Coal Structure vs. Flash Pyrolysis Products

8/10/2019 Coal Structure vs. Flash Pyrolysis Products

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COAL STRUCTURE VS. FLASH PYROLYSI S PRODUCTS

W H. Cal ki ns

E. I . DU Pont de Nemour s L CompanyCent r al Resear ch & Devel opment Depar t ment

Exper i ment al St at i onW l m ngt on, DE 19899

The f ast pyrol ysi s of coal pr oduces t ar , char and ar ange of l ow mol ecul ar wei ght gases i n var i ous pr opor t i ons andamount s dependi ng on t he pyr ol ysi s condi t i ons ( t emper at ur e, pr essur e)and t he coal bei ng pyr ol yzed. Much r esear ch ef f or t has been devot edt o s t udy of t he reac t i on ki net i cs and ef f ec t of pr ocess var i abl es ,at t empt i ng t her eby t o el uci dat e t he pyr ol ysi s mechani sm l ) .ef f or t has been f ocused on coal chem cal st r uct ur e and i t s r el at i on-shi p t o t he pyr ol ysi s r eact i ons and pyr ol ysi s pr oduct s. I t was t oat t empt t o bet t er under st and coal st r uct ur e and i t s i nf l uence onpyr ol ysi s pr oduct s and pyr ol ysi s mechani sms t hat t hi s pr oj ect was

under t aken. Thi s paper wi l l r epor t onl y on t hat por t i on of t he wor kconcer ned w t h t he al i phat i c hydr ocar bon pr oduct s and par t i cul ar l yt he l i ght ol ef i ns .

Less

A cont i nuous bench- scal e pyr ol ysi s appar at us ( Fi g. 1 ) wasconst r uct ed si m l ar t o t he desi gn of Tyl er ( *) . The coal ent r ai nedi n a ni t r ogen st r eamwas i nj ect ed i nt o a sand bed f l ui di zed wi t hni t r ogen and heat ed i n a spl i t f ur nace t o t he t emper at ur e desi r ed.Vol at i l es em t t ed f r om t he sand bed wer e passed i nt o t wo col d t r apsi n ser i es cont ai ni ng cel l ul ose t hi mbl es t o f i l t er out t he t ar andchar f r om t he of f - gas. Gas exi t i ng t he col d t r aps was vent edt hr ough a wet - t est met er wi t h a si de st r eam ent er i ng a Per ki n- El merSi gma One comput er - cont r ol l ed gas chr omat ogr aph whi ch anal yzed f orsome 16 component s. At t he end of a pyr ol ysi s r un, t he t ar andchar caught i n t he t wo t hi mbl es wer e ext r act ed i n a s oxhl et ext r act orw t h met hyl ene chl or i de and met hanol t o obt ai n t he wei ght of t ar andchar pr oduced.

Fi gur e 2 shows t ar yi el ds vs. t emper at ur e f or a TexasLi gni t e. Fi gur e 3 shows how t he quant i t y and composi t i on of t hepyr ol ysi s gas f r om t he same coal var i es w t h t emper at ur e. Onl yt he maj or gases ar e shown. These cur ves ar e t ypi cal of many coal sal t hough t he act ual quant i t i es var y( 3) .i t i s appar ent t hat t he t ar pr oduced goes t hr ough a maxi mum atabout 60OoC and up t o t hat t emper at ur e r el at i vel y smal l amount s ofgases ar e evol ved. Above 6OO0C, t he pr oduct i on of t he var i ousgases i ncr eases r api dl y whi l e at t he same t i me, t he t ar yi el d dr opsof f . The i nf er ence can be dr awn t hat t he gas i s com ng f r om t arpyr ol ys i s . That t hi s i s s o, can be s hown by pyr ol yzi ng t ar whi chhas been pr oduced at 6 0 0 " C , at hi gher t emper at ur es. Si m l argaseous pr oduct s ar e pr oduced and i n si m l ar r at i o as when coal i spyr ol yzed at t he hi gher t emper at ur e

Fr om t hese t wo f i gur es,

) .The yi el ds of t he hydr ocar bon gases pr oduced on coal

pyr ol ysi s var y gr eat l y dependi ng on t he par t i cul ar coal . Thi si s shown f or et hyl ene, one of t he maj or pr oduct s, i n t he f i r st t wocol umns of Tabl e 1. The et hyl ene yi el d i s r el at ed t o t he pr opyl ene

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yi el d as shown by Fi gur e 4. Si m l ar l y, t he et hyl ene yi el d i sr el at ed t o t he but adi ene yi el d, suggest i ng t hat t hese gases have acommon pr ecur sor . The met hane and benzene, however , show no obvi ousr el at i on t o t he et hyl ene yi el ds. These pr oduct s ar e appar ent l yder i ved mai nl y f r om ot her component s i n t he coal .

Coal St r uct ur e vs. Pyrol ysi s Pr oduct s

To t ry t o r el at e t hese yi el d di f f er ences t o st r uc tur aldi f f er ences i n t he coal s t hemsel ves, each coal whose pyr ol ysi sbehavi or was st udi ed was exam ned by I 3C NMR ( wi t h c ros s pol ar i zat i onand magi c angl e spi nni ng) . Thi s wor k was dGne by E. A . Hagaman andH. Zel des of Oak F.ic?ge i i at i onal Labor at or y i n a cooper at i ve pr ogr amw t h i)u Pont . Typi cal pat t er n di f f er ences bet ween a hi gh et hyl ene-pr oduci ng coal ( PSOC 1241, a l ow et hyl ene- pr oduci ng bi t um nous coal( Sewi ckl ey) and t wo i nt er medi at e coal s ( Con Paso Bl ue 2 and PSOC 181) ,ar e shown i n Fi gur e 5 . Whi l e t he PSOC 124 coal shows hi gh al i phat i cchar act er and t he Sewi ckl ey shows t he expect ed hi gher ar omat i ci t y,var i ous ot her evi dence suggest s t hat al i phat i c char act er al one i s not

t he det er m ni ng f act or . The f r act i onal ar ea r epr esent i ng a chem calshi f t at 31 ppm however , whi ch i s associ at ed wi t h met hyl ene chai nsgr eat er t han 5 or 6 segment s l ong, appear s t o cor r el at e wi t h t heet hyl ene yi el d r esul t s . Thi s peak whi ch occur s at a chem cal shi f tof 29 ppm i n subs t ances i n sol ut i on i s appar ent l y shi f t ed s l i ght l yt o 30- 32 ppm i n sol i d coal . Thi s was s hown by r unni ng st ear i c aci di n sol ut i on, and i mpr egnat ed on t o ant hr aci t e coal . The 29 ppm peakwas s hi f t ed up f i el d and br oadened on t he coal .

A pl ot of et hyl ene yi el d vs. t he ar ea f r act i on of t he 13CNMR spect r umat a chem cal shi f t of 31 ppm t i mes t he wei ght f r act i onof car bon i n t he coal i s shown i n Fi gur e 6. The l i ne i s t he l east -squar es f i t t o t he poi nt s shown. Whi l e t her e i s scat t er i n t he dat a,

a cor r el at i on i s appar ent ( Cor r el at i on coef f i c i ent = . 92) .Tar St r uct ur e St udi es

Low t emper at ur e ( 600' C or l ess) pyr ol ysi s of coal pr oduceshi gh yi el ds of t ar whi ch on f ur t her pyr ol ysi s pr oduces t he vol at i l ehydr ocar bon pr oduct s we obser ve on hi gh- t emper at ur e pyr ol ysi s ofcoal . Thi s shows t hat t hi s t ar cont ai ns t he al i phat i c pr ecur sor swe obser ve i n t he coal i t sel f , al t hough t hey may be changed somewhatf r omt he f or m i n whi ch t hey ar e i n i n t he coal . A number of t ar swer e t her ef or e pr oduced by pyr ol ysi s of sever al di f f er ent coal s at600C i n t he l abor at or y coal pyr ol ysi s uni t f or f ur t her st udy.

i n CDC13) f r om 6OO0C pyr ol ysi s i s shown i n Fi gur e 7 . I t showsa ver y st r ong peak at a chem cal shi f t of 29 ppm The 1H NMRspect r umwas r un on t he same t ar i n CDCl 3 sol ut i on ( Fi gur e 8 . I tshows a st r ong peak at 1. 2 ppm known t o be due t o met hyl ene chai nsover 5 uni t s l ong. By usi ng a DOW Cor ni ng si l i cone DC200 f l ui d( %H=8. 06) i nt er nal st andar d i n t he CDC13 sol vent , quant i t at i vedet er m nat i on of t he ( CH2) n peak by r at i o of i t s ar ea t o t hat of t he0 ppm si l i cone peak was possi bl e.t he t ar . Si m l ar pat t er ns ar e shown by t ar s of ot her coal s.

A 13C NMR pat t er n f or a sol ut i on of M l l mer r an t ar ( 10%

Thi s showed 33. 6 wt . % ( CH2) n i n

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To quant i f y t he ass i gnment of t he 1. 2 peak i n t he pr ot onL NMR spect r um a ser i es of model compounds havi ng l ong met hyl ene

chai ns was di ssol ved i n CDC13 cont ai ni ng t he si l i cone i nt er nalst andar d. I n al l cases, t he 1. 2- 1. 3 peak was ver y l ar ge and cl ear l y

i n Tabl e 2. A s can be s een f r om t he Tabl e, not al l met hyl ene gr oupsappear i n t he pr ot on NMR spect r um at 1. 2- 1. 3 ppm Onl y t hose ( CH2)gr oups shown i n br acket s i n t he st r uct ur al f or mul as show up at t hatpl ace.gr oups or benzene r i nqs appear at hi gher chem cal shi f t s, and met hylgr oups appear at 0. 7- 0. 8 ppm Thi s cl ear l y i dent i f i es t he 1. 2- 1. 3ppm peak as due t o ( c H ~ ) ~ ut at t he same t i me i ndi cat es t hat anyanal ysi s based on t hi s met hod wi l l not i ncl ude al l of t he (Cti, )gr oups i n coal . I f t he chai ns ar e l ong, however , most of t hemet hyl ene w l l be i ncl uded.

1 det ect abl e. Wei ght % ( CH2I n cal cul at ed f or each compound ar e s hown

Those CH2 gr oups conj ugat ed wi t h or cl ose t o t he car boxyl

Tabl e 3 shows t he di st r i but i on of t ypes of pr ot ons i n 600Cpyr ol ysi s t ar s f r omf our di f f er ent coal s r epr esent i ng a wi de r angeof ol ef i n yi el ds on pyr ol ysi s. The Tabl e shows t hat r oughl y 35% of

t he pr ot ons i n t he t ar ar e pol ymet hyl ene pr ot ons, t he r est ar edi vi ded bet ween met hyl gr oups, hydr oar omat i c hydr ogens, hydr ogensat t ached t o ar omat i c car bons, and a s mal l number of ol ef i ni c andsome uni dent i f i ed pr ot ons.

Tabl e 4 shows t he di st r i but i on of pr ot ons i n t ar f r om TexasLi gni t e pyr ol yzed at var i ous t emper at ur es f r om 600C t o 92OoC. Thi scl ear l y shows t hat as t he pyr ol ysi s t emper at ur e i s i ncr eased, t hecont ent of pol ymet hyl ene i n t he t ar decr eases as do t he hydr oar omat i chydr ogens. The ar omat i c hydr ogens on t he ot her hand i ncr ease r api dl yt o become t he pr edom nant speci es. Thi s pr ovi des a conveni ent measur eof t he compl et eness of pyr ol ysi s.

To t r y t o i sol at e and pur i f y l ar ger quant i t i es of t hehydr ocar bon pr ecur sor s, a separ at i on was made of t he M l l mer r an t arby Pr epar at i ve Li qui d Chr omat ogr aphy. A number of f r act i ons acr osst he chr omat ogr amwer e anal yzed by FTI R and l H NMR and f r act i on 21r epr esent i ng 38% of t he or i gi nal sampl e t ur ned out t o be hi gh i n( CH2l n ( concent r at i on 68% . An I nf r ar ed spect r um cf t hat f r ac t i on( Fi gur e 9 ) showed a wel l r esol ved peak ;I t 720cm 1, known t o bechar act er i st i c of l ong met hyl ene chai ns. Thi s peak has a l owext i nct i on coef f i ci ent and i s r ar el y descer ni bl e above backgr oundi n coal s t hemsel ves. A GC/ MS pat t er n of t hat f r act i on ( Fi gur e 10)shows ol ef i n/ par af f i n pai r s of peaks f r om C17 t o C24.

The pol ymet hyl ene compounds i n pyr ol ysi s t ar s ar e mai nl y

pr esent as l i near par af f i ns or ol ef i ns , however , t her e ar e i ndi cat i onsof l esser amount s of br anched par af f i ns and ol ef i ns and al kyl ar ylcompounds as wel l i n t he unf r act i onat ed t ar s. The f or m t he pol y-met hyl ene compounds have i n t he coal i t sel f i s not known, butext r act i on of var i ous coal s w t h met hyl ene chl or i de f or sever al daysf ai l ed t o r emove mor e t han 1% of t he mat er i al , suggest i ng t hat t hemaj or par t of t he pol ymet hyl ene compounds may be ei t her chem cal l y. combi ned i n t he coal st r uct ur e or el se t r apped.

Model compound Pyr ol ysi s

Whi l e i t seemed l i kel y on t he basi s of pet r ol eum exper i encet hat pol ymet hyl ene compounds woul d pyr ol yze t o f or m t he l ow mol ecul ar

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wei ght al i phat i c hydr ocar bons we obser ve on coal pyr ol ysi s, knowncompounds as model s of pol ymet hyl ene and ot her st r uct ur es i n coalwer e pyr ol yzed at si m l ar t emper at ur es and cont act t i mes as t hecoal .

Tabl e 5 summar i zes t he r esul t s of pyr ol ysi s of 7 modelcompounds. Pr oduct s ar e onl y shown as maj or and m nor . As can beseen by r ef er r i ng t o t he Tabl e, under t he pyr ol ysi s condi t i ons used,compounds cont ai ni ng met hyl ene chai ns s uch as dodecane, oct adecane,st ear i c aci d, et hyl benzene, pr opyl benzene, but yl benzene, and phenyl -dodecane on cr acki ng gi ve subst ant i al quant i t i es of et hyl ene al ongwi t h but adi ene, pr opyl ene and ot her hydr ocar bons i n amount s r oughl ycompar abl e t o what we obser ve i n coal pyr ol ysi s. The ar omat i cpor t i on i n al kyl ar yl compounds appear s t o go mai nl y t o t ol ueneal t hsugh si nal i amount s of benzene and s ome st yr ene ar e pr oduced aswel l . Some met hane i s al so pr oduced al ong wi t h m nor amount s ofet hane, but ane and ot her hydr ocar bon. These r esul t s ar e qui t econsi st ent w t h what we f i nd i n coal pyr ol ysi s and w t h pet r ol eumcr acki ng t echnol ogy.

I nt er est i ngl y, t he met hyl ar yl compounds i nvest i gat ed t husf ar do not pr oduce met hane on pyr ol ysi s under t he condi t i ons we used.Tol uene and t he t hr ee xyl ene i somer s appar ent l y ar e onl y sl i ght l yconver t ed at 850C and 0. 5 t o 1. 0 s econd cont act t i me i n t he sand bed.9- Met hyl ant hr acene and 3 , 6 - d i m e t h y l p h e n a n t h r e n e pr oduced no met haneor ot her gaseous pr oduct s, al t hough t hey appear ed t o f or m t ar or coke.Thi s i s consi st ent wi t h t he obser vat i ons of Lang et a1 on met hyl -napht hal enes( 5) whi ch f or m condensat i on pr oduct s but not gases underpyr ol ys i s condi t i ons .

Anal ysi s f or Pol ymet hyl ene i n Coal I t sel f

W t h 13C NMR i ndi cat i on of t he ( CH)

moi et y i n coal andevi dence of ( CH2) n i n l ow and hi gh t emper at ugenpyr ol ysi s t ar s, aswel l as model compound pyr ol ysi s i nf or mat i on, i t seemed i mpor t antt o devi se a quant i t at i ve anal yt i cal met hod f or ( CH ) i n coal i t s el f .Thi s r ni sed t he quest i on whet her coal coul d be l i qaeai ed undergener al l y accept ed sol vent r ef i ni ng condi t i ons and s t i l l r et ai nundecomposed t he pol ymet hyl ene component ?l i ber at ed but not dest r oyed, can i t be det ect ed and quant i t at i vel ydet er m ned by pr ot on NMR?

Al so, i f t he ( CH2) n i s

Fi gur e 11 shows t he pr ot on NMR pat t er n of t he l i quef act i onpr oduct of PSOC 124, a hi gh et hyl ene yi el di ng coal whi ch was l i que-f i ed usi ng 3 gr ams of coal , 3 gr ams of t et r al i n as donor sol vent ,

0. 1 gr am each of sodi um sul f i de and f er r ous sul f i de as l i quef act i oncat al yst s and 2000 psi pr essur e ( col d) of hydr ogen i n a 10 mshaker bomb. The l i quef act i on was r un at 425C f or 2 hour s i n a sandbat h w t h ver t i cal shaki ng. The pr oduct l i qui d was washed out oft he shaker t ube w t h met hyl ene chl or i de and f i l t er ed t o r emove t hesol i ds ( ash, unconver t ed coal and cat al yst s) . Af t er r emoval of t heCHZC12 by di st i l l at i on, a wei ghed s ampl e of t he l i qui d was di ssol vedi n deut er o- chl or of or mcont ai ni ng a known amount of DC200 si l i conef l ui d as i nt er nal st andar d. Exam nat i on of t he NMR pat t er n cl ear l yshows t he ( CH2) n peak at 1. 2 ppm and t he CH3 peak at about 0. 8 ppmi ndi cat i ng t hat t he pol ymet hyl ene component of t he coal i s r el easedf r om t he coal mat r i x but not dest r oyed i n t he l i quef act i on pr ocess.

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IThe r est of t he NMR pat t er n ( beyond 1. 3 ppm i s heavi l y af f ect ed byt he pr esence of t he donor sol vent and i t s dehydr ogenat i on pr oduct sso t hat t hi s met hod i s onl y usef ul f or det ect i ng t he ( CH2) n. .

f i r st a ser i es of bat ch shaker t ube l i quef act i on r uns wer e made i n10 m shaker t ubes usi ng t he same r eci pe as pr evi ousl y but var yi ngt he t i me, t emper at ur e and donor sol vent . Test s wer e made w t h t hr eedi f f er ent donor sol vent s [ t et r al i n, di hydr ophenant hr ene ( DHP) ,and t et r ahydr oqui nol i ne ( THQ) ] . The ( CH2) n f i gur es on t he r i ghthand 5 col umns of Tabl e 6 wer e obt ai ned by separ at i ng t he l i qui df r omt he sol i d by ext r act i on w t h CH2C12, f i l t r at i on t o remove t hesol i ds, and di st i l l i ng of f t he sol vent ( CHzC12) . The ( CH2) n cont entof t he l i qui d was det er m ned by di ss ol vi ng a wei ghed sampl e of l i qui di nt o a vol umet r i c f l ask and maki ng up t o t he l i ne wi t h CCl j Dcont ai ni ng a known quant i t y of DC- 200 si l i cone i nt er nal st andar d.Al l conver si ons wer e 85 or mor e and usual l y above 90%

I To devel op a r out i ne anal ysi s based on coal l i quef act i on,

I n most cases, al l t hr ee donor sol vent s gave si m l arr esul t s, but i n a f ew cases t he t et r ahydr oqui nol i ne gave hi gherval ues. THQ was, t her ef or e, sel ect ed f or f ur t her i nvest i gat i on.Li quef act i ons wer e r un, var yi ng t emper at ur e and cont act t i me. Theser esul t s ar e shown i n t he t hr ee r i ght - hand col umns of Tabl e 6 wher er esul t s wer e r epor t ed f or 4OO0C and 1. 65 hour s and 435C f or 4 hour s.The l ower t emper at ur e shor t cont act t i me l i qui ds wer e vi scous andhar d t o wor k up. The hi gh t emper at ur e l onger t i me r eact i ons showedl i t t l e change over t he 425' C/ 2 hour sampl es, so t he l at t er condi t i onswer e sel ect ed as opt i mum

The val ues obt ai ned f or ( CHZ ) ~ ont ent of coal s f r om coall i quef act i on ar e r easonabl e based on t he amount of et hyl ene pr oducedi n pyr ol ysi s shown i n col umn 1 and et hyl ene pl us ot her hydr ocar bons

bel i eved t o come f r om t he same sour ce shown i n col umn 2 of Tabl e6.

These shoul d r epr esent m ni mum amount s i n t he coal . Col umn 3 showst he ( C HZ ) ~ ound i n pyr ol ysi s t ar s cal cul at ed on t he basi s of t heor i gi nal coal whi ch shoul d al so be a m ni mum si nce not al l t he tari s dr i ven out of t he coal at 0. 5 seconds pyr ol ysi s cont act t i me.

For a number of r easons, i t was desi r abl e t o be abl e t or un t hi s l i quef act i on anal ys i s on a m cro ( < l o mg) scal e. Thi s woul dbe much s i mpl er t o do i f no added cat al yst was r equi r ed and hydr ogenpr essur e was not needed. Exper i ment s wer e, t her ef or e, t r i ed t o seewhet her such an anal ysi s coul d be devel oped under t hose condi t i ons.Li quef act i ons wer e r un i n 3 l ong 3 mm pyr ex gl ass t ubes. Appr ox.5 mg of ( - 200 mesh) coal sampl es ( wei ghed t o .01 mg) wer e char ged

t o t he t ubes al ong wi t h 10 mg of cal ci ned cl ean sand, 1. 1 t i mes t hewei ght of coal of t he donor sol vent and a 1 cm l ong 2 mm gl ass r od( f or agi t at i on) and t he t ubes pur ged wi t h ni t r ogen and seal ed.

Two such t ubes wer e packed i nt o each 10 m shaker t ubew t h st eel wool packed ar ound t hem They wer e t hen subj ect ed t o425 C f or 2 hour s i n a sand bat h wi t h r api d ver t i cal agi t at i onw t h appr oxi mat el y 5 m nut es heat up t i me t o t emper at ur e and r api dcool down i n a col d ai r st r eam

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The t ubes wer e wor ked up by br eaki ng i n t he m ddl e andr i nsi ng r epeat edl y wi t h CC13D cont ai ni ng a wei ghed amount of DC- 200f l ui d, t hr ough a gl ass wool pl ug f i l t er i nt o a 1 m vol umet r i c f l ask.The cont ent s of t he f l ask wer e put i nt o an NMR t ube and r un on t heI BM NR- 80 Four i er Tr ansf or m NMR Spect r omet er . The ar ea of t he1. 2 ppm peak was det er m ned r el at i ve t o t he si l i cone peak and t he

wei ght % ( CH2) n cal cul at ed usi ng t he ar ea r at i o.The r esul t s of t hese exper i ment s ar e s hown i n col umns 1,

2 and 3 i n Tabl e 7. They cl ear l y show t hat l ow r esul t s ar e obt ai nedwi t h t et r al i n and di hydr ophenant hr ene under t hese condi t i ons. Thi smay be due i n par t t o l ower donor act i vi t y, but mor e l i kel y due t ol ow hydr ogen cont ent of t he donor i n t he absence of a hydr ogenat mospher e. The r esul t s w t h t et r ahydr oqui nol i ne, however , appeart o be about t he same whet her i n t he m cr o mode wi t hout hydr ogenpr essur e or cat al yst or i n t he macr o mode wi t h bot h. Thi s syst emwas, t her ef or e, adopt ed as bei ng si mpl e, r api d and gi vi ng r esul t sequi val ent t o t he macr o syst em Anal ysi s of pai r s of sampl es f r omsome 40 coal s by t hi s met hod r angi ng i n % ( CH2I n cont ent by

wei ght of f r om 0 t o 17% ( MF) showed a st andar d devi at i on of 0. 59%Tabl e 1 col umn 3 shows t hese val ues f or t he coal s pr evi ousl y di s-cussed t oget her wi t h t he et hyl ene yi el ds. I n vi ew of t he sampl i ngpr obl ems wi t h a het er ogeneous mat er i al l i ke coal and t he smal lsampl e si ze, anal yses wer e nor mal l y r un i n pai r s. The coal wasgr ound f i ne ( - 200 mesh) and wel l bl ended. Wher e gr eat er accur acyi s desi r ed, mor e r epl i cat es can be easi l y r un and t he l H NMR can ber un wi t h mor e scans.

Et hyl ene yi el ds ( 85OOC) vs. ( CH2) n concent r at i on f or t hesecoal s ar e pl ot t ed i n Fi gur e 12 wi t h t he l i near r egr essi on l i ne shown.A cor r el at i on coef f i ci ent of 0. 952 and a 0 i nt er cept shows a goodcor r el at i on.

Si m l ar l y pl ot s of pr opyl ene and but adi ene yi el ds f or t hesame coal s, vs . ( CH2) n cont ent al so show st r ong cor r el at i ons.

Concl usi ons

We concl ude f r omt he exper i ment s descr i bed t hat t he l owmol ecul ar wei ght al i phat i c hydr ocar bons pr oduced by f l ash pyr ol ysi sof coal at t emper at ur es of 700OC and over , r esul t pr i mar i l y f r om t hecr acki ng of l ong met hyl ene chai ns whi ch ar e par t of t he coal st r uct ur eor t r apped i n i t . Low t emper at ur e ( 6OOOC) pyr ol ysi s of t he coaldr i ves of f a por t i on of t he coal as t ar whi ch cont ai ns t hese pol y-met hyl ene moi et i es, pr i mar i l y i n t he f or m of nor mal par af f i ns and

ol ef i ns f r omC17 t o C 2 4 and hi gher . Thi s pol ymet hyl ene pr ecur sor ( s)i n coal i s appar ent l y des t r oyed dur i ng coal i f i cat i on, as i t i sessent i al l y absent i n ant hr aci t e and i s much hi gher i n l i gni t e andsubbi t um nous coal s. However , even i n l ow r ank coal s t he concen-t r at i on of t he pol ymet hyl ene moi et y var i es wi del y, pr obabl ydet er m ned by t he t ypes of pl ant s f r omwhi ch t he coal s ar e der i ved.Cannel coal s gener al l y cont ai n f ai r l y l ar ge amount s of (CHz), , ( upt o 17% or mor e) . Some l i gni t es and subbi t um nous coal s cont ai nas much as 10 ( CH2) n.

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Sever al ot her i nvest i gat or s 6- 15) have r epor t ed t hepr esence of al i phat i c hydr ocar bons i n coal based mai nl y on sol ventext r act i ons. The amount s r epor t ed, however , have been gener al l ymuch l ess t han was f ound i n t hi s wor k. The di f f er ence pr esumabl yi s t hat most of t he pol ymet h l ene i s chem cal l y bound or t r appedand non- ext r act abl e.met hyl ene compounds by chem cal degr adat i on of t he coal , however ,no quant i t at i ve concl usi ons coul d be dr awn f r om t hat wor k.

Deno( l g ) r epor t ed t he pr esence of l ong chai n

The l i quef act i on met hod f or est i mat i on of ( CH2) n cont entof coal s i s bei ng used t o det er m ne t he ( CH21n cont ent of coalmacer al s and t o expl or e t he geochem cal or i gi ns of t he pol ymet hyl enecomponent s i n coal .

Acknow edgement s

The aut hor w shes t o acknow edge t he i mpor t ant cont r i -but i ons by E. Hagaman and Henr y Zel des of Oak Ri dge Nat i onalLabor at or y i n l 3C NMR wor k on t he coal s studi ed i n t hi s pr oj ect ,

and Penn St at e Uni ver si t y f or suppl yi ng many of t he coal sampl esused.

I .

91

I


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REFERENCES

1. H o w a r d , J . B . ,s u p p l e m e n t , W i

2 . T y l e r , R a lp h J

F u e l , 59, 2 1 83 .

4 .

5 .

6 .

7 .

8 .

9 .

1 0 .

11.

1 2 .

1 3 .

1 4 .

1 5 .

1 6 .

C h e m i s t r y of C o a l U t i l i z a t i o n , s e c o n de y I n t e r s c i e n c e , p p s . 6 6 5 - 7 8 3

, F l a s h P y r o l y s i s of C o a l s - l ,1 9 8 0 )

T y l e r , R a l p h J . , F l a s h P y r o l y s i s of C o a l s - 2 ,F u e l , 59 2 18 ( 1 9 8 0 ) .

T y l e r , R a l p h J . , T h e C h e m i s t r y of F l a s h P y r o l y s i s ;S e c o n d a r y C r a c k i n g , 6 t h A n s t r a d i a n W or k sh op o n C o a l H y d r o g e n a t i o n ,N o v e m b e r 1 3 , 1 9 8 1 .

L a n g , K . F . e t a l , C hem . B 2 8 6 6 ( 1 9 5 6 ) .

Va h r m a n , M . , F u e l 49 5 ( 1 9 7 0 ) .

S p e n c e , J . A . a n d Va h r m a n , M . , F u e l 49 3 95 ( 1 9 7 0 ) .Rahman, A a n d Va h r m a n , M . F u e l 2 3 18 ( 1 9 7 1 ) .

B i r k o f e r , I,. e t a l , B r e m m s t o ff C h em i e 3 7 6 ( 1 9 6 9 ) .

C h a u v i n e t a l B u l l d e l a S OC . d e F r a n c e 11 3 91 6 ( 1 9 6 9 ) .B a r t l e , K . D . e t a l , J . A p p l . C h e m . 9 7 ( 1 9 7 0 ) .

B a r t l e , K . D . e t a l , F u e l 54 226 ( 1 9 7 5 ) .

B a r t l e , K . D . e t a l , F u e l 4 1 0 ( 1 9 7 9 1 .

B a r t l e , K . D . e t a l , N a t u r e 277 1 8 4 ( 1 9 7 9 ) .

Z i l m , K . N . e t a l , F u e l 58 11 ( 1 9 7 2 ) .

D e n o , N . e t a l , F u e l 60 2 1 0 ( 1 9 8 1 ) .

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FIGURE1

- 1 GM/HRCOAL PYROLYSISUN T

L BALANCE I

:.,

FL UID IED BED PYROLYZER

FLUDUING Nz

FL UID IED BED PYROLYZER

FIGURE 2

PRODUCT YIELDSFROMTHE FLASH PYROLYSISOF TEXAS LIGNITE

-8 TO GC ANAL

METERa WET TE:

TEMPERATURE O C )

93


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FIGURE3

P Y R O LY S I SOF T E X A S L I G N I T E

Y I E L D SOF PRINCIPAL GASES

I II

COP

BENZENE

TEMPERATURE('C)

F I G U R E4

C 3 6 1 4 1 . X > 14: 56 I&-JCHI-H3ETHYLWE US PROWLWE YIELDS < U T. % >

0 . 0 , , , , , , ,5 . 1 . 2. 5 . 5 . 5. '6. 5 b s . l b . d . 1 2 .C2H4 YIEU) U T. % )

94


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FIGURE 6BB 19 8-MAP-BJCM4 YIELD (UT % >

czw n o us ARER FRWT 31 PPM *UT FRWT c i ieea1 2 s ' " . 1 . ' . . ' " ' . ' , . . ' ' . . . . I . ' ' .

i a o -

7 5

5 a- -

2 s -

a a- -

- 2 3 . . . . , . . , , , , . . , . . I . . , . . I .a e 5 0 j 5 i d e 1 1 5 n eFlWCT 31 FFN M F R S T C t l W 0

PIGURE 5

''CNXR SPECTRA 01 C OA W PRODUCING DlPPERENT EW ENE YIELDS ONPYROLYSIS IB5O.C C8.s. CTI n

A

S S k 1 . y-1

2 0 0 1 5 0 100 50 0PPM

95


12/59

FIGURE 7

,


13/59

FIGURE 9

FIGURE10

GCIMS SPECTRUM- CUT 21 LC FRACTIONATIONOF MILL'IERRANSOFT TAR

1 1 1 . 1 1 0 - 1 1 0 0 5 :D-, *-.1 C " L : C" . .t ~ 7 ~ o s . a s - 2 ~ I L I I " , o n - , CII I D " . D I l , O l 0 2 L It i 7 0 . 7

97

b


14/59

It

i


15/59

TABLE 1

ETHYLENE YI ELDS I N COAL PYROLYSI S AND ( C H , L CONTENT ( UT. % )

( 850C

CoalPSOC 124Ki ng CannelM l l mer r anLovel ady- L- 2Lovel ady Y- 4Lovel ady 81 V L L - ~~Bl i nd CanyonPSOC 435Emer yCon Paso- Bl ue 3

Con Paso- Bl ue 2Con Paso- Yel l ow 4Upper Hi awat haWyodakTexas Li gni t ePSOC 181Con Paso- Yel l ow 6PSOC 464Lower Hi awat haPi t t sbur gh 8PSOC 1106PSOC 657I l l i noi s 6- Bur ni ng St arPSOC 833Sew ckl eyOhi o 9- Egypt Val l eyAnt hr aci t e

*Moi st ur e Fr ee**Moi st ure and Ash Fr ee

0. 5 sec. CT. )

E

11. 99. 476. 085. 914. 904. 824. 824. 754. 504. 36

3. 733. 673. 303. 213. 203. 072. 802. 782. 662. 502. 421. 851. 831. 771. 48

. 610. 0

MAF**

13. 111. 04

7. 017. 946. 687. 005. 074. 984. 954. 88

4. 784. 173. 653. 523. 593. 333. 053. 062. 852. 982. 532. 282. 182. 011. 75

. 680 . 0

- (CHZ), , (MF)*17. 014. 5

9. 659. 118. 408. 486. 568. 867. 125. 72

7. 215. 185. 034. 06. 015. 024. 314. 125. 004. 474. 042. 181. 752. 002. 201. 780. 0

i


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CH3[(CH2

i g 3 r(C H ~r

TABLE 2

( CHZ),, ANALYSIS OF KNOWN COMPOUNDS

(Proton NMR)

TheoryI ] CH2CH2-C-OH 64.0

101 C"3 82,O

CH3 bCH2) 13CH3 85,. 8

CH3 [(CH2)17] CH3 88.8

?

1

CH3 k C H Z ) p dCH3 9 1 , l

CH3 [(CH2)23] CH3 91 ;5

51,2

1

Found62.6

77.7

81.8

84.6

91.7

92,5

49.1


17/59

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0 0 h L n a 3- l O W M . - il - l - l o o o

m hO N

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t w o O N L n NI n k - a h c a m m

1 0 2


19/59

t TABLE 5PYROLYSIS OF MODEL COMPOUNDS (L IQ U I D S )

( 0 . 3 m l / h r L i q u i d F e e d i n ca 2 . 1 l / m i n . N 2 )8 5 0 C 0 . 5 - 1 . 0 S e c . C o n t a c t Ti me

G a s e o u s o r Vo l a t i l e P r o d u c t sM od el Compound P r i n c i p a l P r o d u c t s M i no r P r o d u c t s

S t e a r i c A ci d

D o d e c a n e

O c t a d e c a n e

E t h y l B e nz e ne

P r o p y l B e n ze n e

n - B u t y l B e n z e n e

P h e n y l D o d e c a n e

S t y r e n e

io u e n eM e t h a n e

T o l u e n eE t h y l e n eS t y r e n e

E t h y l e n eT o l u e n eE t h y l B e n z en eM e t h a n eS t y r e n e

E t h y l e n eP r o p y l e n e

M e t h a n eT o l u e n eS t y r e n e

B e n z e n e

C 2 H 6

qH6

C2H6

qH6

C 2 H 6

C 2 H 6B e n z e n e

C2H4

B e n z e n eM e t h a n eE t h y l B e n z en e

C 2 H 6

C3H6B e n z e n e

qH6

C 2 H 6B e n z e n e

1 3


20/59

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105


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FLASH PYROLYSIS OF COAL I N R E AC T IV EAN0NON-REACTIVE GASEOUSENVIRONMENTS

Muthu S. Sundaram, Meye r S t e i nb e r g and Pe t e r T. F a l l o nDepa r tmen t o f Ene rgy and Env i ronmen t

P r o c e s s S c i e n c e s D i v i s i o n

B r o o k h a v e n N a t i o n a l L a b o r a t o r yU pt on , L.I., N.Y. 11973

ABSTRACT

The o b j e c t i v e i s t o o b t a i n p r 3 c e j j ch e mi st ry f o r t h e r a p i d p y r o l y s i s

o f co al w i t h r e a c t i v e and n o n - r e a c t i ve gases f o r t h e p r o d u c ti o n o f l i q u i d

and g as eo us fu e l s and chemica l f e eds tock s . The ga seous p ro du c t s we re

a n a ly z ed v i a an o n - l i n e GC a nd t h e h ea vy l i q u i d s we re c h a r a c t e r i z e d by

HPLC, I R and GC/MS. The t o t a l c a r b o n c o n v e r s i o n was h i g h e r i n t h e p r e -

s e nc e o f r e a c t i v e g as es th a n i n t h e p re s en ce o f n o n - r e a c t i v e g as es . The

h ea t- up r a t e o f t h e c o al p a r t i c l e s i n n o n - re a c t i v e g a s i f y i n g media f o l l o w -

ed t h e o r d e r He>NZ>Ar. The t o t a l c a rb on co nve r s io n f rom New Mex ico sub-

b i t u m i n o u s c o a l i n t h e p r e s en c e o f t h e s e g as es a l s o f o l l o w e d t h e same

o r d e r . E x p e ri m e n ts w e re p e r fo r m e d i n a d o wn - fl ow, e n t r a i n e d t u b u l a r r e a c -

t o r un de r a w id e ra n ge o f p r oc e s s c o n d i t i o n s : 7000 t o I O O O O C , 20-1000

p s i , 0.5 - 5 se c. c o a l p a r t i c l e r e s i d e n c e t i m e . The e f f e c t s o f t h e s e p r o -c es s v a r i a b l e s an d t h e p h y s i c a l p r o p e r t i e s o f t h e p y r o l y z i n g ga ses on t h e

y i e l d and t h e q u a l i t y of p r o d u c t s fr om t h e p y r o l y s i s o f New M e xi co s ub -b i t u m i n o u s c o a l w i l l be d i s cus sed .

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INTRODUCTION

The f l a s h p y r o l y s i s o f c o a l i s a f a s t , g as-p ha se, n o n - c a t a l y t i c ,

d i r e c t c o a l c o n v e rs i on t e c h n i q u e f o r t h e p r o d u c t i o n o f g aseo us h y d ro -

ca rb on s and s i g n i f i c a n t q u a n t i t i e s o f a r om a ti c l i q u i d h yd ro ca rb on s f o r

d i s t i l l a t e f u e l s a nd c he mi ca l f e ed s to c ks . P y r o l y s i s i s a complex p r oc e ss

d u r i n g w h i c h s e v e r a l c h e m ic a l r e a c t i o n s o c c u r s i m u l t a n e o u s l y. A g e n e r a l

c on ce pt o f t h e p y r o l y s i s p r oc e ss i s shown i n F i g u r e 1.

C o n s i d e r a b l e amount o f wo rk h as b ee n d on e i n t h e p a s t on p y r o l y s i s o f

C oa l w h i c h was s um m ar iz ed r e c e n t l y i n a c l a s s i c r e v i e w b y H ow ard (1). The

e x p e r i m e n t a l te c h n i q u e s , r e a c t i o n c o n d i t i o n s an d t h e c o a l u se d w e re s o

d i v e r s i f i e d t h a t t h e i n fo r m a t i o n a v a i l a b l e i s o f l i m i t e d v a l ue i n a

p ro ce ss p o i n t o f v ie w. We h av e, t h e r e f o r e , u n d e r t a k e n a s y s t e m a t i c

g e n e r a l i z e d s tu d y t o m e t h o d i c a l l y d e ve l op and b u i l d a r e l i a b l e d a t a b ase

on t h e f l a s h p y r o l y s i s o f c o a l s w i t h r e a c t i v e and n o n - r e a c t i v e g ase s. The

c h o i c e o f i n e r t gas i s ba se d on c o v e r i n g a r an g e o f p h y s i c a l p r o p e r t y

e f f e c t s , i.e., h e a t c a p a c i t y , th e rm a l c o n d u c t i v i t y and d i f f u s i v i t y e t c .

The c h o i c e o f r e a c t i v e gas i s b as ed on t h e t y p e o f g as es u s u a l l y f or me d i n

t h e p y r o l y t i c r e a c t io n s o f c o a l . The r e s u l t s o b t a i n e d f ro m t h e p y r o l y s i s

of New Mexico sub-b i tum inous co a l i n H2, CH4, He, N2 and A r a tmospheres

a r e p r e se n te d i n t h i s p ap er .

EXPERIMENTAL

New M e x i c o s u b - b i t u m i n o u s c o a l g r o u n d t o l e s s t h a n 1 0 0 mesh a n d

vacuum d r i e d a t 700C was used i n a l l p y r o l y s i s e xp er im en ts . The u l t i m a t e

a n a l y s i s o f t h e c o a l i s g iv en i n Ta bl e 1.

The e x p e r i m e n t a l e q ui pm e nt u se d i n th e s e s t u d i e s ( F i g u r e 2) i s a

h i g h l y i n s t r u m e n t e d 1 - in .- i. d. b y 8 - f t - l o n g e n t r a i n e d d ow nf lo w t u b u l a r r e -

a c t o r s ys te m, w h i ch h as been d e s c r i b e d i n d e t a i l ( 2 ) . Coal p a r t i c l e s 15 0

m i cr o me te r s o r l e s s i n d ia m e te r a r e f e d b y g r a v i t y i n t o t h e t o p o f t h e r e -a c t o r f r o m a c o a l f e ed e r e n c lo s e d i n a h i g h p r e s s u r e v e s s e l . The p y r o l y -

s i s gas e n t e r s th r o u g h a p re h ea te r , c o n t a c t i n g t h e c o al p a r t i c l e s a t t h e

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t o p o f t h e 8 - f t r e a c t o r . The h e a t t r a n s f e r , p y r o l y s i s , and s ec on da ry

r e a c t i o n s t a k e p l a c e as t h e c o a l a nd e n t r a i n i n g ga s m ee t and f l o w c o n-

c u r r e n t l y down t h e r e a c to r . B elo w t h e r e a c t o r i s a 3 - f t f o rc e d a i r c o o l -

i n g s e c t i o n i n w h ic h t h e p r o d u c t - l a d e n g ase s a r e c o o l e d t o 2 500 t o 30OoC.

The c h a r i s r e mo ve d f r o m t h e e f f l u e n t gas i n a h i g h p r e s s u r e v e ss e l w h i c hi s m a i n t a i n e d a t 2500 t o 3OO0C t o p r e v e n t l i q u i d p r o d u c t c o n d e ns a ti o n.

The h ea vy l i q u i d p r o d u c t s i n t h e e f f l u e n t gas a r e rem oved i i i two conden-

se r s , o ne wa t e r coo l ed (15%) and t h e u tn e r F r eon coo l ed ( -4OoC) . The

r e m a i n i n g g as es a r e t h e n r e d u c e d t o a t m o s p h e r i c p r e s s u r e , m e a su r ed v i a a

p o s i t i v e d i s p l a c e m e n t m e t e r , a nd v e n t e d t o t h e a t m os ph er e.

The v e l o c i t y o f t h e co a l p a r t i c l e t h r o ug h th e r e a c t o r i s c a l c u l a t e d

b y a dd i ng i t s f r e e - f a l l v e l o c i t y b a se d on S t o k e ' s l a w t o th e d o wn -f lo w gas

v e l o c i t y . The r e s i de n c e t i m e i s d e t er m i ne d f ro m t h e l e n g t h o f t h e r e a c t o rand th e t o t a l c o a l p a r t i c l e v e l o c i t y .

P ro d uc t y i e l d s , as a f u n c t i o n o f co a l p a r t i c l e r e s i d en c e t im e , a re

d e t er m in e d b y s am p li ng f ro m t a p s l o c a t e d a t 2 - f t i n t e r v a l s a lo n g t h e

l e n g t h o f t h e r e a c t o r . The p r o d u c t a n a l y s i s i s a c co m p li sh e d v i a an o n-

l i n e , p r og r am m a b le g a s ch r o m a t o g r a p h (G C) w h i c h d e t e r m i n e s CO, C02, CH4,

C2H4, C&, and BTX (benzene , t o l ue ne , and xy l e ne ) c o n c e n t r a t i o n s e v e r y 8

m i n u t e s . P r o d u c t s h e a v i e r t h a n BTX ( > C g) c an n o t be m e as ur ed o n - l i n e

b ec au se o f c o n d e n s a t io n i n t h e s am ple l i n e s a nd t h e t e m pe r a tu r e l i m i t

( 23 0o C) o f t h e g as c h ro m a to g ra p h. T he se p r o d u c t s a r e c o l l e c t e d i n t h e

c o nd e n se r s a nd a n a l y z e d a t t h e end o f e ac h e x p e r im e n t . S e l e c t e d l i q u i d

sa mp les a r e s u b j e c t e d t o e l e m e n t a l a n a l y s i s a n d GC/MS s t u d i e s .

The d u r a t i o n o f an e x p e r im e n t i s a t l e a s t o ne h o ur an d s t e a dy s t a t e

i s a ch ie ve d i n 3 t o 4 m i n u t e s . C oa l f e e d r a t e s a r e u s u a l l y a b o u t 500

g / h r. To f a c i l i t a t e u n i fo r m f l o w, 10% b y w t C ab -0 -S il , a s i l i c a f l o u r , i s

a d de d t o t h e c o a l . The n o n - r e a c t i v e g as es u s ed w ere t h e i n e r t g as es ,

a rg o n, h e1 iu m a nd n i t r o g e n ; The r e a c t i v e g a se s i n c l u d e d hy d r og e n , m e th a n e

a nd c a r b o n m on ox id e. Yi e l d s a r e b a se d on t h e p e r c e n t o f t h e ca r bo n i n t h e

f e e d c o a l w h ic h i s c o n v e r te d t o p r o d u c t s a n d d e t e r m i n e d a s f o l l o w s :

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C ar bo n i n P r o d u c t , g x l 0 0% C arb on c o n v e r t e d t o p r o d u c t = - Carbbn-iri TFeT7

A sum o f t h e g as eo us and l i q u i d p r o d u c t y i e l d s , e x p re s se d as c a r b o n

c o n v e r t e d , w i l l g i v e t h e t o t a l c ar bo n c o n v er s io n d ue t o p y r o l y s i s . F ro m

f e e d r a t e s , p r o d u c t y i e l d s , and a n e l e m e nt a l a n a l y s i s o f t h e f e e d c o a l a nd

ch a r p roduced , a comp le t e ma t e r i a l ba l a nce can be made.

RESULTS AND DISCUSSION

C oal p a r t i c l e s e n t e r i n g t he r e a c t o r a r e h e at ed t o r e a c t i o n te m pe ra -

t u r e b y c o n v e c t i o n f r o m t h e p r e h e a t e d g as and by r a d i a n t h e a t f r o m t h e

r e a c t o r w a l l . I n c a l c u l a t i n g t h e c oa l p a r t i c l e h ea t- up r a t e due t o c on-

v e c t i o n , a num ber o f e x p e r i m e n t a l c o n f i g u r a t i o n s w e re c o n s i d e r e d f o r w h i c h

h e a t t r a n s f e r c o e f f i c i e n t s ha d b ee n d e te r m in e d . T he se i n c l u d e d h e a t a nd

mass t r a n s f e r fr o m a f a l l i n g w a t e r d r o p l e t ( 3 ) , h ea t t r a n s f e r t o a

f l u i d iz e d - be d o f p a r t i c l e s ( 4 ) , h ea t t r a n s f e r t o p a r t i c l e s a t R eyn old s

n u m b e r s g r e a t e r t h a n 500 ( 5 ) , h e a t t r a n s f e r i n a d i st e nd e d be d o f p a r t i -

c l e s 6 ) , and t h e t h e o r e t i c a l h e at t r a n s f e r b etw ee n a p a r t i c l e a nd a s t a g -

n a n t f l u i d . S i nc e t h e R eyn old s number f o r t h e c o a l p a r t i c l e s f a l l i n g

t hr o ug h t h e gas i n o u r wo rk i s v e r y lo w, l e s s t h a n 1 0, n e i t h e r t h e

f l u i d i z e d - b e d n o r t h e h i g h R e y no l ds nu mb er w o rk seemed a p p r o p r i a t e . A l s o ,

t h e f l u i d i z e d - b e d w ork g ave v e ry l o w h e a t t r a n s f e r c o e f f i c i e n t s , w h ic h

w ere a t t r i b u t e d t o e x c e s s i ve b yp a ss in g o f gas t h r o u g h t h e b ed d u r i n g t h ee x p e r i m e n t s ( 7 ) . S i n c e t h e w o rk o n d i s t e n d e d b ed s sh ow ed go od c o r r e l a t i o n

o f d at a fr om v o i d f r a c t i o n s o f 0.45 t o 0.78, t h i s a pp ea re d t o p r o v id e t h e

c l o s e s t ap p ro a ch t o o u r ex p e r im e n t a l c o n d i t i o n s . Th e e x p r e s s i o n u se d i s

as f o l l o w s ( 6 ) :

NU = 2.06 N R E ~ * ~ ~ ~ N ~ R ~ / ~

where Nu = Nusse l t numbe r

NRE = Reynolds number = %?-"% I?J9

N ~ R P r a n d t l number =

cI

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hg = h ea t t r a n s f e r c o e f f i c i e n t f o r gas f i l m ,

Dp = d ia m e te r o f p a r t i c l e ,

K g = t h e rm a l c o n d u c t i v i t y o f gas,

V = v e l o c i t y o f p a r t i c l e t hr ou gh gas ( f r e e f a l l ) ,

pg = d e n s i t y o f g a s ,ug = v i s c o s i t y o f gas, a nd

Cpg = h e a t c a p a c i t y o f g as .

By s u b s t i t u t i o n

and

dT

= hg A (Tg-~ , ) ,

dTs = ( T g - Ts ) d t ,

Where

Cp, = h ea t c a p a c i t y o f c o a l

M = mass o f c o a l p a r t i c l e

As = are a o f c oa l p a r t i c l eTg = t e m p e r a t u r e o f gas

Ts = t em p er at ur e o f c o a l p a r t i c l e

T i = i n i t i a l te m pe ra tu re of c oa l p a r t i c l e

t = t im e t o r a i s e t h e p a r t i c l e t em p e ra tu re f ro m T i t o T

E q u a t i o n ( 2 ) was us ed t o c a l c u l a t e t h e g a s - f i l m h e at t r a n s f e r c o -

e f f i c i e n t b etw ee n t h e c o a l p a r t i c l e and t h e p r e h e a t ed gases h yd ro ge n,

m e t h an e , c a r b o n m o n o xi d e, h e l i u m , n i t r o g e n , a nd a rg o n. The v a l u e s o f g a s-

f i l m h ea t t r a n s f e r c o e f f i c i e n t f o r v a r i o u s p y r o l y z i n g gases un de r a se t o fa r b i t r a r i l y c hosen c o n d i t io n s a r e g i v e n i n T ab le 2. Ta b l e 2 s h o w s t h a t

f o r r e a c t i v e g as es , t h e h e a t t r a n s f e r c o e f f i c i e n t d ec re as ed i n t h e f o l l o w -

i n g o r d e r : H 2 > C H 4 > C O ;f o r n o n - r e a c t i v e g as es t h e o r d e r i s f o u n d t o b e

He>Nz>Ar. Equat ion ( 4 ) was u se d t o c a l c u l a t e t h e c o a l p a r t i c l e

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t e m pe r at u re as a f u n c t i o n o f t i m e and i s p l o t t e d i n F i g u r e 3. F i g u r e 3

shows t h a t h yd ro g en g i v e s t h e h i g h e s t h e a t- u p r a t e a nd a r g o n t h e l o w e s t ;

among t h e n o n - r e a c t i v e g a se s, h e l i u m g i v e s t h e h i g h e s t r a t e . A l t h o u g h

c a l c u l a t i o n s o f t h e f i n a l t e m pe ra tu re o f t h e c o a l p a r t i c l e w er e made,

t h e s e s h o u l d be c o n s i d e r e d a s l i m i t i n g v a l u e s be ca us e c h e m ic a l e n e r gyexchan ge a nd d e v o l a t i l i z a t i o n a l s o t a k e p la c e .

C a l c u l a t io n s o f t h e r a d i a n t h e at t r a n s f e r f ro m t h e h o t r e a c t o r w a l l

t o t h e co a l p a r t i c l e s i n d i c a t e t h i s c o n t r i b u t i o n t o be a bo ut 5 t o 1 0% O f

t h e t o t a l h e a t t r a n s f e r . S i nc e t h es e c a l c u l a t i o n s a r e p r o b a b l y n o t ac cu -

r a t e t o b e t t e r t h a n + l o % , r a d i a n t h e at t r a n s f e r was n o t i n c l u d e d i n t h e

c o a l p a r t i c l e h e a t i n g r a t e o r t h e t em p er at ur e e s t i ma te s .

When p y r o l y s i s t o o k p l a c e i n t h e p r es e nc e o f n o n - r e a c t i v e g as es , t h e

t o t a l c a rb o n c o n v e r s i o n f o l l o w e d t h e o r d e r : H e>N z>Ar. F o r e xa mp le , a t

9 O O O Cand 200 p s i p r e s s u r e o f He, N2 and A r , t h e t o t a l c a rb o n c o n v e rs i o n s

w e r e: 21.0%, 20.1% a n d 1 4.5 %, r e s p e c t i v e l y ( Ta b l e 3 ). T h i s i n c l u d e s t h e

y i e l d s d ue t o h y d r o c a r b o n g a se s, o x i d e s o f c a rb o n , BTX an d h e av y l i q u i d s .

I n r u n s u s i n g N2 o r A r as t h e p y r o l y z i n g gas, d i f f i c u l t i e s w ere e xp e r ie n c -

e d i n m e as ur in g t h e CO p r o d uc e d w h i ch a r o s e a s a r e s u l t o f i n a d e q u a t e

r e s o l u t i o n o f t h i s c om pon ent f r o m t h e s o l v e n t p eak (N2 o r A r ) . H en ce , t h e

CO y i e l d s f ro m h e l iu m p y r o l y s i s r u ns un de r i d e n t i c a l c o n d i t i o n s w ere u se d

t o d e t e rm i n e t h e t o t a l c a rb o n c o n v e rs i o n i n t h e s e c as es . T h i s c o u l di n t r o d u c e some e r r o r i n th e t o t a l c ar bo n co n ve r si on d a t a f o r N2 and A r

p y r o l y s i s r un s. I n t h e ca se o f r e a c t i v e ga se s, t h e t o t a l ca rb on c on ve r-

s i o n s w e r e 37.6%, 3 0.4 % a nd 17.5% r e s p e c t i v e l y f o r H2, CH4 and C O atmos-

p he re s. T he re i s a s i g n i f i c a n t in c r e a s e i n t o t a l c o n v e r si o n i n h yd ro ge n

a nd m e th an e a t m os p he r e s o v e r o t h e r i n e r t g a se s . T ho ug h C O i s a r e a c t i v e

g as , no en han cem en t i n p y r o l y s i s y i e l d s we re n o t i c e d d nd er t h e c o n d i t i o n s

i n v e s t i g a t e d . The d e cr e as e i n t h e ga s f i l m h ea t t r a n s f e r c o e f f i c i e n t f o r

r e a c t i v e a nd n o n - r e a c t i v e g ases and t h e t o t a l c o n v e r s i o n b o th f o l l o w t h e

same t r e n d w i t h i n e ach c a t eg o r y. T hu s, t h e r e a p pe a rs t o be a r e l a t i o n s h i p

between t h e h e a t t r a n s f e r c o e f f i c i e n t ( o r t h e h e at - up r a t e o f t h e c oa l

p a r t i c l e s ) and t o t a l c arb on c o n v er s io n ( F i g u r e 4 ) .

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The e f f e c t o f gas p r e s s u r e on t o t a l c a r bo n c o n v e r s i o n was a l s o i n v e s -

t i g a t e d ( F i g u r e 5 ) . As e x p e c t e d , h yd ro ge n g av e t h e h i g h e s t c a r b o n c o n v e r -

s i o n. H ow ev er, i n c r e a s i n g t h e h y d ro g en p re s s u r e f ro m 1 00 p s i t o 5 00 p s i

had l i t t l e i n f l u e n c e on t h e t o t a l c o nv e rs io n . The e f f e c t o f p re s su re on

t o t a l c o n v e r s i o n was m ar ke d f o r a l l o t h e r ga se s. The maximum i n t h e t o t a lc a rb o n c o n v e r s i o n and t h e p r e s s u r e a t w h i c h i t o c c u rs c l e a r l y seem t o b e

d ep en de nt on t h e p y r o l y s i s te m p e ra t u re . These d i f f e r e n c e s i n d i c a t e t h a t a

s t ro n g r e l a t i o n s h i p e x i s t s b etw ee n c oa l d e v o l a t i l i z a t i o n and t h e t r a n s p o r t

p r o p e r t i e s o f t h e p y r o l y z i n g g as es . More e x pe r im e n ts a r e p la n ne d t o

u nd er st an d th e s e e f f e c t s o n c oa l p y r o l y s i s i n g r e a t e r d e t a i l .

The f l a s h p y r o l y s i s o f c o a l p ro d uc e s a w id e r an g e o f g as eo us a nd

l i q u i d p r o d u c t s . The ga s s t r e a m i s m o s t l y made up o f m et ha ne , e t ha n e ,

e t h y l e n e , C O and C O 2 b e s i d e s t h e e n t r a i n i n g g a s . A t y p i c a l p y r o l y s i sp ro d uc t d i s t r i b u t i o n i s shown i n F i g u r e 6. S i m i l a r p r od u ct d i s t r i b u t i o n s

w ere o b t a i n e d f o r o t h e r p y r o l y s i s a t mo sp he re s and o t h e r c o n d i to n s ( 8 ) .

Among t h e s e p y r o l y s i s p r o d u c ts , e t h y l e n e showed g r e a t e s t v a r i a t i o n i n i t s

y i e l d . T h i s i s shown i n F i g u r e 7. U nd er a l l c o n d i t i o n s , e t h y l e n e was

p ro du ce d i n c h a r a c t e r i s t i c a l l y h i g h e r q u a n t i t i e s i n methane a tm osp here

( w h i c h we t e r m " f l a s h m e t h a n o l y s i s " ) t h a n i n t h e p r e s e n c e o f any o t h e r g as

used. As h i g h as 1 0.5 % c a r bo n i n t h e f e e d c o a l was c o n v e r t e d t o e t h y l e n e

a t 8 25 % an d 50 p s i CH4 p r e s s u r e . T h i s i s a p p r o x i m a t e l y tw o t i m e s h i g h e r

t h a n t h a t w i t h t h e i n e r t g ases u n de r s i m i l a r c o n d i t i o n s (10.5% w i t h

m et ha ne a nd 4.9% w i t h h e l i u m ) . F ro m s e v e r a l b l a n k e x p e r i m e n t s , i n t h e

a b se n ce o f c o a l , i t was d e t e rmi ned t h a t homogeneous decom pos i t i on o f

m e th an e d oe s n o t o c c u r i n t h e r e a c t o r ( 8 ). A f r e e - r a d i c a l m echan ism f o r

t h e e nhanced y i e l d o f e t h y l e n e d u r i n g f l a s h m e th a n ol y si s o f D o ug la s F i r

wood, i n t h e same p y r o l y s i s r e a c t o r , was r e c e n t l y p ro p os e d ( 9 ) . F i g u r e 7

a l s o r e ve a ls t h a t i n a l l c as es , t h e e t h y l e n e y i e l d d ec re as ed with gas

p re s su re .

As e x p e c te d , h i g h y i e l d s o f g as eo us h y d r o ca r b on s w er e o b t a i n e d when

p y r o l y s i s t o o k p l a c e i n h y dr og e n a tm o sp h er e. The t o t a l g a se ou s h y d ro -

c a r bo n y i e l d r an g ed f r o m 8 .9% C a t 800oC and 50 p s i t o 28.0% C a t 9OOOC

and 500 p s i . The y i e l d s o f b o t h e t h a ne and e t h y l e n e d c ec re a se d w i t h

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i n c r e a s e i n t h e p r e s s u r e o f hy dr og e n. I n n o n - r e a c t i v e ga s m ed ia , no

e t h a n e was p r o d uc e d i n m e a s u ra b l e q u a n t i t i e s i n m o st i n s t a n c e s . Among

n o n - r e a c t i v e g as es , t h e y i e l d s t r u c t u r e w as c o m p a r ab l e b e tw e e n he1 u m and

n i t r o g e n a tm o sp h er es an d a r e p r e s e n t a t i v e c a se i s s hown i n Ta b l e 3 i n

w h i c h th e p r o d u c t y i e l d s f ro m t h e p y r o l y s i s o f New M e xi co c o a l i n v a r i o u sg a s i f y i n g m e di a, u n d e r i d e n t i c a l c o n d i t i o n s , a r e c om pa re d. F ro m t h e same

t a b l e , i t c o u l d be s ee n t h a t i n a rg o n at m os p he r e, t h e y i e l d o f g a s eo us

h y d ro c a rb o n s a nd o t h e r p r o d u c t s a r e c o n s i d e r a b l y l o w.

T h e y i e l d o f C 0 2 was about 1 - 2 % C u nd er a l l c o n d i t i o n s i n t he p r e -

se nce o f a l l g ases w i t h t h e e x c e p t i o n o f CO. H ig he r y i e l d s o f C O 2 were

o b t a i n e d ( 7 - 9 % C ) when t h e p y r o ly z i n g gas was CO. T h is i s b e l ie v e d t o b e

due t o d i s p r o p o r t i o n a t i o n o f CO u nd er t h e r e a c t i o n c o n d i t i o n s .

The l i q u i d p r o d u c t s ( e x c l u d i n g p r o ce s s w a t e r ) c o n s i s t o f t w o f r a c -

t i o n s : t h e " l i g h t o i l " f r a c t i o n , b o i l i n g be tween 600 and 15OoC, a n d t h e

"h eavy l i q u i d " f r a c t i o n , b o i l i n g a bo ve 1 5 0 o C . T hi s c l a s s i f i c a t i o n i s

a r b i t r a r y , and v a r i o u s d i s t i l l a t i o n ra ng es a r e u se d b y d i f f e r e n t wo rk er s.

I n t he BNL w o r k , u s u a l l y m o re t h a n 9 0 % b y w eig h t o f th e " l i g h t o i l " i s

made up o f b en ze ne , t o l u e n e , and xy l e n e , a nd t h e " h e av y l i q u i d s " o r " t a r s "

c o n t a i n c o n de n se d r i n g a r o m a t i c s t r u c t u r e s a nd h i g h m o l e c u l a r w e i g h t

compounds w i t h h i g h a r o m a t i c i t y (10 ) .

" L i g h t O i l f r o m c o a l i s a p o t e n t i a l s o u r c e o f some ke y c h e m i c a l s

such as bene zene - to luene -xy l ene (BTX). Even t hough t he exac t mechani sm o f

t h e i r p r o d u c t i o n i s n o t known, i t i s g e n e r a l ly t ho ug ht t o c o n s i s t l a r g e l y

o f se co nd ar y p y r o l y t i c r e a c t i o n s . P r ol o ng e d h e a t i n g o f t h e p r i m a r y

d e v o l a t i l i z a t i o n p r o du c ts i nd uc es c r a c k i n g and i f h yd ro ge n i s a v a i l a b l e ,

s t a b l e l i g h t e r p r o du c ts a r e fo rm ed . Thus, t h e y i e l d o f l i g h t o i l depends

on t h e r e s id e n ce t im e o f t h e t a r v a p or i n t h e p y r o l y s i s r e a c t o r and on t h e

t e mp e ra t ur e . W i t h l o n g e r r e si d e n c e t i m e s , m or e l i g h t o i l i s fo rm ed a t t h e

e xp en se o f t h e h e av y l i q u i d s ( t a r ) . Too h i g h a t e m p e r a t u r e (>9OOOC)r e s u l t s i n an i nc re a se d y i e l d o f g ases a t t he exp ense o f b o t h l i g h t o i l

a n d t a r .

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BTX y i e l d r a n ge d 1-3 C i n t h e c as e o f CO a n d n o n - r e a c t i v e g a se s; up

t o 7 c a rb o n i n t h e f e ed was c o n v e r te d t o BTX d u r i n g f l a s h h y d r o p y r o l y s i s

and f l a s h m e t h a n o l y s i s e x p e r i m e n t s . The I R s p e c t ra o f l i g h t o i l s , f r e e

f ro m p r o ce s s w a t er , o b t a i n e d fr om a s e r i e s o f f l a s h h y d r o p y r o l y s i s e x p e r i -

m en ts w i t h New M e xi co s u b - bi t um i n o u s c o a l show ( i ) s t r o n g a b s o r p t i o n i nt h e l o w f r e q u e n c y r a n g e b e t w e e n 900 and 675 cm-1, t y p i c a l o f a r o m a t i c r i n g

C - H o u t - o f - p l a n e b e n d i n g , ( i i ) t r o n g a b s o r p t i o n i n t h e medium f r e q u en c y

range be tween 1600 and 1580 c m - I d u e t o C=C s t r e t c h i n g , d n d ( i i i ) m od era t e

a b s o r p t i o n b e t s e m i 3100 and 3000 cm -1 c h a r a c t e r i s t i c o f th e a r o m a ti c C - H

s t r e t c h . Weak a b s o r p t i o n s a t 2926, and 2853 c m -l ( a ~ - ~ C H 3 , as CH2, and

us CH2, r e s p e c t i v e l y ) i n d i c a t e t h a t th e e x t e n t o f a l k y l s u b s t i t u t i o n i s

smal 1.

P h e n o l s , i f any, w ere p r e s e n t o n l y i n v e r y s m a ll a mounts i n t h e l i g h to i l s p ro du ce d fr om t h e f l a s h p y r o l y s i s o f New Mex ico sub -b i t uminous coa l .

The I R s p e c t r a o f l i g h t o i l s p r od uc ed a t 900C a t 2 0 , 6 0 , and 200 p s i

showed a b s o r p t i o n d u e t o -OH g r o u p s t o be p r e s e n t o n l y i n th e 20 p s i

s am ple , and t h i s sp ec t rum was s i m i l a r t o t h e one o b t a i n e d a t 8OO C and 200

p s i . An i n c r e a s e i n t h e h yd ro g en p r e s s u r e o r r e s i d e n c e t i m e o f t h e

v o l a t i l e s t e n d s t o d e c re a s e t h e a mou nt o f p h e no l s i n t h e p r o d u c t s tr ea m ,

and tem per a tur es above 9OOoC and hyd rogen pr es su re s above 50 p s i f a v o r t h e

d e h y d r o x y l a t i o n / d e c o m p o s t i o n r e a c t i o n s o f ph en ols . The l i g h t o i l f ro m t h e

i n e r t h e l i u m p y r o l y s i s a t 900C a nd 50 p s i had a c o m p o si ti o n q u a l i t a t i v e l y

s i m i l a r t o t h a t f ro m f l a s h h y d r o p y r o l y s i s un de r t h e same c o n d i ti o n s , b u t

f o r d i f f e r e n t r e a so n s : I n t h e p r e se n c e o f e x t e r n a l h yd ro ge n, t h e p h e no l s

i n i t i a l l y fo rm ed un de rg o d e co m po si ti on , b u t d u r i n g i n e r t gas p y r o l y s i s t h e

c o n d i t i o n s a r e n o t f a v or a b le f o r i n i t i a l p henol f or m at io n .

Heavy l i q u i d o r t a r i s an i n h e r e n t p ro d uc t o f c o a l d e v o l a t i l i z a t i o n .

I t s c o m p o si t i o n i s much m ore co mp le x t ha n t h a t o f l i g h t o i l s . T a r

a cc ou n ts f o r o n l y a s m a ll a mount o f t h e c ar b o n i n t h e f e e d c o a l t h a t i s

c o n v e r t e d (0-5% C ) . Ta rs fro m s e l e c t e d r u n s w ere s u b j e c t e d t o d e t a i l e d

i n v e s t i g a t i o n , b u t th e da ta a v a i l a b l e a t p r e s e n t a r e l i m i t e d .

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I A b a s ic pr ob le m i n i d e n t i f y i n g t h e i n d i v i d u a l com ponents i n a t a r i st h a t c ompounds o f w i d e ly v a r y i n g p o l a r i t i e s a r e p r es e n t , p r e c l u d i n g GC/MSa n a l y s i s o f t h e t a r as su ch . By f r a c t i o n a t i n g t h e t a r s on th e b a s i s ofs o l u b i l i t y i n s e l e c te d s o l v e n t s and a n a ly z in g t h e f r a c t i o n s f o r i n d i v i d u a lcom pounds, v a l u a b l e i n f o r m a t i o n c o u l d be o b t a in e d .I n one scheme o f s o l v e n t f r a c t i o n a t i o n , t h e t a r i s se pa ra te d i n t o o i l( he x an e s o l u b l e ) , a s p h a l e n e s ( he x an e i n s o l u b l e b u t b en ze ne s o l u b l e ) , a ndp r e- a sp h a lt e ne s (b en ze ne i n s o l u b l e ) . The y i e l d s o f t o t a l t a r and t a rf r a c t i o n s f ro m s e l e c t e d p y r o l y s i s r un s a r e shown i n Tab le 4 . The pre -

a s p h a lt e n e s , w h i c h i n c l u d e com pounds o f h i g h p o l a r i t y , c o m p r is e o n l y a

v e r y sm a ll p a r t o f t h e t a r . E x ce p t when t h e p y r o l y s i s gas i s m et ha ne , a n

i n c r e a s e i n t a r y i e l d i s accom panied by an in c r e as e i n o i l y i e l d . The t a r

y i e l d fro m f l a s h m e t h a n o ly i s i s b etw ee n t h os e f r om h e l i u m p y r o l y s i s and

from h y d r o p y r o l y s i s . I n t h e ca se o f h e l iu m p y r o l y s i s , t h e t a r y i e l d te nd s

t o i n c r e a s e w i t h i n c r e a s i n g p re ss ur e.

The i n d i v i d u a l c om po ne nts i n an o i l s am p le f ro m t h e f l a s h h y d r o p y r o -

l y s i s o f New M e x i c o s u b - b i t u m i n o u s c o a l a t 1000C a nd 25 p s i h y d r o ge n

p r e ss u r e were i d e n t i f i e d w i t h c a p i l l a r y GC/MS w h ic h i s shown i n F i g u r e 8.

The p eaks a r e i d e n t i f i e d i n Ta b le 5. N a p h t h a l e n e i s t h e m os t a bu n d a n t

p r o d u c t i n t h i s t a r ; h i g h e r - r i n g a r o m a t i c com pounds a nd h e t e r oa t o m co n-

t a i n i n g s p e c i e a cc ou nt f o r less t h a n 10% o f t h e t o t a l . No s u l f u r c o n t a i n -

i n g com pounds w e re d e t e c t e d . The r e a s o n f o r t h e p re s en c e o f r e l a t i v e l y

l a r g e amount o f a c e na p ht h yl en e i n t h i s t a r i s n o t k nown a t p r e s e n t .

CONCLUSIONS

The c o n c l u s i o n s w h i c h c a n be dr aw n f r o m t h i s w o rk t h u s f a r a r e as

f o l l o w s :

1. U n de r t h e same c o n d i t i o n s , t h e t o t a l c a rb o n c o n v e r s i o n was h i g h e r

i n t h e p re se nc e o f r e a c t i v e gas es t h a n i n t h e p re se nc e o f n o n - r e a c t i v e

g as es . Among t h e r e a c t i v e g as es , t h e t o t a l c a r b o n c o n v e r s i o n f o l l o w e d

t h e o r d e r : H2 > CH4 > CO. Among t h e n o n - r e a c t i v e g a se s, t h e t o t a lc a r bo n c o n v e r s i o n f o l l o w e d t h e o r d e r : H e> N2> A r .

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2. P y r o l y s i s i n m eth an e was c h a r a c t e r i z e d b y h i g h y i e l d s o f e t h y l e n e

and l i q u i d pr o du c ts . As h i g h a s 1 0.5% c a r bo n i n t h e f e e d c o a l w as c o n v e r-

t e d t o e t h y l e n e a t 8250C a n d 50 p s i . The e t h y l e ne y i e l d d u r i n g p y r o l y s i s

o f c o a l w i t h me th an e was a p p r o x i m a t e l y t wo t i m e s h i g h e r t h a n t h a t w i t h t h e

i n e r t g as es u n d er s i m i l a r c o n d i t i o n s (1 0.5 % CH4 v s 4.9% w i t h He a t 8250 t o

85OOC and 50 p s i ) .

3. Phenols, i f a ny, w e r e p r e s e n t o n l y j f i v e r y s m a l l a mo un ts i n t h e

l i g h t o i l f r a c t i o n o f t h e l i q u i d p ro du ct s. I n t h e p re se nc e o f e x t e r n a l

h yd ro ge n, t h e p h e n o l s f o rm e d u n de rgo d e c o m p o s i t io n , b u t d u r i n g t h e i n e r t

gas p y r o l y s i s t h e c o n d i t i o n s ar e n o t f a v o r a b l e f o r i n i t i a l ph eno l f or ma -

t i o n . An i n c r e a s e i n t h e h yd ro g en p r e s s u r e o r r e s i d e n c e t i m e o f t h e v o l a -

t i l e s t e n d s t o r ed uc e t h e a mount o f p h e n o l s i n t h e p r o d u c t s t re am , an d

tempera tures above 9OOoCa nd h y d r o g e n p r e s s u r e s a b o v e 50 p s i f a v o r t h e d e -

hydroxylat ion/decomposi t ion r e a c t i o n s o f p h e n o l s .

4. I n t h e c ase o f h e l iu m p y r o l y s i s , t h e t a r y i e l d t e nd s t o i n c re a s e

The t a r y i e l d f ro m m etha ne p y r o l y s i s i s betw eeni t h i n c r e a s i n g p r es s ur e .

t h o s e f ro m h e l i u m p y r o l y s i s a nd f ro m h y d r o p y r o l y s i s .

5. The p r e - a s p h a l t e n e s , w h i c h i n c l u d e com pounds o f h i g h p o l a r i t y ,

c o m p r i s e o n l y a v e r y s m a l l p a r t o f t h e t a r . E xc ep t when t h e p y r o l y s i s g as

i s methane, an i n c r e a s e i n t a r y i e l d i s a cc om pan ie d by an i n c re a s e i n o i l

y i e l d .

6. A c o r r e l a t i o n a pp ea rs t o e x i s t b etw ee n t h e t o t a l c a rb on c o n v e r s i o n

t o g aseous and l i q u i d p r o d u c t s and t h e h e at -u p r a t e o f c o a l p a r t i c l e s f o r

i n e r t gases i n t h e o r d e r o f He > N2 > A r. U nc ov er in g o t h e r e f f e c t s o fh e at -u p r a t e o f c o a l p a r t i c l e s on t h e p y r o l y t i c b e h a vi o r o f c o a l s r e q u i r e

f u r t h e r i n v e s t i g a t io n .

ACKNOWLEDGEMENT

T h i s r e s e a r c h was s u p p o r t e d by t h e U.S. D e p ar t m en t o f E n e rg y u n d e r

C o n t r a c t No. A C02 -76C H00 016. We w o u l d l i k e t o t h a n k Or. C l a r e n c e K a r r ,

Jr., of th e Morgantown Energy Technology Cent e r, Morgantown, West

V i r g i n i a , f or h i s c o n t i nu e d i n t e r e s t i n t h i s p r o j e c t .

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REFERENCES

1. J. 3. H ow ard , F u n da m e n ta l s o f Co al P y r o l y s i s an d H y d r o p y r o l y s i s ,

Chapter No. 1 2 i n C he mis tr y o f Coal U t i l i z a t i o n , Ed. E l l i o t , M.A.,

John Wiley and Sons, New York, NY, p. 665-784 (1981).

2. P. F a l l o n and M S t e i n b e r g , F l a s h H y d r o p y r o l y s i s o f C o a l , T he

D es ig n, C o n s t r u c t i o n , O p e r a t i o n a nd I n i t i a l R e s u l t s o f a F la s h

H y d r o p y r o l y s i s E x p e r i m e n t a l U n i t , BNL 50698, Jan. 1977.

3. R.B. B i r d , W.E. Steward , and E.N. L i g h t f o o t , Tra ns po r t Phenomena ,

W ile y, New Yor k, 1960.

4. W.W. Wamsley an d L.N. Joh ans on, Chem. Eng. Pro g. 50, 347 (1954) .

5. H.F. Joh nsto ne, R.L. P i g f o r d , and J.H. Ch api n, Tra ns. AIChE 37 9 5( 1941 ) .

6. A. Sen Gupta and G. Tho dos , AIChE J. 2, 7 5 1 ( 1 9 6 3 ) .

7. F. A. Zenz, and D. F. O th me r, " He at T r a n s f e r i n P a r t i c l e - F l u i d

S yste m", C h a pt er No. 1 3 i n F l u i d i z a t i o n a nd F l u i d - P a r t i c l e S ys te ms ,

R e in h o ld Pub. Co., New Yor k, NY, p. 4 2 1 (1 96 0) .

8. M. S t e i n b e r g , P. F a l l o n , a n d M. S. Sundaram , " F l a s h P y r o l y s i s o fC o al w i t h R e a c t i v e a n d N o n - r e a c t i v e Ga se s", P r o g r e s s R e p o r t f o r

Oc tobe r 1, 1981 -Sep temehr 30 , 1982 , To be p ub l i sh ed by Depa r t emn t o f

Energy, Morgantown Energy Technology Ce nter, Morgantown, W. Va.

9. M. S. Sundaram, S te inberg , M., a nd F a l l o n , P.T., " F l a s h P y r o l y s i s o f

Biomass w i t h R e a c t i v e a n d N o n -R e a ct iv e G a se s" , p r e s e n t e d a t

I n t e r n a t i o n a l C o n f e r e n c e o n F u nd a m e nt a ls o f T h e r m oc h e mi ca l B io m as s

Conve r s ion , Es t e s Pa rk , CO, BNL 32280 (October 1982).

10. M. S. Sundaram, M. S t e i n b e rg , a n d P. F a l l o n , " F l a s h H y d r o p y r o l y s i s

o f C o a l s f o r C o n v e r s i o n t o L i q u i d a nd Gaseous F u e l s " , BNL 51 53 7,

DOE/METC/82-48, (1982).

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Ta b l e 1

U l t i m a t e A n a l y s i s ( W t Dr y) o f New Mexico Sub- Bi tumin ous CoalU sed i n P y r o l y s i s E x p er im e n ts

Carbon 59.3Hydrogen 4.2Oxygena 16.8N i t r o g e n 1 . 2S u l f u r 0.8P.sh 17.7

a ) B y d i f f e r e n c e .

Ta b l e 2

C a l c u l a t i o n o f Gas F i l m H ea t T r a n s f e r C o e f f i c i e n t sf o r Va r i o u s P y r o l y z i n g G ases

Coal P a r t i c l e S i z e - 100 m i c r o m e t e r sC oal P a r t i c l e I n i t i a l Temp. - 2OOCG a s C o n d i t i o n s - 9OOoCand 1000 D s i

Gas hg (C al /cm2-KO-sec)

Hy d rogen 2 .21 x 10-1Methane 2.02 x 10-1

Carbon D io x i de 9 .9 x 10-2He1 ium 1.73 x 10-1

Carb on Mon oxid e 7.7 x 10-2N i t ro ge n 7.16 x 10-2Arg on 4.96 x 10-2

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Ta b l e 3

P r od u c t Yi e l d s f r om t h e F l a s h P y r o l y s i s ofNew Me xic o Sub -bi tum i nous Coal

a t 9OOOC and 200 p s iCoa l Re sid en ce Time: 2.4-4.6 sec.

-

I

E n tr a in in g Gas He N2 A r

Carbon Conv. t o P rod .CHA 8.1 10.2C ? k l 3.5 0C;Hg 0

Tota l Gaseous H.C. 116

BTX 1.81.2

To t a l L i q u i d H.C. 3.0LC9

coco2

To t a l COX

4.42.06.4

0.710.9

2.70.43.1

-

(4.4)1.76.1

2.63.305.9

2.00.82.8-

(4.4)1.45.8

- -To t a l C a r b o n C o n v e r t e d 213 20.1 14.5

( )CO co u ld no t be r e s o l ve d f rom N2 o r A r on t h e o n - l i n e GC.The va l u e s i n p a r a n t h e s i s a r e CO y i e l d s f r o m i n e r t he l iu mp y r o l y s i s r u n s u nd er i d e n t i c a l c o n d i t i o n s . T h is c o u ldi n t r o d u c e some e r r o r i n t h e d e t e r m i n a t i o n o f t h e t o t a lc a rbon conve r s ion .

119


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m

mc

U m m ho - r m m0 0 0 0

0 0 m w m u0 L O

0 0 0 0m u w

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0 0O L Om u m . . . .

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Ta b l e 5

--- -- _C o m p o s it i on o f H eavy L i q u i d s f r om t h e

F l a s h H y d r o p y r o l y s i s o f New Mexico Coal

Peak NO. Component Peak Are a

1 xy lene 0 .54

2 xylene 0 .27

3 phe nol 3.07

4 ind en e 6.45

5 nap hth ale ne 60.806 q u i n o l i n e 1 . 1 5

7 i s o q u i n o l n e 0.29

a C1-n aph tha1 ene 1.259 C1-na phtha lene 0.32

10 biphenyl 0 .03

11 acen aph thyl ene 14.98

12 acena phthe ne 1.66

13 C 1 - b i p h e n y l l a c e n a p h t h e n e 1.79

14 f l uo rene 2 .64

15 phe nan thran e /an thrac ene 3 .82

1 2 1


38/59

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40/59

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C O A L RESIDENCE TIME: 0.6- 1.7sec

f H e

I I I

100 200 300 400 500PRESSURE, p s i AT 9 0 0 C

F i g u r e 5 . To t a l C o n v e r s i o n v s P r e s s u r e , a t 900C

1 2 6


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46/59

C H A R A C T E R I Z AT I O N OF COAL CHARS FROM A FLASH PYROLYSIS PROCESS BYCROSS P O L A R I Z AT I O N M A G I C ANGLE SPINNING C NYR

Mei-In M. Chou and Donald R. D i c k e r s o nI l l i n o i s S t a t e G e ol o gi c al Su rv ey

615 E a s t Peabody Dr iveChampaign, I L 61820

Dale R. Mckay and James S . F r y eD e p a r t m e n t o f C h e m i s t r y

C ol or ad o S t a t e u n i v e r s i t yF o r t C o l l i n s , co 8 0 5 2 3

I N T R O D U C T I O N

I n t h e l a s t two de c ad e s, f l a s h p y r o l y s i s h a s b ee n used t o i n v e s t i g a t e t h es t r u c t u r e of c o a l and s h a l e ( 1 - 4 ) . S e v e r a l c o a l c o n v e r s i o n p r o c e s s e s b a se d o nf l a s h p y r o l y s i s a r e u n de r i n v e s t i g a t i o n i n t h e u n i t e d S t a t e s ( 5 - 8 ) , West Germany( 9 ) , and A u s t r a l i a ( 1 0 , 1 1 , 1 2 ) . S t u d i e s o f t h e m o l e c u la r p r o p e r t i e s o f t h e f l a s h

p y r o l y s i s p r o d u ct s h av e b ee n co n f in e d t o t h e l i b e r a t e d o r g a n ic m a t t er : v o l a t i l el i q u i d s and g a s e s . C ha ng es o c c u r r i n g i n t h e o r g a n i c s t r u c t u r e o f t h e c h a r s a r ep o o r l y u n d e r s t o o d .

The deve lopment o f "C c r o s s p o l a r i z a t i o n (CP) ( 1 3 ) a n d M a g i c P n g l e S p i n n i n g(MAS) ( 1 4 ) Nuclear Magne t ic Resonance (NMR) s p e c t r o s c o p y w i t h h i g h- p ow e r p r o t o nd e co u p li n g h a s al lo w ed i n v e s t i g a t o r s t o o b t a i n s p e c t r a o f t h e o r g a n i c m a t t er i ns o l i d c o a l (15-25) . S u l l i v a n a n d M a c i e l ( 2 6 ) an d D ud le y a nd F y f e ( 2 7 ) h a v ev e r i f i e d t h e q u a n t i t a t i v e r e l i a b i l i t y o f t h i s t ec hn iq u e as ap p l i ed t o co a l . I 3 CNMR s p e c t r a o f c o a l d em o ns tr at in g t h e u t i l i t y o f b o t h CP and MAS h a v e b e e n r e -p o r t e d p r e v i o u s l y ( 1 5 , 1 6 , 1 8 , 2 1 , 2 2 ) , h o w e ve r , t h e r e h a s b ee n no r e p o r t e d i n v e s t i -g a t i o n o f I3C CP/E/LAS NMR s p e c t r a o f t h e c h a r s pr o du c ed b y f l a s h p y r o l y s i s .

T his pa p er r e p o r t s t h e r e s u l t s o f t h i s t e c h n i q u e a p p l i e d to t h e s t u d y ofc h a r s p ro du ce d by t h e f l a s h p y r o l y s i s o f c o a l a t p r o g r e s s i v e l y h i g h e r t e m p e r a t u re s .The i n v e s t i g a t i o n h a s g i ve n v a l u a b l e i n s i g h t i n t o t h e c ha nq es of o rg a n i c c o m p o s i -t i o n o f c o a l du r i n g c a r b o n i z a t i o n a s w e l l a s t h e o ptimum t e m pe r at u re f o r e f f i c i e n tc o n v e r s i o n of c o a l i n t o l i q u i d s an d q as e s.

EXPERIMENTAL

A h i g h - v o l a t i l e C b i t u m i n o u s (HVCB) I l l i n o i s H a r r i s b u r g ( N o . 5 ) co a l was used .The a n a l y s e s o f t h e raw c o a l s a m p le a r e g i v en i n Ta b le 1. T he c o a l wa s f l a s hp y r o l y z e d i n a q u a r t z t u b e u nd e r a f l o w o f h e l iu m . The t u b e was h e a t e d a t a ramp-r a t e of 75C/msec t o t h e d e s i r e d f i n a l t e mp e ra t ur e w i t h a 20 s ec h ol d a t t he f i n a lt e m p e ra t u r e. S i n c e o n l y s m a l l q u a n t i t i e s o f c o a l w er e u s ed f o r e ac h r u n , as a m p l e o f s u f f i c i e n t S i ze f o r NMR a n a l y s i s a nd e l e m e n t a l a n a l y s i s a t e a ch t e mp er a-t u r e w as p r e pa r e d b y co m bi ni ng t h e p r o d u c t s o f r e p l i c a t e p r e p a r a t i o n s .

C h a r s p r o d u ce d a t 3 0 0 , 400, 5 0 0 , 6 0 0 7 0 0 , a n d 8 00 C w e r e s t u d i e d . Th e' 3C CP/MAS NMR m e a s u r e m e n t s o f t h e c h a r s w er e made on a JEOL FX6OQ NMR s p e c t r o -

m e t e r m o d i f i e d for CP and MAS. The s p e c t r a we r e r e c o r d e d u n d e r s t a n d a r d c o n d i-t i o n s t h a t ha ve b ee n d e s c ri b e d p r e v i o u s l y ( 2 6 ) .

For t h e v o l a t i l e a n a l y s i s , t h e same s am pl e o f c o a l was he a te d i n s t e p s ; f i r s tt o 3OO0C, then s u cc es s i v e l y t o 400C, 500C, 600 C, 700C, and t o ROO'C. Thev o l a t i l e m a t t e r was e n t r a i n e d i n a h e l i u m f l o w o f 3 5 mL/min a nd w a s a n a l y z e d b yg a s c h r o m a t o g r a p h y ( G C ) u s i n g a 2.5m x 3 mm s t a i n l e s s s t e e l c olumn p ac ke d w i th 3

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Ta b l e 1. P ro xi ma te and u l t i m a t e c o mp o si ti on o f t h e I l l i n o i s NO. 5 HVCB) c o a ls a mp le . ( m o i s t u r e - f r e e b a s i s ) .

P r o x i m a t e a n a l y s i s % u l t i m a te a n a l y s i s %

Vo l a t i l e m a tt e r

F i x e d c a r b o nAsh

43.3 Hydrogen 4.72

44.3 Carbon 65.451 2 .4 N i t r o q e n 1 . 1 3

O xy ge n ( b y d i f f . ) 11. 52S u l f u r 3 . 9 1L o w Temp. Ash 13 .2 7

Dexs i l 300 on 80/100 C hrom osorb WHP c o n ne c te d t o a f la m e i o n i z a t i o n d e t e c t o r ( F I D ) .T he co lu mn t e m p e r a t u r e w as p r o g r a m e d f r om 5O oC t o 2 50 C a t 8'C /m in a n d h e l d a tt h e f i n a l t e m p e r a t ur e f o r 1 5 m in.

RESULTS AND DISCUSSION

The GC t r a c e s o f v o l a t i l e p r od u c ts e v o lv ed a t e ac h c h a r r i n g t e m p er a tu r e a r es ho wn i n F i g u r e 1. The e v o l u t i o n o f d e c o m p o si t io n p r o d u c t s , g a s e s a nd l i q u i d s ,s t a r t s a t 5OO0C, m ax im ize s a t 6 O O 0 C , a nd c o m p l e t es a t 7 00 C . A t 800OC t h e mainv o l a t i l e s e v o l ve d a r e h y dr og e n an d l i g h t h y d ro c a rb o n g a s e s . The h y dr og e n t oc a r b o n a t o m r a t i o s (H/C) o f t h e c o a l a n 8 c h a r s a t e ac h t em p e ra t ur e a r e g i v e n i nTa b l e 2 . There i s l i t t l e c h an g e i n t h e H/C r a t i o s a t t e m p e r a t u r e s b elo w 500'C.Above 5OO0C, t h e H/C r a t i o s d e c r ea s e a s t h e t e m p e ra t ur e i s i n c r e a s e d . The d a t ashow a change i n H/C v a l u e f r o m O . R 2 ( h i g h l y be n z en o i d) a t 5 0OoC t o 0 . 3 6 ( h i g h l yg r a p h i t i c ) a t 800C. Based on s i m i l a r r e s u l t s , p o l y c o n d e ns a t io n o f t h e ar o m a t icr i n g s y s t em o c c u r i n g a t t h e s am e t im e a s d e h y dr o g en a ti o n o f t h e h y d r o a r o m a t i c an da l i c y c l i c s ys t em s h a s b ee n s u g g e s t e d a s a m od el f o r c a r b o n i z a t i o n b y e a r l y c o a lwor kers (2 8) . However, 1 3 C CP/MAS NMR r e s u l t s g i ve an i n s i q b t i n t o t h e c h an qe s

o f t h e o r g a n ic m a t t e r o f c h a r s .

Ta b l e 2 . The at o m ic r a t i o of h y d ro g e n t o c a r b o n (H/C) f o r c o a l a nd c h a r s a t ea c ht e m p e ra t u re s t e p .

Tem peratu re ( C) Raw c o a l 300 400 500 600 700 800

H/C 0.R7 0 . 8 7 0 . 8 5 0 . 8 2 0 . 5 7 0 .54 0 .36

I 3 C CP/MAS N M R s p e c t r a of t h e raw c o a l and t h e s i x c h a r s a r e i l l u s t r a t e d i nF i g u r e 2 . I n g e n e r a l , t h e s p e c t r a e x h i b i t two b ro ad c h a r a c t e r i s t i c p ea k s. Thec he mi ca l s h i f t s a r e r e f e re n c e d t o t e t r a m e t h y l s i l a n e (TMS) w i t h h e x a m e t h y l b e n z e n e

( H M B ) u s ed a s a se c o nd a r y e x t e r n a l s t a n d a r d . The c h e m ic a l s h i f t o f t h e a r o m a t i cpeak of HMB i s t a k e n t o b e 1 3 2 . 3 ppm r e l a t i v e t o TMS. T he p e ak a t 1 2 9 ppm i sa s si g ne d t o s p 2s p 3 ( s a t u r a t e d ) c ar bo n.

( m a i n l y a r o m a t i c ) c a r bo n an d t h e p ea k a t 3 0 ppm i s a s s i q n e d t o

The I 3 C CP/MAS NMR s p e c t r a show ( f i g . 2 t h a t t h e a l i p h a t i c c ar bo n peak i sp r o g r e s s i v e l y d e c r e a s i n g a s t h e t e m p e r a t ur e i s i n c r e a s e d ; w h i l e t h e a r o m a ti cc a rb o n p ea k r e t a i n s a p p r o x i m a t e l y t h e same h e i g h t an d s h a p e . The p e a k s a t 298ppm a nd -3 7 ppm a r e s p i n n i n g s i d e b a n d s ( S S B) . F o r a g i v e n t e m p e r a t u r e t h e NMRs p e c t r a p r o v id e a m eas ur e o f t h e r e l a t i v e c ar b on d i s t r i h u t i o n of t h e o r g a n i cm a t e r i a l r em a in in g i n t h e c h a r . The r e l a t i v e p e r c e n t a g e s o f a r o m a t i c ( f a r ) ando f a l i p h a t i c ( f a l l c ar b on s a r e c a l c u l a t e d by d i v i d i n g t h e i n t e g r a t e d a r e a o f ea c hi n d i v i d u a l c a r b o n pe ak b y t h e sum of t h e a r e a s of t h e p e a k s . The f a l v a l u es o f

c h a r s a r e s hown i n F i g u r e 2 . The f a r o f t h e r aw c o a l i s 6 7% . The i n i t i a l s t a g e

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o f h e a t i n g (30O oC) p r o d u c e s a c h a r w i t h 6 8 % o f f a r , and s u c c e s s i v e h e a t i n g s g i v ec h a r s w i t h fa r of 70% (4OO0C), 73%( 8 0 0 C ) . H ow ev er, t h e a c t u a l a mo un t of a r o m a t i c (war ) a n d a l i p h a t i c ( w a l ) c a r b o ni n c h a r can b e c a l c u l a t e d b y u s i n g t h e NMR m e as u re m en ts ( f a r ; f a l ) , t h e o r g a n i cc a rb o n c o n t e n t o f t h e c h a r ( % C o r g ) , a nd t h e w e i g h t o f t h e c h a r ( w c ha r ).

(5OO0C), 89% (6OO0C), 95% (7OO0C), and 96%

F i g u r e 3 sh ow s t h e c a l c u l a t e d v a l u e s an d t h e w e i q h t o f c h a r b a s e d on 1 00 go f r aw c o a l u se d i n r e l a t i o n t o t e m p e r a t u r e : t h e am ou nt o f a r o m a t i c c a r b o n i nc h a r (war) r em a in s r e l a t i v e l y c o n s t a n t a t e a ch t e m p e r a t u re , w h i le t h e amount o fa l i p h a t i c c ar bo n i n c h a r ( w a l l i s r e du c ed d u r i n g h i g h e r t e m p e r a t u r e c h a r r i n g . A t6 00 C , b o t h a l a r g e

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