Thermal Degradation of Ethanolamine in CO₂ Capture with SO₂

Amine degradation in the absorption/stripping process is one of the concerns in this technology. SO₂ is reported to promote amine degradation in both bench scale and pilot scale. This work investigates the impact of SO₂ on thermal degradation of MEA by preloading additives, which are Na₂SO₃, SO₂ and H₂SO₄. 7 m (mol/kg H₂O) MEA with 0.4 CO₂ loading (mol CO₂/mol MEA) at 135°C is the baseline condition. Initial sulfur concentration is 0.4 m in the experiments with additives. The experiment temperature varied from 120 to 150°C. Neither sulfite nor sulfate has significant impact on MEA degradation rate in thermal condition. There is no different cation product in the samples with additives compared to the baseline experiment. The main process of MEA thermal degradation is still carbamate polymerizing. Ammonium was induced by sulfite. The main organic acid product is formate for all the experiment conditions, while there are new anion products with sulfite. Formate formation was promoted by H₂SO₄. Ammonium and formate formation were promoted at higher temperature.