XPS法研究煤表面碳官能团的变化及硫迁移行为.pdf

第 3 9卷 第 2期 2 0 1 1年 2月 燃料化学学报 J o u r na l of Fu e l Ch e mis t r y a n d Te ch no l og y Vo 1 3 9 NO 2 F e b 2 0 1 1 文章编号 0 2 5 3 2 4 0 9 2 0 1 1 0 2 0 0 8 1 0 4 XPS s t ud y o n t he ch a n g e o f ca r bo n co n t a ining g r o u ps a nd s ul f u r t r a n s f o r m a t io n o n co a l s u r f a ce LI U Fe n r o n g LI W e n GUO Hu i qi n g LI Ba o q i ng BM Zo n g q in g HU Ru i s h e n g 1 C o l l e g e o fC h e m i s t r y a n d C h e m i ca l E n g in e e r i n g I n n e r Mo n g o l i a U n i v e r s it y H o h h o t 0 1 0 0 2 1 C h in a 2 S t a t e K e y L a b o r a t o r y of C o a l C o n v e r s i o n I n s t i t u t e of C o a l C h e m is t r y C h i n e s e A ca d e m y of S ci e n ce s T a i y u a n 0 3 0 0 0 1 C h i n a 3 I n n e r Mo n g o l ia Me d i ca l C o l l e g e H o h h o t 0 1 0 0 5 9 C h i n a Ab s t r a ct T wo C h in e s e co a l s L i u z h i L z a n d Z u n y i Z Y w e r e p y r o l y z e d i n a fix e d b e d r e a ct o r u n d e r N 2 a n d H 2 a t mo s p h e r e s f r o m 4 0 0 o C t o 7 0 0 X r a y P h o t o e l e ct r o n S p e ct r o s co p y XP S wa s u s e d t o s t u d y t h e ch a n g e s o f ca r b o n co n t a in in g g r o u p s a n d s ul f ur t r a ns f o r ma t io n o n t he s ur f a ce of ccIa l s an d t he ir cha r s Un de r N a t mos ph e r e on t h e ZY chars s urfa ce t he co n t e n t s o f O C 一0 C H or C C g r o u ps h a v e a d e cr e a s ing t r e n d a n d t h e on e o f C O or O C一0 C O is in cr e a s ing comp a r e d wit h t h a t o f r a w co a l a t a l l t e mp e r a t u r e s F o r L Z co a 1 t h e ch a n g e s o f 0 C一 0 C 0 o r 0一 C一 0 C一 0 co n t e n t s are s imil ar t o ZY co a l h o we v e r t h e o n e of C H a n d C C co n t e n t is co nt r a r y t o tha t o f ZY coa 1 Un d e r H a t mos p he r e f o r ZY coa l no t o n l y O C O co nt e n t b ut a l s o C O a nd O C O C O con t e nt s ha v e a d e cr e a s ing t r e nd wh il e C H a nd C C co nt e n t s incr e as e comp a r e d wit h r a w coa l f o r LZ co a 1 e x ce p t f o r C O a n d O C O co n t e n t h a s a d e cr e a s in g t r e n d a n d o t h e r ca r b o n y l g r o u p s h a v e t h e s a me t r e n d a s t h a t u n d e r N a t mo s p h e r e An d for t h e s e coa l s wit h t h e t e mpe r a t u r e in cr e a s ing t h e S C r a t io on t he char s u rfa ce in cr e a s e s u n d e r N a t mo s p h e r e h o we v e r t h e o n e d e cr e a s e s a t t h e t e mp e r a t u r e s fro m 4 0 0 t o 6 0 0 a n d i n cr e a s e s mu ch a t 7 0 0 u n d e r H a t mos ph e r e This in dica t es t ha t u nd e r b oth a t mo s ph e r e s s ul f u r c a n t r a ns f e r from in ne r t o t he s u r f a ce d ur in g p y r ol ys is b ut hy d r og e n ca n r e a ct wit h s ul fur c o n t a in in g r a d ic a l s s o t he S C is 1 owe r t ha n t h a t un de r n it r og e n Ke y wo r d s ca r b o n y l g r o u p s u l fur t r a n s for ma t io n p y r o l y s is XP S CL C n umb e r TQ5 3 Do cu me n t co d e A Co a l is t he ma i n e n e r g y i n t he wh o l e wo r l d s o ma n y p h e n o me n a t h r e a t e n in g t he n a t u r a l e nv ir o n me n t s u ch a s t h e g r e e n ho u s e e f f e ct o r a ci d r a in s a r e t o a s u bs t a n t ia l d e gr e e ca us e d b y co a l co mb u s t io n a n d pr o ce s s in g d u e t o t he r e l e a s e CO a n d S O Py r o l y s is a s in t e r me d ia t e s t a g e in co a l co nv e r s i on s u ch a s g a s ifi ca t i on co mb u s t io n l iq u e f a ct io n a n d a pa r t ia l de s u l f u r iz a t io n pr o ce s s h a s s t il l r e ce iv e d ma n y r e s e a r che r s co n s id e r a bl e a t t e n t io n 4 j Th r o ug h py r o l ys is t h e f u n ct io na l g r o u ps in t he co a l s u ch a s ca r b o n co n t a i nin g g r o u ps a n d s u l f u r co n t a in in g g r o u ps ma y ch a n g e wit h t h e t e mpe r a t u r e o r o t h e r f a c t o r s Re ce n t l y X r a y Ph o t o e l e ct r o n S p e ct r o s cop y XP S a s n o n s t r u ct u r a l me t h o d is a v e r y p o p u l a r s u r f a ce a n a l y t ica l t e ch n iq u e ca p a b l e o f ch a r a ct e ri z in g o r g a nic f u n ct io n a l g r o u ps in v e r y t h i n o u t e r l a y e r s 2 n m 5 n m o f s o l i d s a mp l e s j An d t h e o r g a n ic ma t t e r in co a l s con t a in s s ig n ifi ca n t a mo u n t s o f ox y g e n s u l f u r n it r o g e n h e t e r o a t o m s in co r p o r a t e d in va r io us ca r b o n co n t a in in g f u n ct io na l it ie s wh ich v a r y in a bu n d a n ce d e p e n d in g o n t he d iffe r e n t co a l r a n k a n d min e r a l l a y e r l o J W h il e XPS i s a s u r f a ce r e s t r ict e d t e ch ni q ue it ca n o f f e r co mp l e me n t a r y in f o r ma t io n a b o u t t h e s e e l e me n t s s p e cia t io n o n t h e co a l s u r f a ce a t t h e s a me t ime Acco r d in g t o l it e r a t ur e s g J t h e p e a k s a t 28 4 8 e V 2 8 6 3 e V 2 8 7 5 e V 2 8 9 0 e V s h o u l d b e a t t r i b ut e d t o C H o r C C C O C O o r O C O a n d O C O r e s p e ct iv e l y Ko z l ows k i lo j u s e d XPS a n d ch e mica l me t ho d t o co mp a r e t h e co mp o s it ion s o f t h e s u r f a ce 1 a y e r s wi t h t h e b u l k o f t he s a mp l e s a n d f o u n d t he r e wa s a l it t l e d if f e r e n ce be t we e n in di vi d ua l e l e me n t o n t h e s u r f a ce a n d in t h e bu l k I n t h is s t u d y XPS wa s u s e d t o in v e s t i ga t e t he ch a n g e s o f ca r b on co n t a in in g g r o u ps a nd s u l f u r t r a ns f o r ma t io n o n t h e co a l s u r f a ce du ri n g p y r o l y s is 1 Expe r im e nt al 1 1 Co al s am pl e s I n t h is s t ud y t wo Ch in e s e co a l s L iu z i L Z h ig h a s h co n t e n t wi t h h ig h p y r it e a n d Z u n y i Z Y h ig h o r g a n i c s u l f u r co n t e n t we r e us e d Th e i r pa r t icl e s s iz e is 6 0 1 0 0 me s h The p r o x ima t e a nd e l e me n t a n a l y s e s o f s a mp l e s a r e s h o wn in Ta b l e 1 a n d t h e s u l f ur f o r ms o f s a mpl e s a r e s ho wn in Ta b l e 2 1 2 Pyr o l ys is ex pe r im ent P yr o l ys is e x p e ri me n t wa s ca ie d o u t in a q u a r t z t u b e fi x e d b e d r e a ct o r i d 2 5 mm l e n g t h 6 0 cm A b o u t 5 g co a l wa s p l a ce d u nd e r N2 a nd H2 a t mo s p h e r e s a t t h e t e mp e r a t u r e r a n ge Re ce iv e d da t e 2 01 04 3 4 2 7 Re ce iv e d in r e v is e d f o r m 2 01 0 0 7 2 0 F o u n d a t i o n it e m T h e P Hi D P r o j e ct o f Na t u r a l S ci e n ce F o u n d a t i o n o f I n n e r Mo n g o l i a 2 0 0 9 B S 0 6 0 6 a n d t h e K e y P r o j e ct o f Na t u r a l S ci e n ce F o u n d a t i o n o f C h i n a 2 1 0 0 6 0 4 2 Aut hor int r o du ct io n LI U Fe n r o n g E ma il f e n r o n g l ya h o o co rn cn 本文的英文电子版 由 E l s e v i e r出版社在 S ci e n ce Di r e ct 上出版 h t t p w ww s ci e n ce d i r e ct co rn s ci e n ce j o u ma l I 8 7 2 5 8 1 3 8 2 燃料化学学报 第3 9卷 f r o m 4 0 0 t o 7 0 0 wit h r e s i d e n ce t ime 2 0 rain a n d fl o w r a t e 2 1 5 mL min a t a h e a t in g r a t e o f 5 C min Ta b l e 1 Pr o x ima t e a nd e l e me n t a na l y s e s o f s a mp l e s b y d if f e r e n ce Ta b l e 2 S u l f u r f o r m s o f s a m p l e s 1 3 XPS The XPS me a s u r e me n t s we r e ca r r ie d o u t us in g VG ESCALAB2 5 0 wi t h Al Ko L s o u r ce a t a b a s e p r e s s u r e o f l 1 0 Pa Th e s p e ct r o me t e r wa s r un a t a n a na l y z e r p a s s e n e r gy o f 3 0 e V a n d 5 0 e V wh e n n a r r o w s c a n n i ng a n d wid e s c a nn i ng r e s p e ct iv e l y A co rre ct i o n f o r b in d in g e n e r g y wa s ma d e t o a cco u n t f o r s a mp l e cha r g in g ba s e d o n t he C 1 s D e a k a t 28 5 0 e V Th e C 1 s a n d S 2 p p e a k cu r v e s we r e r e s o l v e d us in g mix e d Lo r e n t z io n Ga us s io n l in e s h a p e 2 Re s ul t s a nd dis cus s io ns 2 1 Changes e f c a r bo ny l gr oups Th e co n t e nt s o f C H o r C C C O C O o r O C O a n d O C O ca r bo n co nt a in in g g r ou ps wh ich a r e a t t a in e d by t o t a l ca r b o n co n t e n t mu l t i p l y ing e a ch co n t e n t o f ca r b on co n t a in in g g r o u p ca n b e d e t e r min e d s i m u l t a n e o u s l y by XPS Ta b l e 3 s h o ws t h e ch a n g e o f t h e s e carb o n co n t a in i ng g r o u ps o f ZY co a l a nd ch a r s Ta b l e 3 Ca r b o n c o nt a in ing g r o up s o f Z Y c o a l a nd ch a r de t e r mine d b y XPS Ati e r p y r o l y s is t h e t o t a l ca r b o n co n t e n t b y XP S 1 o n t h e ch a r s u r f a ce is h ig h e r t h a n t ha t o f r a w co a 1 Th e r e a s o n is t h a t t h e v o l a t il e o f H O CO CH H a n d CO is e v o l v e d from co a l d u r in g py r o l ys is Th e e f lf e ct o f t e mp e r a t u r e o n t he ch a n g e s o f carb o ny l g r o u ps i s n o t v e r y cl e a r l y i n Ta bl e 3 Bu t u n d e r n it r o g e n a t a l 1 t e mp e r a t u r e s t he co n t e nt s o f C C C H e x ce p t f o r 6 0 0 a n d O C O 5 0 0 g r o u ps h a v e a d e cr e a s in g t r e n d co mp a ri s o n wit h t h o s e o f r a w co a l a t t h e h e a t in g r a r e o f 5 min a t a l l t e mp e r a t u r e s wh il e t h e co n t e n t s o f C O a n d O C O o r C O ha v e a n in cr e a s in g t r e n d Th is i nd ica t e s t h a t t h e v o l a t il e o f H O C0 CU4 H a nd CO co me s f r o m O C O C H g r o u ps s o t h e y d e cr e a s e a fte r p y r ol ys is Und e r h yd r o g e n a t mo s ph e r e t h e co n t e n t of O C O a l s o ha s a n e v id e n t d e cr e a s in g t r e n d u n l ik e n it r o ge n a t m o s p he r e t he co n t e nt o f O C O o r C O d e cr e a s e s a n d t h e co n t e n t o f C C o r C H in cr e a s e s a t a l l t e mp e r a t u r e s co mpa r e d wi t h t ha t o f r a w coa 1 wh il e t h e C O co n t e n t o f ch a r is mu ch l owe r a t 5 0 0 a n d 7 0 0 a n d h ig h e r a t 4 0 0 a n d 6 0 0 t ha n t h a t o f r a w coa 1 As a b ov e a n a l ys is t h e d e cr e a s in g o f O C O is a l s o ca u s e d b y e v o l u t i o n o f CO2 a n d CO d u ri n g p y r o l y s is a n d t h e d e cr e a s in g o f O C O o r C O ma y b e ca us e d b y h y d r o g e n r e a ct i ng wit h C O Th e ch a ng e s of t h e s e ca r b o n con t a in in g g r o u p s o f LZ co a 1 a n d chars are s h o wn in Ta b l e 4 Ta b l e 4 Ca r bo n co n t a in in g g r o u p s o f LZ co a l a nd cha r de t e r mine d b y XPS Ati e r p y r o l ys is t h e who l e ca r bo n co nt e n t on t he LZ ch a r s u r f a ce is a l s o h ig h e r t h a n t ha t o f LZ r a w co a 1 Fo r LZ co a 1 t h e ch a ng e o f O C O g r ou p is t he s a me a s t ha t o f ZY co a l bo t h u nd e r n it r o g e n a n d u n d e r h y d r o g e n a t mo s p h e r e Th e co n t e n t o f O C O is l o we r t h a n t h a t o f r a w co a l a t a l 1 t e mp e r a t u r e s Th e cha n g e o f C O is t h e s a me a s t h a t o f LZ co a l u n d e r n it r o ge n Th e co n t e n t o f C O i s mu ch h ig h e r t h a n 第 2期 L I U F e n r o n g e t a l X P S s t u d y o n t h e ch a n g e o f ca r b o n co n t a i n in g g r o u p s a n d 8 3 ch a t of r a w co a l wh e t h e r u n d e r n it r o g e n o r h y d r og e n a t mos ph e r e Th e ch a ng e s o f C C a n d C H a r e s imil a r t o t h os e o f LZ coa l un d e r hy d r og e n Th e co n t e n t e x ce p t f o r a t 7 0 0 u n d e r n it r o g e n is h ig h e r t ha n t h a t o f r a w coa l a t a l l t e mp e r a t u r e s a n d u n de r bo t h a t mo s p he r e s Th e cha n ge s 0 f 0一C一0 C 0 a re u nl ik e t h os e o f ZY co a 1 Th e co n t e n t is h ig h e r a t 5 0 0 o C a n d 6 0 0 a n d l o we r a t 4 0 0 a n d 7 0 0 t h a n t h a t o f r a w co a l u n d e r n it r o g e n a t mos ph e r e wh il e u nd e r hy d r o ge n a t mos p h e r e it is co n t r a r y t o t h a t u n de r n i t r o g e n 2 2 S ul f ur t r a n s f o r ma t io n I n t h is s t u d y t h e r a t i o o f S C o n t he s u rfa ce wa s u s e d t o in d i ca t e s u l f u r t r a n s for ma t io n 2 2 1 Ef f e ct o f t e mp e r a t u r e o n t h e s ul fu r t r a n s for ma t io n F ig ur e l s h ows s u l f u r t r a n s fom t a t io n o f t h e s e co a l s u n de r n it r og e n a t t h e h e a t in g r a t e o f 5 min Th e r a t io o f S C o n t h e L Z ch a r s u r f a ce i n cr e a s e s wi t h t h e t e mp e r a t u r e i n cr e a s i n g f r o m 4 0 0 t o 7 0 0 a n d t h e S C o n t h e ZY ch a r s u r f a ce a l s o i n cr e a s e s wit h t h e t e mp e r a t u r e in cr e a s i n g f r o m 4 0 0 t o 6 0 0 b u t i t d e cr e a s e s l it t l e a t 7 0 0 T h is i n dica t e s t h a t s u l f u r co n t a in in g co mpo u n d s d e co mp os e t o fo r m mo r e a n d mo r e s u l f u r co n t a in in g r a d ic a l s wit h t h e t e m p e r a t u r e in cr e a s ing a nd t h e r e j s no t e no u g h h y d r o g e n t o r e a ct wi t h t he m du ri n g t he ir tra n s for ma t io n from in ne r t o t h e bu l k u n d e r n it r og e n a t mo s p he r e s o t h e y ca n co mb in e wit h e a ch o t h e r t hu s mo r e o f t he m s t il l r e t a in i n t h e cha r a n d a pa r t o f t h e m con g l o me r a t e o n t h e ch a r s ur f a ce Ho we v e r t h e S C r a t io i n cr e a s e s t h e mo s t a t 5 0 0 for t h e t wo coa l s i t in cr e a s e s a bo ut 5 4 5 t i me s a n d 1 7 4 t ime s o f t h a t a t 4 0 0 for L Z ch a r a n d Z Y ch a r r e s p e ct iv e l y Th is is ca us e d b y t he d e co mp os i t io n o f p l e n t y o f py ri t e o n l y r e l a t e d t o t h e t e mp e r a t u r e L As t he co n t e n t o f p y ri t e in LZ co a l is h ig h e r t h a n t h a t 0 f ZY co a 1 S C 0 f LZ co a l in cr e a s e s mo r e t h a n t h a t o f ZY c o a 1 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 6 5 0 7 0 0 T e mp e r a t u r e C Fig u r e 1 Ef f e ct o f t e mpe r a t u r e on t h e s u l f u r t r a ns f on na t ion LZ N2 ZY N2 2 2 2 Ef f e ct o f a t mos ph e r e F r o m a b o ve a n a l y s is it is o n s u l fur t r a ns f o r ma t io n we l l k no wn t h a t u n d e r n it r o g e n a t mos p he r e S C on t h e ch ar s u rfa ce in cr e a s e s wi t h t he t e mp e r a t ur e in cr e a s in g W h il e u n d e r h y d r o g e n a t mo s p h e r e t h e r a t io o f S C s h o w n in F ig u r e s 2 a n d 3 wh ich is l o we r t h a n t h a t u n d e r n it r o g e n a fte r 5 00 o C d e cr e a s e s wit h t h e t e mp e r a t u r e in cr e a s in g fro m 4 0 0 t o 6 0 0 a n d in cr e a s e s s h a r p l y a t 7 0 0 3 5 3 0 2 5 2 0 1 5 l 0 0 5 0 0 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 6 5 0 7 0 0 T e mp e r a t u r e r C Fig u r e 2 Ef f e ct o f a t mo s p he r e o n t he s u l f u r t r a n s f or ma t ion o fLZ coa l 一 LZ N2 LZ H2 Th is s u g ge s t s t ha t t h e h y d r o g e n ca n r e a ct wit h t he s ul fur co n t a in ing r a d ica l s d u ri n g t h e ir t r a n s f o rm a t io n fro m in n e r t o t h e b u l k a n d mo r e o f t h e m e v o l v e f r o m ch a r i n t h e form o f t h is At 7 0 0 S C in cr e a s in g ma y b e ca us e d b y t h e r e a ct io n t ime d e cr e a s ing W it h t he t e mp e r a t u r e h ig he r t h e flo w r a t e o f ga s a l s o in cr e a s e s t he r e a ct io n t ime o f h y d r o g e n wit h s u l f u r con t a in in g r a d ica l s d e cr e a s e s a n d mo r e o f t h e m s t il l r e t a in in t he ch a r a n d co n gl o me r a t e o n t he s u r f a ce L J 2 J 4 5 4 0 3 5 3 0 2 5 2 O 4 0 0 4 5 0 5 0 0 5 5 0 6 0 0 6 5 0 7 0 0 T e mp e r a t u r e r C Figu r e 3 Ef f e ct of a t mos p he r e o n t h e s u l f u r t r a ns f o r ma t io n o fZY coa l ZY N2 ZY H2 0 B J n 专 I j 0 0 u B J 宝 专 L 1 0u u tj 0 u c 0U 燃料化学学报 第 3 9卷 3 Concl us io ns Th e co n t e n t o f O C O o n t h e cha r s u r f a ce d e cr e a s e s co mp a r is o n t o t h a t o f r a w co a l s a f t e r p y r o l ys is a n d t he con t e n t s o f C H C C d e cr e a s e u n d e r n i t r o g e n a t mo s p h e r e whil e in cr e a s e u n d e r h y d r o g e n a t mo s ph e r e f o r ZY co a 1 a n d i n cr e a s e wh e t h e r un d e r h y d r o g e n o r n it r o g e n a t mo s p h e r e fo r LZ co a l t h e co nt e n t o f C O ha s a n in cr e a s i ng t r e n d f 0 r ZY co a l u n d e r n it r o g e n a n d fo r LZ coa l u n d e r b o t h a t mos p h e r e s t h e ch a ng e s o f C O O C O a r e v e r y d if f e r e n t f r o m e a ch o t he r f o r t h e s e co a l s Un d e r N a t mo s p h e r e t h e r a t io S C o n t h e t wo co a l ch a r s u r f a ce i n cr e a s e s wit h t h e t e mp e r a t u r e in cr e a s in g T h e r a t io S C d e cr e a s e s f r o m 4 0 0 t o 6 0 0 a n d i n cr e a s e s s h a r p l y a t 7 0 0 u n d e r H a t mos p he r e Th is in d ica t e s t ha t u n d e r b o t h a t mos ph e r e s s u l f u r ca n t r a ns f e r f r o m in n e r t o t h e s u r f a ce du r in g p y r o l y s is b u t u n d e r h yd r o g e n a t mos ph e r e wh e n s u l f u r con t a in in g r a d i ca l s t r a n s f e r f r o m in n e r t o t he s u r f a ce h y d r og e n ca n r e a ct wit h t h e m s o t he S C is l owe r t h a n t h a t u n d e r n it r o g e n a t mo s p h e r e Ref e r e nces E 1 C H A D WI C K M J H 1 G H T O N N H L I N D MA N N e d i t o r s E n v i r o n m e n t a l i m p a ct s o f co a l m i n i n g a n d u t i l i z a t io n M O x r d P e r g a m o n P r e s s 1 9 8 7 2 V a n H E E K K H H OD E K W S t r u ct u r e a n d p y r o l y s i s b e h a v i o u r o f d i f f e r e n t co a l s a n d r e l e v a n t m o d e l s u b s t a n ce s J F u e l 1 9 9 4 7 3 6 8 8 6 8 9 6 3 J C Y P R E S R F U RF AR I S F i x e d b e d p y r o l y s i s o f co a l u n d e r h y d r o g e n p r e s s u r e a t l o w h e a t i n g r a t e s f J F u e l l 9 8 1 6 0 9 7 6 8 7 7 8 4 A R E ND T P v a n H E E K K H C o mp a r a t i v e i n v e s t i g a t i o n s o f co a l p y r o l y s i s u n d e r i n e r t g a s a n d H 2 a t l o w a n d h i g h h e a t i n g r a t e s a n d p r e s s u r e s u p t o 1 0 MP a J J F u e l 1 9 8 1 6 0 9