Page 51 - Air Pollution Control Engineering

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Air Quality and Pollution Control 31

Table 5
Dew Point Temperature
Gas stream temperature (ºF)

70 80 90 100 120 140 160 180 200 220 240
Psychrometric
ratio Dew Point Temperature (ºF)
0.000 0 0 0 0 0 0 0 0 0 0 0
0.005 54 58 61 65 70 76 81 86 89 93 96
0.010 62 65 68 71 77 82 86 90 94 97 100
0.015 68 72 75 77 82 86 90 94 97 100 103
0.020 77 80 82 87 91 94 97 100 103 106
0.025 85 87 91 94 98 101 103 106 109
0.030 89 91 95 98 100 104 107 109 111
0.035 95 98 101 104 107 109 110 114
0.040 98 101 104 107 109 111 114 116
0.045 104 107 109 112 114 116 118
0.050 107 109 112 114 116 118 120
0.055 109 112 114 116 118 120 122
0.060 111 114 116 118 120 122 124
0.065 114 116 118 120 122 124 125
0.070 116 118 120 122 123 125 130
0.075 118 120 122 124 125 130 150
0.080 119 122 123 125 130 140 170
0.085 123 125 130 143 168 182
0.090 124 130 140 162 180 205
0.095 128 140 165 180 205 225
Source: US EPA.

pollution equipment, the amount of SO in the gas stream must be considered when
3
determining the dew point temperature for the gas stream. The acid dew point temper-
ature can be determined when the parts per million volume bases (ppmv) of SO and
3
the volume percentage of moisture (vol%) in the gas stream are known. Using Fig. 14,
the acid dew point can be determined. The figure provides dew points for three volume
percentages of moisture levels: 2%, 5%, and 10% H O. Other dew point temperatures
2
for moisture percentages less than 10% and greater than 2% can be estimated using the
provided moisture level curves.
The SO content of each individual stream is converted to lb-mol by using Eq.
3
(32):
6
S = Q (S /10 )(lb-mol/392 scf) (32)
e1,l-m e1 e1
where S is the SO content of gas stream 1 (ppmv) and S is the SO content of
e1 3 e1,l-m 3
gas stream 1 (lb-mol/min). Repeat this converting procedure for each gas stream. After
all streams are converted, then these values are summed to obtain the combined gas
stream content as follows: