1. Absorption of Oxygen in Water in a Packed Colum
Kelly Yates
Quintin Picard
4/30/15

2. Experimental Setup Packing increases area in column
Testing effects of:
Water flow rate (100, 150, 200 L/h)
Pressure (1, 1.25, 1.5 bar)
Gas flow rate (25, 37, 50 L/min)
Set up a 33 factorial design

3. Equations General Mass Transfer ln⁡( 𝑐 𝑎 − 𝑐 0 𝑐 𝑎 − 𝑐 𝑙 ) 𝐾 𝑙 = 𝑁 𝑎
Sherwood-Holloway Correlation
𝐾 𝑙 𝑎 𝐷 𝐴𝐵 =𝛼 ( 𝐿 𝜇 ) .8 ( 𝜇 𝑝 𝐷 𝐴𝐵 ) 1/2
Wilke Chang Correlation
𝐷 𝐴𝐵 = 1.173∗ 10 −16 (𝜑𝑀) 1/2 𝑇 𝜇 𝑉 .6
ϕ= association parameter
Rate
Rate=𝐹𝑙𝑢𝑥∗𝐴𝑟𝑒𝑎
Henry’s Law
𝑃 𝑠𝑎𝑡 =𝐻𝑥
Resistance
1 𝐾 𝑙 = 1 𝐻 𝑘 𝑔 𝑘 𝑙

4. Flux Theory Henry’s constant for oxygen: 44253 bar
Pressure
Gas Flow Rate
Water Flow Rate
Henry’s constant for oxygen: bar
Liquid side controls mass transfer

8. ANOVA and Propagation of Error
At a 95% confidence limit
Only water flow is significant
At 80% confidence limit
Pressure is significant
Milwaukee MW 600: ±1% accuracy
Pressure gauge: ±3% accuracy
Rotameter: ±5% accuracy
ln 𝑐 𝑎 − 𝑐 0 𝑐 𝑎 − 𝑐 𝑙 𝐾 𝑙 = 𝑁 𝑎
9% Uncertainty
𝐾 𝑙 𝑎 𝐷 𝐴𝐵 =𝛼 𝐿 𝜇 .8 ( 𝜇 𝑝 𝐷 𝐴𝐵 ) 1 2
5 % Uncertainty
𝑃 𝑠𝑎𝑡 =𝐻𝑥
3% Uncertainty

9. Scale Up Design 1 million gallon tank House 50 40kg sharks
Sharks requires 800 g/hour of O2 minimum
Scale up by 25% to ensure adequate levels
1 million gallons = 3785 m3
keyword: aquarium sharks
20 m
12 m
Pressure at bottom of tank is 1.18 bar

10. Final Column Design
From ANOVA: use high pressure and high water flow rate
P = 1.5 bar and Water Flow Rate = ? Area = ?
Went with actual values over predicted
𝐾 𝑙 =.0036 𝑚 𝑠 𝑙𝑛 𝑐 𝑎 − 𝑐 𝑙𝑜 𝑐 𝑎 − 𝑐 𝑙𝑓 =.473 𝑚𝑜𝑙 𝑚 3
Area of 5.58 m2 - diameter of 2.67 m (± .11 m)
Volumetric flow rate of 62 L/s
N= 𝐾 𝑙 ln⁡( 𝑐 𝑎 − 𝑐 𝑙𝑜 𝑐 𝑎 − 𝑐 𝑙𝑓 )
𝑅𝑎𝑡𝑒 𝐴𝑟𝑒𝑎 = 𝐾 𝑙 𝑙𝑛( 𝑐 𝑎 − 𝑐 𝑙𝑜 𝑐 𝑎 − 𝑐 𝑙𝑓 )

11. What About Temperature?
Wilke-Chang Method to account for change in diffusivity with temperature
𝐷 𝐴𝐵 = 1.173∗ 10 −16 (𝜑𝑀) 1/2 𝑇 𝜇 𝑉 ϕ= 2.6 for water
𝐷 𝐴𝐵 =1.11∗ 10 −9 𝑚 2 𝑠
Account for evaporation with rise in temperature so increase rate to g/h
Calculate required flow rate with diameter of column and same concentration gradient
Need 80.2 L/s
Using Wilke-Chang
Kl value becomes .004 m/s and the flow rate is L/s

12. Appendix: ANOVA

13. Appendix: Raw Data Water Pressure O2 Conc. Start O2 Conc. Final (mg/L)
Flux (mol)/(m^2*s)
Rate (g/s)
5.56E-05
1.5
1.2
5.7