Page 240 - Air Pollution Control Engineering

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Wet and Dry Scrubbing 219

Fig. 5. Typical Venturi scrubber performance curve.

Annual operational costs of the system also reflect direct and indirect expenses.
Such expenses are given in Table 7. It should be noted that the annual cost factors
for Venturi and packed scrubbers are identical. Direct annual costs of a Venturi
scrubber are also those of a packed scrubber: power, scrubbant liquor, labor, and
maintenance costs.
Electric power cost is similar as for packed scrubbers: A certain amount of horse-
power will be required to move the polluted air through the Venturi scrubber at a given
pressure drop. Please refer to Section 2.4.4 for the formula from the Electric Power
Institute of Palo Alto, California that may be used to estimate the horsepower needed to
move the air volume in cfm if the pressure loss is known in inches of water column
(WC). Annual electric costs of running 1 hp, at various power prices, are also given in
Section 2.4.4.
The electrical costs are a function of the fan power required to move gas through the
system. Equation (23) is used to estimate the fan power requirement assuming a fan-motor
efficiency of 65% and fluid specific gravity of water (1.0).