IEA-CFBC Îj Ï ÿzK B~Fÿ[ ²~ WËÎÒ

(1)

IEA-CFBC Îj Ï ÿzK B~Fÿ[ ²~ WËÎÒ

− Ò WËæzö V B~Fÿ[ ²~ WËÎÒ −

«"^†ÁfÒW

* *Kö B* ²B*

(1999j 4ú 10¢ 7>, 1999j 10ú 1¢ j)

Simulation of the Tonghae Thermal Power Plant CFB by using IEA-CFBC Model

− Determination of the CFB Combustor Performance with Cyclone Modification −

Jong-Min Lee^† and Jae-Sung Kim

Advanced Power Generation & Combustion Group, PGL, KEPRI, KEPCO (Received 10 April 1999; accepted 1 October 1999)

º £

ÿzK B~Fÿ[ ¢º 200 MWe Î Ú Zêj ÒÏ~º & Î~ B*Jj, *Ò 1^V&

çëÚ*7ö ®b, 2^V& '99j 10úö &j Ï J7ö ®. *Ò çëÚ*7ö ®º ÿzK B~Fÿ[

¢º Ò Bö V Ú* n;z 5 Ú* 'z¢ >¯7ö ®b¾, & Î~ ZêÏ B~Fÿ[ö &

Ú*¶òº ~ rJê :& ìÚ, ö & .G jº~. ö öBº IEA-CFBC Îj Ï~ ÿ

zK B~Fÿ[~ WËj ÎÒ > ®º Ò.~ æj BB~&b, ¢ Ï~ Ò ÎN æzö V B

~Fÿ[ WË æz¢ .G~&. 6 Ò B Ò~ WË æz 5 ÒB~ï, Ò ÷ «¶ï j .G~ Bö V WË Ëçj Ö;~&. Ö" ÿzK Ò~ WËf £ 98.7% ;ê ¾æÒb, Ò ÎN Ã&ö V¢ Ú ç¦N{ Ã&~º ãËj, Ò freeboard~ Nê& 6N Ôj^ n;z>º © b ¾æÒ. Ò ÎN~ çßj * Ò vortex finder 5 « ' B¢ >¯ ãÖ, B~F ÿ[ WË Ëç V&>º ©b .G>î.

Abstract−The 200 MWe Tonghae thermal power plant CFB(2-units) is the largest boiler to fire a Korean anthracite coal for generation of electric power. The #1-unit CFB boiler has been operated commercially since October 1998, and the #2-unit CFB boiler, of which commercial operation will be achieved at October 1999, is under construction. The optimization and stabili- zation of the CFB operation have been carried out through the modification of the cyclones for the units of #1 and #2. How- ever the operation data for the large CFB combustor firing the anthracite coal are few, so it is necessary to predict the performance of the CFBC with variation of the operation conditions. Therefore, in this study, the development of the simulation scheme has been achieved by using IEA(International Energy Agency)-CFBC model, and the performance of the CFB combustor with variation of the cyclone efficiency has been determined. The improved performance of the modified cyclone, which have been carried out by increase of the vortex finder length and by decrease of the cross sectional area of the cyclone inlet, also has been determined. The cyclone efficiency has been evaluated 98.7%. As the cyclone efficiency increases, the upper differential pressure increases and the freeboard temperature becomes to be low and stable. The modifications of vortex finder and inlet duct of the cyclone have been predicted to improve the performance of the CFB combustor.

Key words: CFBC, IEA Model, Tonghae Boiler, Anthracite Coal, Cyclone

1. B

*KöBº Ú Zêj Ï *KÖj * 1993j .ö B~Fÿ[ ²~ Jê 5 J *CÞ¢ ·~&. B~Fÿ [f 200 MWe 2V ÿö J>, Jêº ABB-CEöB,

Ò "ê£ 5 /f 7ëöB ~ Úæ ®.

B~Fÿ[ ² 1^Vº 1995jöö Ê& generator¢ J~~&, .V 6z 5 Ê& Bf 1997j öö Úrb, 1998j 3ú¦

V Vÿ Ú*j Û 1998j 10úöº çëÚ* Úr. 2^V 6 *Ò J7ö ®b, 1999j 10ú.ö & Úî .;

.

ÿzK B~Fÿ[ ²º Zê«j &çb ÎöB

†E-mail: jmlee@kepri.re.kr

(2)

z B38² B1^ 2000j 2ú

~Æ. B~Fÿ[ ²~ WË 5 ² ßW, V&Ê ßW

f *Ò VÿÚ* data öº ² rJê © ìb 6 b~ ;çÚ* 7öê Ú* æzö V çV ßW

rJê :& ~ ìV r^ö ö & .G 5 ï&& jº~.

B~Fÿ[ ²ö & Îçf Vö 6Ò rJê VFÿ [ Îj "*b 1990j .¦V B® ê¯>Ú z. B~Fÿ [ ²~ Îç OËf ² »OËòj J~º 1Nö Î

ç¦V[1-7] ²¢ »OË 5 ÇOË ¢¦(coref annulus) ¾*

º 1.5Nö~ Îç[9, 10], Ò »OË 5 ÇOËj Îv J~

º 3Nö Îçb ª>Ú B*> ®[11, 12]. 3Nö Îç

~ ãÖöº "ö ôf & ê¯7ö ®b¾ B wÏö ®Ú Bº 'Ï~V ÚJÚ ¦ª Îj ®Ú jçf BBê¢ ö

> ®. ö > 1Nö 5 1.5Nöf ôf & ê¯>Ú zb

~ wÏ 5 'Ïê ç¦ª Ú^ ®º ©b > ®

5 V&Ê ßW, *" Ò ÒB~ ~ Ï W>Ú ® b, ~ Îç 'Ï.¢ Table 1ö ¾æÚî. ß® B ö.æ V(IEA, International Energy Agency) Ö~ Fÿ[¦^*ö²~ Î

ç öBê 1990j& .¦V B* *CÞ V~ V F ÿ[ Î~ Ëçj Û B~Fÿ[ Î z¢ BB~&b

~ B ÖëÏ B~Fÿ[ ²~ 'Ïj Û Ï &ËWj {~&[13].

ö öBº IEA-CFBC Îj Ï~ ÿzK B~F ÿ[ ²~ Ú* j ÎÒ > ®º Ò.~ æj BB~

~ 'Ïj Û Ú* WË .Gj >¯~¶ . Ú

* WË .G~ . Ò B¢ Û B~ï~ Ã& 5 Ú~ Nê n;W Ò î ÎN Ã&¢ êÎ~¶ ~º ÿz K B~Fÿ[~ ãÖö & WË .G Cj >¯~ 'Ëj

V~¶ .

2. IEA-CFBC Î W

Bö.æV(IEA) Ö~ Fÿ[ öB *CÞz>Ú BB>

, Hannes[10, 13]ö ~ ;Ò, *ÎzB IEA-CFBC Îf

2-1. Fluidization Pattern of Solid Flow

B~Fÿ[öB~ VÚ 5 Ú~ ç^·Ï 5 vªf riserÚ~ ®

¢ vªj ;W~, ©f ² riser ~¦öBº dense '

j, ç freeboard öBº transport 'j, Ò ç~¦ ã

ê'öBº *'~ Vj &Ë~² &. ÎçöBº ' 'j Îv J~&b, *' 5 freeboard öB~ » OË Ú ³êæº Wen" Chen[14] B ç&j 'Ï~&

b, denseç~ [¸ 5 Ú ³ê ªNf {K B¦Ê~ ãê

j ¢ê, r~ Rhodes[15]& B b¦V ' «¶ö &

êÖ~ Ö;~&.

(1)

VB a(exponential decay constant)º Kuniif Levenspiel[16] B n ²Ú~ ÷³êf >jf &êö ®º r~ ç&j ' Ï~&b, ç>º ÎÚö .æ> «K>ê W>Ú ®.

(2)

¢>'b ç>º ·f «¶ ãÖ 2-5 s⁻¹, Ò «¶ ãÖ º 4-12 s⁻¹ &V >¾, &Ë~ «¶~ ßWö V¢ þb

~º © Ò' ©b B>î. öBº parameter sensitivity Vj Û 5.5~ 8j 'Ï~&.

Two phase theory(Davidson" Harrison[17])~ Væj 'Ï dense 'f emulsion" bubble 'b ¾*Ú V~&b, denseçö B~ VªNf Johnsson[18] B ç&j, Ò VVº Darton [19] B ç&j '' 'Ï~&. Freeboard ç~ Ç OË Ú ªN 5 core-annulus~ ãê Ö;&êº &æ~ &;"

þ Seiter 5 Rhodes& B ç&&êö ~ Ö;~&[13, 15].

ç" ? IEA-CFBC ÎöB Úvª~ ãËf ² »OË 5 ÇOËb ¾*Ú V~&b, ÇOËö ®ÚBº coref an- nulusb ¾*Ú ï ßWj 'Ï~&Vö ¢>'b 1.5Nö

~ Îç ;¢ ~ ®.

2-2. Development of Particle Size Distribution

B~Fÿ[Ú "«>º «¶f ² Cê, C²C 5 [bî(Î

¾) ªî > ®b, ' «¶ö & r" ?f mass balance

& î > ®.

(3)

VB mfeedº fragmentationj J feeding flow, oº

¾æÞ ©.

p ρs–ρg

( )g

---= εs d, Hd 0 H h– _d

∫

^[^ε^s^,^∞⁺⁽^ε^{s d}^, ^–^ε^s^,^∞⁾^exp⁽^–^ah⁾^]dh

 + 

 

a u⋅ _o=constant

0 m·

feedw_{i feed}_, (1–η_{i exit}_, )(1–η_{i cyc}_, )m·

bagw_i

– η_segm·

dischargew_i –

= 1 n_io

--- k_io,attr i^o ni^o

∑

⁽ûô^–û^mf^)m^tot^wⁱô^–^k^{i attr}^, ⁽ûô^–û^mf^)m^tot^wⁱ

+

k_io,shrk m_totw_io

( )w_i^o_,_i–k_io,shrkm_totw_i +

Table 1. Overall models for circulating fluidized bed combustors

Ref. Fluid dynamics Size distrib. Coal comb. SO₂ NO_x Heat trans. Steam proc. Recirc. State

Siegen[1] 1-dim + + + + + + + std

Zhang[2] 1-dim - + + + + - + dyn

Mori[8] block - + - - - - + std

Basu[9] 1.5-dim - + + + + - - std

Xu[3] 1-dim + + + + + + + std

Lin[4] 1-dim - + + - - - - std

Halder[5] 1-dim + - - - std

IST[6] 1-dim - + + + + - - std

Alstrom[7] 1-dim - + - + + - - dyn

Haider[10] 1.5-dim - + - + + - - std

Hiller[11] 1.5-dim - + + - - - - std

IEA[12] 1.5-dim + + + + + - + std

std : steady-state, dyn : dynamical, + : consideration, - : no consideration

(3)

ÎçöBº «¶~ "« ÏÏö ~ æº fragmenta- tion 5 Vê' îÎ(attrition), z>wö ~ «¶ »²(shrinking)

j J~&. JB Vê «¶º *Ú [{K"~ ãêj V&b ~¦~ VÂ 5 filter~ VÂ 5 ÷, Ò ÒB~

b ª>Ú mass balance& Úê.

2-3. Gas Flow

ªÖ6j Û "«B Vº core, annulus 5 bubble Ò

emulsion çb ¾~Ú vªj W~ ' vªöB ÇOË~ VÚ

bf ' çöB~ VÚ v~ ³êö ~ Ö;B. Bubble" emulsion ç~ VÚbf Johnsson [18] B ç&j, Ò coref annulus*~ VÚbf Kruse [20] B ç&j 'Ï~

J~&.

6 ÎçöBº NV~ "« 5 V&Ê~ ÒB~ j

J > ®ê W>Ú r.

2-4. Coal Conversion

Cê «¶ö & ²>w~ ¢>zB ìV r^ö Cê

«¶~ ²Ú~ R« Úæ, «¶~ & 5 , Ò

î>B 5 J~ W Ò WJ~ ² >wb Úê.

¢N~ >wöB VÚ {Ö 5 >w ï; Ò >w W

f J~ ²³ê 5 «¶ Nê¢ Ö;~, «¶Nêö V¢ çV

>wf BN'b ¢Ú¾, J ³êº Vç~ Ö² ³êf ï;

j ê Îç çö iteration loopj ;W~ê W>Ú ®.

«¶~ & 5 º «¶~ Ò(radiation) 5 &~(convection)

Ò ÃBvª(evaporation heat flows)j J ç&j 'Ï

~&b[13], Cê «¶~ î>Bf ö²ªCö "¢ v þ', Ûê' Vj Û áf Merrick[21]~ ç&j 'Ï~ J~&

. î>Bê ºJ~ ²º >wÖ²~ {Ö 5 «¶öB~

² Ò «¶~ Nêæz j J Field[22] B ç

&j 'Ï~&b, 7 ÒÏB Cê~ Wz ö.æ 5 frequency factorº adjustable variable .>ê J;>Ú ®. ÿzKö ÒÏ>º Ú Zê~ ãÖ Î~ sensitivity study¢ Û Wzö .æº 158 kJ/mol(=19000/R[K]), Ò frequency factorº 0.79[kg/

(m²sPa)]¢ 'Ï~&b, >wN>º 1N>wb &;~ 'Ï~&

¾æÒ[26].

2-5. Homogeneous and Heterogeneous Gas Reactions

Vç>wf CO, CO2, H₂O, NO, N₂O, SO₂, O₂ ö & >

w 'Ëj J~&b, ÇOË Vçb ' çöB j*~ &

;~ êÖ~&. SO₂ W 5 C²C î>wö &Bº Schouten

" van den Bleek[23]& BB VFÿ[öB~ Î SURE Î

j Wolff[24] Bï B*Î SURE2 Îj 'Ï~&. Ni- trogen~ >wb W>º NOxzbö &Bº Johnsson [25]

homogeneous 5 heterogeneous >w kinetics Îj 'Ï

~&b, <~ VçWb~ Ò² >wf Howard 5 Hautman

B Îj ÒÏ~&[13, 26]. Þ, N2O 5 NO~ Wj º *Ò ôf & Úææ pj IEA-CFBC ÎÚöBº .ç> 8b «K~ê W>î.

2-6. Heat Transfer

B~Fÿ[öB~ * ßWf «¶~ convection 5 radiationö ~

wall membraneb *>º " v~ >, <öê

¦ v~V 5 ash cooler öB *>º Ò > ®.

ÎçöBº çV ' partê *j Wirth 5 VDI-Warmeatlasö B B Îb 'Ï, J~&b, 6 * tube& Úö immersedB ãÖê J > ®ê W>Ú ®[13, 27].

Fig. 1f IEA-CFBC Îj Û Ò.~ procedure¢ ¾æÞ

©. ç" ? IEA-CFBC Îf B~Fÿ[öB jv' J

>Ú¢ ¦ªj &¦ª <¾ Î z FÏ Ö

3. ÿzK Jê 5 Ú* ¶ò

öBº çV IEA-CFBC Îz¢ ÒÏ~ Ò~

ÎN æzö V ÿzK B~Fÿ[ ²~ WË 5 ² ßW Fig. 1. IEA-CFBC model procedure.

(4)

z B38² B1^ 2000j 2ú

j V~¶ . ÿzK B~Fÿ[ ²º Fig. 2ö ¾æÞ :f ? ² Cê 5 C²C R«Ë~ 5 silo, V"«¦, "

²¦(², Ò, loopseal, FBHE 5 FBAC) Ò back- pass W>Ú ®. ²º rectangular(32×19×7 m) ªÖ 6*¦V 7 m æ6öB ~¦ 15^o~ taperedB ;¢ .

ªÖ6f ' 62B~ T-type four jet ¶ 12ö '' vN

>Ú ®º ;¢ . B~ «¶¢ ÷~ ÒB~Êº Ò

(7.6 m I.D.×15.7 m Height)f 3B& J~>Ú ®b, ' Ò

''~ loopseal" FBHE¢ W~² B. Loopsealöº ash control valve& J~>Ú ®Ú FBHE split >º ·j .~² B . ² ~¦öº [bîj FBAC VÂÊº ^2& J~>

Ú ·j .~² >Ú ®b, ¢ Ï *Ú Ú~ {Kj

.~² B. ² "«>º Cê"«º C 6B Ú^

® NVº C 16B~ ¶j Û "«B. ªÖ6b¦V 4.3 m æ6ö J¢ ª. 2V&, Ò dense[ö Lance ª. 5V&

J~>Ú ®b, ¢ Û [bî~ & 5 &¦~öB~ Nê¢

B~B.

ÿzK B~Fÿ[ ¢ö ÒÏ>º Cêf Ú Zêb

ash& 39%, ;ê²& 53.7%, >ª 3.3% Ò >Bª 4%

F>Ú ®b, ê V&b S 5 N~ Fï '' 0.6 5

0.2% F>Ú ®º jv' ² >wW ¾ Cê¢ rJ^ ®

[28]. 6 Cê~ «ê ªº Jê~ V&b 0.1-3.0 mm Ò

~ «¶& 95% ç>Ú¢ ~¾, ÿzK~ ãÖ Jê~ ·

¾ _f «ê& çï Ò~º ©b ¾æÒb, Cê

ò~ >wW 5 «êö & 'Ëf .V B~Fÿ[ Vÿ ê

¦(sealpot 5 cyclone)~ Nê¢ ¸º Ö"¢ &^f Ú*ö ç

® ®n; ºb ·Ï~º ©b C&r[29]. Table 2ö Cê ªC~ 5 V& «ê ª¢ ¾æÚî.

²Ú~ î>wj * "«>º C²Cf Ú BB ©b

CaCO₃Fï 90%, Ò MgCO3& 4.2% ;ê F>Ú ®b, 1 mm ~ «ê& 100%, 0.7 mm ~& 95%, Ò 0.5 mm ~

& 90% >º jv' ·f «ê ª¢ <º C²C ÒÏB.

Ò.~ö ÒÏB ÿzK B~Fÿ[ ²ö />º ¢N

Vï 5 NVï, Ò loopseal 5 FBHE, FBACöB ÒB

~>º Vï 5 feeder />º Vï j ' ¦~ê Table Fig. 2. Schematic diagram of the Tonghae CFB boiler.

Table 2. Analysis of design coal in the Tonghae CFBC

Proximate analysis wt% Ultimate analysis wt%(dry basis) Size distribution(mm) wt%

Moisture Volatile matter Fixed carbon Ash Heating value

(dry basis)

03.3 04.0 53.7 39.0 4600 (kcal/kg)

C H O N S Ash

54.7 00.3 03.8 00.2 00.6 40.4

>9.5 5.6-9.5 4.75-5.6 2.8-4.75 2-2.8 1.0-2.0 0.6-1.0 0.25-0.6 0.1-0.25 0.075-0.1

<0.075

00.0 00.0 01.0 02.0 16.0 31.0 16.0 17.0 10..0 02.0 05.0

Table 3. Operation data for the Tonghae CFBC

# Height [m]

Width [m]

Length [m]

Addition air[m³/s] Tap.

1=y, 0=n Wall ratio

BMCR MGR 100%NR 75%NR 50%NR 30%NR

1 00.00 19.05 3.35 87.22 87.22 87.22 76.30 65.58 68.34 1 1

2 00.43 19.05 3.58 14.60 14.01 10.26 04.40 04.40 04.40 1 1

3 01.37 19.05 4.09 00.93 00.93 00.93 00.93 00.93 00.93 1 1

4 01.70 19.05 4.26 09.14 09.14 09.14 09.14 09.14 07.34 1 1

5 02.44 19.05 4.66 22.19 21.75 18.94 14.54 14.54 14.54 1 1

6 04.48 19.05 5.75 32.86 31.52 23.09 09.90 09.90 09.90 1 1

7 31.90 19.05 7.09 0 0 0 00.00 000.0 000.0 0 1

8 Coal[kg/s] 30.10 29.70 27.30 20.70 14.50 07.90

9 Lime[kg/s] 00.92 00.91 00.83 00.63 00.44 00.38

#1: Primary Air, #2: Secondary Air(4), #3: Feeder(Coal and Lime) Transport Air, #4: Loopseal+FBHE Returned Air, #5: Secondary Air(3), #6: Secondary Air(9), #7 Top of Combustor, #8, #9, Coal, Lime Feed Rate, # Wall Ratio: [Membrane wall area]/[wall area], # Tap.: Tapered type, yes=1, no=0

(5)

3ö ¾æÚî. Ò.~öBº 100% NR(Nominal Rate) V&

b Ò~ WËæzö V B~Fÿ[ WËÎÒ¢ ~&.

4. Ö" 5 V

Fig. 3(a)f (b)º Ò~ WËæzö V ÿzK B~Fÿ[

Ú~ »OË solid hold-up 5 {Kª¢ ¾æÞ ©. Ò~

öB «¶ßW"º Z&~² æ V~ z ÚÇK(saturation carrying capacity)j >º · ªÒ>º *çö ~ ÎN Û «

ÎN(entrance efficiency or vortex efficiency)¢ ;~>º ©", ªÒ>æ p Îj®º «¶ö & centrifugal force 5 drag force balanceö ~ ;~>º ¢ «¶ ÎN(single particle efficiency)

(4)

VB saturation carrying capacity µ_s,satº r~ (5) b *

> ®b, 6 IEA-CFBC ÎöB single particle efficiency

(5)

(6)

(7)

IEA-CFBC ÎöBº çV Ò~ Îj B B~Fÿ[ö

'Ïö ®Ú kcye¢ . æ> ÒÏÆ >Ú ®. Îç~

ãÖ Ò B¢ Û WËæz ' æz >~öò jî

¢, ÎNæzö 'Ëj "º k_cyc,e~ 8j æz(0.01-0.34)B B Ò~ ÎN æz *Ú B~Fÿ[ ²~ WËö ~º 'Ëj ÚÚ~. Fig. 3(a)öB º :f ? kcyc,e~ 8~ .j Û Ò ÎN~ Ã&(99.99-98.67)ö V¢ dense [~ solid hold up 6N 6²(0.187-0.059)~ >ö freeboard(lean phase)öBº 6N Ã&(0.005-0.014)~º ãËj ®. 6 dense [~ [

¸& Ò ÎN Ã&ö V¢ 6N ¸jæ ®rj r >

®. ¢ Û Ò ÎN Ã&ö V¢ B~Fÿ[ ²

Ú~ Ú³ê ª 5 B~ï 'Ëj Arj r > ®b, ß

® Fig. 3(b)öB º :f ? B plantöB Ú* ¶ò áº

áº Ú* {K ¶òº ² ªÖ6 {K;~¢ *Ú {KN f Ò ªÖ6b¦V 0.9 m *¦V ç¦ 28.5 m Ò~ {KN,

Ò ªÖ6 5.2 m *¦V ç¦ 28.5 m Ò~ {KN¢ G; ª C~ ®. 7 ç¦N{¢ ¢º ªÖ6 5.2 m *¦V ç¦

28.5 m Ò~ {KNº Ú B~~ ¦¢ 6ê~º V&b â

®b ;çÚ* 7ö £ 140-170 mmH2O~ {KN¢ ® . 6 7*N{ ªÖ6 * 0.9-28.5 m Ò~ {KNº £ 340-490 mmH₂O~ 8j ¾æÚ ®. Fig. 3(b)öB º :f ?

çV {K º*ö º Ò ÎN~ 8j º; *Ò ÿzK~ Ò ÎNf 98.7%;ê ©b ¾æÂ. ÿz K B~Fÿ[ ¢~ V Jê¶ ABB-CEöBº *Ò~ Ò

ÎNj 96.4% êÖ~ ®b¾ º 'ÏB Ò~ Î

5 B~ï~ êÖ 'Ïö~ N& ®Ú B jvº ÚJÚ ©b

¾æÒ. 6 Ò ÎNçß dense[öB~ {KNº 6 N 6²~ >ö lean phaseöB~ {KNº 6N Ã&~º ãË j ¾æÚ ®Ú B~ï~ Ã&¢ .ç > ®b, Ò ÎN ö V ' {KG;~öB~ {KN¢ .ç > ®.

Fig. 4º ~ ¸ö V annulus 5 coreöB~ Nêª¢ ¾æ Ú ®. Dense[öB~ Nêªº annulus 5 core~ Nêª&

£ 900^oCöB jv' ¢j " > ®b B Nê G;~(symbol)fê jv' ¾ rj " > ®. ¾ lean phaseöB~

annulus 5 core~ Nêªº Ò ÎNö V¢ ² ªj "

> ®b, Ò ÎN Ã&ö V¢ 6N Nê& Ôjöj "

> ®. º Ò B Ú~ ê¦ Nê n;ö Î"

¢ * > ®rj ~. Annulus Nê ª~ ãÖ, dense[j

®b, º annulus~ ~Ëvª Úö ~ membrane wall tube~ * ¢Ú¾V r^b ' > ®. ¯, ç¦ö B~ N~ ~Ëvª Ú& * 6N Nê& Ôjæ

& dense[~ Ú[" &ròæB Ã&~º ;¢ ¾æêj η_{cyc i}_, 1 µ_{s sat}_,

µ_s --- µ_{s sat}_,

µ_s ---η_{part i}_, +

–

=

µ_{s sat}_, k_{cyc e}_,λ

R_cyc R_{cyc vort}_, --- πA_{cyc e}_, k_{cyc acc}^1.5_, --- u_{cyc e}_,

u_t ---

=

η_{part i}_, 1

1 d_{s i}_, –d_{s crit}_, d_{s crit}_, ---

– 

 

exp +

---

=

d_{s crit}_, 18 u_in² --- µ_gu_radr_in

ρ₂–ρ_g

( )

---

=

Fig. 3. Effect of cyclone efficiency on (a) solid fraction, and (b) pressure along the combustor height.

(6)

z B38² B1^ 2000j 2ú

" > ®. Annulus 5 core~ Nêªº dense[j æ¾B freeboard öB Ò ÎN Ã&ö V¢ 6N Ôjæº ãË j , º ÒB~>º Úï Ã&~B Ú~ Nê¢ Ô ºº j ~V r^. *Ò ÿzK B~Fÿ[~ ãÖ(η_cyc

=98.7%), core~ Nêªº ~ ¸& Ã&ö V¢ 6N Nê&

Ã&~º *çj , Ò inlet~ Nê(symbol)& £ 950- 1,000^oCÒö ®Ú ÎÒ Ö"~ ËFöB ÚÚ" ãÖ Ö j

Ö Ôf ²>wWöB j>º ©b F > ®b, Ò

inlet~ ãÖ, ª~ ^«¶ _f V&Ê7~ COf >wB

æÚ ®rj r > ®. º jv' VÚvª B ÚöB

>wB Ö² 5 CO Ò ª Ò inlet ¦"öB ÏR

® b> ÷£>º ©b F > ®. Fig. 4öB º :f

? Ò ÎN~ Ã&º ç¦~ Nê¢ Ôºº j ~º © b ¾æ¾, Ò B¢ Û ÷ ÎNj ¸¢ ãÖ, jv' ¸ f Nê~ Ú*j n;~² Ôºº Î"¢ V& > ®.

Fig. 5º Ò ÎNö V B~Fÿ[ ' ¦*öB~ «êª

¢ ¾æÞ ©. Feedº B~Fÿ[Ú "«>º Cê 5 C²C

~ b «ê, filter VB ¦ªf ÒöB ÷>Ú VÂ>º «êª¢, Ò overflowº [öB VÂ>º «êª

¢ ¾æÚ, recirculation 5 bed-contentº '' ÒB~>º «ê 5 [Úö ®º «êª¢ ¾æÚ ®. âöB " > ®

Ò ÎN Ã&ö V¢ ÷, ÒB~>º «ê& *>'b

·j^ Î ¦ªöB «êª& 6N ·jöj r > ®. âö B symbolf ÿzK B~Fÿ[öB þ2çj ªC «ê

, «êªº ÎÒ Ö"(η_cyc= 98.7%)f ¾ ¢~~º ©b ¾æ Ò. æ, ÒB~ «ê~ ãÖº FBHE ç¦öB þ2ç «ê¢

©b ÎÒB ÒB~ «êº jv' ·f «êª¢ ¾ æÚ ®. º FBHEÚ~ VF³ jv' Ô² Ú*>ê J ê>Ú ®Ú(−∼0.3 m/s), j* b Úææ p Ú¶;ê~ ÞC (segregation) Vº ©b > ®.

Fig. 6f Ò ÎNæzö V Ú «¶~ ÒB~ï 5

bottom ash VÂ>¾ _f ÒöB ÷>Ú ÷êV V Â>º ·j ¾æÞ â. âöB " > ® * ÿzK~

Ú ÒB~f Ò ÎNj 98.7% £ 500 kg/s .G>, VÂ

>º ash~ ;º bottom ash& £ 410-420 ton/day, Ò fly ash

& £ 560-590 ton/day .ç>Ú fly ash~ VÂï . z ¸f

©b .G>î. Ò ÎN Ã&ö V¢ ÒB~ïf 6N Ã&~º ©j " > ®b, 6 bottom ash~ ·" fly ash~ V Âï ;& B Ê:2º ©j V > ®. º *Ú ²

~ Ú*j ¢; *Ú {KN Ú*~V r^ö B~ï Ã&

> bottom ash; VÂ>º ashï Ã&~V r^. * ÿ

zK~ ash VÂïf fly ashf bottom ash~ j& £ 6-5 : 4-5 V> ®b, ·ê fly ash& £ 550-600 ton/day G;> ®Ú

Ò.~ .G~& jv' ¾ rj r > ®.

Fig. 7f Ò ÎNæzö V ² ÂöB~ V&Ê ßW

² ÎN 6²j " > ®. CO~ Ã&º Ò ÷ÎN Fig. 4. Temperature vs. combustor height with variation of cyclone

efficiency.

Fig. 5. Effect of cyclone efficiency on particle separation.

Fig. 6. Effect of cyclone efficiency on the recirculation and ash discharge rate.

(7)

~ Ã& ªê~ ÒB~ï~ Ã&& º, º Ahlstorm Ò~ Pensylvaniaö ®º B~Fÿ[ ¢~ ªê 'Ë þö ®ÚBê Ö"& > ®[30]. SO2~ 6²º jv'

«ê& ·f >w C²C Ò ÷ ÎN~ Ã& ÒB~

, >ö NOx~ VÂï ^~¾î Ã&~º ãËj " ® . º ² n~ C²C~ Ã&& ¢;ï~ NOx~ Ã&¢ &^

Jº Ö" F > ®b, Òf Jones [31]~

~ Scrbrass B~Fÿ[ ëãþ öBê ÚÚ" > ®. 6

Ò ÷ ÎN~ Ã& ª²Ò~ ÒB~ Ã&º jv ' ¸f ²~ ç¦Nê¢ Ôºº Ö"¢ &^Z" ÿö *

ÎN~ Ã&¢ *B ëç~ Ca/S Öj¢ Ã&Êº ê& ® Fig. 7. Cyclone efficiency vs. exit gas concentration and combustion

efficiency.

Fig. 8. Effect of Ca/S mole ratio on SO₂ concentration and sulfur cap- ture efficiency with cyclone efficiency.

Fig. 9. Effect of cyclone modification on the performance of the cyclone.

(8)

z B38² B1^ 2000j 2ú

, ~ Fig. 4öBê " > ® Ò ÎN~ Ã&º ç¦

Fÿ[~ ãÖ Ca/S Öj(1.0-3.6) 5 C²C «ê æzö &

Þ, ÿzK B~Fÿ[~ ãÖ, ÒÚ~ vortex finder~

^ Ã& 5 « ' 6²~ B¢ Û fly ash Ú~ ª j 6²Ê ë Nê¢ n;zÊ V&ÊÚ~ SO2&6 ~

' Ú*j êÂ~º ·ëj >¯7ö ®. Fig. 9º Ò B

finder~ ^æz 5 Ò «~ ¸ 5 .j æzº .ç>º

B~ º* ÚöB ¾æÞ ©. âöB " > ® vortex finder~ ^Ã&ö & *Ò ÿzK~ V&^ 1.28 m ^ Úæº ãÖ, cut-diameter 5 ÷ «¶~ VÂïjº 6²~º ã Ëj ¾æÚîb, >ö ÒB~ïjº Ã&~º ãËj ¾æÚî . º vortex finder~ ^Ã&& ÒÚöB~ öOË~ ³ ê¢ Ã&Ê, ç7 Ò Â ¾&º VÚvªj Ú¶;ê ïj"V r^b F > ®. >ö Ò «öB~ V ÚF³j Ã&B Ò ÎN~ çßj <¶ ~º Ï'b Ò

«~ '(¸ _~ .j¢ *º ãÖ)j *º ãÖ öº âöB º :f ? £*~ Î"º æò vortex finder~

vortex finder 5 Ò «Bº «¶ö ~ Vê' îÎö ~

vÚ, vortex finder~ ææ 5 Ò inlet-ductöB~ fouling

çöB ÚÚ :f ?, Ò ÎNæzº *Ú B~Fÿ[

WË 5 Ú* ¶òö 'Ëj ~, 'Ë~ .Gj Û

5. Ö

IEA-CFBC Îj Ï~ ÿzK B~Fÿ[~ Ò WË

æzö V 'Ëj V~&. ÿzK~ * Ò ÎNf £ 98.7% ;ê ¾æÒb, Ò ÎN Ã&ö V¢ solid hold- up 5 Ú {KN& dense[~ ãÖ 6N 6²~ >ö freeboard

Ú Nêªº Ò ÎN~ Ã&ö V¢ ÒB~ï~ Ã& ç

¦ freeboard~ Nê& 6N Ôj^ n;z>º ©b ¾æÒb « êª 6 6N ·f «êª æ>º ©b .G>î. N ê n;z 5 Ú ÒB~~ Ã& î ÎNê Ã&~¾, >ö Ò ÎN Ö ¸j ãÖöº CO VÂï ¾, ² ÎN

Ôjæº *ç .G>î. 6 Ò ÎN~ çßj *

Ò vortex finder 5 « ' B¢ >¯ ãÖ, B~

ÒÏV^

a : exponential decay constant [1/m]

A_cyc,e: cross section area of cyclone entry [m²]

d_s,crit: critical particle diameter [m]

d_s,i : particle diameter of i class [m]

H : height [m]

H_d : dense bed height [m]

k_cyc,acc : acceleration coefficient of cyclone [-]

k_cyc,e : cyclone entrance efficiency coefficient [-]

k_i,attr : attrition constant of i class [1/m]

k_i,shrk : shrinking constant of i class [1/s]

: mass flow rate [kg/s]

w_i : particle size fraction [-]

p : pressure [Pa]

R_cyc : radius of cyclone [m]

R_cyc,vort: radius of vortex finder [m]

r_in : radius of cyclone inlet [m]

u_cyc,e : entrance gas velocity in cyclone [m/s]

u_o : superficial gas velocity [m/s]

u_in : inner directional gas velocity in cyclone [m/s]

u_rad : tangential gas velocity in cyclone [m/s]

: terminal velocity of mean particle size [m/s]

ÒÊ ^¶

: average solid volume fraction in dense bed [-]

: average solid volume fraction at infinite height [-]

λ : wall friction coefficient [-]

η_cyc,i : cyclone separation efficiency of i class [-]

η_part,i : eddy separation efficiency of i class [-]

η_seg : segregation function [-]

µ_g : dynamic gas viscosity [kg/ms]

µ_s : solid load in gas [kg/kg]

µ_s,sat : saturation solid load in gas [kg/kg]

ρ_g : gas density [kg/m³] ρ_s : solid density [kg/m³]

^^ò

1. Heinbockel, I.: Ph. D. Dissertation, Siegen University, Germany(1995).

2. Zhang, L., Li, T. D., Zhen, Q. Y. and Lu, C. D.: 11th Int. Conf. on FBC, Montreal, Canada, 1289(1991).

3. Xu, X. and Mao, J.: Proc. 4th Int. Conf. on CFB, Somerset, PA, USA, 104(1993).

4. Lin, X. and Li, Y.: Proc. 4th Int. Conf. on CFB, Somerset, PA, USA, 547(1993).

5. Halder, P. K. and Datta, A.: Proc. 4th Int. Conf. on CFB, Somerset, PA, USA, 696(1993).

6. Saraiva, P. C., Azevedo, J. L. T. and Cavalho, M. G.: 12th Int. Conf.

on FBC, San Diego, CA, USA, 375(1993).

7. Hypannen, T., Lee, Y. Y., Ketunen, A. and Riiali, J.: 12th Int. Conf.

on FBC, San Diego, CA, USA, 1121(1993).

8. Mori, S., Narukawo, K., Yamada, I., Takebayashi, T., Tanii, H., To- moyasu, Y. and Mii, T.: 11th Int. Conf. on FBC, Montreal, Canada, 1261(1991).

9. Sengupta, S. P. and Basu, P.: 11th Int. Conf. on FBC, Montreal, Can- ada, 1295(1991).

10. Hannes, J. P., van den Bleek, C. M. and Renz, U.: Proceedings of the 13th Int. Cong. on FBC, Orlando, FL, USA, 287(1995).

11. Prichett, J. W., Blake, T. R. and Garg, S. K.: AIChE Symp. Ser., 74, m·

u_t

εs d,

εs,∞

(9)

134(1978).

12. Balzer, G. and Simonin, O.: Proc. 5th Int. Symp. on Refined Flow Modelling and Turbulence Measurements, Paris, France(1993).

13. Hannes, J. P.: Ph. D. Dissertation, Delft University of Technology, The Netherlands(1996).

14. Wen, C. Y. and Chen, L. H.: AIChE J., 28, 117(1982).

15. Rhodes, M.: Powder Technology, 53, 155(1987).

16. Kunii, D. and Levenspiel, O.: “Fluidization Engineering ,” Robert E.

Krieger Publishing Company, Huntington, New York(1977).

17. Davidson, J. F. and Harrison, D.: “Fluidized Particles,” Cambridge University Press, New York(1963).

18. Johnsson, F., Andersson, S. and Leckner, B.: Powder Techonlogy, 68, 117(1991).

19. Darton, R. C., LaNauze, R. D., Davidson, J. F. and Harrisson, D.:

TransIChemE, 55(1977).

20. Kruse, M., Hartge, E. U. and Werther, J.: Powder Technology, 70, 293(1992).

21. Merrick. D.: Fuel, 62, 534(1983).

22. Field, M. A., Gill, D. W., Morgan, R. B. and Hawksley, P. G. W.:

“Combustion of Pulverized Coal,” British Coal Utilization Research

Association, Great Britain(1967).

23. Schouten, J. C. and van den Bleek, C. M.: Chemical Engineering Science, 43, 2051(1988).

24. Wolff, E. H. P.: Ph. D. Dissertation, TU-Delft University, The Neth- erlands(1991).

25. Johnsson, J. E.: Presented at the 21th IEA-AFBC Meeting in Beo- grad(1990).

26. Hautman, D. J., Dryer, F. L., Schug, K. P. and Glasman, I.: Combus- tion Science and Technology, 25, 219(1981).

27. Wirth, K. E.: Chemical Engineering Science, 50, 2137(1995).

28. Sun, D. W., Bae, D. H., Hee, K., Son, J. E., Kang, Y., Wee, Y. H., Lee, J. S. and Ji, P. S.: HWAHAK KONGHAK, 34, 321(1996).

29. Lee, J. M. and Kim, J. S.: Proceedings of the 6th Asian Conference on Fluidized-Bed and Three-Phase Reactor, CheJu Island, Korea, 501 (1998).

30. Cheliand, P. K. and Gamble, R.: “Fluidized Bed Combustion Volume- 1,” ASME, 535(1995).

31. Jones, P. A., Syngle, D. V. and Sinn, B. T.: “Fluidized Bed Combus- tion Volume-2,” ASME, 1211(1995).

IEA-CFBC Îj Ï ÿzK B~Fÿ[ ²~ WËÎÒ