| The South China Sea is vast in area and has a lot of precious natural resources.However,its harsh natural environment such as high temperature,high humidity,and high salinity has put a severe test on offshore platforms and other offshore engineering equipment.In order to reduce the corrosion of marine engineering equipment and prolong its service life,people usually use anti-corrosion coating and cathodic protection to protect the marine steel structure.However,as the service life increases,the corrosion medium gradually penetrates the anti-corrosion coating and reacts with the metal under the coating,resulting in the gradual peeling of the anti-corrosion coating.With the consumption or failure of the anode in the cathodic protection system,the protective capacity of the cathodic protection system gradually decreases.In turn,the entire marine engineering equipment is at risk of corrosion.These corrosion risks are usually implicit and difficult to find directly.In order to discover these corrosion risks in time,it is essential to install an appropriate corrosion protection monitoring system.Aiming at the practical needs of a test platform in the South China Sea,this paper has designed a corrosion protection monitoring system based on engineering practicality,which can realize the online monitoring of parameters of the platform such as underwater external surface potential,sacrificial anode’s current,and underwater anticorrosive coating’s impedance.Meanwhile,it could also evaluate the sacrificial anode’s consumption status,remaining life and underwater anti-corrosion coating’s damage rate.After the actual sea test,the reliability and effectiveness of the corrosion protection monitoring system were verified.First of all,according to the DNV specification and the boundary element numerical simulation method,the cathodic protection system of the platform is checked with precise boundary element conditions.At the same time,the corrosion protection monitoring technology commonly used in the current project is studied,and the monitoring methods of the underwater external surface potential of the platform,the release current of the sacrificial anode and the impedance of the underwater anti-corrosion coating are determined,and a method considering the influence of the coating damage rate is proposed evaluation method of sacrificial anode life.Then,based on the previous research results,the structural forms,pre-packaged processes,and software functions of the sensors and the host computer in the corrosion protection monitoring system were designed,and the system layout scheme was designed according to the structural characteristics of the external surface of the platform.In addition,it briefly introduces the on-site installation,commissioning process before and after launch of the corrosion protection monitoring system.Finally,the state of the system before operation was checked through the offshore commissioning test of the corrosion protection monitoring system,and then through the long-term offshore operation test,the stability of the corrosion protection monitoring system,the effectiveness of the online monitoring method of the state of the anticorrosive coating and evaluation method of remaining life of sacrificial anode considering influence of coating breakage rate was verified. |
PDF Full Text Request