Evaluation of the models available for the prediction of pressure drop in venturi scrubbers

The major running cost derived from the operation of venturi scrubbers is p ressure drop. In the present study, the predictions of different models ale compared to experimental data from venturi scrubbers of different sizes (t hroat diameter from 1.9 to 16 cm), geometries, operating variables and liqu id injection arrangements. As a result, it is concluded that most of the mo dels must be used with caution. Much attention must be paid to the validity of the assumptions employed in the mathematical models. The equations prop osed by Calvert [Scrubbing, Air Pollution, 3rd Edition, Vol. IV, Academic P ress, New York, 1982], Yung et al. [JAPCA 27 (1977) 348] or Hesketh [Atomiz ation and cloud behaviour in wet scrubbers, in: Proceedings of the US-USSR Symposium Control Fine Particulate Emissions 1974, San Francisco, 15-18 Jan uary 1974] produce good results only in very specific situations. The model proposed by Poll [Ind. Eng. Chem. Fundam. 12 (1973) 40] is simple, easy to compute and agrees reasonably well with the experimental data. Unfortunate ly, it cannot predict the effect of different liquid injection, arrangement s. The model by Azzopardi and coworkers [Filtr. Sep. 21 (1984) 196; Trans. IchemE. 69B (1991)237; Chem Eng. J. 67 (1997) 9] was the only one to give g ood predictions for all the range of variables studied. On the other hand, this model is not simple and requires from the engineer an additional effor t in terms of computation. In order to apply this model to the rectangular geometry, the concept of hydraulic equivalent diameter was used. (C) 2001 E lsevier Science B.V. All rights reserved.