Potential Carryover of Amine-Based Corrosion Inhibitor to Isomerisation Feed: Analytical and Operational Experience in a Light Naphtha Hydrotreating (LNHT) unit. A film-forming amine-based corrosion inhibitor is injected at the stripper overhead. The stripper bottoms are routed as feed to a downstream chlorided-alumina isomerisation unit. We are observing gradual catalyst deactivation in the isomerisation reactors.
Known contaminants such as moisture, sulphur, oxygenates, and CO are within specified limits. However, we suspect that excess corrosion inhibitor dosing may be contributing to nitrogen carryover into the feed. Based on dosing estimates, nitrogen levels could be on the order of 1–1.5 wtppm, exceeding the feed specification limit of 0.1 wtppm. Total nitrogen analysis using ASTM D4629 has not indicated elevated nitrogen levels, which may reflect analytical limitations in detecting long-chain surface-active amines in light paraffinic matrices.
We would appreciate insights from others who may have encountered similar situations:
- Have you observed corrosion inhibitor carryover impacting isomerisation catalyst activity?
- What analytical methods have proven reliable for detecting or confirming amine-based inhibitor presence at trace levels in light naphtha?
- Are there recommended sampling or extraction techniques to improve detection sensitivity?
- What mitigation strategies (dosing optimisation, relocation, guard beds, etc.) have been effective in practice?
Any shared experience or guidance would be greatly appreciated.