What is the service life of sodium hydroxide stress corrosion cracking inhibitor for oil refining carbon steel equipment?
Thread Content
Based on the previous background on SSCC prevention and control of LPG storage tanks, the service life of corrosion inhibitors is affected by working conditions and agent types. The specific duration is as follows: Conventional circulating water system corrosion inhibitors such as sodium tungstate dihydrate compound system can operate stably for 3-6 months in dynamic circulating water systems, and the protective life in static water bodies can reach more than 6 months without frequent replenishment. Special film-forming corrosion inhibitor for liquefied petroleum gas storage tanks is an imidazoline film-forming corrosion inhibitor for SSCC prevention and control. The protective film formed under normal working conditions can be stably maintained for 3-12 months and needs to be replenished regularly to maintain the integrity of the film layer. Corrosion inhibitors under special high-temperature working conditions In the high-temperature oil and gas refining environment, organic corrosion inhibitors are susceptible to thermal decomposition, and the effective protection life is only a few hours to a few days. Continuous filling is required to continuously replenish the agent. The actual service life of the corrosion inhibitor will also be affected by the medium flow rate, temperature, and impurity content. Regular corrosion monitoring must be carried out to timely add the agent to ensure the protective effect.
The author's analysis is very good, and these data are of great reference value for actual selection. A few additional points that may need attention: In actual working conditions, pH, temperature fluctuations, and impurity ions (such as chloride) will significantly affect the film formation speed and life of the corrosion inhibitor. It is recommended to regularly monitor electrochemical parameters or weight loss to judge the replenishment cycle. Imidazoline film-forming agents are easily washed away at high temperatures or high flow rates. If necessary, you can consider adding molybdate or zinc salt to improve the durability of protection. It is recommended to dynamically adjust the corrosion inhibitor replenishment frequency based on actual on-site operating data (such as corrosion rate, hydrogen flux). Different manufacturers have large differences in formulas, and the specific life span needs to be subject to actual measurements. Of course, this is just general experience. For specific devices, it is best to conduct targeted tests or consult material corrosion experts.