Coupling between Mass Transfer and Chemical Reactions during the Absorption of CO2 in a NaHCO3-Na2CO3 Brine : Experimental and Theoretical Study

摘要

This work deals with the study of the gas-liquid mass transfer, coupled withnchemical reactions. The case of carbonic gas absorption in a brine of sodiumncarbonate and bicarbonate is investigated. It is performed in collaboration withnSolvay SA. The aim of this work is to get a better understanding of this phenomenon.nIt would permit an optimization of the refined sodium bicarbonatenproduction process. The basis of developed mathematical models is presented.nThe CO2 absorption is coupled with several chemical reactions taking place in thenliquid phase. A mathematical modelling of this coupling is first developed. Thenequations of the model are solved numerically, using COMSOL Multiphysics. Tonmodel the bubble-liquid mass transfer of CO2, this diffusion-reaction model isncompleted by a representation of the liquid phase flow around the bubble. In ordernto validate experimentally each scale of modelling, two experimental devicesnare proposed.