82-01.fm

Transcription

1 w y wz 8«( 2y) 57~61, 2005 J. of the Korean Society for Environmental Analysis p w w Á Á w w» y l Analysis of Influence Factors and Corrosion Characteristics of Water-pipe in Potable Water System Jae Seong Rhee, Kyung Hee Min, and Su Won Yi Water Environment and Remediation Center, Environment & Process Technology Division, Korea Institute of Science and Technology (KIST), 39-1, Hawolgok-dong, Seoungbuk-gu, Seoul , Korea The experiment was investigated for studying the ion generation and corrosion rates that occured in the pipe system. Application of water treatment device named SB in water-pipe systems produces the electromotive force from galvanic reaction. This electromotive force is named as galvanic electronic. Above reaction decreases leakage, scale, rust, slime such as bacteria inside of water-pipe. Thus, SB can be used as the pipe protection device in the water distribution system. A study uses the loop type water circulation system connected with iron pipe and galvanized steel pipe with/without SB. Results showed that the Fe concentrations in the water pipe system without SB connection was about two times higher than these of the water pipe system with SB connection. The corrosion rates of the pipe system installed SB were about 17~28% less than these of the pipe systems with out SB. Therefore the control of pipe rust by SB was proved by this study. Key words: iron pipe, galvanized steel pipe, zinc, water pipe, corrosion, scale 1. x y y öe w ƒ. ƒ œ w š œ» w w ƒw š w w v š. x ù f Áòw œ w 2 w w. y w w ƒš w z w, hw Áý, w w w û ¾ üš. 1,2) ƒ xk w š ƒ 0.3 mg/l ù š k w. w 3) w w ü ü f j k. ü f m w j w w. 4) 20 w 90 œ k 60% ƒ 14 w p w ƒ wz 5 ü ƒ To whom correspondence should be addressed.

2 58 Á Á ƒvw, 20 ù. w w 5,000 wš š, w z w vwƒ j w v w y. 5) 1980 z ü, f w wš š š f wš w z ˆ œ» ù ü ù ù. ù», f wš w» wš. 6) y w w ƒ y f wš w, 1824 š w wš w l w. l e w sƒwš d w l w š w. 2. x 2.1. x e yx l x e Fig. 1. x e (Fe) (Zn) w y loopx e ƒ 2 4 loop w š rv 1 ƒ loop ew. 7) 15 mm w š ¼ ƒ 300 mm 1 q v ü t w 50 mm 2 ƒ loop ew. e(sb) 15 mm š ¼ ƒ 120 mm e w š e ew loop ew loop w. w d w q v ü xr(coupon) ƒ Loop 2 ¼ ƒ 50 mm ew. w w» L5 w x l p sƒw» w Fig. 1 x ³ x e w. e ƒ yw xk 60 w wš 24 w. ƒ loop, 0.5 m/sec wš 7 L w. yƒ w w e j» l y g ù mw w v ƒ. w w Loop w 7 L w. Table 1 ƒ loop w d ³ m xr l. Fig. 2 ƒ 15 mm, 15 mm Fig. 1. Experimental setup (Loop).

3 p w w 59 Table 1. Operating parameters. Parameters Type of experiment Total pipe length Flow rate Source of water Volume of water Running Time Temperature Value Loop type 400 mm 0.5 m/sec L5 tap water 7 L 60 hour Room temperature xr w t w z 0.1 mg ¾ d w 15 mm, ¼ 50 mm q v ü xr ew» x w. x óù z 20% NaOH 1 L 200 g Zinc dust ƒw w xr 5 ò w. 8) w» w xr d wš» w y w w UV-Visible spectrometer Varian Cary 50 probe UV-Visible Spectrometer w š, w y Ÿ d w w. AAS Hitachi Z-8200 Polarized Zeeman Atomic Absorption Spectrophotometer w. t d w w z w Fe 2+ d w. 3. š l z w» w e ew loop( ) ew loop w. Table 2 ü xr ew d w w š, Fig. 3~Fig w w z ƒ loop w w. Table 2. Corrosion rate. Pipe mm/yr mpy Fig. 2. Experimental setup (Coupon). w MPY(mils penetration per year : 1 mpy = in) ƒ l ƒ š. mm/yr w mpy(1 mpy = mm/yr) yw w. 9) Fe Fe_SB Zn Zn_SB d w» w q v ü ew xr w z d w Eq. 1 w w. Fig. 3. Effect of SB and types of pipes on Fe 2+ concentrations.

4 60 Á Á Fig. 4. Effect of SB on the water absorbance values by iron pipe. Fig. 5. Effect of SB on the water absorbance values by galvanized steel pipe. mm yr 87.6W = DAT where, W = mass loss (mg) D = density (g/cm 3 ) A = area (cm 2 ) T = running time (hour) (Eq. 1) (Fe) e ew (Fe_SB) e ew ƒ 18% š, e ew (Zn-SB) ƒ 17% w Loop 60 ww Fe y AAS w 24 w. Fig. 3 (Fe) (Zn) Fe y v w. (Fe) e e w (Fe_SB) Fe y e ew ƒ s³ 67% Fe ƒ û. ƒ Fe y e e w (Zn-SB) ƒ s³ 56% Fe ƒ û y ùk ü y Loop 60 ww y w» w UV-Vissible w 24 w Ÿ d w. Fig. 4 (Fe) e e w (Fe_SB) Ÿ y v w. e ew Ÿ 0.1, ew Ÿ ƒ 0.1~0.2¾ d.

5 p w w 61 Fig. 5 (Zn) e ew (Zn_SB) Ÿ y v w. e ew Ÿ 0.11, ew Ÿ ƒ 0.05~0.15¾ d. 4. xr ü ew d w z mm/yr w 4ƒ w. (Fe) e ew (Fe_SB), e ew ƒ 18% š, w e ew (Zn-SB) ƒ 17% w. e ew w ƒ d e z û y w. 60 loop w z w, (Fe) e ew (Fe_SB) Fe y e ew ƒ s³ 68% Fe ƒ û. w Fe y e ew ƒ s³ 56% Fe ƒ û y ùkü. w e ew loop Ÿ ƒ 0~0.11 û d. e ew ƒ w Fe û d š Ÿ ƒ û d e z û y w. mw Loop ƒ Fe ƒ y w š e wš z. š x 1.,, e (1999), z ƒ e w, wy œwz, 14(4), pp ½, ½ (2001), ü w Ÿ w p z, w y wz w w wz œ w tz, pp Wagner l., Kuch.A., Corrosion ( ), Vol.54, No.4,84-85(1985) 4. ½, ½ (2002), ü f w Ÿ w p z, w wz, 16(3), pp x(2005), x, z y z 38z y s. 6. g yr (2005),, f, < accessed x,, w, (1998), n y, wy œw z, pp Laboratory Corrosion Testing of Metals for the Process Industries NACE standard TM (1976 Revision). Reprinted by permission, Natural Association of Corrosion Engineers. 9. y, w, y, ½Ÿ (2004),, q y», 687 pp.