Page 259 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition
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Mechanical Separations                                     231























































       Figure 4-5. Efficiency curves for various types of dust collection equipment as of 1969. Only marginal improvements have been made since
       then. By permission, Sargent, G. D., Chemical Engineering, Jan. 27, 1969, p. 130.

       and hence, particles influence adjacent particles. This is   If, K < 3.3, then Stokes’ law applies. If 3.3 S K S 43.6, the
       often  termed  hindered  settling  [ 23,461. Depending  upon   intermediate  law  applies, and if  K > 43.6, Newton’s law
       the  particles  concentration,  the  hindered  terminal  set-   applies. If K > 2,360, the equations should not be used.
       tling velocity will  generally be  somewhat lower than for
       the terminal settling velocity of a single desired particle in   Values of a and bl
       the same medium.
          From Reference  [46] :
          K  is  a  dimensionless  number  that  establishes  the   Law   __   Range             bl          a
       regime of settling class, reference to the settling laws:   _.         K< 3.3            24.0         1 .o
                                                             Stokes’
                                                             Intermediate     3.3 S K  43.6     18.5        0.6
          K= 34.8Di[ P f  (P ~* - P f  ) ]                   Newton’s         K > 43.6        ~~~   0.44    0   -
                                                                                                             ~
                                 1/3
                          p
                                                    (4-10)
                                                                                               (text continued on page 234)
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