Thermal Decomposition and Nonisothermal Kinetics of Monoethanolamine Mixed with Various Metal Ions

Ethanolamine is a critical chemical for petrochemical enterprises. When corrosion occurs in pipelines, equipment, and containers in petrochemical enterprises, minute amounts of metal ions are released. In this study, the thermal decomposition and nonisothermal kinetics of monoethanolamine (MEA) and MEA mixed with copper and zinc ions were analyzed using thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG tests revealed that MEA mixed with copper (II) and zinc (II) began thermal decomposition at 75.2 and 60.3 °C, respectively, whereas pure MEA began thermal decomposition at 89.7 °C. Two exothermic peaks were observed in the DSC curves for MEA mixed with copper (II) and zinc (II), and thermokinetic parameters were obtained from DSC data. The apparent activation energy (E_a) of each stage was calculated using several nonisothermal kinetic methods, namely the ASTM E698, Kissinger-Akahira-Sunose, Starink, and Flynn-Wall-Ozawa methods. The E_a of pure MEA was 28.7 ± 2.5 kJ/mol, whereas that of the copper and zinc mixtures were 80.5 ± 1.1 and 46.8 ±1.7 kJ/mol, respectively. The results can be used to improve the intrinsic safety of storage tanks and petrochemical plants.