In the control of acid rain, power plant sulfur emissions can be controlled by s
ID: 488913 • Letter: I
Question
In the control of acid rain, power plant sulfur emissions can be controlled by scrubbing and spraying the flue gases with a lime slurry, ca(OH)_2, the calcium reacts with the sulfur dioxide to form calcium sulfate, CaSO_4, a white powder suspended in water. The volume of this slurry is quite large, so it has to be thickened. Suppose the power plant produces 27 metric tons of CaSO_4 per day, and that this is suspended in 108 metric tons of water. The intention is to thicken this to a solid concentration of 40% solids, (a) What is the solids concentration of the CaS04 slurry when it is produced in the scrubber? (b) How much water (tons/day) will be produced as effluent in the thickening operation? (c) Acid rain problems can also be reduced by reducing the amount of electricity produced and used. What responsibility do individuals have, if any, not to waste electricity? Argue both sides in a half-page paper.Explanation / Answer
Ca(OH)2 + SO2 = CaSO4
M = 27 ton of CaOS4/day
m = 108 ton of water
thicken so solids = 40%
a)
initial concentration
C = mass of CaSO4 / volume = 27/108 = 0.25 or 25%
b)
if we required 40% of solids
we will require...
108 /0.25 = 432 metric ton of water
c)
In order to avoid waste of electricity, consider neutralicing all SO2 in order to decrease SO2 emissions
SO" emissions will favour H"SO3 and H2SO4 formation in water
Water will form acid rain, so an decrease in the production of CaSO4 will not favour the acid rain, which wastes electric power