Current Situation And Countermeasure Analysis Of Cathodic Protection Of Multiple Coatings In The Same Pipeline

There are different types of outer coating on the old pipeline,and the common situation of the oil asphalt and the three layyer PE coating is common.The two kinds of coatings have a large gap in the insulation performance,which directly affects the size of the cathodic protection current needed,thus affecting the negative protection effect of the whole pipeline.In the process of pipeline operation and management,due to the inhomogeneity of the coating performance,the under protection and overprotection of the cathodic protection results are common on the above old pipe line.If the pipeline anticorrosion measures or the cathodic protection system are not designed properly,the overprotection is not only a waste of investment,but also the cathodic stripping may be caused;when the protection is under protection,it will be strict.The operation safety of the pipeline is seriously affected.Therefore,the scientific and quantitative assessment of the reliability of cathodic protection measures,research and exploration of the application of cathodic protection for the same pipeline of various coatings,in order to supplement and enrich the existing protection means,is an urgent technical problem to be solved in pipeline integrity management.Through collecting and studying the data of the pipe section,the paper makes statistics on the basic data of the 3 lines to be studied,and combines the effectiveness evaluation data of the cathodic protection to master the current situation of the cathodic protection of the line changing pipeline.Carry out field tests on 3 target pipelines,collect relevant test data,and carry out potential tests in different ways for target pipelines.At the interface of 3 pipes,two kinds of interface positions were carried out at 5 sites,and 4 groups of corrosion specimens were installed on the target pipeline(Luwei line)to understand the corrosion status of the interface position of the multi coating pipeline coating.The corrosion conditions at the junction of the same pipeline and the 3PE coating pipeline and the two kinds of coatings were tracked.The adaptability of the optimization design and evaluation software for multi line common cathodic protection is carried out.The numerical simulation calculation of the target pipeline is carried out by using the multi line common cathodic protection optimization design and evaluation software,and the verification shows that the calculation coincides with the numerical requirements.Study on the distribution of cathodic protection potential distribution under the common condition of petroleum asphalt and 3 PE coating.The main factors affecting the cathodic protection of various coatings in the same pipeline include soil resistivity,surface resistivity of asphalt coating pipeline,distribution position of two kinds of coatings,two kinds of coating pipe length ratio,different types of anode ground bed and anode The distance between the ground bed and the pipeline is greater than 100m,which has little effect on the potential distribution of the pipeline.The influence of various factors on the potential distribution and protection effect of various coating cathodic protection systems in the same pipeline is investigated.The distribution of cathodic protection potential distribution of various coatings in the same pipeline is put forward,and 9 regular countermeasures for the cathodic protection under the common condition of the oil asphalt and 3PE coating are obtained.The verification shows the calculation interval character Field test values..In this paper,the effectiveness of cathodic protection for various coatings in the same pipeline is studied.The cathodic protection effect of the pipeline under this special condition is studied,the applicable evaluation criterion for the effectiveness of cathodic protection is established,and a reasonable cathodic protection method is put forward.The method of providing cathodic protection for pipelines shared by petroleum asphalt and three layer PE coating has a certain theoretical and practical value for improving the management of long distance pipeline.