Quantification of Amines in Refinery Process Water via Surface- Enhanced Raman Spectroscopy

Amines are used in crude oil production, natural gas recovery, and hydrocarbon refining as hydrogen sulfide scavengers, corrosion inhibitors, and pH control neutralizers. Residual amines can be detrimental to the refining process, such as forming heat-stable salts that lead to corrosion inducing deposits or causing nitrification of wastewater streams. Traditional methods for amine analysis such as ion chromatography are complex, timeconsuming, and not adapted to field deployment. We present a new method using surface-enhanced Raman spectroscopy for amine quantification with a focus on two problem-causing tramp amines: monoethanolamine and methylamine. This method is calibration-free, accurate across spectrometers, stable over years in laboratory-standard solutions and in real-world process samples, and can be performed by minimally trained operators within less than 5 min.

Automated summary

Amines are utilized in various areas of the petroleum industry for different purposes such as hydrogen sulfide removal, corrosion prevention, and pH control. However, leftover amines can negatively affect the refining process by causing corrosion or nitrification. Traditional analytical methods like ion chromatography are inconvenient for field use. This study presents a new calibration-free technique for amine quantification using surface-enhanced Raman spectroscopy, specifically targeting problem-causing amines like monoethanolamine and methylamine. This method is accurate, stable, and can be performed quickly by minimally trained operators.