Online Emission Monitoring of a Water-Lean Solvent with Proton Transfer Mass Spectrometry for Point Source Carbon Capture Systems
CAMERON NAYLOR, Changcheng Pu, Charlotte Rutnik, Lauren Burrows, National Energy Technology Laboratory
Abstract Number: 426
Working Group: Chemicals of Emerging Concern in Indoor and Outdoor Aerosol: Sources, Vectors, Reactivity, and Impacts
Abstract
Amine solvent-based carbon capture is a growing technology designed to reduce CO2 emissions from power and industrial sources. As this technology scales up, there is a motivation to monitor the contents of the flue gas to ensure harmful byproducts are not released. In this study, an Ionicon 6000 X-2 proton transfer reaction-time of flight-mass spectrometer (PTR-TOF-MS) was deployed at the National Carbon Capture Center (Wilsonville, Alabama) to monitor gas-phase emissions from a CO2 capture test of a water-lean solvent at a 0.5 MWe-equivalent scale. PTR-TOF-MS data was collected both of ambient air near the emissions outlet, and of the flue gas in the stack using a sampling port and probe. Manual isokinetic sampling—wherein flue gas is condensed into an aqueous liquid solution—was performed at a nearby sampling port for two hour-long sampling periods, six times throughout the test campaign. These liquid samples were later analyzed offline using an Agilent 6520 Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometer (LC-QTOF-MS).
Using the PTR-TOF-MS, over 60 compounds were detected within the flue stack. The results of the PTR-TOF-MS were verified by analysis of the condensed flue gas samples using the LC-QTOF-MS. Tandem mass spectrometry was used to determine the structures of non-targeted compounds. Quantitation of the PTR-TOF-MS measurements was performed using the Ionicon Data Analyzer. In the flue gas exhaust stack, several volatile organic compounds including acetaldehyde, formic acid, ethanol, and morpholine were found in the range of 3-10 ppmv, whereas other compounds were observed within the ppbv range. All compounds in the ambient air near the emissions outlet were present in the single-digit ppbv or sub-ppbv range.
The results of this work further the goal of characterizing emissions from carbon capture sources and developing more sensitive methods to monitor emissions.