高加热速率和高压下的石油焦热解和CO2气化速率

PyrolysisandCO2GasificationRatesofPetroleumCokeatHigh

HeatingRatesandElevatedPressure

高加热速率和高压下的石油焦热解和C02气化速率

AaronD.Lewis,EmmettG.Fletcher,andThomasH.Fletcher.18thU.S.National

CombustionMeeting.OrganizedbytheWesternStatesSectionoftheCombustionInstituteand

hostedbytheUniversityofUtah.May19-22,2013

ThepyrolysisandCO2gasificationoftwopetroleumcokesamplesfromindustrywasstudied

inapressurizedflat-flameburneratparticleheatingratesof1O'K/satpressuresupto15atm.The

ASTMvolatilesvalueofpetroleumcokeappearedtobeagoodapproximationofthemassrelease

experiencedduringpyrolysisatconditionsofhighinitialparticleheatingrate.Themorphologyof

thetwopetroleumcokeswasdrasticallydifferentafterexperiencingrapidinitialparticleheating

rates.Thecharstructureofonepetroleumcokesampleappearedverysimilartothatofraw

petroleumcoke,withtheonlydifferencebeingcracksthatformedonthecharsurface.Although

thispetroleumcokesamplecontainedlessthan10wt%(daf)volatiles,itisbelievedthatthe

crackswerelikelyaresultofthevolatilesescapingtheparticleinteriorquickly,whichwas

influencedbythehighparticleheatingratesexperiencedintheflat-flameburner

experiments.Thestructureofthesecondanode-gradepetroleumcokecharcontainedan

appreciablefractionofswollen,thin-shcllcdparticlesthatappearedtohaveanear-hollowinterior.

ThepctcokeCO2gasificationexperimentswereconductedattotalpressuresof10and15atmin

ahigh-pressureflat-flameburner(HPFFB)reactoratconditionswerethebulkphaseconsistedof

-40and〜90mol%CO2.TheapparentCO2chargasificationratesofthesetwosamples(45-75

pm)weremeasuredfollowingin-situpyrolysisintheHPFFBreactorinthegastemperatureand

bulkCO2partialpressurerangesof1169-1909Kand4.1-13.5atm,respectively.TheCO2

gasificationratesfbrthetwopetroleumcokecharswerefittoaglobal1st-ordermodel.The

measuredandmodeledcharCO2gasificationratesarebelievedtoberepresentativeofthosefrom

anentraincd-flowgasifiersincetheyweremeasuredinsimilarconditionsofelevatedpressureand

highinitialparticleheatingrates(10,K/s)withshortparticleresidencetimes.Themeasured

kineticsofthetwopetcokesamplestookplaceunderZoneIIconditions,whichisatransition

regionbetweensurface-reactioncontrolandfilm-diffusioncontrol.Itwasshownthatboth

petroleumcokesamplesgasifiedatahigherrateatpressurizedconditionsthanabituminouscoal

sample.Theseresultsdifferfromreportsintheliteraturebasedonatmosphcric-prcssurc

experimentsthatpetroleumcokehasalowerCO2gasificationreactivitythancoal.

在加压平焰燃烧器中，最高压力为atm,颗粒加热速率105K/S,研究了两种工业石油

焦品的热解和CO?气化。石油焦的ASTM挥发物俏似乎非常接近较高初初始颗粒加热速

率条件下热解过程中出现的质量释放。经过快速的初始颗粒加热速率后，两种石油焦的形

态完全不同。一种石油焦样品的炭结构看起来与原始石油焦非常相似，唯一的区别是焦炭

表面形成裂缝。尽管这种石油焦样品中的挥发份含量少于10wt%(daf),但是，认为裂缝

可能是由于挥发物跨苏从颗粒内部逸出，受到平焰燃烧实验中经过的较高高颗粒加热速率

的影响。第二种阳极级石油焦炭的结构包括相当一部分的膨胀、薄壳颗粒，内部似乎接近

空心。在高压平焰燃烧器(HPFFB)反应器中，以10和15atm的总压力下，进行了石油

焦的CO?气化实验，条件为体相含s40和〜90mo1%的CCh。在HPFFB反应器中的原位

热解之后呢，检测了两种样品45-75R力的表观CO2气化速率，气相温度和体CO2分压范围

分别为1169/909K和4.1/3.5atm。这两种石油焦炭的CO2气化率符合全局一阶模型。由

于在相似的高压和较高初始颗粒加热速率(105K/S)检测，且颗粒停留时间短，相信检测

和模拟的石油焦CO2气化速率夹带■流气化炉的速率。两种石油焦样品的监测动力学是在

区域II进行，是表面-反应控制和薄膜-扩散控制之间的过渡区域。表明两种石油焦样品在

加压条件下的气化率均高于烟煤样品。这些结果与基于常压实验的石油焦炭的CO2气化反

应性低于煤的文献报告不同，

1.Introduction弓|言

Agrowingworldpopulationandincreasedmodernizationindevelopingcountriesplacean

ever-increasingdemandfbrenergy.Thesolutiontomeetingtheenergyneedsofthefuturewill

mostlikelycomefiomacombinationofenergysources,oneofwhichispetroleumcoke.Thisby­

productfromoilrefiningconsistsprimarilyofcarbon,resemblescoalinappearance,andisoften

referredtoaspetcoke.Petcokeresultsfromthecokerprocess,whichheatsheavyresidualfuel

oiluntilitcracksintomorevaluablelightcompoundsthatareeventuallyincorporatedintojetfuel,

diesel,andothercomponents.Currentestimatesofpetroleumcokegenerationare60milliontons

peryear,andpetcokeproductionisexpectedtoincreaseascokerunitsareaddedtooilrefineries

(Fisher,2011).Onewaythatpetroleumcokecanbetransformedintousefulproductssuchas

energyandchemicalsisthroughgasification,whichconvertsanyhydrocarbonthroughpartial

oxidationintogaseousfueltermedsynthesisgas(orsyngas)thatismainlycomposedofH2and

CO.Bothhomogeneousandheterogeneousreactionsoccurduringgasificationofasolidfuel.

Whilethermodynamicequilibriumcalculationsadequatelypredictthehomogeneousgasphase

reactionsinmostcommercialgasifiers(SmootandSmith,1985;HigmanandBurgt,2003),the

heterogeneousreactionbetweensolidcharandgasificationagents(suchassteamandCO2)can

becomeverycomplicatedwhenconsideringalltheinfluencingfactors.Someoftheseinclude

diffusionofreactantsthroughtheexternalboundarylayer,reactionswithbothH2OandCO2,

particlesizeeffects,porediffusion,charashcontent,temperatureandpressurevariations,and

changesinsurfacearea(SmootandSmith,1985).Predictingchargasificationkineticstherefore

reliesheavilyonmeasuredratedata.Beingabletopredictchargasificationratesisofresearch

interestbecausetheheterogeneousreactionbetweencharandgasoftengovernstheoverall

reactionrateingasificationprocesses(LiuetaL,2010).Otherprocessessuchaspyrolysisor

volatilescombustionoccurmorequicklyduringthegasificationofasolidfuel.Althoughcoalis

theleadinggasifierfeedstockincommercialgasification,thereisindustrialinterestinthe

gasificationofpetcokeaswell.AccordingtotheNationalEnergyTechnologyLaboratory's

(NETL)GasificationWorldwideDatabase(2010),theprojectedsyngascapacityin2016forcoke

andpetcokeis75,500and12,900MWth,respectively.

世界人M的增长和发展中国家现代化程度的提高导致能源需求与日俱增。满足未来能

源需求的解决方案很可是多种能源的组合，其中之一是石油焦。这种炼油的副产品主要由

碳组成，外观与煤炭类似，通常被称为石油焦。加热重质渣油使之裂解为加最终混合航空

然燃料、柴油和其他组成的价值更高的轻质化合物的焦化过程中产生石油焦。目前石油焦

的年产生量估计值为6000万吨，随着炼厂增加焦化装置，预计石油焦的产量增加。石油焦

可转化为可用的产品，如能源和化学品，一种方法是通过部分氧化将燃转化为主要由H2和

CO组成的称为合成气(合成气)的气态燃料。固体燃料的气化过程中出现均质和非均质反

应。尽管热力学平衡计算足以预测大多数商业气化炉中的均相气相反应，但是，考虑所有

影响因素时.固体炭和气化剂(如蒸汽和CCh)之间的异相反应会变得非常复杂°其中一

些包括反应物通过外边界层的扩散、与H2O和CCh的反应、粒径影响、孔隙扩散、炭灰含

量、温度和压力变化，以及表面积的变化。因此，预测炭气化动力学很大程度上取决于测

得的速率数据。由于炭和气之间的异相反应通常控制着气化过程中总体反应速率，能够预

测炭的气化速率举一个研究意义。在固体燃料的气化过程中，其他过程会更快地进行，如

热解和挥发物燃烧。虽然煤炭是商业气化中主要的气化炉原料，但是，石油焦气化也具有

工业意义「根据国家能源技术实验室(NETL)的全球气化数据库(2010),预计2016年焦

炭和石油焦的合成气规模分别为75,500和12,900MWtho

Aslongassolidfuelparticlesgasifyinaregimethatisnotlimitedbyfilmdiffusion,

gasificationreactivityofsolidfuelparticlesissignificantlyinfluencedbythestructureevolution

duringdevolatilization(Wuctal.,2012).Itisbelievedthatthecharstructureevolutionofthe

petroleumcokecharsinthisworkarcsimilartothosethatwouldbegeneratedinacommercial

entrained-flowreactor,duetotheirgenerationatbothhighheatingrateandpressure.Thismakes

themeasuredgasificationratesinthisworkveryrealisticandmeaningful.Abetterunderstanding

ofthegasificationreactivitywillenablethepredictionofresidencetimeandtemperature

requirementsforcompletereactioninhighlythermal-efficientprocessessuchasIntegrated

GasificationCombinedCycle(IGCC)togeneratepower(Cetinctal.,2005).

只要固体燃料颗粒以不受膜扩散限制基质气化，固体燃料颗粒的气化反应性受挥发过

程中结构变化的影响很大c由于在较高加热速率和压力下产生，相信本研究石油焦炭的炭

结构变化与在商业气流床反应器中产生的结构相似。这使得本研究中检测的气化率非常现

实和有意义。更好地认识气化反应性有助于预测高效热过程中的完全反应所需的停留时间

和温度，如综合气化联合循环(IGCC))。

2.ExperimentalProcedure实验方法

Samples.Twocommercially-obtainedpetroleumcokesampleswerestudiedinthisresearch.

Thesamplesarereferredtoas€PetCokeA'and'PetCokeB'inthispaper.SampleAislikelyfuel­

gradepetcoke,andhasbeenusedinpreviousresearch(Lewis,2011).SampleBisanode-grade

petcoke.Theprimarydifferenceindifferentgradesofpetroleumcokeisthemetalcontent(V,Fe,

Ni)intheash,whichisdeterminedbythecrudeoilfromwhichthesamplesarederived(Fisher,

2011).Thesamplesweregroundusinganelectricwheatgrinder(BlendtecKitchenMill)and

sievedtocollectthe45-75pmsizerange,whichwasusedinalltheexperiments.Themassmean

ofPetCokesAandBwere62.0and68.8pm,respectively.Thesmallparticleswereusedto

representthepulverizedparticlesizeusedinindustry,toensureahighinitialheatingrateofthe

particles,andtoassumenotemperaturegradientswithintheparticleformodeling.Figure1shows

SEMimagesofthesizedpetcokesamples.Thesepictures,alongwithotherSEMimagesinthis

work,weretakenusingaFEIXL30ESEMinstrumentwithaFEGemitter.

样品。在这一研究中，研究了两种商业■取得的石油焦样品。在本文中，样品分别称为

“石油焦A”和“石油焦B”。样品A可能是燃料级的石油焦，在先前的研究中已经使用。

样品B是阳极级石油焦。不同等级的石油焦的主要区别是灰分中的金属含量(V、Fe、Ni),

这取决于样品的来源的原油。采用电动小麦研磨机，研磨样品，筛分收集45-75um的粒

径范围，用于所有实验。石油焦A和B的质量平均值分别为62.0和68.8um。采用较小的

颗粒代表工上使用

粉碎颗粒尺度，保

证颗粒初始加热速

率高，建模假定颗

粒内没有温度梯

度。图1表示选定

(PetCokeA)(PetCokeB)

尺度的石油焦样品的SEM图像。这些图像片以及本研究中的其他SEM图像采用配有FEC

发射潜的FEIXL30ESEM仪器取得。

Figure1.SEMimagesofrawpetcokesamplescollectedfromthe45-75micron

sievetray.45-75微米筛板收集的原始石油焦炭样品的SEM图像。

Theresultsoftheultimateandproximateanalysesofthesamplesusedinthisresearchare

showninTable1.TheultimateanalysesforthepetcokesampleswereperformedbyHuffinan

LaboratorieswhiletheproximateanalyseswereperformedatBrighamYoungUniversity(BYU)

followingASTMprocedures.InfbnnationregardingIllinois#6coalisincludedinTable1sinceit

wasusedinalimitednumberofexperiments.

研究中是所有的样品的最终分析和近似分析结果见表10石油焦炭样品的最终分析在

实验室进行，而近似分析按ASTM方法。由于用于数量有限的实验，表1中包括了#6煤

炭的信息。

Table1.Ultimateandproximateanalysesofthefeedstocks表1.原料的最终和近似

分析

b/e

Sample样品Ww耙

)

冠

他)f

(f)f)a

东qaad

a(SJdd,

l送uB,,

sffl三Pt%

卜%%

(。

s％C,tt(w

oSo%ww

n-V>>((

MHNS

PetCokeAl.290.358.7887.621.811.772.156.30

PetCokeB0.200.3010.5290.973.781.331.042.88

Ill#6coal煤炭3.326.9844.7977.72d5.00d1.37d13.52d2.38d

Aasreceivedbasis收到基.Bdaf=dryandash-freebasis干基和无灰分基.Ccalculated

bydifference按差值计算.D(Smithetal.,1994)

ApparatusandOperation.Ahigh-pressureflat-flameburner(HPFFB)reactorwasusedin

thisstudytomeasuregasificationratesofthepetroleumcokesamples.Aschematicofthereactor

isshowninFigure2.TheHPFFBisusefulsinceitwellapproximatesthereactionconditionsin

industrialentrained-flowreactorsbyreacting|||

smallparticlesincocurrentflowathigh4卜，1口1

temperaturesandpressureswithrapidinitial32_________II■________LongQuartzTubt

particleheatingrates（〜10、K/s）andshort

Mt.fn

reactiontimes（＜1s）..一.一-ColkcoonProbe

匚

一^Stream

装置和运行。本研究中使用了高压平MncttO.

——一一一一ShortQuartzTube

焰燃烧器（HPFFB）反应器，检测石油焦样.A.一一Flat-Cla»eBurner

品的气化速率。反应器的示意图见图2。在

高温和高压下的同向流中，颗粒的初始加

热速率快(〜105K),反应时间短(<1S),与使颗粒反应的工业气流床反应器反应条件非常

接近，可采用HPFFBo

Figure2.ExternalandcutawayviewsofBYU'sHPFFBreactor(Lewis,2011;

Shurtz,2011).HPFFB反应器的外部和断面图

Similartocommercialentrained-flowreactors,particlesintheHPFFBtypicallyreactina

regimewheresolidconversionislimitedbyacombinationofbothchemicalreactionandpore

diffusion.Theflat-flameburnerusedhundredsofsmall-diamctcrtubestocreatenumerous

diffiisionflameletsbyfeedinggaseousfiielthroughthetubeswhileintroducinggaseousoxidizer

inthevacantspacesbetweenthetubes.Thecombinationofallthediffiisionflameletscreateda

flatflameaboutImmthickabovetheburner.

与商业气流床反应器类似，HPFFB中的颗粒通常固体转化受到化学反应和孔隙扩散限

制的区域中反应。平焰燃烧器使用几百个小直径的管，在管子之间的孔隙引入气态氧化剂，

气态燃料通过管子时形成很多小火焰。所有扩散小火焰的混合，在燃烧器上方形成约1mm

厚dl平火焰。

Particleswereentrainedinnitrogenandcarriedtothemiddleoftheburnersurfacethrougha

smallmetaltube(0.053"ID)atafeedrateof<1.5g/hrtoensuresingle-particlebehavior.Thelow

flowrateofcarriernitrogen(-0.2SLPM)inthefeedtubewasconsiderednegligiblewhen

comparedwiththe16-25SLPMflowratesofothergasestotheburner.Uponexitingthefeed

tube,theparticlesreactedwhiletravelingupwardinlaminarflowbeforetheparticleswere

collectedinanitrogcn-quenchcd,water-cooledcollectionprobe.Theparticleswereassumedto

stopreactingupontheirentranceintothecollectionprobeduetothehighflowrateofinertgas

andthesuddendecreaseintemperature.Theflowrateofquenchnitrogeninthecollectionprobe

wasabouttwicetheflowrateofgasestotheburner.Particleresidencetimewascontrolledby

adjustingtheheightbetweenburnerandcollectionprobe,andwascalculatedusingparticle

velocitymeasurementsfromahighspeedcamera(KodakEktaPro)incombinationwithaquadratic

scalingfactor(Lewis,2011).Avirtualimpactorandcycloneinthecollectionsystemseparated

thecharacrodynamicallywhileanysoot/tarcollectedonwatcr-coolcdfilters.Thenon-isothcrmal

centerlinegastemperatureprofilesintheHPFFBwereobtainedthroughtemperature

measurementscorrectedforradiationlossesfromaB-typethermocouplebeadusingequations

thathavebeendocumentedpreviously(Lewis,2011).

颗粒被夹带在氮气中，通过一个小金属管(ID0.053”)到达燃烧器表面中间，进料速

度<1.5g/hr,保证单颗粒特性。与进入燃烧器其他气体的16-25SLPM流量相比，进料管

中载体氮器的流速低(〜0.2SLPM),可以忽略不计。流出进料管后，颗粒反应，通过在层

流向上流动，然后将颗粒收集在氮气急冷、水冷收集探头中。由于惰性气体的流量高和温

度的突然降低，假定颗粒在讲入收集探头后停止反应。收集探头中急冷氮气的流量约为通

入燃烧器的气体流量的2倍。通过调整燃烧器和收集探头之间的高度，控制颗粒停留时间，

采用高速相机的颗粒速度检测值和二次比例因子计算。收集系统中的取样器和旋风分离器

以空气动力学方式分离焦炭，所有烟灰/焦油则收集在水冷过滤器上采用之前表明的方程式,

通过校正的B型热电偶辐射损失温度检测，取得HPFFB中的非等温中心线气体温度曲线，

Thediflerentgasconditionsinthispaperareidentifiedbythemaximumgastemperature

measuredineachprofile.Themeasuredcenterlinegastemperatureprofilefbrthe15atm1848K

conditionat90mol%CO?isshowninFigure3asareference.Additionaldetailsconcerningthe

HPFFBreactorhavebeenreportedelsewhere

(Lewis,2011;Shurtz,2011;Shurtzetal.,

2012).

本文中不同的气体条件通过每个曲线

中测得的最高气体温度确定。90moI%CO2

的15atm1848K条件下测得的中心线气体

温度曲线见图3,作为参考。其他地方报告HeightAboveBurner(inches)

了HPFFB反应器的更多详细信息。

Figure3.RepresentativecenterlinegastemperatureprofileinHPFFBreactorat

15atmtotalpressurewithTmax=1848Kand90mol%CO2inthepost-flame

environment.15atm总压力与Tmax=1848K和90mol%CO2后•火焰环境中的代表

性中心气体温度曲线

ThegaseousfuelsuppliedtotheHPFFBwasmainlyCO,withatraceamountofH2forflame

stability.FlowingdifferentcombinationsofCO2,air,O2,CO,andH2totheburnerenabledpct

cokeparticlestoreactinpost-flameenvironmentswithCO2near40and90mol%.Thegasesto

theburnerforthe40mol%CO2conditionswereCO2,air,CO,andH2,whereasthe90mol%CO2

gasconditionsdifferedfromthe40mol%CO2conditionsbysubstitutingO2forair.The

equivalenceratiosforthe40and90mol%CO2gasconditionswere~1.12and1.05,respectively.

提供给HPFFB的气态燃料主要为CO,含微量的H2,保持火焰稳定。不同的CCh、

空气、02、CO和H2组合入如燃烧器，使得碳颗粒在火焰后环境反应，其中CCh接近40

和90moI%。对于40mol%CO2条件，进入燃烧器的气体为CCh、空气、CO和H2,90mo1%

CO2的气体条件不同浴40mo1%CO2条件，采用02代替空气。40和90mo1%CO2气体条件

的当量比分别为〜1.12和1.05o

Thefuel-richCO2gasificationexperimentsinthe40mol%CO2post-flameenvironmentwas

alsocomposedof〜45and12mol%ofN2andCO,respectively,aspredictedbythermodynamic

equilibrium.Thegasificationexperimentsinthe90mol%CO2post-flameenvironmentcontained

about9mol%CO.Additionaldetailsofthegasconditions,aswellascenterlinetemperature

profiles,areincludedelsewhere(Lewis,inprogress2013).Thegasificationpost-flame

environmentsinthisstudycontainedCO2with〜10mol%CO,whichisknowntobeaninhibitor

totheCCh/chargasificationreaction.ThemeasuredCO2gasificationratesofpetcokeinthisstudy

arestillvaluablesincecommercialgasificationtypicallyoccursinanenvironmentcontainingboth

CO2andCO.Inaddition,ithasbeenshownthattheretardinginfluenceofCOontheCOz/char

gasificationreactionhasthemostpronouncedeffectatconditionsoflowertemperatureandhigher

CO/CO2atomicratiosthanstudiedhere(TurkdoganandVinters,1970).

与热力学平衡预测的一样，在40mol%CCh火焰-后环境中，富含燃料的CO2气化实验

也分别由645和12mo1%的N2和CO组成。90mo1%的CO2火焰■后环境中的气化实验含

约9m01%的CO。其他地方包括了气体条件的其他详细信息以及中心温度曲线。本研究的

气化火焰.后环境含CO?与~10mol%的CO,认为后者是CO2/炭气化反应的抑制剂。由于

商业气化通常是在含CCh和CO的环境中进行，因此，本研究中测得的石油焦的CO2气化

速率依然具有价值。另外，己经表明，在比本研究的温度低和CO/CO2原子比高的条件下，

CO对co/碳气化反应的延滞影响的作用最为明显。

GastemperaturewascontrolledintheHPFFBbyadjustinggasflowratestotheburner.No

heaterswereutilizedduringchargasificationexperimentsinthisstudy(seeFigure2)sincea

significantlevelofpetcokeconversionwasobtainedwithouttheiruse.TheCO2gasificationrates

ofpetroleumcokeinthisresearchweremeasuredforparticlesthatunderwentin-situpyrolysisin

theHPFFB,experiencingmaximuminitialparticleheatingratesnear105K/s.Particleresidence

timevariedfrom51-302msoverthestudiedconditionsattotalpressuresof10and15atm.The

partialpressureofCO2inthebulkphase,PcQ,buik,wasvariedfrom4.1to6,4atmatthe40mol%

CO?conditions,whilePcOi.buikwasvariedbetween9.0and13.5atmatthe90mol%CO2

conditions.ThemaximumconversionsonacharbasisforPetCokeAandPetCokeBwere55.5

and44.4wt%(daf),respectively.

通过调节流入燃烧器的气体流量，控制HPFFB中的气体温度。由于不使用也达到高

水平的石汕焦转化率，本研究中的灰气化实验中没有使用加热器(见图2)0在木研究中，

测量了，测量了石油焦的CCh气化速率，颗粒在HPFFB中进行了原位热解，出现的最大

初始颗粒加热速率接近IO,K/s。在10和15atm的总压力下，研究条件的颗粒停留时间

在51〜302ms之间变化。在40mo1%CO2条件下,体相中的CCh分压PCCh在4.156.4atm

之间变化，在90mo1%CO2条件下，PcCh.buik在9.0至13.5atm之间变化。石泊焦A和石

油角B的焦基最大炭转化率分别为55.5wt%(daf)和44.4wt%(daf)o

MassRelease.Massreleaseonacharbasisreferstohowmuchofthemassleavesthechar

particle,andisanindicatoroftheextentofgasification.Equation1(1)showshowmassreleaseon

acharbasiswascalculatedintheCO2gasificationexperimentsintheHPFFB:

质量释放。炭基质量释放是指多少质量流出炭颗粒，是气化程度的指标。式1(1)表

示如何计算HPFFB中CO?气化实验中的炭基质量释放：

%优ass(孙)■掰:一叫/0°

IcWr~WaMztar),

wheremOcharisthefiilly-pyrolyzedweightofpetcokefed.Sincerawpetcokesampleswere

fedintheHPFFBreactor,thisweightwascalculatedusingtheweightofdrypetcokefedandthe

volatilecontent(drybasis)fromproximateanalysis(seeTable1).ThetennmChar,cOiiectedisdefined

asthedrymassofgasifiedcharcollectedaftertheexperiment,andm°ash.charisthedrymassofash

inthefullypyrolyzedweightofpetcokefed.

其中，m°char是完全热解的石油焦进料重量。由于原始石油焦样品进入HPFFB反应

器，因此，这一重量采用干燥石油焦的重量和近似分析的挥发物含量(干基)计算(见表

1人术语me,cOn”⑹定义为文睑后收集的气化焦炭的干燥质量，而m°asll,diai是石油焦进料

完全热解后中灰分的干燥质量。

Massreleasevalueswerecalculatedfromamassbalance,whichinvolvedweighrsoffedpct

cokeandgasifiedcharfromtheHPFFBcollectionsystem.Althoughitcansometimesbedifficult

toobtainanaccuratemassbalance,itisbelievedthatthemassreleasenumberscalculatedbya

massbalancearefairlyaccuratesince(I)manyreplicateexperimentswereperfbnned,(2)special

carebetweenduplicateexperiments.Thebestmassbalancepossiblewasensuredbyshuttingdown

betweendifferentexperimentalconditionsinordertocleanoutthecollectionsystem,and

weighingtheamountofpetcokefedaswellasthecollectedchar.Theuseofaquartztube

immediatelyaroundtheburnerthatextendedallthewaytothecollectionprobefavoredgood

collectionefficiency(seeFigure2)aswell.Thelengthofthisquartztubedependedonthe

collectionheightoftheexperimentsincethistubeextendedfromthebottomvesselcapto〜1/8”

belowthecollectionprobe.

根据质量平衡计算出质量释放值，包括进料石油佳利HPFFB收集系统的气化胶重量。

尽管有时可能难以取得准确的质量平衡，但是，相信通过质量平衡计算的质量释放值相当

准确的，因为(1)进行了很多重复实验，(2)重复实验之间特别仔细。通过在不同的实验

条件之间关闭收集系统清理，称重进料的炭和收集的炭量，可以保证最佳质量平衡。紧邻

燃烧使用石英管，延伸到收集探头，也有利于较高的收集效率(见图2)。石英管的长度取

决于实验的收集高度，由于石英管从底部容器盖延伸到收集探头下方〜1/8”。

Althoughitispossibletocalculatemassreleaseusingashasatracer(Lewis,2011),this

methodwasnotusedinthisstudysinceupto40wt%oftheashvaporizedinapreviousstudy

(Lewis,2011)whenPetCokeAwasfedintheHPPFB.Theash-tracermethodofcalculatingmass

releaseonlyyieldscorrectvalueswhenashtrulyactsasatraceranddoesnotleavetheparticle.

Eachmassreleasedatapointistheaveragetakenfromtypically2to3replicateexperiments.The

averagestandarddeviationsinmassreleasevalues(charbasis)forPetCokeAandPetCokeB

experimentswere3.7and2.1wt%daf,respectively.

尽管可以采用灰分作为示踪剂，计算质量释放，但是，由于之前的研究中石油焦炭A

进入HPPFB时高达40wt%的灰分蒸发，本研究没有采用这种方法。只有灰分真正作为示

踪剂且不离开颗粒时，计算质量释放的灰分0示踪迹方法才得出蒸汽值。每个质量释放数

据点是通常2〜3次重复实验的平均值。石油焦A和石油焦B实验的质量释放值(炭基)

的平均标准偏差分别为3.7和2.1wt%dafo

3.ResultsandDiscussion结果和讨论

PyrolysisofPetCokeatHighHeatingRate.BothPetCokeAandPetCokeBwerefed

throughaflat-flameburnerreactorinordertotesttheeffectofparticleheatingrateonthepyrolysis

volatilesyieldofpetroleumcoke.Highinitialparticleheatingratehasbeenshowntoincreasethe

volatilesyieldduringpyrolysisforothersolidfuelssuchasbiomassandcoal(JamaluddinetaL,

1986;Solomonetal.,1993;BorregoandAlvarez,2007;BorregoetaL,2009).Forexample,

Borregoctal.(2009)measuredupto12%greatervolatileyieldsthantheASTMvolatilestest

whenpyrolyzingwoodchips,forestresidues,andricehusksathighheatingrateinadroptube

furnace.

高加热速率下的石油焦热解。为了试验颗粒加热速率对石油焦的热解挥发物产率的影

响，石油胶A和石油焦炭B都均进入平焰燃烧器反应器。已经表明较高的初始颗粒加热速

率可增加其他固体燃料热解过程中的挥发物产产率，如生物质和煤。例如，在滴管炉中以

高加热速率热解木屑、林业残余物和稻壳时，检测出的挥发物产率比ASTM挥发物试验高

于12%。

BothPetCokeAandPetCokeBwerefedthroughaflat-flameburnerreactorthathasbeen

documentedpreviously(Ma,1996;MaetaL,1996;Zhang,2001;ZhangandFletcher.2001),and

operatedinaverysimilarmannerastheHPFFBreactorwiththeexceptionofoperatingat

atmosphericpressure.PctCokeAwasfedattwofuel-richgasconditionswherethepeakcenterline

gastemperatureswere1751and1929K,withparticleresidencetimesrangingfrom33-102ms.

Theaveragemassreleasefrom10runsfeedingPetCokeAwas8.86wt%(daf)withastandard

deviationof0.9wt%.Theserunswerepreliminaryninstodetermineifpetcokewouldgasifyin

lessthan102mswithpartialpressureofCO2,Pc。2，near0.23atm,butalsoserveaspyrolysisdata

athighheatingrateconditionssincenoCO2gasificationwasmeasured.PetCokeBwas色dattwo

differentfuelrichgasconditionswherethepeakcenterlinegastemperatureswere1320and1433

K,withparticleresidencetimesnear50msusinga2"collectionheightabovetheburner.The

averagemassreleaseofPetCokeBfrom3runswas10.57wt%(daf)withastandarddeviationof

1.1wt%.

之前已经记录了石油A和石油焦B进料通过平焰燃烧器，且以与HPFFB反应器非常

相似方式运行，只是在常压下运行。石油焦A在富含两种燃料气的条件下进入，峰值中心

线气体温度为1751和1929K,颗粒停留时间为33-102ms。石油焦A10次进料的平均质

量释放为8.86wt%(daf),标准偏差为0.9wt%。这些运行是初步运行，确定石油焦炭是

否会在不到102亳秒的时间、CCh分压PcCh接近0.23atm下气化，但是，由于没有测量到

CO2气化，因此，也可以作为高加热速率条件的热解数据。石油胶B以两种不同的富含燃

料的气体条件下进料，峰值中心线气体温度为1320和1433K,采用燃烧器上方2”的收集

高度，颗粒停留时间接近50mso3次运行的石油B的平均质量释放为10.57wt%(daf),

标准偏差为1.1wt%。

TheresultsofpyrolysismassreleaseofPetCokeAandPetCokeBatbothlowandhigh

heating-rateconditionsaresummarizedinTable2.TheASTMvolatilesvaluewastakenfrom

Table1andservesasalowheating-ratepyrolysisvalue,whereasthehighheating-ratepyrolysis

valuewastakenasthemeasuredmassreleaseduringflat-flameburnerexperiments.Thereisless

than0.9%differenceinthelowandhighheating-ratepyrolysismassreleasevaluesfbrbothpet

cokesamples.

表2总结了在低和高加热-速率的石油焦A和石油焦B热解质量释放结果。ASTM挥

发物值取自表1