Page 168 - Air Pollution Control Engineering

03_chap_wang.qxd 05/05/2004 12:48 pm Page 147
Cyclones 147

1 1
 aD  −1  2.6538x1.25  −1.837
1
b
Q =  c  =  
 D   D 50 
50
Table 25 lists the calculated gas flow rates for cut diameters ranging from 1 to 10 µm. For
the sake of illustration, let us suppose that the measurements of particle concentrations for
each flow rate are given by c in Table 25. In this case, the percentage of particles with
in
average diameter D can be estimated as
50
% in range ≈ c in
∑ c in
Figure 23 shows the calculated particle size distribution. It is worth mentioning that the
use of a microgram balance (10 −6 g sensibility) in this study is likely to occur.

NOMENCLATURE
a Height of the cyclone entry duct (m)
a Empirical parameter in Eq. (73) or (74), given in Table 18 or 21
a Constant in Eq. (52)
d
a Constant in Table 7
f
a Constant in Table 8
s
a , a , a Parameters in Eq. (68), listed in Table 15
1 2 3
A Empirical parameter listed in Table 11
2
A Cyclone inlet area (ft )
cyc
b Width of the cyclone entry duct, (m)
b Empirical parameter in Eq. (73) or (74), given in Table 18 or 21
b Constant in Eq. (52)
d
b Constant in Table 7
f
b Constant in Table 8
s
B Diameter of the dust exit, at the base of the cyclone (m)
B Empirical parameter listed in Table 11
c Parameter in Eq. (74)
3
3
c Overall particle concentration at the cyclone entry [kg/m or gr/ft in
in
Eq. (35)]
3
c Particle concentration at the cyclone exit (kg/m )
o
cost The cost in the month–year of a (US$)
a
cost The cost in the month–year of b (US$)
b
d Parameter in Eq. (74)
d Diameter of the cyclone central axis (m)
c
d Duct diameter (in).
duct
d Fan diameter (in).
fan
D Particle aerodynamic diameter [µm, or m in Eq. (75)]
ae
D Diameter of the cyclone cylindrical body [m, or cm in Eq. (73)]
c
D Diameter of the dust receiver cup (m)
cup
D Duct diameter (ft)
duct
D Diameter of the exit cyclone duct (vortex finder) (m)
e
D Particle diameter (m)
i