Drop size measurements in Venturi scrubbers

Venturi scrubbers are high efficiency gas cleaners in which suspended particles are removed from gas streams by drops formed by liquid atomisation, usually in the Venturi throat. The size of the drops formed are of fundamental importance to the performance of the equipment, both in terms of pressure drop and dust removal efficiency. In this study, drop sizes in a cylindrical laboratory-scale Venturi scrubber were measured using a laser diffraction technique. Gas velocity and liquid to gas ratios varied from 50 to 90m/s and 0.5 to 2.0l/m3, respectively. Water was injected using two different arrangements: either as jets in the throat or as a flim just upstream of the convergence. Drop size measurements were performed at three positions in the case of jet injection: two located along the throat, and the last one at the end of the diffuser. The present data shows that the Sauter mean diameter of the spray can be well correlated by the equation of Boll et al. (J. Air Pollut. Control Assoc. 24 (1974) 932). Drop size distributions are satisfactorily represented by a Rosin–Rammler function. This paper also provides a simple method for calculating the parameters of the Rosin–Rammler function. As a result of this work, drop sizes in Venturi scrubbers can be estimated with much higher accuracy.

[1]  Werner Strauss,et al.  Industrial gas cleaning , 1966 .

[2]  B. Azzopardi,et al.  Gas/Liquid Flow in Laboratory-Scale Venturis , 1999 .

[3]  R. A. Pulley,et al.  Modelling the performance of venturi scrubbers , 1997 .

[4]  Norman Chigier,et al.  Response Characteristics Of Laser Diffraction Particle Size Analyzers: Optical Sample Volume Extent And Lens Effects , 1984 .

[5]  Tetsuo Yoshida,et al.  Pressure Loss for the Acceleration of Atomized Droplets , 1965 .

[6]  A. R. Jones,et al.  Electromagnetic Scattering and its Applications , 1981 .

[7]  G. Gee,et al.  Particle-size Analysis , 2018, SSSA Book Series.

[8]  R. H. Boll.  Particle Collection and Pressure Drop in Venturi Scrubbers , 1973 .

[9]  T. J. Hanratty,et al.  Relation of deposition to drop size when the rate law is nonlinear , 1996 .

[10]  G. J. Parker,et al.  Air-water tests on a venturi for entraining liquid films , 1973 .

[11]  B. Azzopardi.  A diffraction drop sizing technique: Its testing and application to confined sprays , 1984 .

[12]  S. Calvert.  Venturi and other atomizing scrubbers efficiency and pressure drop , 1970 .

[13]  L. Dodge,et al.  Performance comparison of Malvern instruments laser diffraction drop size analyzer , 1986 .

[14]  R. H. Boll,et al.  Mean Drop Size in a Full Scale Venturi Scrubber via Transmissometer , 1974 .

[15]  H. Johnstone,et al.  Collection of Aerosols in a Venturi Scrubber , 1951 .

[16]  D. B. Roberts,et al.  ATOMIZATION IN A VENTURI SCRUBBER , 1981 .

[17]  S. Nukiyama,et al.  An Experiment on the Atomization of Liquid : 5th Report, The Atomization Pattern of Liquid by means of an Air Stream , 1938 .

[18]  L. K. Peters,et al.  Analysis of particulate removal in venturi scrubbers—effect of operating variables on performance , 1981 .

[19]  David Leith,et al.  Liquid utilisation in a venturi scrubber , 1985 .

[20]  D. Atkinson,et al.  Droplet Size and Surface Tension in Venturi Scrubbers , 1978 .

[21]  B. Azzopardi.  Liquid distribution in venturi scrubbers: the importance of liquid films on the channel walls , 1993 .

[22]  K.G.T. Hollands,et al.  Optimum design of venturi scrubbers , 1977 .