The approach to the commissioning of a heat-recovery steam generator in the industry has varied from project to project. One school of thought contends that no chemical cleaning (or minimal) is required. The second school of thought contends that a complete chemical cleaning is required. This report discusses these differences, and a properly designed and well executed cleaning with desired results.
The new passivation mechanism in steam-assisted gravity drainage (SAGD) process is discussed through theoretical approach in this paper. A corrosion mitigation program was implemented that included the pigging both slug and batch corrosion inhibitors chemistry analysis corrosion rate (CR) monitoring and non-destructive tests.
Traditional solutions for the chemical passivation of stainless steel are nitric acid based, with the addition of sodium dichromate as an inhibitor for precipitation hardened and free machining stainless steels. These passivation chemistries are difficult to handle from an environmental health and safety point of view, particularly the dichromate inhibited versions. Citric acid passivation has been pursued as a replacement for both nitric acid and inhibited nitric acid based chemistries for many years, and has been incorporated into consensus specifications such as ASTM A967 and SAE AMS2700.