Membrane–solvent selection for CO2 removal using membrane gas–liquid contactors

Abstract

Membrane gas-liquid contactors can provide very high interfacial area per unit volume, independent regulation of gas and liquid flows and are insensitive to module orientation, which make them very attractive in comparison with conventional equipments for offshore application. However, the membrane adds an additional resistance in the process of mass transfer. The mass transfer resistance of the membrane is affected by the presence of the liquid inside the membrane pores. This wetting of the membrane is determined by the properties of the membrane and the liquid mutually. Hence, a proper choice of the membrane-solvent combination is a critical and determining step in developing membrane gas absorption processes.Important criteria for the selection of the membrane-solvent combination for membrane gas-liquid contactors, such as the critical entry pressure, contact angle and critical solvent surface tension are evaluated in this paper. These characterizing properties of membranes and solvents are experimentally measured for various membrane and solvent combinations for the case of bulk CO 2 removal. For selected combinations the actual gas-liquid mass transfer process for CO 2 absorption is explored experimentally in the flat sheet as well as in the hollow fiber membrane configuration. The experimental results were compared to the theoretical calculations to determine possible mass transfer limitations due to wetting effects. The polypropylene membrane in combination with propylene carbonate as an absorption liquid was found to be a suitable combination for bulk CO 2 removal using membrane gas-liquid contactors.

CO2 Absorption from Biogas by Glycerol: Conducted in Semi-Batch Bubble Column

“…Physical absorption is the absorption process of dissolved gas (solute) by physical interaction, diffusion of gasses into the water, or gas dissolving into the liquid phase without chemical reaction. Physical absorption process is primarily used when the concentration of dissolved CO 2 is high [5]. The main problem is high potential of solvent loss [3]; [6].…”

Atmospheric CO2 capture for the artificial photosynthetic system

“…The resistances are: the gaseous phase boundary layer (1/kG), the membrane (1/km) and the liquid phase boundary layer (1/kL). The overall process is well-known as a "resistance in series" model and overall mass transfer resistance (1/Ko) can be obtained by adding the individual resistances [7].…”

Characterization of partial pore wetting in hollow fiber gas absorption membrane contactors: An EDX analysis approach

“…Despite a concern over the additional mass transfer resistance of the coated layer [9], Kreulenet al [10] proved by that a thin silicone rubber layer coated on the inner surface of hollow fibers did not contribute any additional mass transfer resistance to the absorption of CO 2 and N 2 O by aqueous NaOH solutionAs for the pore wetting, it was eliminated.completely. Different solvents were used to fabricate polymeric membranes and their effects on the key characterization parameters affecting the pore wetting such as the critical entry pressure of water, critical surface tension of the membrane and contact angle were studied by Dindore et al [11].. To simulate CO 2 absorption by water in microporous hollow fiber membrane contactors, Wang et al developed a theoretical model for the non-wetted and wetted mode, respectively [12]. The performance deterioration that occurred in the wetted mode was due to the extra mass transfer resistance resulting from the liquid trapped in the pores.…”