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Investigation of Alkanol-Amine Solvents and their Blends for CO2 Removal from Natural Gas using Aspen-Hysys


O.A.A. Eletta
D.T. Awotoye
A.A. Zubairu

Abstract

The removal of carbon dioxide (CO2) from natural gas is vital towards meeting pipeline sales gas specifications and evading operational complications during the liquefaction of natural gas. Therefore, the removal of CO2 from natural gas is necessary for the efficient utilization of natural gas and for the reduction of global CO2 emission. It is also vital for the effective liquefaction process in the liquefied natural gas project A common and widespread technique used at natural gas plants in Nigeria is the removal of carbon dioxide (CO2) from natural gas through chemical absorption using alkanolamine solutions. In this research, an amine sweetening process is simulated using Aspen HYSYS V10 with a typical Nigerian natural gas composition. The simulation is used to investigate four different kinds of amines and their blends (mixed amines). The investigated amines are Monoethanolamine (MEA), Diethanolamine (DEA), Diglycolamine (DGA) and Methyldiethanolamine (MDEA) while the blends are MDEA + MEA, MDEA + DEA and MDEA + DGA. Results obtained from the simulation show that the mixed amine “MDEA + MEA” with lean amine strength of 11% MEA and 39% MDEA, absorbs 99.97% of CO2 present in the gas and hence, amine blends absorb carbon dioxide from natural gas better than the individual amines. It was also concluded that increasing the composition of the primary or secondary amine while decreasing the composition of the tertiary amine in the lean amine solution (amine blend) led to an increase in the amount of CO2 being absorbed. The study provides useful information on the absorption of CO2 using alkanolamine solvents and their blends in a standard amine sweetening plant.


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eISSN: 2437-2110
print ISSN: 0189-9546