and forms free radicalsand radicals are passed from one molecule to another (chaingrowth) until they form hydroperoxide Hydroperoxides candecompose into a pair of radicals this is a branching chainreaction Such reactions rarely occur in hydrocarbons (chainbranching factor is small so the oxidation of hydrocarbons iscalled the oxidation with degenerate chain branching)

Next is the destruction of free radicals with the formationof oxidation products Products are oxidized compoundsacid aldehydes ketones or CO CO2 and water The processof low-temperature and then the high-temperature oxidationbegins with consumption of peroxides Another variantof oxidation is a high-temperature oxidation where chainmechanism takes place but it is not the main one Athigh temperatures peroxide decomposes without radicalmechanism [10]

Thus the initial stages have the same mechanism regard-less of the temperature a radical chainmechanism and high-temperature oxidation can occur by two different mecha-nisms Nonradical peroxide decomposition takes place athigh temperature above 250∘C and radical decompositionmay also occur at a low temperature (lower that 50∘C) andmay stay unfinished

For the first time in a theoretical paper [11] an attemptto describe the oxidation kinetics of in situ combustionwithin the idea of the radical chain mechanism of aliphatichydrocarbon oxidation reactions was made

There are several interesting conclusions in the paperassuming these conclusions we are building our model ofoxidation

(i) It is shown that oil oxidation occurs with the for-mation of intermediates hydroperoxides At insuffi-ciently high temperatures oxidation ends at this stage

(ii) Isomerization and decomposition reactions occur athigher temperatures CO2 and CO can be releasedat this stage Decomposition reaction dominates attemperatures above 500∘C resulting in completecombustion with formation of b2 and X2

(iii) Crude oil contains aromatic compounds which act asinhibitors of the initial stages of oxidation Inhibitorsbecome inactive at temperatures of 180ndash220∘C Aro-matic oxidized compounds are not decomposed aslong as the temperature does not rise to the HTO(350∘C) Below this temperature only these com-pounds continue to be oxidized forming oxidizedheavy residue which is a fuel for high-temperaturecombustion

(iv) There is an area of the negative temperature gradientOxidation in the gas phase through this area occursbefore the liquid phaseThenegative temperature gra-dient arises due to overlapping of peroxides formationeffects and their decompositionwith the release of gasand the formation of oxidized heavy residue

(v) Complexity of the heavy oil reservoir ignition isexplained by overlaying of inhibition and stabiliza-tion of oxidized compounds in the area of negativegradient further oxidation of which is inhibited byinsufficient temperature

Further we analyze different types of reaction in orderto derive the most complete and common set of chemicalreactions

21 Initiation of theOxidation Studies of hydrocarbon oxida-tion with oxygen suggest that oxidation always proceeds witha separation of the C-H bond both in branched chain and inunbranched process [12] Liquid hydrocarbons are resistantto dissociation of the C-C bond up to 200∘C If oxidation isinitiated without specific molecular reaction initiator suchinitiation is called autoxidation of oil Bimolecular initiationreaction is as follows

Oil +O21198961997888rarr Rlowast +HOOlowast (11015840)

Rlowast is the alkyl radical Initiation rate depends on thefollowing concentrations V0 = 1198961119862Oil119862O2

Intramolecular initiation reaction can occur in case ofliquid phase oxidation Oil + O2 + Oil

11989610158400997888rarr 2Rlowast + H2O2

Then the reaction rate can be written as V10158400 = 119896101584001198622Oil119862O2 The activation energies of the first and second reactionsrespectively are 197 kJmol and 577 kJmol The probabilityof the first reaction is higher than the second one due to thegain in energy but it is possible to check the implementedmechanismwhen determining the order of initiation reactionby fuel












P1198966997888rarr CO2 + CO +H2O (61015840)




















C16

minus10

10

30

50

70

90

130

110

0 100 150 200 250 300 350 40050T (∘C)

C16 + 05 oilC16 + 10 oilC16 + 20 oil

dQd

t(W

tg)








minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

1

DTG

(m

in)

0

20

40

60

80

100TG

()

200 300 400 500 600 700100Temperature (∘C)

Peak 19811∘C

Peak 46452∘C

Peak 31445∘C

Onset 15027∘C







(a)

CO

200 300 400 500 600 700100Temperature (∘C)

0

02

04

06

08

10

12

14

Abs

orba

nce

H2O

CO2

Peak 36273∘C

Peak 56377∘C

Peak 30041∘C

Peak 42506∘C

Peak 57081∘C

(b)











440 kJmol


















119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)




minus 1198967119862Oil119862RO

(3)




+ 1198965119862Oil119862P + 1198967119862Oil119862RO



(5)






119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation




















P1198966997888rarr CO2 + CO +H2O (61015840)




















C16

minus10

10

30

50

70

90

130

110

0 100 150 200 250 300 350 40050T (∘C)

C16 + 05 oilC16 + 10 oilC16 + 20 oil

dQd

t(W

tg)








minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

1

DTG

(m

in)

0

20

40

60

80

100TG

()

200 300 400 500 600 700100Temperature (∘C)

Peak 19811∘C

Peak 46452∘C

Peak 31445∘C

Onset 15027∘C







(a)

CO

200 300 400 500 600 700100Temperature (∘C)

0

02

04

06

08

10

12

14

Abs

orba

nce

H2O

CO2

Peak 36273∘C

Peak 56377∘C

Peak 30041∘C

Peak 42506∘C

Peak 57081∘C

(b)











440 kJmol


















119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)




minus 1198967119862Oil119862RO

(3)




+ 1198965119862Oil119862P + 1198967119862Oil119862RO



(5)






119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation


















C16

minus10

10

30

50

70

90

130

110

0 100 150 200 250 300 350 40050T (∘C)

C16 + 05 oilC16 + 10 oilC16 + 20 oil

dQd

t(W

tg)








minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

1

DTG

(m

in)

0

20

40

60

80

100TG

()

200 300 400 500 600 700100Temperature (∘C)

Peak 19811∘C

Peak 46452∘C

Peak 31445∘C

Onset 15027∘C







(a)

CO

200 300 400 500 600 700100Temperature (∘C)

0

02

04

06

08

10

12

14

Abs

orba

nce

H2O

CO2

Peak 36273∘C

Peak 56377∘C

Peak 30041∘C

Peak 42506∘C

Peak 57081∘C

(b)











440 kJmol


















119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)




minus 1198967119862Oil119862RO

(3)




+ 1198965119862Oil119862P + 1198967119862Oil119862RO



(5)






119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

1

DTG

(m

in)

0

20

40

60

80

100TG

()

200 300 400 500 600 700100Temperature (∘C)

Peak 19811∘C

Peak 46452∘C

Peak 31445∘C

Onset 15027∘C







(a)

CO

200 300 400 500 600 700100Temperature (∘C)

0

02

04

06

08

10

12

14

Abs

orba

nce

H2O

CO2

Peak 36273∘C

Peak 56377∘C

Peak 30041∘C

Peak 42506∘C

Peak 57081∘C

(b)











440 kJmol


















119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)




minus 1198967119862Oil119862RO

(3)




+ 1198965119862Oil119862P + 1198967119862Oil119862RO



(5)






119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













440 kJmol


















119896119894 = 1198600119894 sdot exp (minus 119864119894RT

) (1)




minus 1198967119862Oil119862RO

(3)




+ 1198965119862Oil119862P + 1198967119862Oil119862RO



(5)






119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











119862RO = 1198964119862P1198967119862Oil+ 1198965119862P1198967 (7)




(9)


120597120597119905 (119862P) = 120593119862P + 1198963119862Oil1198968119862Ing1198961119862O2119862Oil (10)





ln(1 + 120593119862P(1198963119862Oil1198968119862Ing) V0) = 120593119905 (11)




120597120597119905 (119862CO) = 1198962P119862P

120597120597119905 (119862H2O) = 1198963P119862P

120597120597119905 (119862R) = 1198964P119862P

1198961P + 1198962P + 1198963P + 1198964P = 1198966

(13)


100 200 300 400 500 6000T (∘C)

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70

b = 80

0

100

200

300

∘Cmin∘Cmin

∘Cmin

∘Cmin

∘Cmin


dqd

t(W

tg)






(14)









200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation















200 300 400 500 600100T (∘C)

b = 8

b = 6

b = 4

b = 10

b = 15

b = 20

b = 40

b = 50

b = 60

0

100

200

300

400

dqd

t(W

tg)







3000 4000 5000 6000 70002000Time (s)

minus8

minus4

0

4

8

Ln(d

qd

t(1

minus120572))

b = 5

b = 10

b = 15

b = 20

b = 35

b = 40

b = 50

b = 60

b = 70


∘Cmin


∘Cmin

∘Cmin





11989631198964119862Oil (2119862Oil + 1) ge 11989661198968119862Ing (15)



(21198965119862Oil + 1198964) [exp (120593119905) minus 1])(16)


120597120597119905 (119862Ing) = minusV0 (17)




R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












R2 = 09899y = 18585x minus 33945

R2 = 08944y = 13553x minus 25391

R2 = 0981y = 12133x minus 20971

R2 = 09931y = 85892x minus 17875

0

2

4

6

8

10

12

14

16

Nat

ural

loga

rithm

of t

he in

duct

ion

perio

d

00017 00019 00021 00023 00025 00027 00029000151T (1K)




120597119862P = minusV0 int120591Ind0


(18)



RT) 120591Ind


+ 1198640RT

(19)



















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

















300 400 500200T (∘C)

0

100

200

300

(1998400)-(2998400)-(3998400)

(1998400)-(2998400)-(8998400)

mechanism sim



(3998400)-(4998400) and (3998400)-(5998400)



t(W

tg)

sim exp(minusEaRT)

exp(minusEaRT)












6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











6 Conclusions





Competing Interests


Acknowledgments


References






















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Study of the Radical Chain Mechanism of Hydrocarbon Oxidation … · 2019. 7. 30. · Study of the...

Documents

Transcript of Study of the Radical Chain Mechanism of Hydrocarbon Oxidation … · 2019. 7. 30. · Study of the...