Experiments in large scale venturi scrubber: Part II. Droplet size

Venturi scrubbers are used for gas cleaning in a wide variety of industrial applications. Their performance is strongly dependent upon the droplet size and distribution. Most of the work available in the literature concerns the experimental study of small-scale venturis, whose extrapolation to industrial large scale facilities is open to discussion.The present work reports droplet size measurements inside a large-scale venturi scrubber. The liquid phase flow rates were varied between 0.013 and 0.075 kg/s and the maximum velocity at the throat was 70 m/s.The results show that the droplet size depends on both the gas and liquid phases flow rates and on the method for liquid injection, either film or direct atomization. The data suggest two competing mechanisms for droplet formation: turbulent break up and coalescence, the later being dominant for high gas velocity and liquid loading.Comparisons between the experimental data and available correlations for the droplet size show that these are not adequate for describing the atomization in large diameter venturis, particularly in the converging section, where the break up may not be complete.