Non-oxidative thermal degradation of amines: GCMS/FTIR spectra analysis and molecular modeling

A review of gas chromatographic techniques for identification of aqueous amine degradation products in carbonated environments

Degradation of amines is a significant issue allied to amine-based carbon dioxide (CO₂) absorption in post-combustion CO₂ capture. It becomes essential to have a detailed understanding of degradation products for advanced post-combustion CO₂ capture technology. Identification and quantification of degradation products of amines help in practicability and environmental assessment of amine-based technology. Gas, liquid, and ion chromatographic techniques are the benchmark tools for qualitative and quantitative analyses of the amines and their derivatives. Among others, gas chromatography has been more in use for this specific application, especially for the identification of degradation products of amines. This review focuses on the critical elucidation of gas chromatographic analysis and development of methods to determine the amine degradation products, highlighting preparation methods for samples and selecting columns and detectors. The choice of detector, column, sample preparation, and method development are reviewed in this manuscript, keeping in view the industry and research applications. Furthermore, obtained results on the quantitative and qualitative analyses using gas chromatography are summarized with future perspectives.

Correlation of CO2 absorption performance and electrical properties in a tri-ethanolamine aqueous solution compared to mono- and di-ethanolamine systems

The study investigates the correlation of CO₂ absorption performance and electrical properties in a tri-ethanolamine (TEA) aqueous solution compared to the mono-ethanolamine (MEA) and di-ethanolamine (DEA) systems. While the absorption rate of the MEA and DEA systems varies with amine concentration, and the maximum rate is observed at 30.0 and 50.4 wt% amine solution, respectively, the rate of the TEA system according to concentration follows a parabolic curve and the maximum rate is observed at 15.0 wt% solution. The ionic conductivity of carbamic acid in the TEA system is estimated to be the smallest with 37.60 S cm²/mol z and the decreasing ratio of ionic activity coefficient according to the concentration is the largest. The results are mostly attributed to differences in amine molecular structure and the unique reaction mechanism. Finally, based on these values, the correlation equations are obtained to estimate CO₂ absorption capacity by measuring electrical conductivity in situ.

Cocoa bean skin waste as potential raw material for liquid smoke production

Cocoa bean skin is a waste of chocolate industries that mostly contains hemicellulose, cellulose, and lignin. This material shows to be a promising feedstock for the production of liquid smoke and charcoal. The study was aimed to analyse the influence of temperature and heating rate of cocoa bean skin pyrolysis to the production of liquid smoke. Optimization of pyrolysis process variables, i.e. by adjusting the suitable temperature and heating rate, is the key to obtain a high-quality product. The pyrolysis process was carried out using heating rates between 5°C/min and 15°C/min at three pyrolysis temperatures of 450°C, 500°C, and 550°C. The yield of the produced liquid smoke was in the range of 18-23%. It showed that at a faster heating rate, the reaction produced more charcoal, ash, and water content for all pyrolysis temperatures. The highest yield of charcoal was ca. 39% with a caloric value of 22.97 MJ/kg, while the lowest ash and water content was in the range of 16.5-19% and 6.5-8.5%, respectively. This result shows that the utilization of this organic waste compounds could be promising for large-scale production.

ATR-FTIR Model Development and Verification for Qualitative and Quantitative Analysis in MDEA–H2O–MEG/TEG–CO2 Blends

A Fourier transform infrared (FTIR) spectroscopy method was developed to identify and quantify various components in an amine-based combined acid gas and water removal process. In this work, an attenuated total reflectance (ATR) probe was used. A partial least-squares (PLS) regression model was also developed using up to four components (methyl diethanolamine (MDEA)-H2O-CO2-ethylene glycol/triethylene glycol (MEG/TEG)), and it was successfully validated. The model was applied on thermally degraded CO2-loaded MDEA blends to predict the weight percentages of MDEA, H2O, CO2, and MEG or TEG to test the performance spectrum. The results confirmed that FTIR could be used as a simpler, quicker and reliable tool to identify and quantify various compounds such as MDEA, MEG/TEG, H2O and CO2 simultaneously in a combined acid gas and water removal process.