DEVELOPMENT AND MODELLING OF HIGHINTENSITYIMPINGING STREAM REACTORSFOR ENHANCED GAS-LIQUID MASS TRANSFER

摘要

A high intensity impinging stream reactor has been developed to enhance gas-liquid mass transfer. Thechemical absorption of carbon dioxide gas into sodium hydroxide solutions was chosen to determine themass transfer parameters of the new reactor. Experimental results collected for various reactor geometriestested have shown that mass transfer coefficients of up to 3x10-3 m/s can be realised, which, coupled withvalues of interfacial areas of up to 20 000 m2/m3, yield values of up to 20 s-1 for the volumetric mass transfercoefficient (kLa). Compared to kLa values for most other conventional processes in the range of 0.025 - 1.25s-1, these results represent a significant improvement in reactor performance.A mechanistic model for the prediction of the interfacial area production in these jet reactors hasbeen developed. It is implemented in the form of a Monte Carlo simulation, based on the fact that bubblebreak-up in a turbulent environment is governed by the interactions of bubbles with turbulent eddies. Bubblepopulation balance equations, combined with a collision rate function and collision efficiency probabilities,yield a bubble size distribution that is used to compute the interfacial area. The simulation has been verifiedagainst alternative gas-liquid systems and breakage rate equations.