Carbon dioxide capture by absorption in carbonates solutions supplemented with the enzyme carbonic anhydrase (CA) has been studied as a novel strategy alternative to the amine based absorption. The enzyme immobilized on fine dispersed solids promotes the heterogeneous biocatalysis of CO2 hydration reaction and the enhancement of CO2 absorption rate. In the present work, a theoretical model of a slurry absorption unit for CO2 capture in CA supplemented K2CO3 solutions was developed and solved using the commercial software package Comsol Multiphysics®. The model was developed through the 'tanks-in-series' approach applied to both the gas and liquid phases; the slurry biocatalyst was modelled as pseudo-homogeneous fine dispersed solids. The reversible Michaelis and Menten kinetics described CO2 conversion by the slurry biocatalyst. The role of mass transfer rate and heterogeneous enzyme catalysis on the CO2 capture rate and on the CO2 concentration profiles in the liquid boundary layer was investigated. Simulation results showed that the CO2 capture rate poorly increased when dissolved CA was used within the enzyme solubility limit, and that in the presence of CA immobilized on fine particles the CO2 absorption rate was enhanced about three fold with respect to carbonate solvent. Support from grant PON03PE_00157_1 'Smart generation' is gratefully acknowledged.
Modelling of Slurry Staged Bubble Column for CO2 Capture in Carbonates Solution with Enzyme Catalysis
2016
Abstract
Carbon dioxide capture by absorption in carbonates solutions supplemented with the enzyme carbonic anhydrase (CA) has been studied as a novel strategy alternative to the amine based absorption. The enzyme immobilized on fine dispersed solids promotes the heterogeneous biocatalysis of CO2 hydration reaction and the enhancement of CO2 absorption rate. In the present work, a theoretical model of a slurry absorption unit for CO2 capture in CA supplemented K2CO3 solutions was developed and solved using the commercial software package Comsol Multiphysics®. The model was developed through the 'tanks-in-series' approach applied to both the gas and liquid phases; the slurry biocatalyst was modelled as pseudo-homogeneous fine dispersed solids. The reversible Michaelis and Menten kinetics described CO2 conversion by the slurry biocatalyst. The role of mass transfer rate and heterogeneous enzyme catalysis on the CO2 capture rate and on the CO2 concentration profiles in the liquid boundary layer was investigated. Simulation results showed that the CO2 capture rate poorly increased when dissolved CA was used within the enzyme solubility limit, and that in the presence of CA immobilized on fine particles the CO2 absorption rate was enhanced about three fold with respect to carbonate solvent. Support from grant PON03PE_00157_1 'Smart generation' is gratefully acknowledged.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
