Page 268 - Air Pollution Control Engineering

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Wet and Dry Scrubbing 247

Table 15
Effluent Characteristics for a Municipal Incinerator Emission Stream

1. Flow rate (Q ) = 110,000 acfm
e,a
2. Temperature (T ) = 400°F
e
3. Moisture content (M ) = 5%
e
4. Required collection (removal) efficiency (CE) = 99.9%
5. Mean particle diameter (D ) = 1.0 µm
p
6. Particulate content = 3.2 grains/scf fly ash
7. HAP content = 10% of total mass of cadmium
B. Permit Review Data to be presented by applicant:
Given a required collection (removal) efficiency of 99.9% and the mean particle
diameter in the emission stream from the incinerator is estimated as 1.0 µm, from Fig.
5. Note that the value of P is outside the range of data presented in Table 8. The value
v
of 47 in. H O is less than 50 in. H O, therefore, it may still be safely used in this
2 2
exercise. The Venturi scrubber should perform properly.
1. Reported pressure drop (across Venturi) (P ) = 47 in. H O (see Fig. 5)
v 2
2. Pertinent performance curve for Venturi scrubber (from supplier)
3. Reported collection (removal) efficiency (CE) = 99.9%
C. Determination of Pretreatment Requirements
As previously discussed, for the Venturi principle to be applied to an air pollution
control need, the air being treated should be at 50–100°F above its saturation (dew)
temperature. If the air to be treated does not meet this condition, then pretreatment of