Enzyme-enhanced CO2 absorption process in rotating packed bed

Abstract

Carbon dioxide is considered the most important contributor to the global warming effect. To reduce greenhouse gas emissions, CO 2 should be separated from the exhaust gas stream in a selective way. The most often applied technology to capture CO 2 from exhaust gases is the reactive absorption in aqueous amine solutions, which is currently widely used in different industrial applications. The efficiency of this technology could be improved by applying high-gravity technologies that intensify mass transfer and can enable substantial equipment size reduction compared to the traditionally used packed columns. Rotating packed bed (RPB) technology meets these requirements very well. Applying innovative materials such as the highly efficient enzyme carbonic anhydrase can further improve the efficiency of the CO 2 absorption process. This combination of intensified technology together with new solvents is expected to improve the total efficiency of CO 2 absorption. In this study, we present our experimental results of CO 2 absorption using 30 wt% N-methyldiethanolamine (MDEA) solution in water in an RPB unit with and without carbonic anhydrase for different gas and liquid flow rates. The results indicate significantly improved performance of CO 2 absorption, up to 18 times compared to the solvent without enzyme. Keywords Rotating packed bed • RPB • CO 2 absorption • Carbonic anhydrase • MDEA Symbols a Specific surface area of the packing m 2 m −3 A Cross-section area m 2 c %MDEA MDEA concentration in water solution % F factor F factor Pa 0.5 M MDEA Molar mass of MDEA kg kmol −1 n CO 2 ,abs Molar flow rate of total absorbed CO 2 mol h −1 n CO 2 ,abs,packing Molar flow rate of absorbed CO 2 inside the packing mol h −1ṅ CO 2 ,abs,case Molar flow rate of absorbed CO 2 in the casing mol h −1 n G in CO 2 Molar flow rate of CO 2 in gas inlet mol h −1 n G inside CO 2 Molar flow rate of CO 2 in the casing mol h −1 n G out CO 2 Molar flow rate of CO 2 in gas outlet mol h −1 p Pressure Pa R Gas constant J mol −1 K −1 T Temperature K u L Specific liquid load m 3 m −2 h −1 v in CO 2 Volume fraction of CO 2 in gas inlet m 3 m −3 v inside CO 2 Volume fraction of CO 2 in gas m 3 m −3 v out CO 2 Volume fraction of CO 2 in gas outlet m 3 m −3 V G Volumetric gas flow m 3 h −1 V L Volumetric liquid flow m 3 h −1 Y CO 2 CO 2 loading mol mol −1 Greek letters Porosity of the packing m 3 m −3 G Density of gas kg m −3 MDEA Density of MDEA kg m −3

Biocatalytic CO2 Absorption and Structural Studies of Carbonic Anhydrase under Industrially-Relevant Conditions

“…No positive effect was observed at pH 9 as well as at pH 11. The best pH condition observed in the present study was within the range reported by Wojtasik et al [24] (pH 10-10.3) during CO 2 capture in a 30 wt% methyldiethanolamine (MDEA) solution. When considering a buffered environment, the observation was that S CO2 was increased by 35% in the presence of the enzyme, as compared to an unbuffered condition at the same initial pH.…”

“…The S CO2 and r CO2 values reported in this case can be increased in future tests by the adoption of the following conditions: (1) addition of an absorption promoter (e.g., amine, inorganic carbonate), (2) higher partial pressure in the absorption cell since it is well known that pressure exerts a strong effect in gas solubility in liquid phases [25]. Additionally, r CO2 may be improved by utilization of a mixing device in the absorption cell, as previously stated during the comparison of fixed and rotating packed beds for biocatalytic CO 2 capture [24].…”

Carbon dioxide desorption intensified by metal atom

“…Postcombustion capture is categorized into chemical absorption, physical adsorption, and membrane separation. Chemical absorption has been developed as one of the most promising methods for industrial CO 2 capture 2‐7 . During the chemical absorption process, the solvent significantly influences CO 2 capture performance 8‐11 …”

“…Chemical absorption has been developed as one of the most promising methods for industrial CO 2 capture. [2][3][4][5][6][7] During the chemical absorption process, the solvent significantly influences CO 2 capture performance. [8][9][10][11] Amine solutions, such as monoethanolamine, methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP)/piperazine solution, and mixture amines, are conventional solvents used to capture CO 2 .…”

Novel Wire Mesh Packing with Controllable Cross-Sectional Area in a Rotating Packed Bed: Mass Transfer Studies

“…With the advantages of free design for complex geometries and rapid manufacture with high controllability, the threedimensional (3D) printing technology has been widely employed for the fabrication of chemical reactors and internals in recent years. 19 Gładyszewski et al 20,21 3D-printed packing was applied for CO 2 absorption in an RPB. Unlike the above procedure, Qammar et al 22 designed and printed a Zickzack packing to provide better mass transfer performance for distillation.…”