.316 L Stainless Steel Corrosion Behavior, The High Chlorine Ions Glycol Solution

The oil and gas fields often use the glycol to prevent the formulation of natural gas hydrate. In order to recycle the ethylene glycol, it must use the glycol dehydration system to removal the water in recycling glycol rich fluid. Because the formation water includes the high chloride ion and cause the recycled glycol high chloride content, the glycol evaporating tower made by 316L stainless steel has emerged corrosion phenomena.For conducting the corrosion injury research to the glycol evaporation tower, autoclave, stress corrosion testing machine combined with SEM, EDS, XPS, XRD modern surface research methods were used to have studied the corrosion behavior of 316L stainless steel in the high chloride ion of ethylene glycol solution. The experiment studied that the temperature,Cl-,Fe3+ concentration and flow rate effects on the dynamic behavior of 316L stainless steel corrosion; The stress corrosion cracking sensitivity of 316L stainless steel was also studied in the ethylene glycol solution of different concentration of chloride ion at 60℃.Finally, the tendency of 316L intergranular corrosion was determined.The experimental result shows that the corrosion rate of 316L stainless steel increases with rising of temperature in the ethylene glycol solution of high chloride ion. When the temperature is over 60℃, the corrosion rate increases rapidly and up to maximum 0.0781 mm/a to 120℃; when the temperature is 120℃and Cl- concentration is 36516mg/L, the 316L pitting behavior affects larger Fe3+ concentration is greater than 388 mg/L; a comparison was carried out to corrosion rate when the temperature is 120℃, Cl- concentration 36516mg/L, Fe3+ concentration 776mg/L under static and flow rate of 2m/s, and found that static corrosion rate is greater than the dynamic corrosion rate.The corrosion test specimens were observed in the scanning electron microscope and found that corrosion holes shape is round under static, but corrosion holes shape is sharp horseshoe under dynamic. The Static and dynamic of the corrosion products are basically the same, and is made up of Cr2O3, Fe2O3, and FeOOH. When the temperature is 60℃and Cl- content is 36516mg/L,316L stainless steel has no obvious tendency to stress corrosion cracking.316L stainless steel has a tendency to intergranular corrosion.