CO2 and H2S absorption by MEA solution in packed-bed columns under inclined and heaving motion conditions - Hydrodynamics and reactions performance for marine applications

Abstract

Two-phase countercurrent flow dynamics and simultaneous CO2 and H2S removal performance were studied in countercurrent randomly packed-bed columns with fourth generation Raschig super-Rings exposed to static inclination and heaving motion via an unsteady-state comprehensive three-dimensional model. Gas-liquid countercurrent flow displays a gradual deviation to axial symmetry with the increase of angle of the packed-bed column inclination. CO2 absorption process is negatively impacted in inclined packed-bed columns and the deficit in CO2 removal performance increases with the increase of H2S concentration in gas phase. H2S removal efficiency is marginally reduced and mostly at considerable packed bed inclinations. Under heaving motion of the packed-bed column, an oscillatory two-phase flow and CO2-monoethanolamine (MEA) absorption process performance develop around the steady-state solution of the column stationary state prior to heaving application. As externally-generated packed-bed column oscillations, the heaving motion impacts more CO2 absorption because of very high rate constant of the reaction between H2S and MEA and because the packed-bed column is exposed only to small episodes of time to maximum/minimum heaving acceleration where H2S removal efficiency can be affected.