Agitated vessel Design

For use in chemical industry , pharma and biopharma.

1. Basic Agitated vessel design Dipak Babu seminar

2. Mixing Agitation

3. Basic definitions Agitation : Induced motion of a material in a specified way ,usually in a circulatory pattern inside some sort of a container. Mixing : Random distribution into and through one another ,of two or more initially separate phases.

4. A simple example Gas A Gas B blending Sample A Sample B Same composition = Agitation

5. Rotating drum Different compositions = Mixing

6. B lending of two miscible liquids ( ethyl alcohol and water ). D issolving solids in liquid ( salt in water ). liquid-liquid dispersion (dispersion of pigment in solvents ). S uspending of fine solid particles in a liquid ( catalytic hydrogenation of a liquid). A gitation of the fluid to increase heat transfer between the fluid and a coil or jacket in the vessel wall. dispersing a gas in a liquid as fine bubbles, such as oxygen from air in a suspension of microorganisms for fermentation or for the activated sludge process in waste treatment. Where is it used….??

7. The basic design Influencing factors for achieving a needed amount of mixture or quality of mixing : 1) Dimensions of the liquid content of the vessel. 2) Dimensions and arrangement of the impellers , baffles . http://commons.wikimedia.org/wiki/File:Agitated_vessel.svg

8. The vessel shape . The type , size , position and speed of the impeller. Flow patterns. Vortex formation. Baffles. Power correlations. Design factors

9. The vessel Rounded to eliminate sharp corners or regions into which fluid currents would not penetrate . Height of fluid = diameter of the vessel http://commons.wikimedia.org/wiki/File:Agitated_vessel.svg

10. “The impeller”

11. Types …..!!!

12.   Vessel illuminated with a number of thin light sheets with different colors. www.bakker.org  

13. Pitched blade turbine Three blade marine propeller Straight blade turbine Concave blade impeller Disc turbine

14. Image source : www.fusionfluid.com Double flight helical ribbon impeller

15. Impeller location : 1/6 the liquid level from the bottom Impeller speed : standard speeds are 37, 45, 56, 68, 84, 100, 125, 155, 190, and 320rpm. Power requirements usually are not great enough to justify the use of continuously adjustable steam turbine drives. Impeller size : the ratio of diameters of impeller and vessel falls in the range, d/D,= 0.3-0.6 . Another rule is that a second impeller is needed when the liquid must travel more than 4 ft before deflection.

16. Depend upon : The type of the impeller The characteristics of the liquid(especially viscosity ) The size and proportions of : 1) tanks 2) baffles 3) impeller Flow patterns

17. V r V t V l

18. http://www.dynamixinc.com/baffled-by-baffles

19. Vortex elimination

20. Small tank http://www.dynamixinc.com/baffled-by-baffles

21. Angle with the radius http://www.dynamixinc.com/baffled-by-baffles

22. “Baffles” http://www.dynamixinc.com/baffled-by-baffles

23. Power consumption Pumping number Power number Reynolds number Power correlations

24. A simple numerical For a vessel containing 5000 gal of liquid with specific gravity = 0.9 and viscosity of lOOcP , find size and speed of a pitched turbine impeller to deliver 2 hp/1000 gal . Check also the superficial linear velocity Solution : Size : d = 0.40 = 0.4(9.5)(12) = 45.6 in , say 46 in . P= 2V = 2(5) = lO hp. (1 hp = 0.74 kW) = 7.4 kW .

25. Standard speeds Developed formulae Formulae source : www.pacontrol.com Above 1000

26. 1.3

27. N = 84 Rotations per minute

28. I fps = .308 m/sec So 0.68 fps = 0.207 m/sec 1 cubic foot per second = 0.0283168466 cubic meters / second 48.1 cfs = 1.362 cubic meters / second

29. Input parameters www.checalc.com

30. identical identical www.checalc.com

31. The performance of a particular agitator usually cannot be predicted quantitatively. Agitator design is largely in exercise of judgment so a considerable variety has been put forth by various manufacturers. Developing software . Conclusion

32. www.fusionfluid.com www.checalc.com www.wikipedia.org www.bakker.org   www.pacontrol.org www.safaribooks.org Unit Operations of Chemical Engineering (7th edition)(McGraw Hill Chemical Engineering Series) Warren McCabe    Julian Smith    Peter Harriott   www.dynamixinc.com Bibliography