International Journal of Greenhouse Gas Control 39 (2015) 407–419 Contents lists available at ScienceDirect International Journal of Greenhouse Gas Control journal homepage: www.elsevier.com/locate/ijggc Evaluation of methods for monitoring MEA degradation during pilot scale post-combustion capture of CO 2 Alicia J. Reynolds a , T. Vincent Verheyen b , Samuel B. Adeloju a,c,∗ , Alan L. Chaffee c , Erik Meuleman d a School of Applied Sciences and Engineering, Faculty of Science, Monash University, Australia b School of Applied and Biomedical Sciences, Faculty of Science and Technology, Federation University, Churchill, Victoria 3842, Australia c School of Chemistry, Monash University, Clayton, Victoria 3800, Australia d CSIRO Energy Flagship, Bayview Ave, Clayton Vic 3800, Australia article info Article history: Received 2 April 2015 Received in revised form 2 June 2015 Accepted 3 June 2015 Available online 23 June 2015 Keywords: Post-combustion capture of CO2 Monoethanolamine Coal-fired flue gas Heat-stable salts Degradation abstract Amine degradation is an important and current focus in the development of chemical absorption tech- nology based on the use of aqueous amines for post-combustion capture (PCC) of CO 2 . The oxidative degradation and carbamate polymerisation of monoethanolamine (the current industry standard amine for PCC) has been studied extensively at the laboratory scale. However, methods for monitoring long- term amine degradation during pilot, demonstration and commercial scale PCC are needed to enable researchers and operators to optimise amine management (e.g. minimising degradation and optimis- ing reclamation strategies), improve PCC plant operation and avoid operational instabilities. The current industry standard method, based on the measurement of heat-stable salts (HSS) is not suitable for con- tinuous monitoring of amine degradation. This study discusses the organic structural changes of severely degraded 30% (w/w) aqueous monoethanolamine samples obtained from a PCC pilot plant operating at a brown coal-fired power station in Australia. It demonstrates that absorbance measurement at 313 nm by UV–vis, change in infra-red absorbance and the organic carbon content of degradation products cor- relate strongly with HSS concentrations. These parameters are easily measured using well established technology and are suitable for monitoring the degradation of aqueous monoethanolamine during PCC. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Chemical absorption with aqueous amine absorbents is the current industry standard for post-combustion capture (PCC) of CO 2 from coal-fired power station flue gas (International Energy Agency, 2012, 2013; Boot-Handford et al., 2014). This gas sepa- ration technology is suited to the low CO 2 partial pressure and high moisture content of typical flue gases (Kohl and Nielsen, 1997). Despite substantial progress in recent years, a number of challenges for commercial-scale operation remain (International Energy Agency, 2012, 2013; Boot-Handford et al., 2014). For exam- ple, corrosion and degradation of the aqueous amines are still Abbreviations: ATR-IR, attenuated total reflectance-infra red spectroscopy; GC- FID, gas chromatography with flame ionization detection; HS, Sheat-stable salts; MEA, monoethanolamine; NMR, nuclear magnetic resonance spectroscopy; PCC, post-combustion CO2 capture; TOC, total organic carbon; UV–Vis, ultraviolet and visible light spectroscopy. ∗ Corresponding author: Tel.:+61 3 9905 4555. E-mail address: sam.adeloju@monash.edu (S.B. Adeloju). significant challenges for these PCC systems despite development of low corrosivity, degradation resistant absorbents (Knudsen et al., 2009; Nainar and Veawab, 2009). Managing amine degradation is crucial for (i) minimising potential human and environmental impacts; (ii) maintaining operational stability and energy efficiency of PCC processes; and (iii) minimising the need for amine recla- mation and disposal (Reynolds et al., 2012; Léonard et al., 2014b). However, there is a clear need to identify simple, rapid measure- ment techniques that could be used to monitor the accumulation of aqueous amine degradation products. This would enable amine degradation to be managed proactively during PCC at pilot, demon- stration and commerical scales. Research into degradation of aqueous amines has focused on three key pathways: oxidative degradation; formation of heat- stable salts (HSS); and carbamate polymerisation or thermal degradation (Gouedard et al., 2012; Vega et al., 2014). Oxidative degradation is the most rapid amine degradation pathway during PCC and is driven by both the reactivity of amines and the high oxygen content [typically 4–5%, (Kittel et al., 2012)] of flue gases. Dissolved metals (from corrosion and fly ash intrusion) are also http://dx.doi.org/10.1016/j.ijggc.2015.06.001 1750-5836/© 2015 Elsevier Ltd. All rights reserved.