Study On Pre-filming Corrosion Prevention Technology Of A Sour Gas Pipeline

In the exploitation of sour gas field,due to the existence of carbon dioxide,hydrogen sulfide and elemental sulfur,the corrosion of gas-gathering pipelines can be directly affected.In order to prevent and control the corrosion of the pipelines in sour gas field,regular injection of corrosion inhibitor is used to control corrosion at home and abroad.G pipeline is a dry gas transmission pipeline containing hydrogen sulfide and carbon dioxide.After two intelligent pigging tests,it is found that natural gas with high hydrogen sulfide and carbon dioxide can cause serious internal corrosion to the gas transmission pipeline even after dehydration of triethylene glycol.Based on the research on the application of corrosion inhibitors in sour gas field at home and abroad,this paper starts with corrosion inhibitor screening evaluation,field test and the corrosion effect,taking G pipeline as an example,study the research on corrosion inhibitor pre-filming technology,the main results are as follows:(1)Through the evaluation of corrosion inhibitor performance,comparison of sustained release performance of slow release film and compatibility of corrosion inhibitor with three glycol solution in the field,two kinds of corrosion inhibitors suitable for G pipeline were screened out.(2)Through the comparison and analysis of three kinds of common pre-filming technology in foreign countries,the pre-filming process of the Holland PNS company was selected for the G pipeline.(3)The principle and characteristics of the common corrosion monitoring methods at home and abroad are compared,and the corrosion coupon and the resistance probe are selected to monitor the corrosion effect of the G pipeline.The residual concentration analysis of the gas phase inhibitor and the nondestructive hydrogen flux are used to evaluate the pre-filming effect of the G pipeline corrosion inhibitor.These methods were feasible and effective.(4)The dosage of the inhibitor was determined by the formula V = 2.4DL.(5)The pre-filming period of two inhibitors was determined by the pre-filming effect evaluation.Study on pre-filming corrosion prevention technology of a sour gas pipeline provided technical support for the corrosion control of G pipeline.At the same time,it is of significance for the sour gas field corrosion in this area.