1) A pure gas, A is entering to a counter-current tray tower separation unit and leaves the tower with 1.5 mol % of gas, B. The inert gas flow rate is 500 mol gas/h ·m2. The liquid entering the tower contains 0.1 mol % B and it is leaving the tower with 0.02 mol % B. Equilibrium curve for this tower is given by y = -817140 x3 + 6500 x2 + 16.755 x where x and y are mole fractions.
a) Determine whether this processes is a stripping process or an absorption process.
b) What is the total liquid and vapor flow rates at the entrance and exit of the tower?
c) Determine the inert liquid flow rate.
d) What is the equation of the operating line?
e) How many theoretical trays does that tower have? Obtain your solution graphically using Excel. Analytical answers will not be accepted.
2) In a counter-current stage tower, gas C is absorbed in a liquid. Equilibrium relationship is given by y=3x. The total inlet gas flow to the tower is 50mol/h and total inlet pure liquid flow rate is 120mol/h. The entering gas contains 1 mol % C. Exiting total gas flow rate is 49.7 mol/h and the exiting gas of the mole fraction y1 = 0.004024145.
a) What is the exiting total liquid flow rate and composition?
b) Can you assume that the operating line for this case is a straight line? If you can justify that assumption, use the inlet and outlet compositions to draw the operating line and fit a linear equation for the operating line.
c) How many stages the tower has? Obtain the number of stages graphically using Excel with the given equilibrium relationship and a suitable operating line.
d) Can you use analytical equations to obtain the number of stages for this case? If you can, what justifies the use of analytical equations?
e) How many stages do you get if you use the analytical equation?
Use the textbook: https://4lfonsina.files.wordpress.com/2012/11/christiegeankoplis-transportprocessandunitoperations.pdf