Lifetime Estimation for Metal Sheet Cladding and Roofing in Wang-Noi Combined Cycle Power Plant

Abstract

Abstract. This research aimed to study corrosion behavior and evaluated lifetime of the metal sheet cladding and roofing when exposed to actual usage environment using electrochemical impedance spectroscopy (EIS) test method. The sample plates were galvanized steel grade 550 and thickness of 0.6 mm which was coated with 55% of Al-Zn and a polyvinylidene fluoride layer which were prepared for metal sheet cladding and roofing of Wang-Noi combined cycle power plant in Phra Nakhon Si Ayutthaya province of Thailand. The specimens were tested under wet-dry cyclic condition by immersing in the simulated acid rain solution for an hour, then the specimen was removed from the solution and allowed to dry in open air environment with exposing to sunlight for 7 hours a day. The wet-dry cyclic treatment was repeated 3 times a day which was considered as the severe usage condition therefore the 3 wet-dry cycles might lead to extreme corrosion due to raining about 3 times a day. The EIS was used to evaluate the corrosion rate of specimens after the wet-dry cyclic treatment. Analysis results were expressed in Bode and Nyquist plot and used to calculate for corrosion current by using Stern-Garry equation which was used to calculate corrosion rate by using Faraday's law. The first order polynomial regression was appropriate to estimate corrosion rate beyond the real time usage of the metal sheet, and total mass loss over time was estimated by integrating the polynomial regression model to obtain the governing equation of the total mass loss of the cladding and roofing sheet in the usage environment. The evaluated mass loss over 20 years of usage under severe condition was estimated which had the maximum penetration of 1.04004 milli-inch and could be converted into penetrating thickness of 26.41 m.

Evaluation and Modeling of Corrosion Rate of Selected Roofing Sheets Using Tetraoxosulphate (vi) Acid and Trioxonitrate (v) Acid as Simulated Acid Rain

“…Ujam et al [1] defined corrosion as an attack on metallic materials due to reaction with its environment. In other words, it is electrochemical oxidation of metal with strong oxidation agents such as oxygen and sulfate [2,3]. A typical example of this type of reaction is the formation of iron oxide which is as a result of electrochemical oxidation.…”

“…Oji and Okon; CSIJ, 28(4):[1][2][3][4][5][6][7][8][9] 2019; Article no.CSIJ.53598 Model equation for weight loss and rate of corrosion for 1mole solution of H 2 SO 6E-06x 4 -0.0002x 3 + 0.031x 2 -0.8595x + 6.9997 R = 2.4E-04t 3 -0.0006t 2 +0.062t -0009t -0.0192 R² = 0.9963 Model equation for weight loss and rate of corrosion for 1mole solution of HNO 2E-06x 4 + 0.0002x 3 -0.0041x 2 + 0.0144x + 0.9182 R = -8E-06t 3 + 0.0006t 2 -0.0082t + 0.0144 R² = 0Model equation for weight loss and rate of corrosion for 0.5mole solution of H 2 SO 8E-06x 4 + 0.0005x 3 + 0.0007x 2 -0.5009x + 6.6976 R = -3.2E-05t 3 + 0.0015t 2 + 0.0014t -0026t -0.0214 R² = 0.9948 Model equation for weight loss and rate of corrosion for 0.5mole solution of HNO -07x 4 -2E-05x 3 + 0.0003x 2 -0.0114x + 0.9346 R = 1.6E-06 -6E-05t 2 + 0.0003t -0.0114 R² = 0.9949 of 0.46 g during the period of study.…”

A Prediction Algorithm for Paddy Leaf Chlorophyll Using Colour Model Incorporate Multiple Linear Regression

“…For example, the regression analysis is used to predict the factors affecting the use of Information Technology in small and medium businesses [12]. Furthermore, regression analysis is used in predicting science and social science, as the Lifetime prediction of a metal sheet [13], the adsorption of Free Fatty Acid from Crude Palm Oil on Magnesium Silicate Derived from Rice Husk [14], the factors that influence satisfaction in the lives of the American people [15], and the size of the leaf in soybean [16]. There are two types of variables in the regression analysis; independent variables and the dependent variable.…”