Modeling of CO₂ Stripping in a Hollow Fiber Membrane Contactor for CO₂ Capture

Abstract

Membrane stripping is a promising method for carbon dioxide (CO 2 ) desorption with low energy demand. We developed a mathematical model to simulate the CO 2 stripping from the CO 2 -rich monoethanolamine (MEA) solvent in a hollow fiber membrane contactor. The modeling results agreed well with literature experimental results. To improve the understanding and facilitate the optimization of the membrane based CO 2 stripping process, we investigated the effects of different operating variables including liquid flow velocity, sweeping gas flow rate, regeneration pressure, and temperature on CO 2 desorption performance. The effects of membrane's length and diameter of membrane fiber on CO 2 desorption were also studied. Results showed that increasing membrane's length will improve CO 2 stripping performance, but not infinitely, because of the thermodynamic limitation of absorbent, and shorter membrane module is preferred for thinner membrane. Membranes with a smaller diameter favor CO 2 desorption. To predict the influence of membrane wetting on CO 2 stripping performance, the change of CO 2 lean loading with the wetting ratio was investigated. Membrane wetting significantly deteriorates CO 2 membrane desorption performance, with CO 2 lean loading increasing suddenly once the membrane is wetted.

Membrane Stripping Technology for CO2 Desorption from CO2-rich Absorbents with Low Energy Consumption

“…This is expected since a lower liquid velocity leads to an increase in residence time (reaction time) in membrane module. The similar result was also reported by Wang et al [10] and Fang et al [12]. Additionally, PP membrane module presents a better performance than PVDF membrane module.…”

“…Therefore, membrane stripping technology, which has the potential to reduce energy requirement of CO 2 separation, is a novel method for CO 2 desorption [8][9][10][11]. In this process, CO 2 is desorbed in a hollow fiber membrane contactor instead of packed column.…”

Modelling, simulation, and membrane wetting estimation in gas‐liquid contacting processes

“…The resistance‐in‐series model is the usual approach to the analysis of mass transfer through the membrane pores, which approach consists of the resistance of the gas‐filled and the liquid‐filled parts of the membrane pores as follows: where R m­ is the total membrane resistance, x is the extent of wetting ranging from zero to one, and R mg­, R ml­ are the individual resistances of the gas‐filled and liquid‐filled pores, respectively. In the corresponding literature the extent of wetting, x, has been used to adjust computational models to experimental data .…”

Modelling of CO2 absorption in a rotating packed bed using an Eulerian porous media approach

“…The absorption of CO 2 by MEA can be described by the Zwitterionic mechanism with twostep reactions (Ma et al 2015;Wang et al, 2013). The first step is to form a Zwitterion as an intermediate and the second step is for the Zwitterion to react with a base, such as a MEA, to deprotonate.…”