Views: 0 Author: Site Editor Publish Time: 2026-02-26 Origin: Site
Hastelloy® C-22 (UNS N06022) shell-and-tube heat exchangers are widely used in the oil & gas sector where process streams are highly corrosive, variable, or contain contaminants such as H₂S, chlorides, CO₂, organic acids, and wet chlorides. When designed to ASME BPVC Section VIII and TEMA standards, C-22 exchangers deliver long service life and high reliability in upstream, midstream, and downstream operations.
Amine treating units (lean/rich amine coolers, reboilers)
Sour gas processing and acid gas handling
Produced water cooling with high chlorides
Crude and condensate stabilization systems
Refinery overhead condensers (wet chloride + H₂S environments)
Sulfur recovery units (SRU) & tail gas treating
Offshore and FPSO process coolers exposed to seawater and aggressive atmospheres
C-22 is a Ni-Cr-Mo-W alloy engineered for environments where both oxidizing and reducing conditions coexist—common in oil & gas processing.
Key advantages:
Exceptional resistance to pitting and crevice corrosion in high-chloride media
Superior performance in wet H₂S, CO₂, and acid gas streams
High resistance to stress corrosion cracking (SCC)
Stable corrosion behavior during process upsets and shutdowns
Proven reliability where 316L, duplex, and even C-276 may fail prematurely
Design codes: ASME BPVC Section VIII Div.1 / Div.2
Mechanical standard: TEMA R (refinery duty)
Tube materials: Solid Hastelloy C-22 (ASTM B622 / B619)
Tube sheets: Solid C-22 or C-22 clad on carbon steel
Shell: Carbon steel with C-22 clad or corrosion allowance
Channel / bonnet: C-22 or CS with C-22 overlay
Tube-to-tubesheet joint: Strength-welded and seal-welded (oil & gas best practice)
| Service Environment | C-22 Performance |
|---|---|
| Wet H₂S + chlorides | Excellent |
| Sour water | Excellent |
| Amine solutions (DEA, MDEA) | Excellent |
| Refinery overheads | Superior to 316L / duplex |
| Seawater exposure | Outstanding |
| Mixed acid contaminants | Excellent |
C-22 offers wider corrosion immunity than C-276, especially under fluctuating oxygen content.
Operating temperature: up to ~425 °C (800 °F), depending on service
Low-temperature toughness: suitable for cryogenic and offshore conditions
Pressure rating: defined by ASME design calculations rather than alloy limitation
Excellent weldability using ERNiCrMo-10 filler
No post-weld heat treatment typically required
ASME Section IX qualified WPS/PQR
Pickling and passivation recommended after fabrication
Full PMI, NDT, and material traceability mandatory for oil & gas projects
Although Hastelloy C-22 has a higher initial cost, oil & gas operators benefit from:
Reduced unplanned shutdowns
Lower corrosion-related maintenance
Extended exchanger service life
Improved safety in sour and toxic services
In many refinery and gas processing units, C-22 delivers the lowest total cost of ownership.
NACE MR0175 / ISO 15156 compliance (as applicable)
EN 10204 3.1 MTCs
Hydrostatic testing per ASME
Helium or air leak testing for critical services
Full QA/QC documentation and data book
