Cathodic Protection System Design Framework

13th Selected Issues of Electrical Engineering and Electronics (WZEE), 2016

The presented paper describes the principles of cathodic protection (CP) of underground tanks using the sacrificial anode as well as method of calculation of the potential, current density and polarization distribution on all sides metallic tanks buried underground. Differential equations with boundary conditions are developed and next solved by FEM in 2D and 3D cases. The main goal of this publication is the computation of such distribution of the external protecting electrodes where protected structure will not corrode and next the calculations in 2D and 3D were compared. The article shows that it is sufficient to use 2D analysis for which the speed of equations solution is significantly larger than in 3D space.

2015

Cathodic protection is an electrochemical technique used to prevent the corrosion phenomena for metallic underground materials and pipelines. It is essential because the external coating could be insufficient for corrosion protection. The real corrosion protection level of a structure, a pipeline for example, is usually evaluated through measures made in few points of the pipe, generally once a day. In this way, the protection level of the whole structure is unknown. Advanced cathodic protection simulation software are spreading in order to fill this gap, especially for application in the oil and gas industry. The aim of this study is to evaluate what kind of advantages can derive from the application of simulation software to model the cathodic protection level for natural gas distribution pipeline. A real case study has been conducted in order to examine the real potentiality of this instrument. The main evaluated aspects are about the improvement of the process control effectiven...

Nigerian Journal of Technology, 2021

The investigation in this paper provided an outline of the used scientific models for the cathodic protection frame-work modeling and relatively assessed current modeling strategies. The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) investigation was applied in six alternatives and five criteria. Among the criteria, a high criticality was put on the strengths in complex geometries and the unwavering quality of the results. From the study outcomes, it can be established that the best cathodic protection modeling technique considering a number of factors like, the strength in complex geometries like subsea structures, simplicity of use, time allotment required for estimation, industry track record and robustness of the results was the Finite Element Method (FEM) with a score of 0.73 which is a value of relative closeness to the ideal solution of 1. The second best modeling procedure was Boundary Element Method (BEM) having a value of 0.72, while the least ...

Iraqi Journal of Chemical and Petroleum Engineering, 2013

Iraq has a huge network of pipelines, transport crude oil and final hydrocarbon products as well as portable water. These networks are exposed to extensive damage due to the underground corrosion processes unless suitable protection techniques are used. In this paper we collect the information of cathodic protection for pipeline in practical fields (Oil Group in Al Doura), to obtain data base to understand and optimize the design which is made by simulation for the environmental factors and cathodic protection variables also soil resistivity using wenner four terminal methods for survey sites; and soil pH investigations were recorded for these selected fields were within 7-8, and recording the anodes voltage and its related currents for the protection of underground pipelines. Modeling enables the designer to build cathodic protection for buried structure and predicting the places of anodes sites and its operating voltages and currents under various operational conditions, and compa...

This paper deals with the evaluation of the subsea pipeline integrity through the combination of potential profile, electric field gradient and the modeling of the electric field originated by the bracelet galvanic anodes by Finite Element Method (FEM).

2015

Cathodic protection is an electrochemical means of corrosion prevention techniques to ensure that the structure to be protected becomes the cathode of an electrotlytic cell. The purpose of present work is to design an impressed current cathodic protection system (ICCP) to protect 11 uncoated steel tanks partially buried in a soil with a resistivity of 600 ohm.cm with varying content temperatures and surface areas, located in Petronas Portsudan bulk depot (P.S.B.D.). A study was carried out to the previously installed system and it was found that it was faulty. The scope of work included the design and determination of all necessary materials of ICCP of tank bottoms utilizing Silicon cast iron anodes. The results showed that the cathodic protection system requires a total of 25 anodes with a 3.6 Amp current output per anode, distributed as shallow horizontal groundbeds according to the tank’s current demand. The groundbeds are located 3 meters deep and 3 meters away from the orifice ...

WIT Transactions on Engineering Sciences, 2009

Computational modelling of cathodic protection (CP) systems involving thin multi-layer media represents a real challenge in terms of accuracy and efficiency required in the numerical calculation. In the case of CP for transmission pipelines, these long metallic structures are usually buried a distance H (approximately a metre or so) below ground level and extend horizontally typically more than ten thousand times H. A number of impressed current anode beds are distributed along the pipeline, providing protection against corrosion of the structure. In addition, the vertically stratified nature of the soil needs to be considered in the model, in order to obtain more accurate representation of the environment. This is particularly relevant when considering the effect of different types of rocks, soil porosity, or water saturation, at different depths. This type of scenario requires three dimensional modelling involving a thin multi layered electrolyte, with a typical aspect ratio (lateral extension to thickness) of the order 1E4 to 1E6. The paper presents an efficient and accurate computational approach based on the Boundary Element Method for simulating the level of protection against corrosion of the pipeline as well as current densities and electric potential in different points of the soil. The resulting modelling approach is then applied to assessing real case scenarios. The simulation approach considers the non linear electrode kinetics on the metal surfaces in the form of polarisation data and also the internal resistance of the pipeline and other electrical connections involved in the CP system. Example applications are presented showing how the model can be used to predict the "signatures" associated with different defect types in the pipe coating.

B&H Electrical Engineering

Cathodic protection system is commonly employed approach for the protection of the metallic infrastructure placed in electrolyte against corrosion. Adequate design of the cathodic protection system requires the determination of electrical potential and current density distribution on the protected object surface that meets the defined criteria. In this paper, the application of the direct boundary element method in conjunction with Newton-Raphson method was considered for the calculation of the electric potential and current density distribution on the surface of the cathodically protected underground object. The considered method was applied on the sacrificial anode cathodic protection system of the underground pipeline. The non-linear boundary conditions of the electrode surfaces of the cathodic protection system are taken into account. The method was used to determine the current density and electric potential distribution on the external wall of the protected pipeline.

Environmental Research Journal, 2012

Corrosion of metals has been known to be disastrous in industrial setup and even more so in the petroleum industry. Transportation of crude oil, gas and processed petroleum products takes place in pipes, most often steel pipes. Several methods have been used to combat the problem of buried pipeline corrosion among which is cathodic protection. Cathodic protection of a buried steel pipe using zinc anode and a 12 volt DC power source has been studied. The experiment was set up in the laboratory for 35days using moist soil sample from Niger Delta region of Nigeria and weight loss recorded every seven days. Results show that after twenty one days, the protected steel began to lose a very small amount of weight, compared to weight losses for unprotected steel and the anode. A total of 0.04g of the cathodically protected steel was lost after 35days compared to a loss of 0.43g for the unprotected steel. The experiment shows that 90.69% protection was achieved with cathodic protection method of corrosion control. The work demonstrates that buried steel pipes in Niger Delta region of Nigeria can be cathodically protected against failure with very small quantity of electricity. It is recommended that this study be carried out in a soil with high salinity, typical of the Atlantic Ocean shore of Niger Delta where several oil pipelines are laid.