Question

(17 pt) Suppose a bonfire emits CO at the rate of 20 g/s on a clear night when the wind is blowing at 2 m/s. If the effective stack height at the fire is 6 m:

(a) (6 pt) What would you expect the ground-level CO concentration to be along the centerline at 400 m downwind (in mg/m3 )?

(b) (6 pt) Estimate the maximum ground-level concentration using empirical method (in mg/m3 ).

(c) (4 pt) Estimate the maximum ground-level concentration using graphical method (in mg/m3 ).

(d) (1pt) At what distance downstream does the maximum ground-level concentration occur (in meters)?

Answer 1

ANSWER :
Given, Qm=20915 2 m/s 2 Hal = 6m As the might is clear, by pasquill confford stability model. the stability class in e (a): x = 400 ml downward distance) can be calculated as The dispersion coefficients follows: oy cm) = 0.06 x C1+ 0.00010)-Y2 al = 0.06X 400 C 170-0001X400) = 23.53m Pre (m) - 0.03 211+0.00031) = = 0.03 X 4 00(1+0.0003 x 4007-72 = 11.338 m So wind distance of is calculated as 400m tee ground level centre tre concentration at down, as follows: exp[-t lehet 2 C<400, 0,o) - am Turyoz

20915 3.14% 2 m/s X23.63 xll: 938 mop (14) 0.010377 glm? = 10.377 mg Im3 b) The maximum ground level concentrations is caluated where T2 = Ha 12 6 J2 4.243 m. 12 12 0.03% (1 + 0.00032) - 4.243. *) 4.999 x 1052 0.0003 * - ) = 0 #) OC = 144.46 (01) ox= -138.46 (not possibk) 144.46 m. (227 og <C>mar 2 Om * og = 8:605 m ett ut 2x20x 103 mals 2:718 x 2 m/s *3.14% 6?m? (c) max 4.243 (8.605 32₂097 mg/m3 le) Now, bor mendimum concentration, 2 = 4,243

from the graph its found that at around = 0.15 km or 150m. oy 8.933 m. <c) max 2x20x103 4.243 X (4 1933 2.718 x 2x 3.14x36 = 30.918 malm (d). The distance down wind where maximum. concentration occurred was! x = 150m 144.46 m ( Em pirical method] (Graphical method)