Rapid quantification of degraded products from methyldiethnolamine solution using automated direct sample analysis mass spectrometry and their removal

Abstract

Natural gas sweetening using methyldiethanolamine (MDEA) solution requires a specific and accurate technique for quantifying organic degraded products and their removal to overcome operating problems such as corrosion and foaming issues. Some of the techniques presently available are gas chromatography, liquid chromatography, and proton-transfer-reaction with mass spectrometry. However, these analytical methods require extensive sample preparation, standards, and long analysis time. The present work aimed at developing an analytical technique using Direct Sample Analysis Time of Flight (DSA-TOF) mass spectrometry for quantifying the degradation products in the industrial grade lean MDEA solution. This technique involves instant sample introduction, rapid analysis, and offers immediate results. The DSA and TOF parameters were optimized to quantify the degraded products accurately. The high correlation coefficient (obtained for the calibration of different wt. % diethanolamine (DEA) in 50 wt. % MDEA solution justified the accuracy of the developed method. Finally, the removal of these organic degraded products were carried out using batch and column adsorption experiments. Carbon impregnated on calcium alginate (CAC) bio-polymer was used as an adsorbent to remove the degraded products. Thus, the method developed using DSA-TOF provided the basis to quantify the degraded products and the CAC adsorbent easily removed the contaminants from the lean MDEA solution.