Page 73 - Air Pollution Control Engineering

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Air Quality and Pollution Control 53

These values are substituted into Eq. (38) for heat content and yields

3
h = 4.11 Btu/scf or (4.11 Btu/scf)/(0.0739 lb/ft ) = 55.6 Btu/lb
e1
12.2. Example 2
Outline the step-by-step procedures for calculation of air dilution requirements.
Solution

Step 1: Determine the dilution airflow rate from Eq. (40) to decrease the heat content of
the emission stream from h to h as follows:
e d
Q = Q [(h /h ) −1] (40)
d e e d
Q = scfm
d
Step 2: Determine the concentrations of the various components in the diluted emission
stream as follows:
[
d (
2(
O 2,d = O hh ) + 21 1− hh e)] (41)
d
e
O = %
2,d
M = M (h /h ) + 2[1− (h /h ) ] (42)
e,d e d e d e
M = %
e,d
Q = Q (h /h ) (43)
e,d e e d
Q = scfm
e,d
Step 3: Redesignate emission stream characteristics as follows:
O = O = %
2 2,d
M = M = %
e e,d
h = h = Btu/scf
e d
Q = Q = scfm
e e,d

NOMENCLATURE
atm Atmosphere
Btu British thermal units
C Cunningham correction factor
CFC Chlorofluorocarbon
CAA Clean Air Act
CERLA Comprehensive Environmental Response, Compensation, and Liability
Act
CEQ Council on Environmental Quality
DA Dry air content of combined gas stream (lb/min)
e
2
g Gravitational acceleration (980 cm/s )
H Humidity, mass water/mass of air
H Combined emission stream heat content (Btu/scf)
e