https://doi.org/10.1016/j.petlm.2016.11.002
“Cyclic loading and cyclic capacity are all integral performance parameters that also contribute to the potentials of an amine blend towards CO2 capture. The cyclic loading (CL, mol CO2/mol amine) is the difference in CO2 loading between the amine solution at equilibrium with CO2 after the absorption process and the CO2 loading of the amine solution after the desorption process, while the cyclic capacity (CC, mol CO2/l-amine soln.) is the cyclic loading multiplied by the amine concentration as shown in Eq. (9) [111].
(9)CC=(αCO2_rich−αCO2_lean)Camine
where; αCO2_lean, is the CO2 loading at the desorption condition (mol CO2/mol amine).
High cyclic capacity lead to an increased CO2 carrying capacity hence reduced amine circulation rate and regeneration energy [57], [73], [76], [77], [111]. Reduction in the amine circulation rate will in turn minimize the diameter of both the absorber and regenerator [72], and can be seen from the correlations in Eqs. (10), (11), (12), (13), (14), (15), (16), (17) [151].
(10)GG=vGρG
(11)GG=(CP(ρGρL−ρG)0.5Fp0.5v0.05)ρG
(12)FLG=LG(ρGρL)0.5
(13)ΔPflood=0.115Fp0.7
where; ΔPflood is pressure drop at flooding (in. H2O/ft height of packing) while Fp is the packing factor (ft−1), FLG is the flow parameter (dimensionless), ρG is the gas density (kg/ft3), ρL is the liquid density (kg/ft3), L is the liquid mass flow rate (kg/hr), G is the gas mass flow rate (kg/hr).
The FLG and ΔPflood are both used to extract the capacity parameter (CPm) from the flooding curve or pressure drop correlation graph [152].
(14)vG=(CPm(ρGρL−ρG)0.5Fp0.5v0.05)
(15)GG=vGρGwhere; v is the kinematic viscosity of the liquid (cSt), vG is the superficial gas velocity (ft/s), f is the flooding factor and GG is the gas flux at operating condition (kg/m2·s).
Following Eqs. (10), (11), (12), (13), (14), (15) step wise, the cross-sectional area (A, m2) and diameter (D, m) of the absorber column is determined with Eqs. (16), (17).
(16)A=GfGG=GGG_flood
(17)D=(4Aπ)0.5
The desired amine solution is required to possess a high initial absorption rate and high cyclic capacity. In a plot of initial absorption rate vs cyclic capacity, the desired amine solution is expected to be at the top right portion of the graph (Fig. 14).
Fig. 14. Initial absorption rate vs cyclic capacity plot.
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