Research On Corrosion Behavior Of Core Components Of Reciprocating Compressor In Jiannan Gas Field

In this paper,aiming at the corrosion problem of the cylinder and valve of the reciprocating compressor in use in Jiannan Gas Field in the coexistence environment of H₂S and CO₂,cylinder（A105 carbon steel）and valve（F316 stainless steel）are used as the research objects,and the corrosion experimental device-high temperature is used as the research object.Corrosion weight loss experiments were carried out in an autoclave.Corrosion rates of both materials under different influencing factors（p H value,H₂S partial pressure,temperature,Cl^-concentration,etc.）was tested by the weight loss method,and the influence of each factor on the corrosion rate was quantitatively evaluated by the grey correlation analysis method.The corrosion behavior of A105 carbon steel and F316 stainless steel under various factors was tested by electrochemical workstation.Using electron microscope（SEM）,energy dispersive analyzer（EDS）,X-ray diffraction analysis（XRD）and other micro-analysis methods,the surface micromorphology of both materials and the components of corrosion product film were studied,and the A105 carbon was explored.Corrosion behavior of steel and F316 stainless steel.The research conclusions are as follows:（1）The HP-HT reactor was used to simulate the corrosion environment of Jiannan Gas Field,and the effect of different factors on the corrosion of A105 carbon steel and F316 stainless steel was studied.The experimental results show with the change of p H value,H₂S partial pressure and Cl-concentration,the corrosion rate of A105 carbon steel also changes greatly,and the three have a competitive and synergistic relationship.The order of their influence on corrosion is as follows:Cl^-concentration>H₂S partial pressure>p H value.Under the conditions of various factors,the corrosion degree of F316 stainless steel is mild corrosion,The corrosion degree of A105 carbon steel is in the severe corrosion stage.（2）The experimental data of corrosion weight loss were analyzed by gray correlation analysis method.On this basis,the influence degree of each factor on corrosion was determined,and the corrosion correlation degree was obtained,so as to find out the key factors affecting the corrosion rate of A105 carbon steel and F316 stainless steel.The influence of A105 carbon steel is:Cl^->H₂S partial pressure>p H value>Ca²⁺>Mg²⁺>temperature>HCO₃^->SO₄^2-;the influence of F316 stainless steel is:H₂S partial pressure>Ca²⁺>Cl^->p H value>Mg²⁺>temperature>HCO₃^->SO₄^2-.According to the results,the most critical factors leading to the corrosion of A105 carbon steel and F316 stainless steel are Cl^-,H₂S partial pressure,p H value and Ca²⁺.（3）Through microscopic analysis,it is found that the corrosion rate of A105 carbon steel in the simulated medium containing sulfur generally increases with Cl^-potency,and corrosion product films with different compositions are formed,and the main product is iron sulfide.On the other hand,with the increase of SO₄^2-concentration of F316 stainless steel,the surface micro-morphology does not change much,and a layer of corrosion product film containing Cr compounds is formed on the surface of the coupon.It plays a very good protective role in itself,thereby slowing down corrosion.（4）Using the BP neural network algorithm,the corrosion rates of A105 carbon steel and F316 stainless steel under p H value,H₂S partial pressure,temperature,Cl^-concentration and other influencing factors were predicted.The comparative analysis of prediction results and corrosion experiment results shows that the average error between the prediction value and experimental value of A105 carbon steel and F316 stainless steel is less than 15%,which meets the engineering error range and provides support for the prediction of corrosion rate of reciprocating compressor cylinder and valve in Jiannan Gas Field.