Meteorology and Air Pollution 373the area (in terms of x and y coordinates) where H2S could be detected by its odor.
A programmable calculator or a computer spreadsheet program may facilitate this
calculation, or you can write a computational program.
18.9 A facility emits 100 g SOz/s. On relatively clear nights (slight cloud cover)
and a wind speed of 2 m/s, the maximum ground level SO2 concentration cannot exceed
60 pg/m3, If the only control on SO2 emission is stack height, what would the effective
stack height have to be?
18.10 A copper smelter processes 1000 metric tons of ore per day, principally
CuFeS2, producing SO2 as a pollutant. The stack is 80 m tall and 2 m in exit diameter,
and heat loss through the stack is 3000 H/s. For an overcast night with a wind speed
(measured at 5 m) of 4 ds:
a. Calculate the effective stack height.
b. Calculate the maximum ground level concentration of S02.
c. Estimate the percent SO2 control needed to meet the EPA 24-h secondary18.11 A power plant has a 90-m stack with an outlet diameter of 10 m. The plant
burns 15,500 metric tons of coal per day, with a sulfur content of 3.5% by weight,
and all the sulfur is converted to S02. The coal has a heat content of 12,500 Btdlb,
and about 6% of the heat generated is lost out the stack. The temperature of the plume
emerging from the stack is 200°C. Wind measurements at 3 m from the ground on an
overcast winter afternoon, when the ground temperature is O"C, show a wind from due
north at 4 mls.
ambient air quality standard (see Chap. 20).a. Estimate the eflective stack height by two methods.
b. Using the more conservative value of the effective stack height, plot a graph
of the ground level SO2 concentration with downwind distance. At the 10-km
point, plot the SO2 at right angles to the wind (as in Fig. 18-16) in both the y
and z directions.
18.12 If an air sampling site were located on the ground 8 km SE of the plant in
Problem 18.11, what SO2 concentration would the sampler expect to measure?
18.13 The concentration of H2S 200m downwind from an abandoned oil well
is 3.21m3. What is the emission rate on a partially overcast afternoon when the wind
speed is 2.5 ds at ground level?
18.14 A power plant burns 2% sulfur coal and has a 70-m stack with a diame-
ter of 1.5 m. The exit velocity and temperature are 15 m/s and 340°C, respectively.
The atmospheric conditions are 28°C and a barometric pressure of 90kPa, and the
weather is a clear summer afternoon with a wind speed of 2.8 mls measured at 10 m.
At a point 2.5 km downwind and 300 m off the plume centerline, the ground level
SO2 conaentration was measured at 143pg/m3. How much coal does the plant
burn?
18.15 The power plant in Problem 18.14 burns coal with a 10% ash content, and
20% of the ash (by weight) is emitted into the air. The ash has an average density of
1.0 g/cm3 and an average diameter of 2 Vm. Calculate the deposition rate at the point
indicated in Problem 18.14.