Application of Extreme Value Analysis for Degradation Characteristics Evaluation of Organic Coating on Internal Bottom Plate of Oil Storage Tank

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Bruce Curtis
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1 274 Application of Extreme Value Analysis for Degradation Characteristics Evaluation of Organic Coating on Internal Bottom Plate of Oil Storage Tank Koya TOKUTAKE Haruki NISHI Naoya KASAI Shinji OKAZAKI A reasonable evaluation method is proposed based on an extreme value analysis for the appropriate management of a high performance anticorrosion organic coating applying to the internal surfaces of the bottom plates of oil storage tanksthe analysis was applied to the values of constant phase elementcpeparameters extracted from the field impedance data obtained from the actual oil storage tanksit was found that the representative degradation characteristics of the coating before the formation of visual defects can be evaluated by using the probability plots of the maximum values In additionthe comparative evaluation of the degradation degree of the coatings between oil storage tanks was performed using this method Key words : Oil storage tanksorganic coatingsimpedance measurementscpe Extreme value analysis 1) 2) 30

2 275 2)3) 4) 5)6) tan 7) tan khz cm 2 8) 5)6)9)12) CPEConstant phase Element CPE R resistanceccapacitance L inductance R C L 9) CPE R C L 10)12) j Z 1 n T Z CPE [Z Z jz ] j [ j 2 [rads] n CPE [ n JHPI Vol No 31

3 276 T CPE [s n ] m F ( 2)x ( )x2 CPE T 1 CPE n f n n n n 12)13) CPE CPE Gumbel 14) Aziz 15) 8) 16) Gumbel Frechet 8)15)21) Gumbel Frechet F ( 1)x ( )expx )15) F n ( x) n n m m x Gumbel x k Frechet 18) GEV 18) 1 F( x) 1xGEV GEV m Gumbel Frechet GEV 17) Tank A B kl m Tank A Tank B Fig 32

LCR GPIB LCR Fig Van Westing CPE i CPE d 22) CPE d 2) CPE Fig ZviewScribner AssociatesInc CPE CPE d T

4 277 Hz khz Fig Measured regions of the organic coatings of two oil storage tanks Fig Schematic diagram of impedance measurements by using LCR meter Fig wt wt NaCl cm cm cm 2 LCR A : Agilent TechnologiesInc LCR GPIB LCR Fig Van Westing CPE i CPE d 22) CPE d 2) CPE Fig ZviewScribner AssociatesInc CPE CPE d T d n d CPE CPE d CPE i T n n n Tank A Tank B CPE d T d n d T d T d 10 9 n d n d JHPI Vol No 33

278 Fig Degradation model of the coating on internal bottom plate of an oil storage tank Fig Schematic representation of a method of extracting maximum values 18)21) Fig Representative field data for

5 278 Fig Degradation model of the coating on internal bottom plate of an oil storage tank Fig Schematic representation of a method of extracting maximum values 18)21) Fig Representative field data for a vinyl ester resin organic coating containing glass flakes and the fitting curves using the equivalent circuit of two CPEs in parallel Fig Tank A CPE d T dmax n dmax Tank A Tank B Gumbel 20)21) AB n dmax T dmax Gumbel Fig FigGumbel ln ln F( x) x lnln F ( 1)x ( ) 11 x1 1 Gumbel Fig n dmax 5)6)22) CPE n n 34

6 279 Fig Comparison between the regression lines of the Gumbel plots for maximum values of CPE parameters obtained from two oil storage tanks for the following n d and T d An enlarged view of Fig is inserted in that figure Fig Comparison between the regression lines of the Frechet plots for maximum values of CPE parameter of T d obtained from two oil storage tanks n n Gumbel FigTank B Tank A ln ln F n dmax 1 1 Tank B Tank A 1 Tank B Tank A F( x) n dmax Tank B Tank A n Tank B Tank A FigT d 10 9 T d 10 9 Gumbel Chaves 20) Frechet Gumbel T d 10 9 Frechet T d 10 9 Frechet FigFrechet ln{lnf ( x) lnx2 1 lnm In x22 F 2 ( x) Frechet 2 JHPI Vol No 35

7 280 2GEV GEV 2 GEV 2 Tank AB s n FigFrechet T d 10 9 Frechet T d 5)6) Frechet Fig m Tank B Tank A F( x) T d Tank B Tank A n dmax Tank B T dmax Frechet n dmax Gumbel Tank B CPE d CPE d n dmax Gumbel T dmax Frechet 36

8 281 pp pp pp Funke W Blistering of paint films and filform corrosion ProgOrgCoatVol No pp Van Westing EPMand Ferrari GM In situ determination of the loss of adhesion of barrier epoxy coatings using electrochemical impedance spectroscopy ProgOrgCoatVol pp Lobnig REVillalba WGoll KVogelsang JWinkels ISchmidt RZanger Pand Soetemann J Development of a new experimental method to determine critical pigment volume concentrations using impedance spectroscopy Prog OrgCoatVol pp pp pp Jorcin J BOrazam MEPebere N and Tribollet B CPE analysis by local electrochemical impedance spectroscopy ElectrochimActaVol pp Schiller CAand Strunz W The evaluation of experimental dielectric data of barrier coatings by means of different models ElectrochimActa Vol pp Hirschorn BOrazem METribollet BVivier VFrateur Iand MusianiM Constant Phase Element Behavior Caused by Resistivity Distributions in Films JElectrochemSocvol No ppcc Amand SMusiani MOrazem MEPebere NTribollet Band Vivier V Constant phase element behavior caused by inhomogeneous water uptake in anti corrosion coatings Electrochim ActaVol pp Musiani MOrazem MPebere NTribollet B and Vivier V Determination of resistivity profiles in anti corrosion coatings from Constant phase element parameters ProgOrgCoat Vol pp Gumbel EJ Statistics of extremes Colombia UnivPress Aziz PM Application to the statistical theory of extreme values to the analysis of maximum pit depth data for aluminum Corrosionvol pp tt pp Tiryakioglu M On the size distribution of fracture initiating defects in Al and Mg alloy castings MaterSciEngAVol pp Rivas DCaleyo FValor Aand Hallen J M Extreme value analysis applied to pitting corrosion experiments in low carbon steel : Comparison of block maxima and peak threshold approaches CorrosSciVol pp Melchers RE Extreme value statistics and long term marine pitting corrosion of steel Prob EngMechVol pp Chaves IAand Melchers RE ; Pitting corrosion in pipeline steel weld zones CorrosSci Vol pp Chaves IAand Melchers RE Extream value analysis for assessing structural reliability of welded offshore steel structures Structural Safety vol pp Van Westing EPMand Ferrari GMand De Wit JHW The determination of coating performance with impedance measurements In sitiu determination of loss of adhesion Corros SciVol No pp TEL FAX tokutake@frigojp TEL FAX nishi@frigojp TEL FAX nkasai@ynuacjp TEL FAX sokazaki@ynuac JHPI Vol No 37

Organic coating capacitance measurement by EIS: ideal and actual trends

Electrochimica Acta 44 (1999) 4243±4249 Organic coating capacitance measurement by EIS: ideal and actual trends F. De orian*, L. Fedrizzi, S. Rossi, P.L. Bonora Laboratory of Industrial Corrosion Control,