How is the sulfiding process monitored?
A controlled sulfiding procedure includes:
- Drying the catalyst bed (200–250°F).
- Wetting with clean straight-run feed.
- Injecting DMDS or DTBPS at 450–500°F in hydrogen-rich atmosphere.
- Monitoring H₂S concentration to detect catalyst activation (“breakthrough”).
- Holding temperature (600–660°F) until sulfiding is complete.
Modern refineries use online H₂S and hydrogen analyzers to ensure precision and safety throughout the process.