Optimization of factors influencing the sacrificial anode used in cathodic protection

مقدم أطروحة جامعية

Kaskah, Sad Ilyas

مشرف أطروحة جامعية

Saraji, Wisam Kazim Hamdan
Hafiz, Muhammad H.

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

-In this work the problem which studied to solving it is the large number of experiments which are required to obtain on the optimum factors effects to achieve optimum protection potential by sacrificial catholic protection.

Any traditional way to study this objective by process which has four factors and three limits will be need to 81 experiments in minimum while in this work by using Box-Behnken Design (BBD) method this objective is satisfied by just 27 experiments.

BBD is a powerful method with no embedded factorial or fractional factorial points where the variable combinations are at the midpoints of the edges of the variable space and at the center.

BBD statistical experiment design and the response surface method (RSM) are used to investigate the effects of the four independent variables on the response functions and to determine the optimal conditions minimizing the potential protected.

For protection potential assessment the BBD receives (resistivity of environment, sacrificial anode alloy, distance between anode and cathode and surface area of the structure to be protected) as input and gives the protection potential and current density as output.

The experimental work is made depend on design of experiment (DOE).

The experiment design matrix is build based on BBD and its' consisting from 27 experiments.

Experimental work including many steps, inspection and analysis the conditions work at Al-Zubair harbour, laboratory tests (potentiostatic tests) to evaluate sacrificial anode alloy which selected in this work, and do all 27 experiments as a simulation to the real work conditions at Al-Zubair harbour to collect the data which is used in analysis and optimization.

The manners used to obtain the results are divided into two main parts, the first part is analysis of factors effect and this part is PDF created subdivided into two types; individual factors effect and interaction pair factor effect.

The second part is optimization to predict the optimum protection potential with optimum factor levels and this part is divided into three types firstly is response surface method (RSM), secondly mean based levels optimization and third type is variance of mean optimization.

By applying BBD with their analysis tools we get many results and the important results which are the factors individual effectiveness on the sacrificial catholic protection (SCP) process are the resistivity which has the greatest effect on the potential protection (rank = 1) followed by sacrificial anode alloy type (rank = 2), surface area for structure protected required (rank=3) and distance between anode and cathode (rank = 4).

The interaction of sacrificial anode alloy and cathode area (24) has significant effect on CP process with the limits which are used in this work while the other factors interaction (1 2 1 3 1 4 2 3, 3 4) has insignificant effect on the limits which used in this work.

The final predict equation by RSM is Potential (predicted) = 806 72 (resistivity) + 0.333 (anode alloy) 2 (distance) 8.7 (cathode area) + 36 (resistivity) 2 92.8 (anode alloy) 2 + 15.75(cathode area) 2 14.5 (resistivity / anode alloy) 11.25 (resistivity / cathode area).

But this optimization method is not satisfied the optimum protection potential and it was (-752 mV) and this value is less than optimum experiment potential (-969 mV)The optimum protection potential obtained in this work by applying theoretically mean equation Potential optimum = 891+ 843 + 803 + 815 + 823 -1013 = 4 (790.53) mV and (-979 mV) practically and that ensures the precision advantage for the Box-Behnken Design practically.

In the last variance optimization gives same mean optimization method in this work.

التخصصات الرئيسية

الهندسة المدنية

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305082