Question

7 Consider the air over a city to be a box 100 km on a side that reaches up to an altitude of 1.0 km. Clean air is blowing into the box along one of its sides with a speed of Suppose an air pollutant with reaction rate is emitted into the box at a total rate of Find the steady-state concentration if the air is assumed to be completely mixed.

Answer 1

Explanation:

V= 100*100*1 = 10000 km^3

Q = 4/1000*1*100 = 0.4 km^3/s

m (loading) = 10kg/s, k = 0.20/hr

1 km^3 = 10^12 L (if u want kg/L as concentration)

Cin = 10kg/s / 0.4 km^3/s = 25 kg/km^3

for CSTR: Cout = Cin/(1+k*t), t = V/Q = 25000 s or 6.94 hr

Cout = 25/(1+0.20*6.94) = 10.47 kg/km^3