Study On The Corrosion Reasons Of The Ethanolamine Desulfurization System Of Jingmen Petro-chemical Co

With the increase of crude oil processing capacity,the development amine desulphurization has been more and more important.In the purification of sulfur refinery gas,MDEA is in the dominant position.However,in the process of using the desulfurization solution,serious foaming phenomenon has led to the desulfurization device appearing to block liquid and decreasing the processing capacity,at the same time,the solution can also cause the foam to entrainment.In addition,most of the low carbon carbon steels are used in the desulfurization unit,and the service environment mostly exist in the H2 S and CO2.Therefore,in the production operation process,it is inevitable that the corrosion of pipeline equipment will occur,so that it will seriously affect the safety of the desulfurization unit and stable operation.The five sets of the ethanolamine desulfurization system in Jingmen corporation had different degrees of MDEA degradation,heat stable salt accumulation,amine liquid foaming,equipment corrosion and so on.Thisexperiment mainly analyzes the samples of several sets of the desulfurization system in Jingmen corporation.We useHSS determination,foaming experiment,simulated corrosion experiment to study,in order to detain the cause of equipment corrosion and amine solution foaming.In this study,the total content of heat stable salt and the ion distribution of the rich and the poor were first studied.It is concluded that the heat stable salt content of rich and poor coking solution is higher,and the rich and poor of sulfur solution is lower,the content of formic acid,acetic acid is higher.The total content of the solution heat stable salt of five sets of desulfurization unit in Jingmen Petrochemical Company is in the order of:coking rich solution,coking poor solution,1#catalytic rich solution,1#catalytic poor solution,2#catalytic rich solution,2#catalytic poor solution,sulfur rich solution,180 diesel oil hydrogenation rich solution,sulfur poor solution,180 diesel oil hydrogenation poor solution.The foaming experiments were carried out to prepare different concentrations of ethanol amine solution,proved that in the low temperature,high flow rate and high concentration,it is easier to foam,and the foaming is more stable.Jingmen Petrochemical five sets of desulfurization unit solution have a certain degree of foaming phenomenon,sulfur rich solution and 1#catalytic rich solution are the typical.We also analyzed the properties and foaming conditions of ethanol amine solution,only the WuHan Petrochemical Company solution accorded the technical requirements of SY/T6538-2002.Then the corrosion analysis of carbon steel was carried out under the simulated conditions,and the kinds of corrosion products were analyzed by EDS energy spectrum.The result was that the corrosion products contained S,O elements.And the simulation experiment was conducted to explore the effects of different time,temperature,extraction and other conditions on the corrosion of carbon steel under the condition of amine solution.It showed that there was a balance point of corrosion,the corrosion rate was slow and even stopped,and it is concluded that heavy hydrocarbon residue in the desulfurization solvent will aggravate corrosion.Finally,orthogonal experiments were carried out to analyze the influence factors of thermal degradation.It was concluded that the temperature was the most influential to the degree of degradation,and the content of formic acid and acetic acid in the heat stable salt anions of the degradation products were the highest.The heat degradation data of three industrial pure MDEA under different conditions showed that the weight loss percentage of the solution were different.