Mass Transfer Correlation and Optimization of Carbon Dioxide Capture in a Microchannel Contactor: A Case of CO2-Rich Gas

Nattee Akkarawatkhoosith,Amaraporn Kaewchada,Attasak Jaree,Wannarak Nopcharoenkul

doi:10.3390/en13205465

Abstract

This work focused on the application of a microchannel contactor for CO2 capture using water as absorbent, especially for the application of CO2-rich gas. The influence of operating conditions (temperature, volumetric flow rate of gas and liquid, and CO2 concentration) on the absorption efficiency and the overall liquid-side volumetric mass transfer coefficient was presented in terms of the main effects and interactions based on the factorial design of experiments. It was found that 70.9% of CO2 capture was achieved under the operating conditions as follows; temperature of 50 °C, CO2 inlet fraction of 53.7%, total gas volumetric flow rate of 150 mL min−1, and adsorbent volumetric flow rate of 1 mL min−1. Outstanding performance of CO2 capture was demonstrated with the overall liquid-side volumetric mass transfer coefficient of 0.26 s−1. Further enhancing the system by using 2.2 M of monoethanolamine in water (1:1 molar ratio of MEA-to-CO2) boosted the absorption efficiency up to 88%.

Highlights

High concentration of carbon dioxide in the synthesis gas or biogas product is one of the major issues regarding the environmental pollution and fuel quality, leading to the requirement of post-treatment process(es) for CO2 removal
The main effect of variables including the amount of CO2, volumetric flow rate of water, volumetric flow rate of gas mixture, and absorption temperature on the mean absorption efficiency (%)
For high CO2 concentration level, the adsorption capacity of CO2 in water proceeded via the hydration reaction

Summary

Introduction

High concentration of carbon dioxide in the synthesis gas or biogas product is one of the major issues regarding the environmental pollution (greenhouse effect) and fuel quality, leading to the requirement of post-treatment process(es) for CO2 removal. Many CO2 separation methods have been proposed such as absorption, adsorption, and membrane separation [2]. Among these methods, CO2 absorption is the most widely used due to the relatively lower operating cost and higher efficiency [3]. A wide range of toxic solvents have been reported for the use of CO2 removal with the high absorption capacity such as monoethanolamine (MEA) and diethanolamine (DEA) [3,4]

Methods

Results

Conclusion