HWAHAK KONGHAK Vol. 39, No. 4, August, 2001, pp (Journal of the Korean Institute of Chemical Engineers) Polystyrene * * ( ,

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1 HWAHAK KONGHAK Vol. 39, No. 4, August, 2001, pp (Journal of the Korean Institute of Chemical Engineers) Polystyrene * * ( , ) Pyrolysis Characteristics of Polystyrene Wastes in a Fluidized Bed Reactor Jun-Sik Kim, Sa-Jung Kim, Jong-Sung Yun, Yong Kang and Myoung-Jae Choi* Dept. of Chemical Engineering, Chungnam National University, Daejeon , Korea *Advanced Chemical Technology Division, KRICT, Daejeon , Korea (Received 15 June 2001; accepted 29 June 2001) (GPPS) (EPSW)!. "#$ %& '' ( )$ *" +!.,-( o C)$ ).( m/s)+ / :; <= >?! @,-$ ).8 A) BC D:E FGHI> D: 4 9 D: 567 9@ J) GPPSK LM '' 93 wt%(600 o C) $ 65wt%(500 o C) FGNOP *"+ EPSWK LM '' 95 wt%(600 o C)$ 60 wt%(550 o C) FGN!. PS8 J,-3 01*8 Q1 R <= STI> ( ).@ 01*8 9 /U R <= FGHI!. Abstract Pyrolysis of polystyrene wastes was investigated in a fluidized bed reactor. The feed materials were GPPS(general purpose polystyrene) and EPSW(expanded polystyrene waste). Nitrogen and silica sand were used as a fluidizing gas and a bed material, respectively. Effects of temperature( o C) and gas velocity( m/s) on the yields of oil and styrene monomer were determined. It has been found that the yields of oil and styrene monomer exhibited maximum values with increasing pyrolysis temperature or gas velocity in the reactor. The maximum yields of oil and styrene monomer were 93 wt% (600 o C) and 65 wt%(500 o C), respectively in the beds of GPPS and 95 wt%(600 o C) and 60 wt%(550 o C), respectively in the beds of EPSW. The pyrolysis temperature affected the composition of products for the pyrolysis of PS and the velocity of fluidization gas affected the determination of product yield in the fluidized bed reactor. Key words: Fluidized Bed, Monomer Recovery, Oil Recovery, Polystyrene Waste, Pyrolysis 1.!"# $% & '() *+,-. / ' :28 ;< = 786 BCD E% &. FG, H?IJK 6 L '() MN H?IJ(EPS, expanded polystyrene) 3O P QR NS TU V 2 W# QX#Y H?IJ(GPPS, general purpose polystyrene)z 50[ 1\ ]^2 & 786 _ ` a bc d 6 ef#y >? 4g- hi j 2% &[1-3]. 786 >? kl a Mm D kangyong@hanbat.cnu.ac.kr n# _4o p qrz st!u hv#y -K & wx 6- kl y)z{ wxs6!x i1}? % 2~#Y : #!. ƒ 6- >? D 4 >?% OD '} ˆ & S D!% &!u (Š { T9, Œ6 k Ž }ˆ 6 Mm?%,, ˆ V6 s " [ '8 ` 2 ~ D M! d #A- kl 8. Xc, O )z >? :#Y bcd wx ƒf? 2~ D k! ˆ &D šu œ #Y bcd,, P %(ž6 }Ÿ 9: ˆ & 6 78 >? kl # # M6 '@ ˆ &. FG, H?IJK 786 L O)z4 m ( ž IJ 3 W Rˆ ) V 6, ˆ & 6 78Z 465

2 466 ªZ bcd «6 2% &[3-6]. H?IJ6 # \d ±² )z2 QX# 23K 6,"#Y O)z X³ C 13 -C 24 6 }ˆ )z µ 4 C 6 - C 11 6 ) 6 }ˆ )z2 PS O)z4 st- m s IJ 3 W6 ˆ D p. ¹ º R)Š P,"Š X», ¼ X³8, ½ X³8, ¾ X³8 V - X³8d,+ À!% &[7-9]. FG, ¾ X³8 O9 ` Á9 amg ÀÁ ˆ & )zx³ X³8 * \)N ÂQ m6 )N à m6 ÄÅ D Q ˆ & V6 S D Æ% &8 ;< ¾D - O)z 1 /0# ³ Dz 8'2 1 ˆ &[9-11]. d, È,+d H?IJK 78 s S «sd ~! 7 MN H?IJ(EPSW, expanded polystyrene waste)d ¾ X³8d O)z FD %É% Ê. X³8* X³ \ { } " V Ë9̈6 Ì} Qf IJ 3 W6 ˆ ` Q6»D ÍÎ% FD %É Ï#6 Ë9»ÐD Ñ1% Ê. 2. È,+ - ¾ O)z X³ Sž6 Ò\¹ Fig. 1 Ó Ô. Õd Ö ˆ & vøsž ÙOSž, ¾ O) z X³8, ÚÛ, O :8, ³Ü8?% ÝÞ ßà +2 &. ¾ X³8 8W )/á(à m +â! 9W 1.5 m, ¾ ã 8)/á(à 1m ä må, æ?z ã ä 0.10 my çyè é ƒƒ ÃÊ. Y Á¹ ¾ *( ÂQ² ) /8 ºz )/á perforated plate¼ê ä 1.5 mm6?ë ¹ ìƒëž ÂQ² [ž í 1.5% 2\î Ê. X³8 ïð2 8W6 \¹ 8 º ÙO8¹ Ñ ž% ¾ X³86 ñ 4kW 6 G๠ў% òó ô õö 0.2 m6 3O¾D u= PID \» 8¹ X³ 8 *(6 \¹ Ê. ð 3mmY QX H?I J(GPPS, general purpose polystyrene-basf Korea Co.)f MN H? IJ 78(EPSW, expanded polystyrene waste) EPSW MN IJ(EPS, expanded polystyrene) 78D 250 o Cd O ½4ø _- µ ùâðd 1mm úû Ê. 6 ïð 2 s üý¹ 86 ð þ\î 20 gÿd X³8 gê. m { ö O :8¹ ³Ü2\î Ê%, ³Ü8 µ3 U9¾ ÝÞ ßà ¹ m6 D Ï}\î Q Rˆ Ê. Ý³Ü Ý๠D b1% N N )D )Ê. ¾6 ¾Á \ 2,500 kg/m 3 % ùâð 0.3 mmy ¹ Ê ( 2 Ýòð ¹ N8 º ÚÛD ÑžÊ. m Q q²¹ b1 Š (1) 16 kl Q ˆ (Y Oil )D 1Ê. m Q6 ) ) GC-MS(HP-5890 plus, column: DB-1HT){ FID Í 8 S GC(\ DS6200, column: HP-5) )Ê. GC )D IJ 3 W6 q² (à IJ 3 W ˆ (Y SM )D Š (2) 16 kl 1Ê. Y oil Y SM weight of obtained oil = weight of obtained SM = = weight of obtained SM Y Oil weight of obtained oil (1) (2) m X³ 4à µ 5) 5 N N GC )Ê. X³45 i N=(à ùâ m \(C Gas, g/l)¹ +% } g Á6 (Q N2, L/min)f X³45(time, min)(à m D K/ Š (3)f ˆ (Y Gas )D 1Ê. Y Gas weight of gas product = C Gas Q = N2 time Á QX H?IJ(GPPS){ 7 H?IJ (EPSW)6 )f¹ Table 1 Ó*å. P-, È,+6 vø»ðd Table 2 tê. (3) Fig. 1. Experimental apparatus 1. Pre-heater 5. Freeboard 9. Condenser 2. Wind box 6. Electric heater 10. Mist filter 3. Distributor 7. Cyclone 11. Gas sample bag 4. Main column 8. Heat exchanger 12. Gas meter Table 1. Ultimate analysis and calorific value of waste expanded polystyrene Feed material Element [wt%] Carbon Hydrogen Nitrogen Sulfur Oxygen GPPS EPSW

3 Polystyrene 467 Table 2. Comparison of experimental conditions for the pyrolysis of PS Conditions Present study Shun et al.[7] Liu et al.[8] Reactor Fluidized bed(52 mm-id) Fluidized bed(74 mm-id) Fluidized bed(60 mm-id) Temperature o C o C o C Gas velocity m/s m/s m/s Bed material Silica sand(d p =0.3 mm) Silica sand(d p =0.31 mm) Quartz sand(d p = mm) Feeding Batch(20 g) Continuous(852 g/hr) Batch(10 g) Feed material GPPS(d p =3 mm) EPSW(d p =1 mm) PS(d p =3 mm) Waste PS(d p =34 mm) Fig. 2. Oil yield from the pyrolysis of PS in a fluidized bed reactor. 3. ¾ X³8d H?IJ6 O)z FD %É8 º X ³45 Q ˆ (Y Oil )6 Ì}¹ Fig. 2 Ó*å. Õ d Ö ˆ & O)z X³456 $ 7 H?IJ (à Rˆ2 Q ˆ $, X³ ) wt%6 Q! p Ó. ƒ X³»Ðd Ï Q ˆ X³ Ì}Z X³ \6 Ì} «~¹ Z p Ó. FG, X³ \ 400 o CY L{ o C L h- Qm"\6 ~¹ Z% &. { Qm"\~ O)z X³d X³ \6 Ñ1 wl st% ˆ & 86,+f, PS O)z¹ º- X³ \ R)Š X³8d6 O)z D %B- Ï# X³ \ 465 o C Z%2% & ¾ X³8d # % Y o Cd Ë92 p B &[4, 7-9]. PS6 O)z m 6 éjf æßj D ) m m2, O)z \6 $ m ˆ (Y Gas )6 ã D Fig. 3 Ó*å. Õd Ö ˆ &, O)z \ 500 o L Y Gas gg $ Ê% Shun V[7]f Liu V[8]6 ¾ X³8d6 O)z,+ f{ - D Ó*å.!u, È vøf =6,+5 f6 ~¹ Ó*% & O)z \ 6 vø Ì ˆY } ", 4 6 f ð ` gkl, ¾Á6 ð V d 8 ;< (Table 2). FG, Shun V[7]6,+fd m p } " 8 ;< PS6 )z 456 $ m $- p mƒ ˆ Fig. 3. Effects of temperature on the gas yield in a fluidized bed reactor(u G =0.5 m/s). &. { f=(à vø»ð sd } " m6 ˆ «ã D % ˆ &. PS6 O)z4 m2 m 8@ m %W Fig. 4. Effects of temperature on the yields of oil and styrene monomer in a fluidized bed reactor(u G =0.5 m/s). HWAHAK KONGHAK Vol. 39, No. 4, August, 2001

4 m Ç(coke)¹ = ˆ &, PS O)z4 78Z Ý 6 Ç m2 O)z \6 $ m $!u 0.2 wt% 1\ Ý 700 o \d Z $ p Z%2% &[7, 8]. O)z \6 $ = Q ˆ (Y Oil )f IJ 3 W ˆ (Y SM )D Fig. 4 Ó*å. Õd Ö ˆ & Y Oil f Y SM \6 $ ~ $ o Cd Ï'D Ó µ! \ $c ˆ GB _Ê. { 600 o \ $c m6 $ 6- Y Oil f Y SM _8 ;< Ñ" ˆ &. P-, = ˆ _6 st- Y \6 $ X³ m6 Ý³Ü 6- # vf Ý!u Ç6 m\ %B ˆ &. È vød Y Oil f Y SM 6 Ï' Á GPPSY L, ƒƒ 93 wt%(600 o C), 65 wt% (500 o C) Ó EPSWY L ƒƒ 95 wt%(600 o C), 60 wt% (550 o C) Ó. Shun V[7]6,+fd Ï' Y Oil f Y SM 550 o Cd ƒƒ 97 wt%, 51 wt% Ó%, Liu V[8]6,+f 600 o Cd ƒƒ 98.7 wt%, 78.7 wt% Ó. È vød F- Y Oil f Y SM 6 Ï'd6 \ d p \ 6 $ Y Oil $!\ Q s6 IJ 3 W6 ÄÅ _Ê8 ;<. P-, Fig. 4d Y Oil EPSWY L GPPSY LZ 5 D Ó Xc Y SM EPSWY L GPPSY L Z D Ó*å. EPSW6 L, ùâð ð «GPPS (d p =3 mm)z ±² m 9: p á3 ˆ &. Y SM EPSW MNIJ 78 Á $ ˆ & D šu œ ƒ % & & O)z4 GPPSZ Y SM D Ó% ˆ &. ¾ X³8d st- Ë9̈Y } "6 $ Q ˆ (Y Oil )f IJ 3 W ˆ (Y SM )6 Ì}¹ Fig. 5 Ó *å. Õd Ö ˆ & Y Oil f Y SM } "(U G ) 6 $ $ U G m/sd Ï'D Ó*å. } "6 Ì} X³8* 4 6 W 45 ', )z X ³45f ä28 ;< z ˆ &. ', " L(U G =0.3 m/s) O)z X³45 md m 9:2 $ Y Oil f Y SM _ p Ñ" ˆ &. Ó,+ fd\ "d m 6 ˆ D Ó pf Qž-[7, 8]. P-, "6 Ì} X³8* 4 { ¾ÁY 6 * ` +, h@ ã D Ýž -q "6 L +, ` * ef6 (Ž ÂQm6 )N¹ 8 ;< Yz Y Oil f Y SM _ ˆ &. Xc, } "(U G =0.6 m/s)d. W 45 ; m m 4 )z2 h@d. ˆ & Y Oil f Y SM $ ˆ &!u vøf Y Oil f Y SM _ D Ó*å. "6 $ O :8{ ³Ü8 *d m6 W 45 P- _2 ef# m Rˆ2! % } { ö / X p z. Fig. 6d H?IJ6 O)z4 m6 Ç0Î1f PS6 2d 3 m )z 4 & }Ÿ m 6 56¹ 7 Ó*å. PS O)z m '() k Ž } W Rˆ2 p B & [12-14] t m IJ 3 W(monomer), W(dimer)?% ì W(trimer)Y Fig. 66 Ç0Î1d ƒƒ 4, 6, 75 ' ³. 6 m %? Y 89, :À;, é89, α-<éij ƒƒ 1, 2, 3, 55 ëç za. ¾ O)z X³8d Ë9̈Y O)z \{ } "6 Ì} m6 )NÌ}¹ =>Z8 º Q s6 t) )f¹ Table 3f 4 ƒƒ Ó*å. Table 3 Óy p Fig. 6. Gas chromatogram of liquid products from polystyrene pyrolysis. 1. Benzene 5. α-methyl styrene 2. Toluene 6. Styrene dimer 3. Ethyl benzene 7. Styrene trimer 4. Styrene monomer Fig. 5. Effects of gas velocity on the yields of oil and styrene monomer in a fluidized bed reactor Table 3. Effects of temperature on the oil composition(epsw, U G =0.5 m/s) Product 400 o C 450 o C 500 o C 550 o C 600 o C 650 o C B T EB SM α-ms SD ST B: benzene, T: toluene, EB: ethylbenzene, SM: styrene monomer, α-ms: α- methylstyrene, SD: styrene dimer, ST: styrene trimer

5 Table 4. Effects of gas velocity on the oil composition(epsw, Temp.= 600 o C) Product 0.3 m/s 0.4 m/s 0.5 m/s 0.6 m/s B T EB SM α-ms SD ST B: benzene, T: toluene, EB: ethylbenzene, SM: styrene monomer, α-ms: α- methylstyrene, SD: styrene dimer, ST: styrene trimer >? IJ 3 W6 \ (500 o C)d D ÓÔ% F- IJ W{ ì W6 L 400 o C ã d D \d gg _ D Ó*% &. P-, 89, :À;, é896 L O)z \6 $ m $ D Ó*å. PS6 O)z 23K6,"X³ IJ W ì W V(C 13 -C 24 )6 }ˆd 3 W V(C 6 -C 11 )6 ) 6 Ó,+f{\ Qž [13, 14]. d, ¾ X³8d IJ 3 W6 ˆ D 8 º- O)z \»Ð 400 o C 1\6 O)z \ IJ 3 W T9- ) z Q8 -q \% ˆ & 600 o C@6 \»Ð )z m IJ 3 Wd ) 6 }ˆ 9: ˆ &8 ;< o C 1\¹ # - \»Ð mƒ ˆ &. } "6 Ì} m Q6»(Table 4) "(U G =0.3 m/s)d IJ 3 W ` t m6 m D Ó*å. f\- O)z 45 PS qãº# )z2 Q ) - m )N p mƒ ˆ " $d ) 6 }ˆY 89f :À ; ) _% 6 ) AB- D Ó*! CD. { f=(à Q6» '- O)z X³8 Ë9̈ 6 ã O)z \6 ã } "6 ã Z![# ED ˆ &%, ¾ X³8d } "6 ã m Q6»Z ˆ «ã D ÓFD ˆ &. 4. È vød ¾ X³8d QX H?IJ(GPPS){ 7 M N H?IJ(EPSW)D O)z¹ ˆ@Ê. m Polystyrene ˆ X³ \6 $ gg $ D Ó*å % Q ˆ (Y Oil ) 600 o C, IJ 3 W ˆ (Y SM ) 550 o Cd Ï 'D Ó*å. P-, Y Oil f Y SM "6 $, m/sd Ï'D Ó*å. Ï' Y Oil f Y SM Á GPPS Y L ƒƒ 93 wt%(600 o C){ 65 wt%(500 o C) Ó EPSWY L ƒƒ 95 wt%(600 o C){ 60 wt%(550 o C) Ó. ¾ X³ 8d PS6 O)z4 O)z X³ \ m6» «ã D Ó*å% } " m6 ˆ «ã D Ó*å. È,+ /078 a 8G M 036,+!0(f 56: A-B-1)6 Q: ˆ@2å H 03 _ xœ. 1. Sasse, F. and Emig, G.: Chem. Eng. Technol., 21, 777(1998). 2. Hirose, T., Takai, Y., Azuma, N., Morioka Y. and Ueno, A.: J. Mater. Res., 13, 77(1998). 3. Ide, S., Ogawa, T., Kuroki, T. and Ikemura, T.: J. of Applied Polymer Sci., 29, 2561(1984). 4. Song, H. S. and Hyun, J. C.: Korean J. Chem. Eng., 16, 316(1999). 5. Puente, G., Arandes, J. M. and Sedran, U. A.: I&EC Research, 36, 4530(1997). 6. Kim, J. S., Lee, S. B., Lee, K. W, Choi, M. J. and Kang, Y.: Theories and Applications of Chem. Eng., 6, 4337 (2000). 7. Shun, D. W., Ghim,Y. S., Cho, S. H. and Son, J. E.: J. Korea Solid Wastes Eng. Soc., 10 (1993). 8. Liu, Y., Qian, J. and Wang, J.: Fuel Processing Technology, 63, 45 (2000). 9. Kaminsky, W. and Kim, J. S.: J. of Analytical and Applied Pyrolysis, 51, 127(1999). 10. Kim, S. D. and Kang, Y.: Chem. Eng. Sci., 52, 3639(1997). 11. Kim, J. S., Woo, K. J., Kang, Y., Nam, C. H. and Kim, S. D.: J. Chem. Eng. Japan, 34, 185(2001). 12. Pinto, F., Coast, P., Gulyurtlu, I. and Cabrita, I.: J. of Analytical and Applied Pyrolysis, 51, 57(1999). 13. Woo, O. S. and Broadbelt L. J.: Catalysis Today, 40, 321(1998). 14. Kim, S. S., Chun, B. H., Park, C. J., Woon, W. L. and Kim, S. H.: HWA- HAK KONGHAK, 38, 732(2000). HWAHAK KONGHAK Vol. 39, No. 4, August, 2001