What measures can be taken to mitigate corrosion of pressure vessels?

I. Material and Design Optimization

1. Selection of Corrosion-Resistant Materials: High-chromium-nickel austenitic stainless steel (such as 316L) is preferred for acidic media; duplex stainless steel or ultra-pure ferritic stainless steel is used in brine environments.

For special operating conditions, linings (such as glass enamel or nickel-based alloy cladding) or composite steel plates (corrosion-resistant inner layer + carbon steel outer layer) can be used.

Material suppliers must provide full-element chemical analysis certificates and metallographic testing reports.

2. Structural Design Improvement: Avoid stress concentration; use multi-layer, multi-pass welding processes to reduce intergranular segregation; molybdenum-containing materials require post-weld solution treatment.

Eliminate "dead corners" and rough surfaces to prevent the concentration of corrosive media.

II. Process and Operation Control

1. Media Management: Add alkaline neutralizers to adjust the pH to 8-10, keeping the steel in a passivated and stable state.

Desulfurization treatment is required in hydrogen sulfide environments; automatic addition of corrosion inhibitors is necessary when the sulfur concentration exceeds 20 ppm.

2. Operating Procedures
Control the temperature below the critical creep temperature of the metal; the continuous operating temperature rise should be ≤40℃/hour.

Pressure fluctuations should be limited to within 15% of the design pressure to avoid tensile stress exacerbating pitting corrosion.

III. Application of Anti-corrosion Technology

1. Coating and Lining
After sandblasting to Sa2 cleanliness, apply an epoxy zinc-rich primer + metal spray composite coating.

When the damaged area exceeds 3%, local repair is required; periodically re-inspect the coating integrity.

2. Electrochemical Protection
Use sacrificial anodes (such as aluminum alloy blocks) or forced current schemes; control the cathodic protection potential between -850mV and -1100mV.

IV. Maintenance and Inspection

1. Daily Maintenance
Keep the anti-corrosion layer intact; repair any damage promptly.

Eliminate leaks; regularly drain and empty containers; clean and dry containers when not in use.

2. Periodic Inspection
Establish a three-stage re-inspection system: macroscopic inspection, DR flaw detection for thickness measurement, and endoscopic recording of corrosion morphology.

Wall thickness measurement should be performed at 8 points per square meter. Replacement is required if the annual wear rate exceeds the expected 35%.

V. Special Environmental Response

Stress Corrosion Protection: Avoid the introduction of moisture into the medium (e.g., CO gas requires drying), and control the concentration of alkaline solutions to prevent alkaline embrittlement of carbon steel.

High Temperature Protection: Select creep-resistant materials, avoid localized overheating, and regularly check for graphitization tendencies.