1.
 Thermal Analysis Study on Kinetics and Heats of Carbonization Reaction for the Imported Coking Coals
  

      
   

^†*

 / 

660-701
   900

*(

545-090   ! 699 (2002" 8# 16$ %&, 2003" 4# 14$ '()

Thermal Analysis Study on Kinetics and Heats of Carbonization Reaction for the Imported Coking Coals

Young-Cheol Bak^† and Sung-Su Lee*

Department of Chemical Engineering/Engineering Research Institute, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701, Korea

*Iron & Steel making Process team, RIST at Kwangyang, 699 Kumho-dong, Kwangyang 545-090, Korea (Received 16 August 2002; accepted 14 April 2003)



(TGA) 
(DSC)      ,   kinetics 


.    !"# $% Clintwood(CW), & Goonyella(GY) % Tianchen(TH)'.

() *+ 100 mL/min ,-./ *
01 1-10^oC/min 2, 3./ 45./ 950^oC67 895  . 

 TGA : ;.< $=> Kissinger, Freeman-Carroll, Chatterjee-Conrad= ?= ? , DSC : ;

.< Borchardt-Daniel= ? . TGA : ;="#< Chatterjee-Conrad= *@ AB,  CD E.F7< 61.2-65.9 kJ/g-mol, . G < 0.92-1.29'. DSC 
   Borchardt-Daniel= H I  CDE.F7* 39.5-56.0 kJ/g-mol, < 0.98-1.05# JKL. 45./ 1,000^oC67 . MN

 CW 828 J/g, GY 823 J/g, TH 1,077 J/g"# JKL.

Abstract−Carbonization reactions were studied experimentally in thermogravimetric analyzer (TGA) and differential scan- ning calorimeter (DSC), and the reaction kinetics obtained by serveral analysis methods were compared. The sample coals were U.S.A. Clintwood (CW), Australia Goonyella (GY), and China Tianchen (TH) bituminous coal. About 10-15 mg sam- ples were nonisothermally heated from 30^oC to 950^oC in the flow of 100 mL/min He gas with various heating rates such as 1^oC/min, 3^oC/min, 5^oC/min, and 10^oC/min. TGA data were analyzed by using the differential methods of Kissinger, Free- man-Carroll, and Chatterjee-Conrad method, and integral method. DSC data were also analyzed by using the Borchardt-Daniel method. The Chatterjee-Conrad method was the most effective method for the analysis of TGA carbonization data in these experimental conditions. Activation energies of carbonization reaction were calculated as 61.2-65.9 kJ/g-mol, and the reaction orders were 0.92-1.29. For the DSC data, the activation energies of carbonization reaction by using the Borchardt-Daniel method were 39.5-56.0 kJ/g-mol, and the reaction orders were 0.98-1.05. The carbonization heat requirement from a room tem- perature to 1,000^oC were 828 J/g(CW coal), 823 J/g(GY coal), and 1,077 J/g(TH coal).

Key words: Bituminous Coal, Carbonization, TGA, DSC, Carbonization Heat, Kinetics

1.  

       ,  


   ! !" #$ % &

'( )*+,-. . /0! 1234 /' 5 6  

7  89 1-3^oC/min 8" : ;<="> ?&@

(A(carbonization reaction)) )*+&, 6 BC ) DE

6 oC/s )H flash heating 

 (devolatilization reaction)) )*+,-. IF JK 

 #$ LM  <"" N$,-. #$  O8 P QR O8S K8F  ="R LM <"> ?& T

†To whom correspondence should be addressed.

E-mail: ycbak@nongae.gsnu.ac.kr

 U2 VE-. W )T
 , XYK Z U2 [ \] ^_`-.

  6 Va Xb) c dbKe )

f  g&$"  G #$ % &  h  iH`-. #$ ) 
  % &  jk) /l cm-.
  kinetics> no  Vp

(Thermogravimetric Analyzer: TGA)> )!F % qh r[1,2] s

, )t 
uv 
w #$"  kinetics N$&_ ` -[3,4].

 zF 
   5{| pQ(Differential Scanning Calorimeter: DSC)> )!} F-[5]. DSC u  8

K no  6) !c s-. DSC> )!F
 

 G2  V 5v ~_ X g+x )T  X>

} , IF € ‚ ƒ  8pKe 
) „-…-. #

$ Mahajan ƒ[6] 5.6 MPa, JanikowskiR Stenberg[7] 2.07 MPa

 †DSC> )! ‡ˆ ‰-.
 5v> !F DSC ‡ˆ

 ‡ˆ Š ‹ 1234> !F DSC‡ˆ  Œ8 w"

K!cm-[8-11]. ŽZK" M DSC 
 600^oC )„

& 
) F G2 6‘x, L’ 1,200^oC„& 
) 

"“ ”•c–— DSC> )!F (A LM<" ˜> ™z š

› s-.

œ qh ž /0! 1234 /'! ›Ÿ  ¡ ! DSC R TGA> )!F (A kineticsR (A  ‡ˆK h

 
u F-.

2.  

2-1. TGA


 (A % & w 
) &¢ œ ‡ˆ

 Wen ƒ[12]) £¤ž
  
 

/lF ¥g¦ (1) ’§ , ‡ˆ r>   PQ ƒ a¥¨ K!š › s"“ ‰-.

(1)

="H› <" © ¦ (2)R f Arrhenius¦ ª«`-.

(2)

#$ ¦ (1) (2) ¦ (3)) 7+&@, ¦ (3) Vp ¬•

­® hF (A ="Z­® ¯w Kw ƒ -°F 

w[3, 4] K!  ±Z> hš › s-.

(3)


 7 ‡ˆZ (A BC ¢ ² F r

³´$ 1234R q
µ> ¶·F ¸ ² ="

Q¹` T)– º›F BC ² F ¸ »¹} F -. . ¼»½ X -¾ f) ›8 Q¹`-.

(4)

  Wo:  ¿  5vp, W_H

2O:
 ž ›p,

  W_c:
 ž 1234 °, W_a :
 ž À °,

  W : +Á g8 ºa 5v ~_

  (A LŠ Âp) WaR Wc> bF °) `-.

2-2. DSC


DSC ‡ˆZ> !  kinetics> h w Borchardt- Danielsw, ASTM E-698w, ƒ<w ƒ) s-[13]. ASTMw G2  hF-. )T DSC ¬•  =" Å›“ DSC Lz Æ3 ¸ ) Å& Æ3 ¸ x€ž <"" Å&– )> )! kinetics

> h w)-.

Borchardt-Danielsw ¥g  =" Ç ‡ˆZ> ! kinetics

> h w)-. )T DSC ÃÄ  p ÈÉ F-

8 ="¦ (3)   ² F ¦ (5) ª5F T) -.

(5)

(6)

  : ÃÄ(W/g)

  H_T: ÊC p(J/g)

  H: 5a t ËK  (J/g)

¦ (6) 2” ÌÍ›> Î ·› z=a+bx+cy ¦ ª5 Ï

<"  ›R )Ç ËK  ÃÄ ¸ K! H› ¸

hš › s-.

3.  

3-1. 

 ›ŸÐv & K ± Ñ ¯ Clintwood, Ò| Goonyella, V Tianchen) ÏÏ •8cm-. W OÓ
ZR ÐÔ
Z Table 1 f-.   ASTM A Õ Goonyella

 8Ô(dmmf basis) 73.5%, BC(dmmf basis) 26.5% Va BC ¡(medium volatile bituminous) A`-. Tianchen

8Ô(dmmf basis) 61.3%, BC(dmmf basis) 38.7%, C p(mmf basis) 8,259 kcal/kg BC ¡ A(high volatile A bituminous)

Ac Clintwood 8Ô(dmmf basis) 65%, BC(dmmf basis) 35%, C p(mmf basis) 8,540 kcal/kg  5 BC ¡

dX

---dt =k 1 X( – )ⁿ

k A –E

RT---

 

  exp

=

dX

---dt A 1 X( – )ⁿ –E RT---

 

 

= exp

X W_o–W_H2O–W W_o W_H

2O

– –W_c–W_a ---

=

1 H_T ---dH

---dt k H_T–H H_T

--- ⁿ A (–E RT⁄ ) H_T–H H_T ---ⁿ

= = exp

dH ---dt

 

 

ln AH_T

H_Tⁿ ---

ln E

R----1

T--- n+ ln(H_T–H) –

=

dH ---dt

Table 1. Chemical analysis of sample coals Coal name Abbrev. Calorific value

(kcal/kg)

Proximate analysis (%) Ultimate analysis (dmmf basis, %)

H₂O ash V.M. F.C. V.M.dmmf C H O N S

Tianchen TH 7,567 2.03 8.38 34.64 54.95 38.67 85.13 5.13 7.56 1.51 0.67

Clintwood CW 7,904 1.32 7.44 31.93 59.31 35.0 86.64 5.07 5.90 1.56 0.84

Goonyella GY 7,852 1.31 8.70 23.84 66.15 26.49 89.14 4.80 3.62 1.92 0.52

A(high volatile A bituminous) Acm-.

3-2.
 


‡ˆ !` Vp£¤ TA  TGA-2050)@ 5{| pQ

 TA  SDT 2960)-.   º" He !‰

@ 4 ž ¯p › /§>  ~› Ö¹×Ø trap PZ‰

, ¯p ¹Ô supelpure oxygen trap ! /§‰-.

TGA‡ˆ
 5v Ù 15 mg 5v Ú5 ÛÑÜ,  ž

 © O >  e He Ý  8/` He 4

> 15a p Þьß-. )Ç He  balance sensor ­ 10

mL/min, S ­ 90 mL/min ?= ?Ÿcm-. 5v l8

XR   Ý àxÕ ¯ r8` < =" #$ 950^oC

„& ȃ< <‰-. iÈ ‡ˆ r8` ŸG \]) á

 . ™¹ âÂ) á 120 mesh(0.117 mm)) ŸG &

5v> !  =" 1^oC/min, 3^oC/min, 5^oC/min W 10^oC/min

 ;<="> X5ãÕ ‡ˆ‰-. DSC‡ˆ ŸG 0.1 mm)

 5v Ù 10 mg 5v Ú5 ÛÑÜ 5v äå æ reference Ú5 ç Ú5 è,  ž © O >  e He

Ý  8/` He 4> 100 mL/min ?= 15a p Þьß-. 5v l8XR   Ý àxÕ ;< ="

10^oC/min 1,000^oC„& ȃ< <‰-. ‡ˆ) àé Š  > & ê He 4> Q= ÞÕ ë 1234 s 5 vÚ5> H<„& ìÏ 5í-. H< -5 1234>  ="

10^oC/min 1,000^oC„&  5ãÕ p X> î8‰-. ‡ˆ

) àé ï  >  H<„& ìÏ Š, 1234> /§ ç 5vÚ5R 5v äå !  =" 10^oC/min 1,000^oC„&

  ²• ð‘-.

4.  

4-1. TGA


4-1-1.  =" #ñ (A=" X

òK œ
 (A 3_ è ­ xó › s-. . 250^oC„& › ôC «H 300^oC­®
 ž BC

 «H õ › sö, œ ‡ˆ BC  «H¢

 Ñu F-. Fig. 1 350-550^oC ) BC  g +x ha TH ~_ X> x€žm-.

)t ~_ XZ> 5a xËÕ (A =" h&ö, CW

  (A 350-550^oCR 600-900^oC ) -ñ =" ÷ø

> x€ž T ù › s-. GY TH G2" CW ? F ÷ø 350-550^oC
 ž­ BC  ú=F BC) g +x 600-900^oC ) 2{Ke  «H) ¨ x€û-.

 =" ôš›“ =" ô‰-. )R f)  =

" ôš›“  =" ô T  =" ôš›“

) ÿÔc Ç
)-. W%x AnthonyR Howard[14] 180-1,000 ^oC/s

X á T r&m-. . 2{ ) g+xö DEF 8

5aŒ-   5a Î G2  =" \]) á T

 ocm-.

4-1-2. (A Z 

="¦ 
w ƒ<w ȃ<w xó › s-. ƒ<w

g8F 'Ó<" ¿Z> hš › s+
 qÔ,  4X ƒ K!c&¢, 6 ‡ˆ › DE (A G 2 g8F <"„&   ýl 5v ž ) g+x– ȃ

<w) gK K!`-. ȃ<w" ="> ! ¯w

 ¼»½ ! Kw A š › s-[3, 4].

4-1-2-1. ¯w

â Kissinger[15]w  =" ô #$ Lz ="> 

& <" ô T )! X &> h w) -. ¦ (3) Lz=" x€x <"(T_m)   0e ±

 Ñ  ="(β) ¶·` ¦ (7) f ÷ø `-.

(7)

%
 5v z ln(β/ ) z 1/Tm "5Õ Fig. 3 f,

 ¸ 7m-.

Feeman-Carroll[16]w ¦ (3) ° z› , 5a z

(8) β

T_m² ---

ln RA

---E E RT_m --- ln –

=

T_m²

dX ---dt

 

 

∆ln 1 X–

( )

∆ln

--- n E R---- 1

T---

∆ 1 X–

( )

∆ln --- –

=

Fig. 1. Weight conversion of Tianchen coal in the TGA.

Fig. 2. The effect of heating rate on the conversion rate of carboniza- tion reaction for Clintwood coal.

š › s-. Fig. 4  =" 1^oC/ming Ç GY zF r> x

¸ 79.1 kJ/g-mol), {› 0.92-1.25 x€û, CW G2

( ¸ 84.7 kJ/g-mol)Œ- -Ô  ¸ x€û-.

& Chatterjee-Conrad[17]w ) 1{$ 8 ln[(

dX/dt)/(1-X)]z 1/T> "5  ±Z> h T)-. TH

z Ï  =" ‡ˆZ> Fig. 5R f) x€žm, Q¹F

70.0 kJ/g-mol( ¸ 64.6 kJ/g-mol), CW 59.8-71.9 kJ/g-mol(

¸ 65.9 kJ/g-mol) ¸ -.

4-1-2-2. Kw

Kw G2 (A="¦ K 7+& 5a ¼»½

w) sx,   Kasaoka ƒ[18]) /lF w !‰-.

(A 1{¦ a|Õ g8F  ="> Î ȃ< ( A¦ ¦ (9)R f) x€ › s-.

(9)

  ¼»½ ¦ (10) f) 3” H›> Î &›·› ÷ø

x€ › s- 8F-.

(10)

¦ (10) ln[−ln(1−X)]=ln a+b ln(T-c) ÷ø ÷c– 3” H›

oC/

min G2 Fig. 6 ‡ˆZR  gZ T õ › s-.

¦ (9), (10) ="H› -¾ f) ª5`-.

k=βab(T-c)(b-1) (11)

#$   hF ="H›> Arrhenius ÷ø ="H›¦ (2) K! X&R ç"eu> hš › s-.

Table 5 %
 (A ‡ˆZ> !F Q¹ r> x€žm dX

---dt βdX

---dT k 1 X( – )

= =

X=1–exp[–a T c( – )^b] Fig. 3. Application of Kissinger’s method for the TGA data of various

coals.

Table 2. Kinetic values by Kissinger's method for various coals Coal name Activation energy

(kJ/g-mol)

Frequency factor (min⁻¹)

Correlation coefficient

TH 260.0 2.62×10¹⁸ 0.998

GY 290.0 3.52×10¹⁹ 0.998

CW 279.0 1.33×10¹⁹ 0.998

Fig. 4. Application of Freeman-Carroll’s method for the TGA data of Goonyella coal.

Fig. 5. Application of Chatterjee-Conrad’s method for the TGA data of Tianchen coal.

Table 4. Kinetic values of tianchen coal by Chatterjee-Conard’s method Heating rate

(^oC/min)

Activation energy (kJ/g-mol)

Frequency factor (min⁻¹)

Correlation coefficient

1 68.7 5.97×10⁴ 0.986

3 64.7 7.58×10⁴ 0.969

5 59.1 3.30×10⁴ 0.976

10 53.7 2.29×10⁴ 0.973

Table 3. Kinetic values of Goonyella coal by Freeman-Carroll's method Heating rate

(^oC/min)

Activation energy (kJ/g-mol)

Order of reaction

Correlation coefficient

1 72.9 1.25 0.866

3 72.3 0.99 0.899

5 89.5 1.26 0.915

10 97.0 1.06 0.928

¸) h& T ù › s-. )T  ¯w G2 300-550^oC   ha ² kinetics¸) 7+x, Kw G 2 300-550^oC ha¢ ³´$ 600-900^oC„& ha kinetics ¸"

¶· 7+, ¸)– -Ô  ¸) h, T)-.

4-2. DSC


4-2-1. (A 

 /lcm-[8-11]. W V Tromp ƒ[11]) /lF w) bK )-. )T
 5v> ! DSC ¬• 7 Š -5 ‹©F 1234> ! DSC ‡ˆ  )T TGA uvR · K!

 ²• ð w)-.

)T ¦ x€žÕ ¦ (12)R f-.

(12)

V_c : corrected base line V_b : base line V_coke: DSC of coke M_coal: instant coal weight M_coke: instant coke weight

)T CW K!Õ Fig. 7 f-.   LMKe ÃÄ

c) ÃÄ Œ8F T)
 (A  ÃÄ) `-.

Fig. 8 ^oC„&

ÃÄ) ¯¯- 350^oC­®  ) ú=¨ ,c T õ

› s, 700^oC L  ) x€x T õ › s-. )T

 Fig. 2 ~_ ÿp ¬• 500^oC L (A ="> x

€ž T ÈÝ`-. TH GY G2" 400^oC­® 

) g+x 700^oC L   x€žm-. Lzp

V_c V_b (V_coke–V_b) M_coal M_coke ---

 

 

+

=

Fig. 6. Application of integral method for the TGA data of Goonyella coal.

Table 5. Rate constant of the carbonization reaction obtained by nonisothermal integral method Coal name Heating rate

(^oC/min)

Activation energy (kJ/g-mol)

Frequency factor (min⁻¹)

x=1−exp[−a(T−c)^b]

a b c(K)

TH 1 31.2 0.678 1.37×10⁻⁴⁵ 13.82 −879.0

3 22.8 0.325 2.39×10⁻¹⁶ 5.25 −25.9

5 25.5 0.664 8.60×10⁻²⁰ 6.29 −99.5

10 23.2 1.114 1.60×10⁻¹⁶ 5.30 −15.2

GY 1 35.5 1.781 1.34×10⁻¹⁵³ 41.71 −3,756.0

3 27.5 0.727 2.58×10⁻²⁶ 8.27 −313.4

5 27.4 1.199 1.85×10⁻²² 7.15 −163.1

10 30.0 4.459 4.43×10⁻³⁴ 10.57 −521.5

CW 1 30.7 0.435 1.26×10⁻²⁰ 6.70 −17.9

3 23.0 0.252 1.51×10⁻¹³ 4.37 123.6

5 23.2 0.440 6.27×10⁻¹⁴ 4.49 110.4

10 24.3 1.182 1.14×10⁻¹⁵ 5.06 52.6

Fig. 7. DSC curve of coal, coke, and base line for Clintwood coal.

Fig. 8. Corrected heat flow for Clintwood coal.

X=" x€x <"R Lz pX=" x€x <" {)  x T p X G2 ) &¢ <" X G2 <

" ¼N âÂ) s Ç
 Po`-.

¼K g8F <" 5v ~_ ² ºa ÃÄ ¿ 5vp ² x€ž G2R (A <" ‹© 5vp

ö  R f) BC) 6) ·?` Ðv G2 ) è ¸ ) {) jè 3_ x€û-.

žm-.   CW G2 H< 1,000^oC„& (A DEF

1,077 J/g 5v jè  )m )> 8Õ Table 6 f-.

Hefta ƒ[9] ¯  !F 600^oC„&  DSC ‡ˆ

 70-110 J/g C ) g+x T -. Mahajan ƒ[6] 

 ~q„& % & ƒú
 !F 580^oC„&

PDSC(1.6 MPa)‡ˆ Ô ·p 75%(d.a.f. ²)„&  ²  ¡ G2 C ) g+x&¢ W )H  ¡ ~q G 2   x€žm-. C  G2 Lz 140 J/g)m, 

 G2 Lz 280 J/g)m-. Lospez-Peinado ƒ[10] ­

® ~q„& 17MA
 !F 780^oC„& DSC ‡ˆ

¼K (A    )m, 200-500^oC ha :

ƒú
 G2 g­ C ) x€û-. ¼K  p

450-550 J/g(d.a.f., ¿ 5vp ²) x€žm-. Yun Suuberg[8]

¯  ¡ !F 500^oC„& ‡ˆ 9.7-11.3 J/g  

 x€žm-.

#$ œ ‡ˆ r> ŒÕ ©
Z È -Ô ! ›Z>

Î T ù › s-. )T œ ‡ˆ G2 LM (A<" 1,000^oC

 ! T) W )? Ï`-.

4-2-2. Kinetics 

 ¦ (5) {›> 1{ 8š G2, dH/dt=k(HT−H) ÷ø

 c+ ÊC p 5a t ËK C p ‡ˆZR ºa ÃÄ

! x€žÕ Fig. 11 f-.   f BC  ¡ A Q e TH, CW G2   ? _ x€û-. ¦ (6) !

X&R {›> hŒÕ Table 7 f) x€û-.

4-3.    

TGA

-. W%x Fig. 2 Lz =" x€x # <" a$)

~ %– &{ Cš Ô& '-.

Table 2

x€x -ñ 
w È F {› ! ¸) x€û-.

I Fig. 4 Freeman-Carrollw K!Õ {›> · h

#ñ \]) 3_ x€û-. #$ ¼K correlation coefficient

¸" 0.767-0.928 -Ô :_ x€û-. Chatterjee-Conradw G2  Fig. 9. Corrected heat flow based to unit weight for Clintwood coal.

Fig. 10. Accumulated carbonization heat for Clintwood coal.

Table 6. Accumulated carbonization heat from 30^oC to 1,000^oC Coal name Accumulated carbonization heat (J/g)

Initial weight-based Instant weight-based

CW 828 1,062

GY 823 987

TH 1,077 1,424

Fig. 11. Arrhenius plot for the DSC data of various coals.

Table 7. Kinetic values of sample coals by Borchardt-Daniels’s method Coal

name

Activation energy (kJ/g-mol)

Order of reaction

Correlation coefficient

TH 56.0 1.05 0.980

GY 39.5 0.98 0.975

CW 50.4 1.03 0.967

) 1{e G2 8 ‡ˆZ 
w) Íc@ ) 1{

 {› 0.92-1.29¸ x€ž, Wen ƒ[12] G2" 1{

x€û– (A=" ‡ˆZ Chatterjee-Conradw K!5)

› s-. X& 61.2-65.9 kJ/g-mol 7+* (A 
w

 Ž ?+‰-. Kw G2 300-900^oC ha 7+, ¸ )– X& 25.3-30.1 kJ/g-mol -Ô : ¸) h

-. ;<=" #$" kinetics ¸t) {) x€ûx g8F G ] Œ)& ê³ ä,F )?> Poš › á Q=Ke Ñ Â )-.

DSC ‡ˆ G2   kinetics> · hš › s- Ž# 

& sx,  Q¹ ²• P8ö -Ô &{> ? C š › s- ¥#" s-. 300-900^oC ha 7+, DSC uv

56.0 kJ/g-mol TGA ‡ˆZ Kw È -Ô [ ¸ x€

û-. Kissingerw ? F ASTM E-698w G2
 (A DSC ‡

oC/min  =" X #

$  LzZ ¸) ä,_ h-c& ê³ K!) +Ñ.-.

Bak

‡ˆ r 20.0-129.2 kJ/g-mol ˜ X& ¸ h‰-.

Fig. 12

&> ÈÝ compensation effect> "5‰-. ) W/ ( ) •÷ X0 ù › s-.

5.  

(AZ> 
‰-. TGA ‡ˆ 450-550^oC ha Lz (A=" x€ûx, DSC ‡ˆ 650-700^oC ha L

" (A ±Z N$-. Chatterjee-Conradw)
 (A

 
w Ž °Ò‰@, X& TH 61.2 kJ/g-mol, GY 64.6 kJ/g-mol, CW 65.9kJ/g-mol h-.
p zF

{› TH 0.92-1.25, GY 0.99-1.26, CW 0.98-1.29 x€

û-. < DSC ‡ˆ ‹© 1234> )!F ²Z Œ8w K

! (A   kinetics> · hš › sm-. H<

1,000^oC„&
 (A DEF p TH 1,077J/g, GY 823J/g, CW 828 J/g x€û-. DSC   )!F Borchardt-Danielw

 G2 (A X& TH 56.0 kJ/g-mol, GY 39.5 kJ/

g-mol, CW 50.4 kJ/g-mol x€û-. {› 0.98-1.05 ¸

-.



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Fig. 12. Compensation effect for various coals.