Numerical Simulation and Analysis of CO2Removal in a Polypropylene Hollow Fiber Membrane Contactor

Zhien Zhang,Yunfei Yan,Shunxiang Ju,Li Zhang

doi:10.1155/2014/256840

Abstract

This present study shows a comprehensive 2D numerical model for removal of CO2in a polypropylene (PP) hollow fiber membrane contactor (HFMC) using the computational fluid dynamics (CFD) method. Monoethanolamine (MEA) solution was used as the liquid absorbent in a nonwetting mode. The simulation results represented that higher liquid velocity and concentration and lower gas velocity and concentration led to higher percent of CO2removal. The most proper parameters for CO2removal were less than 1 mol m−3gas concentration and 0.2 m s−1gas flow rate, and for MEA the values were above 8 mol m−3concentration and approximately 1 m s−1liquid velocity. Furthermore, the model was validated with the experiment results. Therefore, the modeling results provided references to the selection of absorbents and operation parameters in the experimental study and pilot-scale applications.

Highlights

In recent years, human-induced CO2 severely results in global climate change [1]
This paper sets up a comprehensive 2D mathematical model for chemical absorption of pure CO2 under nonwetting condition in a PP hollow membrane contactor
In the case of using MEA aqueous solution, the modeling results and experimental data showed that the removal efficiency rose with an increase of the velocity and concentration of MEA, which was similar to others’ work [21, 22]

Summary

Introduction

Human-induced CO2 severely results in global climate change [1]. Especially the combustion of fossil fuels produces a large number of gas emissions. In a hollow fiber membrane contactor, the absorbent always flows on one side while gas mixture flows in the other side. In the membrane absorption process, gas mixture initially diffuses through the gas-liquid interface, and CO2 reacts with the liquid. After that the rich liquid is sent into a gas-liquid separator or other membrane contactors. Compared with conventional absorption technologies, the gas membrane separation provides faster mass transfer rate, good operational flexibility, and bigger gas-liquid contacting area. It runs well without entrainment, flooding, foaming, and so forth. Since Qi and Cussler [6] first investigated the hollow membrane contactor, a large number of scholars studied gas absorption in these devices in succession.

Objectives

Results

Conclusion