Theoretical Study of Liquid Droplet Dispersion in a Venturi Scrubber

Abstract

The droplet concentration distribution in an atomizing scrubber was calculated based on droplet eddy diffusion by a three-dimensional dispersion model. This model is also capable of predicting the liquid flowing on the wall. The theoretical distribution of droplet concentration agrees well with experimental data given by Viswanathan et al.1 for droplet concentration distribution in a venturi-type scrubber. The results obtained by the model show a non-uniform distribution of drops over the cross section of the scrubber, as noted by the experimental data. While the maximum of droplet concentration distribution may depend on many operating parameters of the scrubber, the results of this study show that the highest uniformity of drop distribution will be reached when penetration length is approximately equal to one-fourth of the depth of the scrubber. The results of this study can be applied to evaluate the removal efficiency of a venturi scrubber.

Mathematical Modeling of SO2 Absorption in a Venturi Scrubber

“…In fact, this source strength is used instead of the liquid stream provided by each nozzle. Further details on evaluating the parameters needed for solving eq 1 are given by Fathikalajahi et al 3 Distribution of droplet concentration throughout the scrubber is determined by solving the above equation. In the next step, the gas absorption rate and pollutant concentration distribution should be evaluated.…”

“…The distribution of droplet concentration, C d , is evaluated by a three-dimensional dispersion model. 3 The main equation of that model, which expresses material balance for droplets in each increment of the scrubbing zone, is:…”

“…Many investigators 1,2 have shown that droplets are dispersed nonuniformly throughout the scrubber. Fathikalajahi et al 3 have shown that droplet concentration distribution depends on the key parameters of a venturi scrubber, including liquid-to-gas flow rate, gas throat velocity, and nozzle diameter. The extent of droplet dispersion will affect the rate of absorption in such a manner that the maximum absorption rate is achieved when droplets are dispersed quite uniformly throughout the scrubber.…”

Droplet dispersion angle measurements on a Pease-Antony Venturi scrubber

“…These concepts are simplified models of reality in the sense that, strictly speaking, a jet does not have a single atomization point or a centerline. Nonetheless, these ideas proved to be very useful in Venturi scrubbers modeling and design (Fathikalajahi et al, 1995;Gonçalves et al, 2003a). By using these concepts, a designer is able to optimize the total area covered by liquid injection.…”

“…Several models based on computational fluid dynamics are available to calculate droplet dispersion in Venturi scrubbers with a transversal injection (Taheri and Sheih, 1975;Fathikalajahi et al, 1995;Fathikalajahi et al, 1996;Viswanathan et al, 2005;Gonçalves et al, 2003a). Yoon (2005) used a Lagrangian simulation to study the dispersion and size distribution of droplets emerging from a jet that is parallel to the gas stream.…”