Pushing Technology Boundaries: Monitoring and Optimization of Carbon Capture Solvents

Abstract

The central idea of the dissertation is to provide insight into options to reducing the cost of amine-based PCC technology. Solvent management and high energy demand are two of the challenges that have increased the operational cost of the technology.

To enable effective solvent management in a capture plant, the chemical absorptiondesorption process needs to be regularly monitored and controlled. Articles 1 and 2 and Proceeding 2 present a study that offers process analytical technology (PAT) tools for solvent management using Fourier-transform infrared (FTIR) spectroscopic data. This study provides a tool to establish degradation boundaries, initiation, and completion stages of the reclaiming process. Furthermore, these findings provide insight to maintain the accuracy and effectiveness of regression models when CO2 and amine species in the solvent are monitored over an extended timeframe. Moreover, this study demonstrates the potential use of regression model prediction residuals for the detection and monitoring of degradation species. Furthermore, this work entails the means of providing chemometric assistance for a study aimed at conversion of in-service degradation species of the MEA solvent to MEA (Articles 7 and 8).

Introduction of non-aqueous solvents is a new alternative to current aqueous solvents and is influential in reducing the solvent regeneration-energy demands. Articles 3, 4, 6, and Proceeding 1 report results of a proposed sulfolane-based low viscosity non-aqueous solvent. In Article 3, the proposed solvent produces monomethyl carbonates (MMC) through a reaction with CO2; MMC can be desorbed at 58°C. Article 4 disclose blend composition optimization and the effect of flue gas humidity on CO2 up-take including respective solvent speciation. This solvent forms DPAH+ carbamate, causing the blend to solidify under certain conditions.

Additionally, this thesis presents an initiative in applying chemometric tools with the goal of understanding the chemistry behind the simultaneous SOx/ NOx removal process. Results show that Raman spectroscopy is a practical tool for quantifying species in an aqueous SOx/ NOx removal system (Article 5).

Overall, this dissertation presents the prospective application of PAT tools, specifically spectroscopy with chemometrics, in monitoring and optimizing of CO2 capture solvents.