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1 Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006, pp q mm Furan oi l sm o m i s Çom Çm s m d p e ( o 24p r, o 13p }ˆ) Development and Field Installation of a System of Simultaneously Removing Dust and Volatile Organic Compounds from Furan Process in Foundry Jin Soo Park, Jae Hak Jung and Tae-Jin Lee School of Chemical Engineering and Technology, Yeungnam University, 214-1, Daedong Gyeongsan, GyeongBuk , Korea (Received 24 November 2005; accepted 12 January 2006) k t ql t~p l k p. k p o p t l p tp l p t~p Œp. t qp furan rp p rp p lv, p t furan r p l t l rp. Furan rp ~ t l l p o r p v q vp furan t l p t~p p l p ml p p o VOC. rsll furann p t l l, p o dm vp p vp furan vp pl slqp l rp n, p p sl p e l p l r k l ml p p. l p sl p opp r r sl p r o o VOC m vvp el p o VOC v er edšp r k ql rn m. k p n VOC 0ppm, v 4µg/m 3 p sl p lp, slq p sl npp m., n p n r, qlp p eˆ pl. h Abstract A foundry makes various machinery parts made by iron. For manufacturing machinery parts, they usually uses wooden mold with molding sand and pour the molten iron into wooden mold through inlet. A foundry have many processes including Furan process, In Furan process workers prepares a wooden mold in the molding sand. So they fixes wooden mold in sand housing and then they fill the molding sand in the sand housing. Molding sand should be sticky enough to sustain the shape of wooden mold, so several materials are needed to prepare the suitable molding sand. The first step of Furan process is making the molding sand with molding sand and Voltaic Organic Compounds (VOC) and the second step of Furan process is pour the molding sand into the wooden molding housing. This two step of process generated noxious VOC and various size of dust. So the process is very dirty and dangerous one. Because of these, Workers frequently shrink out of the plant. The company related with foundry usually faced on the difficult situation for engagement and always have shortage of hiring problem. Through this study, we developed a system which removes toxic VOC and dust simultaneously. We design and construct real system and install it at real plant. Before setting up this system, the working surroundings VOC (for formaldehyde) 15 ppm and Dust(for PM 10 ) 8,000 µg/m 3. After setting up this system, working surroundings is improved by VOC (for formaldehyde) 0 ppm, Dust(for PM 10 ) 4 µg/m 3, and the work evasion factor is removed. So we contribute to solve hiring problem of this company and increasing the productivity also. Key words: Voltaic Organic Compounds(VOC), Dust, Removing Technology, Furan To whom correspondence should be addressed. jhjung@yumail.ac.kr 136

2 t qp Furan rl o vp er edš q l VOC sm o o ts lp, q, lp lp ql p lk, l m l r rp 3D lsp k r p l rp k p., ts rl v ts rl n t p ~ rp o l o (VOC, volatile organic compounds p VOC )p el r p p f slqp p~l o p r sls p r l p l np t, v p pr kp rp p ts ll pr v r o v r l q rp r v r p q r l edšp p t ts ll rp l p. VOC p~l o p ˆ d eˆ ~ qn l qlqp qlqp l m p v. nl 1991 o te p VOC p o skp ~ l, p, EU l l VOC p ms o v o vp r p o l VOC vp r l rp r l m p. l v 1995 r rkl VOC e r rs p lp, rvlp n r, Š l p VOC vp lqp r edš(tms)p k. vp n ql l ˆk p ek l ql p n lk l slqp l m p t. vp l n vl p q k v v vp ppˆ,, v v v p 1 r npp p. pl p t l p Table 1l, r pq v n tp Table 2l ˆ l. pp Table 1, 2l p v l t r o v p r [1] VOC o VOC } l r, r, r } p p. VOC } o v v mm v k v o n p rk p, p t, p p o r kr vp mr o p l,, plasma p, p rk p. sp l p VOC } p q rp ˆ Table 3 } vp Table 4l p,, p p o VOC r p m lp l p r p VOC k 10 mg/m 3 r p mm r p p, p l ˆ n t r np p n on p ˆ. Fig. 1l de scrubberm p s rrp de scrubber o eˆ e } tlk p, p t ll l Œq, v r np o o v p l o r v kp p Ž l [2-8] s o v r o l }ˆ p r qnl t, oe,, vr,, rr p p, t r p t p pn l rel pqp 50 µm p p r 7.5 m/sec p p pq r o l pn. oe ~ p k~ ˆp vp d eˆ o l d reˆ oe p pn dr n d p n p l pq p yp p p r l r. r d p n p n p, v p tkp p l. Table 1. Modification of ambient air standard by year <Dust generated by a foundry> (unit: µm/m 3 ) ~ ~ ~ Measurement TSP Yearly average: 150 µg/m µg/m 3 Deletion β ray absorption Daily average: 300 µg/m µg/m 3 Deletion β ray absorption PM 10 Yearly average: 150 µg/m 3 80 µg/m 3 70 µg/m 3 β ray absorption Daily average: 300 µg/m µg/m µg/m 3 β ray absorption TSP: Total Suspended Particle, PM 10 : Dust below diameter 10 µm Table 2. An Emission standard of particle according to Environmental laws Facility Standard Permissible standard(mg/m 2 ) (~ ) ( ~) Facility using liquid fuel More than 6000 m 3 /h Less than 6000 m 3 /h Facility using solid fuel More than 6000 m 3 /h Less than 6000 m 3 /h Facility dealing with a metal Arc furnace, Induction furnace Melting furnace, Cupola Sintering furnace Heating furnace Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

3 138 v Ërq Ëpˆv Table 3. The Merits and defaults of a treatment technology for VOC Strength Heat Incinerator - Widespread Technology Catalyst Incinerator - Able to use the existing boiler or Incinerator - Complete destruction of VOC Flame phlogiston - Suitable for treating a mixing VOC Adsorption - Simple operation - Able to treat a mixing VOC - Able to recollect VOC Absorption - Low-priced installation and treatment - The effective method in case of selecting the suitable solvent Condensation - There is no by-product excepting Liquid VOC - Simple operation - There is no restrictions as to the feasible range of VOC Biological Treatment - The most effective method of treating VOC under 20 ppm - Small size - Low-priced installation and treatment Weakness - The maximum VOC concentration of catalyst incineration is under 10,000 ppm - Decreasing efficiency in case of changing the concentration of VOC - Require the second equipment in case of generating by-products - Unsuitable for treating a material including sulfur of nitrogen - Generate the secondary pollutant - Increasing cost in high concentration - Increasing a supply of absorbent In the use of an aplastic absorbent - After design an absorption tower, unable to change a composition of VOC - Increasing cost because of an chemical addictive - Impossible to treat for heterogeneous VOC - re-boiling VOC to prevent freezing in the condenser - Unable to use under 3,000 ppm - Unable to use under saturation concentration in a condensing point - Decreasing tradability in the influx of an excess VOC - Lack of a accumulated data Table 4. Comparison of a treatment technology for VOC Permitted limit (unit: scfm) Thermal oxidation without heat recovery (1-20,000) Thermal oxidation with heat recovery (20,000-1,000,000) Catalytic oxidation (1-1,000,000) Adsorption (200-1,000,000) Absorption (1,000-1,000,000) Condensation (1-2,000) Bio-filtration (1-1,000,000) Membrane Technology (1-150) UV oxidation (2, ,000) Treatable VOC Thermal oxidation: Aliphatic HC, Aromatic HC, Halogen HC, Alcohols, etc. Ketones, etc Catalytic oxidation: Aliphatic HC, Aromatic HC, Alcohols, etc., Ketones, etc Adsorption: Aliphatic HC, Aromatic HC, Halogen HC, Alcohols, etc. Ketones, etc Absorption: Alcohols, etc. Ketones, etc Condensation : Aliphatic HC, Aromatic HC, Alcohols, etc. Ketones, etc Bio-filtration : Aliphatic HC, Aromatic HC, Alcohols, etc. Ketones, etc Membrane : Aliphatic HC, Aromatic HC, Halogen HC Alcohols, etc., Ketones, etc. UV oxidation : Aliphatic HC, Aromatic HC, Halogen HC, Alcohols, etc., Ketones, etc Fig. 1. Concentration comparison by unit price A) Heat Incineration, B) Catalyst Incineration, C) Activated Carbon-no regeneration, D) Activated Carbon-regeneration, E) Multiple Absorbent, F) Wet Scrubber, G) Chemical Oxidation, H) Biological Precipitator, I) Bio-filter r p n vp d rl p 0.2~10 µm p qp pq vr k~ nl e r p rp p t rp p. r p qrp v d el r p, qp p o44 o k qp r pp p, r pq e d l pp l p. d p l p p k l l p dp tn p nl r r., vr l n n k~ } l n k vmmp ppˆ p. l vr p q m p q p n p. l l d l p p pq qk qnp pl. l l p rvp vr,,, rr p t rl p pl r p. 1 µm p p pq vr,, t p q nl p r 0.001~5 µm r p pq rr r p l p r. qnl p r vp kp q l erp. rrvv k r l p carrier gas ( ) pm eˆ pm p vpql l pq pm eˆ. pm pq rv vrž p vv p r. vv l r vp v p ˆ l p vv p r. kl v} p ˆp l ql n v r l v pp qp l rr l l vv q r p s l. l vv v p vp v o p eˆ n q. p o p q n

4 t qp Furan rl o vp er edš q l 139 Table 5. The properties of dust collector Equipment Mechanism Shape Separable Size(µm) P(Pa) Max Temp.( o C) Surface Dust collector Gravity sedimentor Gravity Plane >20 150> 1,000 Centrifugal sedimentor Centrifugal force Cylindrical plane >10 2,000> 1,000 Electric precipitator Electrostatic force Plane/Cylindrical plane > > 1,000 Crash dust collector Inertial force Plane > > 1,000 Target Dust collector Membrane filter Inertia/Diffusion/Blocking Fiber/Particle >0.1~0.01 3,000> 250 Bag house Direct Blocking Fiber >0.01 2,000> 250 Ceramic filter Direct Blocking Particle > ,000> 1000 Cleaning dust collector Inertia/Diffusion/Blocking Waterdrop >0. 20,000> - pp o, p rv, p vr sls l l n pl., vv n kn vv s e p ˆ q Table 5l ˆ l [9-14]. 3. m o A p n t ql q l p vp kp k ql q p ek n p o p d lp qlq l vp m. A p t Š flow mixer rp v k furan p v m m qlp p VOCp m p d lp slp m, r slp,, vm, k v p opp r ppp k pl m o v r e v rp PM 10 TSP l 10 µm p p v v v p Žk m. 10~20 l e p mmr ll l q mm l t l m. v p e p o n v r n mp, q e v r p. Ò n v r n e p l s eˆ. Ò r vr e p l l rqrn r n v r l q. Ò TSPm PM j r v rqrnl r. qlq p v p (1)e p m. qlq p v [mg/m 3 ]=( v v / ~ ) =( v /(o Ë e )) (1) q r PM 10 TSP 8,000 µg/m 3, 22,000 µg/m 3 p l. v p q qle ˆ p v r p p. v p TSP 2,000 µg/m 3 l 125,000 µg/m 3 p p. p ql q qle t r l p p., PM 10 r 500 µg/m 3 l 101,000 µg/m 3 p ppp Fig. 2. The result of TSP measurement in company A. Max: 22,000 µg/ m 3, min: 30,000 µg/m 3 Fig. 3. The result of PM 10 measurement. Max: 8,000 µg/m 3, Min: 800 µg/m 3 p m. A p n v p PM 10 p 8,000 µg/m 3, TSP 22,000 µg/ m 3 pmp, TSPm PM 10 p r Fig. 2m Fig. 3l ˆ lp v p k kk o 300 pp rq vp l Fig. 4l ˆ l VOC r e p s p o d VOC p targetp n n r o nrp p ˆp tn mmnpp q e qlp m. e p sl ql air sampler pn l sl qp } } e e e e p l FID q GC pn l m. Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

140 v Ërq Ëpˆv Fig. 4. The result of TSP analysis in company A (Size: 0.001 µm~ 54.429 µm). Fig. 5 p p t GC p, Fig. 6p A p ql t q GC p, Fig. 7p ekp p k 0.35Í l GC p, Fig. 8p ekp p lžk mp 10Í l GC p.

5 140 v Ërq Ëpˆv Fig. 4. The result of TSP analysis in company A (Size: µm~ µm). Fig. 5 p p t GC p, Fig. 6p A p ql t q GC p, Fig. 7p ekp p k 0.35Í l GC p, Fig. 8p ekp p lžk mp 10Í l GC p. Fig. 5l ˆ v kk peak Fig. 6l ˆ. p p o vp Ž p vp kp r e p m. retention time 1.004l ˆ peak k p p Ž, l peak k m Ž l. ql tp ql k k 15 ppm, k m k 87 ppmp p. 4. l VOC s o m n t Š rp v k VOC o e Fig. 5. The result of GC analysis for air. o44 o k

t qp Furan rl o vp er edš q l 141 Fig. 6. The result of GC analysis for working surroundings. qlq r~p l n km p p., t l furan k p l flow mixer t Š v el VOC tp ql e mp p VOC el l Fig.

6 t qp Furan rl o vp er edš q l 141 Fig. 6. The result of GC analysis for working surroundings. qlq r~p l n km p p., t l furan k p l flow mixer t Š v el VOC tp ql e mp p VOC el l Fig. 9m p flow mixer Š r p eˆ p } p q ˆ p p nvp p duct edšp l qlqp r rl vv VOC el v edšp, v VOCm vp r r } l p v VOC } edšp } p q pl. p p sl q p slp p r l rp p p vr k. r p l p p p v VOC p q m. p v VOC qlq p r m rl sll vqp v k ˆp t Š p n mp p ˆp l p vv lrp l ol p ll n p } p ˆ ~ w p. n edšp m Fig. 10l ˆ l. pl o VOC v er edšp r o n p np ˆ l. vp PM 10 TSP e m t lp l ov Œq p vp le sp vv e t bag filter ep q r p. v l vv np r Œq n r v p n n p ˆ [10, 15, 16]. A p flow mixer rp o vv l tp k m. Type: pulse jet, e, l e l (A/C ratio): 2~5 m/min Pa: 5~8 cm H2 O, Pm: 10~15 cm H 2 O(20~80 cm H 2 O ) Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

142 v Ërq Ëpˆv Fig. 7. The result of GC analysis for formaldehyde. Duct o : 10 m/s housing o : 60 m/min p ov l : Ø100~Ø300, L3000~L10000 l qv:, ld l Ž: lˆd hard coating Stack p: Duct Ø 3~8 vv n p p l.

7 142 v Ërq Ëpˆv Fig. 7. The result of GC analysis for formaldehyde. Duct o : 10 m/s housing o : 60 m/min p ov l : Ø100~Ø300, L3000~L10000 l qv:, ld l Ž: lˆd hard coating Stack p: Duct Ø 3~8 vv n p p l. vv p blower n : 200 m 3 /min v v : 20 mg/m 3 200m 3 /min = 4,000 mg/min = 240 g/hr = 5.7 kg/day(max) Ë k 6 Kg/day n l p( qs ): 2~4 m vv v (trial & error): 0.15 m = m 2 } v n p vv v rp p p l. vvl housing r( qs p): 2 m 2.5 m = 5 m 2 o44 o k l p( qs ): 2~4 m vv v (trial & error): 0.15 m = m 2 l trial & errorl p p p l. : 200 m 3 /min Dust size: (duct o : 10 m/s p t) Ë Size: 0.25 (0.55 m)2 π =0.24m 2 Ëo : 200 m 2 min m 2 = 14 m/sec housing ( housing o : 60 m/min p t) 200 m =40m/ min 0.83 m/sec 5.0 m 2 vv φ0.15 L = m (vv 2 r) l

8 t qp Furan rl o vp er edš q l 143 Fig. 8. The result of GC analysis for ethanol. 200 m 3 min = 2 m/ min 0.03 m/sec 113 m 2 VOC v e l p VOC s m kl p q r p, r ˆ, rm p, k 3 vl l e p mp, r 1g total VOC } (emission k)p lp pl. Fig. 11 Fig. 12 ql VOC p k m m k l r 1g total VOC } (emission )p lt p., 3 v rp kn rp ~rp l l r p l Table 6l ˆ l. ol ˆ r e r p ˆ p rm p o r p. m mll p ˆ rm p p p kk o m dl rp p kk e p m. Fig. 13l ˆ l. ˆ rm p p ˆ l p rp ˆ m m p p k plp, r p n n m p p t furan rp m o l n n p p p., l p rp VOC k 10 mg/m 3 r p mmp pl p r t r p rp p Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

144 v Ërq Ëpˆv Fig. 11. The total emission amount of an absorbent 1 g for alcohols. Total Emission Amount(µl): Σ[5min 100ml/min Concentration (ppm) 1000 µl/ml] Fig. 9.

9 144 v Ërq Ëpˆv Fig. 11. The total emission amount of an absorbent 1 g for alcohols. Total Emission Amount(µl): Σ[5min 100ml/min Concentration (ppm) 1000 µl/ml] Fig. 9. The example of hood system desired for installing in the field. Fig. 10. The schematic diagram of flow mixer s hood. Fig. 12. The total emission amount of an absorbent 1 g for formaldehyde. Total Emission Amount(µl): Σ[5 min 100 ml/min Concentration(ppm) 1000 µl/ml]. Ž l ˆ rm p n m e ˆp n p. q v k 15 ppm, k m 87 ppmp p n ˆ 1gp n k m p n k 40, k n le k 40 r l emissionp e q ppp k. rm p n n k m, k k 50 emission p eq p Fig. 11 Fig. 12l lt p. n p t p lv ˆp tp n p m ml/minp k 15 ppm k m 87 ppmp 1gp ˆp } k 4,000 mlp ˆ 1gp } p k p. qp vv e v flow mixerp sle p k 1p 4e p p r 6 o(k 180p) e v n p rp kp m.v, 4e o44 o k Table 6. The treatment amount and economic efficiency of absorbents Absorbent Quantity Price Total Activated carbon 3.5~4 l/g inexpensive good Zeolite NaX 4.5~5 expensive moderate γ-alumina 2~2.5 expensive bad p = 43,200 p 43,200 r n p. qp vv blower 200 m 3 /min p 200,000 l/minp o p kr qt p k 15 ppm, k m 87 ppmp 200 m 3 /minp k p p n t p kk. opp k 500~1,000 r p p 200,000 = 200 v k 200 l/minp

10 t qp Furan rl o vp er edš q l 145 chamber l l l p m rm p 120~130 o C, ˆp k 200 o C sr p m. rp ˆp Fig. 14l ˆ l p pn l r ~ t n v rp p 6 o p p n p. 5. m Fig. 13. The desorbed amount of absorbent according to temperature. k 15 ppm, k m 87 ppmp mm } p. 6 o } mm p ,200 l = 8,640,000 lp } p. 1 g ˆp mm } p 4 l p 2,160,000 gp ˆp 6 o rl q lp n o k 2.1 tone r p kp n. k 2.1 tonep ˆp p. p ˆp 0.56 kg/l p. v 3,750 l p p ˆ chamber n. o el p ˆ chamberp 5,000 l r m rm p rp p chamber l m. r q o chamber l p k lp tp f VOC ˆ eˆ edšp m. ˆ rm p p ˆ m r 5-1. m Fig. 15l vv rp d p d p lt p. Fig. 15l slq p l sl p n krrp d p v VOC p ll d n lp q slp pp r (ql r d n ve pp) o s l p p., v VOC el r s qlq n l l p Fig. 16p ql dp lt p. p n l bag filterl p l vv ep vv m s p ˆ r m p p r vˆp v p. Fig. 14. The schematic diagram of absorption tower. Fig. 15. Comparison of work surroundings for Flow Mixer s Process. Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

146 v Ërq Ëpˆv Fig. 16. The picture of system for removing simultaneously dust and VOC. 5-2. l sl ql k 2~3 o nr s q slq p pp ll. q l rp edšp v v v VOC } t e o q e p r l k.

11 146 v Ërq Ëpˆv Fig. 16. The picture of system for removing simultaneously dust and VOC l sl ql k 2~3 o nr s q slq p pp ll. q l rp edšp v v v VOC } t e o q e p r l k. ~w, vp n k 20 l q rp e l TSP k 22,000 µg/m 3, k 3,000 µg/m p ll p 3 PM 10 p n k 8,000 µg/m k µg/m p 3 ll ppp k re k pl. q l nr v k 2 o 10 l ~ e kp TSPp n 16 µg/m 3, 10 µg/m p l 3 PM 10 p n k 4µg/m 3, 0µg/m p 3 l. p p Fig. 17l ˆ l. TSPp n sl tp v Íp TSP v } lt p PM 10 p n v 99.67Íp v } p lt pp PM p n r v kkp p 100Íp vp } l. vp vl p p p TSPp n rp vp 300 p m mp. p v vp rp pl k 50 pp lk v pq p pp r v l p ll. rl µm p vpq mp l v pq 0.5 µm v p. o44 o k Fig. 17. After setting up a system, the result of measurement for PM 10 and TSP. PM 10 l l µm q pqp p ll p vp } š l mp l n r pl. Fig. 18, Fig. 19l sll p TSPm PM 10 p m vp ˆ l. VOC v e l k q rp GC datal p k 15 ppm p k m 87 ppmp, ˆ VOC l. q 0.1 ppm o v GC k m k m v kk GC le l e p m p p ˆ p k pl. Fig. 20l p sl p GC ˆ l. l v Fume, ˆ o p el r p p p ts l r v VOC p o o p el ll p o v VOC r p lr o 3D lsp p lsp sl p l p p o ql p p mm rp p sp lp pp p. v 99.6Í p VOC 99.9Í p p r ˆ p

After setting up a system, the result of analysis for PM 10. Fig. 20.

12 t qp Furan rl o vp er edš q l 147 Fig. 18. After setting up a system, the result of analysis for TSP. Fig. 19. After setting up a system, the result of analysis for PM 10. Fig. 20. After setting up a System, the result of GC analysis. Korean Chem. Eng. Res., Vol. 44, No. 2, April, 2006

13 148 v Ërq Ëpˆv l p lp p t p. r l r o mmop e r p Œq r p p pnp n o lp rn pp p. l ql vp e r m VOC l p p r el v l slq p slp p p erl v mmop e r p sl p r p vrrp p, p p pv r p p p pp p p. y Kang, S. H., Lee, T. J. and Bae, K. S., Adsorption of Methylene Chloride and Freon-12 on the Some Adsorbents, HWAHAK KONGHAK, 26(4), (1988). 3. Kang, S. H. and Paik, S. K., Kinetics of Batch Adsorption on Active Carbon from Aqueous Fuchsine Solution, HWAHAK KONGHAK, 10(2), 51-56(1972). 4. Kang, S. H. and Paik, S. K., Kinetics of Adsorption in Fixed Bed Packed with Active Carbon from Aqueous Fuchsine Solution, HWAHAK KONGHAK, 11(4), (1973). 5. Park, Y. G., Moon, J. W. and Ko, M.-S., Estimation of the VOC Fugitive Emission Released from Process Units, HWAHAK KONG- HAK, 41(3), (2003). 6. Hwang, K.-S., Choi, D.-J. and Gong, S.-Y., The Thermal Regeneration Characteristics of Volatile Organic Compounds on an Activated Carbon Bed(I): Adsorption Step, HWAHAK KONGHAK, 36(2), (1998). 7. Song, K. S., Seo, Y. S., Jeong, N. J., Yu, S. P., Ryu, I. S., Lee, S. N., Choi, J. J. and Jung, J. D., Incineration Characteristic of Volatile Organic Compound in the Regenerative Catalytic Oxidizer, HWAHAK KONGHAK, 41(3), (2003). 8. Kim, H. J., Yang, J. C., Jung, K. T., Shul, Y. G., Chun, K. Y., Han, H. S., Joe, Y. I. and Kim, Y. W., Performance of Ceramic Composite Membrane for the Separation of VOCs, Korean J. Chem. Eng., 18(5), (2001). 9. Choi, H. K., Park, S. J. and Lim, J. H., A Study on the Characteristics of Improvement in Filtration Performance by Dust Precharging, Korean J. Chem. Eng., 19(2), (2002). 10. Kang, S. H., Ahn, H. K. and Ryoo, P. J., The theory and applications of Particulate control technology, Yeunganam University press, Gyeungsan(2004). 11. Saleh Abd El-Aziz M. Atia, Study on Performance Improvement of a Water Powered Scrubber for Coal Dust Control, Graduate School of Seoul University, Seoul(1992). 12. Lee, T. S., A Study on the Optimization of the Discharge and Dust Collection Characteristics of Dry Electrostatic Precipitator, Graduate school of Ulsan university, Ulasn(1998) Peters, M. S., Timmerhaus, K. D. and West, R. E., Plant Design and Economics for Chemical Engineers, 5 th Ed., McGraw-Hill, Seoul (2003)U o44 o k

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<30372E31362D323028BDC5C7F6C5C32DB9CCB1B970626D292E666D> k m v r1 r1 16~20 (2009) J. Korean Academy of Managed Care Pharmacy Vol. 1, No. 1 Pharmacy Benefit Management iç 1# x sƒ, 1 w w w Overview on Pharmacy Benefit Management in USA Kyung Eob ChoiGand Hyun