Degradation and Corrosivity of MEA with Oxidation Inhibitors in a Carbon Dioxide Capture Process

抄録

The effect of the oxidation inhibitors, ethylenediaminetetraacetic acid (EDTA), formaldehyde, and Na₂SO₃, on the oxidative and thermal degradation and the corrosivity of monoethanolamine (MEA) were investigated, and the products of oxidative and thermal degradation of MEA were analyzed. There was no difference in the CO₂ absorption/desorption rates between MEA solutions with and without the oxidation inhibitors. The oxidation inhibitors prevented the oxidative degradation of MEA, and the extent of prevention was in the order EDTA≫formaldehyde>Na₂SO₃. Among the products of oxidative degradation of MEA in the oxidation condition, formate and acetate were the dominant degradation products, and EDTA decreased the amount of products formed to a greater extent than any other inhibitors. Oxidation inhibitors had no effect on the thermal degradation of MEA, and no oxidation products such as anion species of carboxylic acids (glycolate, formate, acetate, and oxalate) and nitrogen products (nitrite and nitrate) were formed under thermal degradation conditions. The corrosion rate of MEA with the inhibitors was in the order Na₂SO₃<EDTA<formaldehyde. Na₂SO₃ and EDTA decreased the corrosion rate of the MEA solution, while formaldehyde slightly increased the corrosion rate.