Investigation of natural gas sweetening process in corrugated packed bed column using computational fluid dynamics (CFD) model

In this work, a mathematical model based on computational fluid dynamics (CFD) is developed for absorption of acid gases, H2S and CO2, into amine solution in a structured packing with corrugated sheets. Localization of boundary conditions and hydrodynamic of the model are similar to the work of Shilkin. Two-dimensional mass and energy transfer equations with incorporation of chemical reactions between amines and acid gases are developed for moving liquid and gas in a cylindrical coordinate system for the channels produced from counter course assembling of the corrugated sheets. Solution to the governing equations based on mass and energy conservation concepts provides temperature and concentration profiles along the bed height and across the gas and reacting liquid film. Since methyl diethanol amine (MDEA) selectively absorbs H2S in the presence of CO2, to maintain the generality of the model, it is extended to investigate removal of CO2 with a mixture of mono ethanol amine (MEA) or diethanol amine (DEA) and MDEA solutions. Structured packed column shows a better performance for absorption of acid gases in comparison with random packed column at equal height and diameter. In structured packed column, MEA shows to be more efficient for absorption of CO2 in comparison with DEA.