Enhanced Absorption of Carbon Dioxide Gas by Methanol Based Nanofluids in a Taylor-Couette Absorber

Abstract

Mass transfer enhancement by the use of nanoparticles suspended in a liquid phase (known as nanofluids) has been studied in recent years with positive results. Different theories have been proposed to explain the improvement in mass transfer, however it has not been possible to elucidate a definite answer. While the theory is still uncertain the experimental work continues in areas that will benefit much such as non-reactive gas absorption. In this study carbon dioxide (CO2) absorption experiments are performed in a Taylor-Couette absorber at different rotational speeds. The base fluid for the experiments is methanol. Al2O3 and SiO2 nanoparticles are combined with methanol to produce nanofluids with the purpose of enhancing the absorption of the CO2 gas into the methanol. The system is equipped with a mass flow controller at the inlet and a mass flow meter at the outlet to obtain the absorption rate. The Taylor-Couette absorber performance is compared to a modified version in which trays were added to enhance the absorption rate. Experiments in co-current and counter-current flow modes are carried out. The results of continuous absorption are presented. In addition, the two-phase flow pattern of the CO2 gas bubbles and the liquid methanol in the Taylor-Couette absorber and the modified version is analyzed with pictures obtained by a high speed camera.