1. SO2 is removed from an air stream by absorption into water at 1atm and 20oC. The air flow rate is 10.0 lbmol/h and the SO2concentration is 3.0%. The exit concentration of SO2 is 0.5%. Thewater flow rate is 1.2 times the minimum (L = 1.2 x Lmin). Thecolumn is 1.0 ft diameter and packed with 25 mm ceramic Raschigrings. kL is 1.3 ft/h and the driving force is concentration(lbmol/ft3). kp is 0.195 lbmol/h ft2 atm and the driving force ispartial pressure (convert to torr). The equilibrium constant at 1atm and 20oC is K = y/x = 20.
a. Make equilibrium graphs of x vs. y and c (lbmol SO2/ft3) vs. p(torr).
b. Use the xy plot to find the specified liquid flow rate.
c. Use a mole balance to find the liquid effluent concentration (xand c).
d. Draw the operating lines on both graphs.
e. Determine the number of theoretical stages using both graphs.(Should be about the same number.)
f. Use the Kremser equation to determine the number of theoreticalstages with K = slope of xy equilibrium line. If A = 1 then youwill have division by 0. So try K = 19 and 21.
g. Determine the NTU and HTU using both overall mass transfercoefficients based on y and p. (Derive these equations with thehelp of class notes.)
h. Determine the height of the packed column.
2. Perform a similar analysis of a stripping column. In this case,100 lbmol/h of water with a concentration of 0.0045 lbmol SO2/ft3is stripped with air to a concentration of 0.0005 lbmol SO2/ft3.The air flow rate is 1.5 times the minimum.
3. Specify as many variations of problems 2 and 3 as you can.
1. SO2 is removed from an air stream by absorption into water at 1atm and 20oC. The air flow rate is 10.0 lbmol/h and the SO2concentration is 3.0%. The exit concentration of SO2 is 0.5%. Thewater flow rate is 1.2 times the minimum (L = 1.2 x Lmin). Thecolumn is 1.0 ft diameter and packed with 25 mm ceramic Raschigrings. kL is 1.3 ft/h and the driving force is concentration(lbmol/ft3). kp is 0.195 lbmol/h ft2 atm and the driving force ispartial pressure (convert to torr). The equilibrium constant at 1atm and 20oC is K = y/x = 20.
a. Make equilibrium graphs of x vs. y and c (lbmol SO2/ft3) vs. p(torr).
b. Use the xy plot to find the specified liquid flow rate.
c. Use a mole balance to find the liquid effluent concentration (xand c).
d. Draw the operating lines on both graphs.
e. Determine the number of theoretical stages using both graphs.(Should be about the same number.)
f. Use the Kremser equation to determine the number of theoreticalstages with K = slope of xy equilibrium line. If A = 1 then youwill have division by 0. So try K = 19 and 21.
g. Determine the NTU and HTU using both overall mass transfercoefficients based on y and p. (Derive these equations with thehelp of class notes.)
h. Determine the height of the packed column.
2. Perform a similar analysis of a stripping column. In this case,100 lbmol/h of water with a concentration of 0.0045 lbmol SO2/ft3is stripped with air to a concentration of 0.0005 lbmol SO2/ft3.The air flow rate is 1.5 times the minimum.
3. Specify as many variations of problems 2 and 3 as you can.
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