Packing Free Gas Absorption Columns for Amine Scrubbing of CO2
Carbon Management Technology Conference
Conventionally for carbon capture the amine solvent is introduced in the absorption column with packing in a counter-current form to facilitate gas-liquid contact to combat the slow kinetics thereby increasing the mass transfer for the gas absorption. But the capital cost of packed bed is a dominating drawback to implement the CO2 capture to the power industry. The University of Kentucky Center for Applied Energy Research (UKy-CAER) is introducing a packing free approach to the absorption column that makes it possible to alter the current packed absorption column into a continuously rising froth column of the amine solvent using additives where the froth bubbles essentially act as reaction interface. Advantages of this approach include low-pressure drop across the column, higher mass transfer coefficient, zero capital cost of packings, and shorter columns. With the inclusion of frothbed instead of structured packing in the column, the height of the column can be reduced to less than 50% of the original for the same efficiency of gas absorption keeping all the operational parameters same. A comparative parametric study is conducted using two different solvents, 5M 1-Amino-2propanol (new generation solvent), and UKy advanced solvent and three different types of surfactants. Primarily the stability of froth is related to the type and concentration of the surfactant, typically increasing from 0.001 wt% to 0.1 wt%. Froth rheology is studied under the superficial gas velocity between 0.05 m/s to 1 m/s. Results demonstrating the tunability of the physical structure and rheology of froth using the process parameters, surfactant, and solvent properties at different carbon loadings will be presented in detail.