CHEN 3006 Lecture Notes - Lecture 25: Heat Transfer Coefficient, Partition Coefficient, Water Gas

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11 Mar 2015

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Problem 7: absorption of a gas a into water. T = 50 oc, p = 200 kpa ya in gas bulk is 0. 085 xa in liquid bulk = 0. 001. Partition coefficient (based on mole fractions): m = 50, where y a = mxa gas liquid. Experimental values of mass transfer coefficients: kl = 0. 18 m/h kp = 0. 040 kmol/(h m2 kpa: calculate kx and ky. Chen3006_masstransferandseparations page 3: calculate the overall mass transfer coefficient k x. Chen3006_masstransferandseparations page 4 add eqns 1 and 2 together solve for kx (plug in little k values and m) => liquid: calculate flux of a, na; Problem 5 impermeable faces and ends (striped parts) permeable sides (solid white) c = 0 outside device permeable side c = 0 permeable side x = -h 0 x = h. Rate of dissolution of drug per unit volume. General eqn: all = 0 b/c dilute, so velocity = 0.

Related Questions

air-H2S mixture is flowing by a film of water that is flowing as a thin film down a vertical plate. H2S is being absorbed. P = 1.5 atm and T= 303K. K'c= 9.567*10^-4 m/s and pA (atm) = 609xA (liquid mole fraction). Na=-1.485 *10^-6 kg-mol/s*m^2.

a) Convert the gas-phase mass-transfer coefficient, kc ' , to k y ' and k G ' .

b) Based on the flux calculated above, calculate the liquid-phase mass-transfer

coefficient, kc ' , at this point in the tower.

c) Convert the liquid-phase mass-transfer coefficient, kc ' , to k x ' .

d) Calculate Kyâ, Kxâ and the percent resistance offered by the gas and liquid phases.

e) Sketch both the concentration profiles (i.e., cA vs distance) and the mole-fraction

profiles (i.e., xA and yA vs distance) in the gas and liquid phases. Clearly indicate

values at the interface and bulk.

Again consider the falling film in TP 7.2-3, but assume negligible gas-phase mass

transfer (i.e., xA1 â 2 Ã 10-5). What value of z (see Equation 7.3-22) corresponds to NA

= -1.485 Ã 10-6 kg-mole/sâ m2? Assume the diffusion coefficient for water-H2S is DAB =

10-9 m2/s, the liquid has the properties of pure water, and the liquid film is

approximately 2 mm thick (see section 2.9C for more information on the velocity

profile in a following film). Calculate kcÊ¹ in the gas and liquid phases at this z and at a

z half this value. Sketch both the concentration profiles and the mole-fraction profiles

in the gas and liquid phases. Again, clearly indicate values at the interface and bulk.

the problem is in the picture.

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A pending refinery operation is being designed. A gas stream in this operation is to be partially condensed at 80 degrees. The composition of the gas is:

A: 5% (mole)

B: 30%

C: 55%

D: 10%

Determine the pressure for the partial condenser required to condense 75% of the gas stream. Assume Raoultâs law is valid.

Use Excel to do the following:

1.Calculate the vapor pressures of the pure components.

2.Assume 100 moles of feed gas and calculate the moles of vapor and liquid that must come from the condenser.

3.Write material balances for each component around the condenser.

4.Use Raoultâs Law to relate y to x for each component in terms of its vapor pressure and the to-be-determined total pressure P.

5.Substitute the expressions you found for y into the material balances, which should each now have two unknowns --- x and P.

6.Solve for each x

7.Add the four expressions for the mole fractions x in the liquid.

8.Find P that makes the sum of the mole fractions in the liquid equal to 1.

CHEN 3006 Lecture Notes - Lecture 25: Heat Transfer Coefficient, Partition Coefficient, Water Gas

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