Process modelling and analysis of intensified CO2 capture using monoethanolamine (MEA) in rotating packed bed absorber

Abstract

Rotating packed bed (RPB) absorber using monoethanolamine (MEA) as the solvent to capture CO2 is modelled at steady state condition in this study according to the first principles in gPROMS ®. The effect of eight different kinetic reaction models and five enhancement factors is examined based on the newly developed model. Selection of kinetic model has significant effect on the carbon capture level (CCL) but the effect of enhancement factor relation is not important. The steady state process model is validated against the experimental data and showed good agreement. The average absolute relative deviation for 12 case-runs is 3.5%. In addition, process analysis is performed to evaluate the effect of four factors namely rotor speed, MEA concentration in lean MEA solution, lean MEA solution temperature and lean MEA solution flow rate on CCL. Finally, orthogonal array design (OAD) method is applied to analyse the simultaneous effect of the above-mentioned factors in the CCL and motor power of RPB absorber by considering 25 scenarios. The result of using OAD revealed that rotor speed has the most important effect on CCL, and after that lean MEA solution flow rate has the second importance. In addition, the OAD method is used to find the proper combination of four factors that resulted in about 90% CCL with low motor power.

Process modelling, validation and analysis of rotating packed bed stripper in the context of intensified CO2 capture with MEA

“…In the case of desorption energy, same trend and behaviour are illustrated in the work of Joel et al [26]. The rotor speed and centrifugal force created small liquid droplets and consequently increase the mass and heat transfer area and hence the mass and heat transfer coefficients can be increased [23]. It must be mentioned that higher speeds can have a negative impact on the mass and heat transfer which is due to the reduction of the contact time between phases.…”

“…It has also been used in other gas-liquid processes such as H2S absorption [21], liquid-liquid processes such as liquid liquid extraction [22] and also in solid-liquid processes such as adsorption. As mentioned in the previous study [23],…”

“…The list of the methods and correlations that used in the current study to calculate the required physical properties and other parameters are illustrated in Table 3 and proper details about these correlations and methods can be found in Borhani et al [23]. Liquid density [40] and [41] Gas heat capacity [10] Liquid heat capacity [42] Gas side mass transfer [43] Liquid side mass transfer [44] Interfacial area [43] Henry's constant [45] Liquid diffusivity Chilton and Colburn Analogy Gas diffusivity [46] Thermal conductivity Multiflash package in gPROMS Pressure drop [47] Liquid holdup [48] Heat transfer coefficient [49] Vapor pressure [10] Activity coefficient Wilson model [50] As mentioned in Section 2.2, K-values are calculated using GA-MLR model and the regression constants are illustrated in Table 4.…”

“…where k is the observed reaction rate constant which is calculated based on reaction (23). D is diffusivity of CO2 in the lean MEA solution and k is the mass transfer coefficient of CO2 in lean MEA solution.…”

“…D is diffusivity of CO2 in the lean MEA solution and k is the mass transfer coefficient of CO2 in lean MEA solution. In this study, the k defined in the previous study [23] have been used.…”