Page 215 - Air Pollution Control Engineering

04_chap_Wang.qxd 05/05/2004 1:15 pm Page 194
194 Chung-Shin J. Yuan and Thomas T. Shen

E Precipitating or collecting field (V/m)
p
E Radial component of electrical field near particle (V/m)
r
F Electrostatic force (N)
0
F Viscous drag (N)
d
H Height of plate
i Current (A)
2
i Average current density at plate (A/m )
a
i Linear current density (A/m)
i
I Corona current
c
3
J Power requirement [kW/(m /s)]
k Boltzmann’s constant, 1.38×10 −23 (N m/K)
k' Adjustable constant
k" Empirical constant
K Power cost ($/kWh)
l Path length in the direction of current flow (cm)
L Electrode duct length (m)
L Length of inlet section (m)
in
L Length of outlet section (m)
out
L Length of collecting plate (m)
p
L Spacing between electrical section (m)
s
2
L Overall length of precipitator, m plate (A/m )
t
m Particle mass (kg)
2
m Ion mobility (m /V s)
i
3
M Maintenance cost, $/(cm /s)
N Ion concentration in potential Field m −3
3
N Initial ion concentration (m )
0
2
N Number of ducts (m /V)
d
3
N Particle number density (m )
p
p Particle resistivity (Ω-cm)
P Pressure (atm)
P Standard pressure (1 atm)
0
P Corona power
c
P Dimensionless, Eq. (18)
q Particle charge (C)
q' Ion charge 1.602×10 −19
q Diffusion charging of particle (C)
d
q Field charging of particle (C)
f
q Ion charge (C)
i
q Limiting particle charge (C)
max
3
Q Gas flow rate (m /s)
r Radius, radial distance from particle center, radial distance from cylin-
der axis (m)
r Wire radius (m)
0
r Cylinder or tube radius (m)
1
r Aspect ratio
a