Effect of Operating Conditions on Co Absorption into Aqueous Alkanol amine Solutions in Packed Column

Abstract

This paper highlights the importance of operating parameters to mass-transfer in CO2 absorption in columns with different packings. The study compares the performance of two packings, Gempak 4A and Raschig ring. Mass-transfer efficiency of these packings was determined by carrying out absorption experiments in a pilot-scale absorption unit with aqueous solutions of monoethanolamine (MEA), Diethanolamine (DEA),2-amino-2-methyl-1-propanol (AMP) and methyldiethanolamine (MDEA) as test solvent. The overall mass-transfer coefficient (KGav) can be considered to be indicative of the CO2 removal efficiency of the system and can be calculated from experimentally gas-phase CO2 concentration profiles within the test columns. The results of this study indicate that mass-transfer coefficient of these packings tested varies significantly not only with operating parameters such as liquid load, liquid CO2 loading, solvent concentration, solvent type and feed CO2 concentration but also with packing arrangement. In absorption experiments the results show the typical behavior of liquid controlling system. Gas flow rate has no influence on overall mass transfer coefficient (KGav), and an increase in liquid flow rate yields a greater (KGav). CO2 loading lowers the (KGav) and an increase in amine concentration induces a higher (KGav). Increasing the CO2 concentration within the feed gas was found to reduce the value of (KGav) within the system. Structured packing offers superior performance to random packings, structured packing provides almost twice greater (KGav) than random packings.