The Carbon Dioxide Corrosion Mechanism And Corrosion Inhibitor Optimization Of Shuangliu Gas Storage

Qin-shen peak shaving gas storage in natural gas pipeline engineering(double six gas storage)of injected gas is the qin dynasty,shen natural gas pipeline to dry gas,component analysis showed that produced gas for moisture,carbon dioxide content is higher,extremely easy to form carbon dioxide corrosion,leakage,explosion and other accidents often occurred in the endanger safety in production enterprises.Therefore,improving the safety reliability and service life of oil and gas pipelines has a positive impact on enterprises' saving and maintenance costs,reducing operating costs,stabilizing production,increasing production and increasing efficiency.In order to solve this problem,this paper on the static method and dynamic method is used mainly for L485,L360 and L245 steel carbon dioxide corrosion electrochemical behavior and its influencing factors were studied,found L485,L360 and L245 three kinds of pipeline steel carbon dioxide corrosion with soaking time,temperature,CO2 partial pressure,the increase of gas velocity has the trend of corrosion intensifies,carbon dioxide corrosion electrochemical behavior and can be divided into three stages,namely is the "bare metal" stage,the stage of corrosion current density increased,L485,L360 and L245 three kinds of pipeline steel by carbon dioxide corrosion;During the period of "film coverage",the increase of corrosion current density in this stage is hardly increased,and the corrosion product film has a certain inhibitory effect on carbon dioxide corrosion.During the "reaction" phase,the corrosion current density continues to increase,and the corrosion has an increasing tendency.After through to the three kinds of steel corrosion products under different temperature and corrosion status analysis,found L485,L360 and L245 steel under 50 ???,the corrosion product film without adhesion,a metal uniform corrosion condition.Around 50 ??? to 90 ???,the metal surface is not closely FeCO3,local corrosion is serious.When the temperature is above 120,the metal surface produces dense film,and the corrosion rate decreases.Project team to L485,L360 and L245 steel temperature,pressure,impact test,found that pressure respectively for 8 mp,L485,L360 and L245 steel at 80 ???,82 ??? and 81 ???,the corrosion rate of metals has a maximum value.Finally,it was found that L485,L360 and L245 had the highest corrosion rate at 2.1Mpa,1.9Mpa and 2.2Mpa respectively.After the study of CO2 corrosion behavior and mechanism,through the analysis of the "bubbling effect",ac impedance test,to test the performance of 21 kinds of corrosion inhibitors,are preliminary scope of application and the best working concentration of each inhibitor and mixed according to the Key rules,combined with the produced gas properties,the corrosion inhibitor dosage calculation,and finally determine the resistance to carbon dioxide corrosion inhibitor implement optimization scheme for:SYZK resistance to carbon dioxide gas phase corrosion inhibitors(oil soluble)plus the amount of 94.36 kg/h,use the concentration range of 50 to 100 mg/L,the best concentration of 100 mg/L,suitable for coating or continuous filling;The dosage of cro-316 anti-carbon dioxide inhibitor(oil soluble)is 94.36kg/h,and the concentration range is 50?90 mg/L,and the optimal concentration is 90 mg/L,which is suitable for coating or continuous injection.Champion anti-carbon dioxide inhibitor(water solubility)is 193.2kg/h,with a concentration range of 50?100 mg/L,and the optimal concentration is 90 mg/L,which is suitable for continuous injection.