Agitation and mixing
Download as PPT, PDF40 likes38,142 views
The document outlines agitation and mixing in chemical engineering, defining key concepts and purposes such as suspending solids and blending liquids. It details various impeller types, including axial and radial-flow impellers, and their specific functions like promoting circulation and gas dispersion. The conclusion emphasizes the importance of impeller agitators in efficient mixing processes within vessels.
Agitation and mixing
- 1. “ START WITHTHE NAME OF ALLAHWHO IS THE MOST BENEFICENT ANDMOST MERCIFUL.”
- 2. IHSAN ALI WASSAN (14CH18) DISCIPLINE: CHEMICAL ENGINEERING SUBJECT: UNIT OPERATIONS-I QUAID-E-AWAM UNIVERSITY OF ENGINEERING, SCIENCE AND TECHNOLOGY NAWABSHAH, SINDH PAKISTAN
- 4. PRESENTATION OUTLINE -Definitions -Purposes of agitation -Devices to produce agitation -Conclusion
- 5. DEFINITIONS
- 6. AGITATION It refers to the induced motion of a “homogenous” material in a specified way, usually in circulatory pattern inside some sort of container.
- 7. MIXING Mixing the random distribution, into and through one another, of two or more initially separate phases.
- 8. PURPOSES OF AGITATION Suspending solid particles Blending miscible liquids Dispersing a gas through the liquid Dispersing a second liquid to form an emulsion or suspension Promoting heat transfer
- 10. IMPELLERS DEFINITION The rotating part of a centrifugal pump, compressor, or other machine designed to move a fluid by rotation is called Impeller. OR A rotor used to increase (or decrease in case of turbines) the pressure and flow of a fluid. OR A device turned by the flow of water past a ship's hull, used to measure speed or distance travelled.
- 11. IMPELLERS Impeller agitators divided into two classes.
- 12. AXIAL-FLOWIMPELLERS Those impellers that generate currents parallel with the axis of the impeller shaft are called Axial-Flow Impellers. Axial-flow impeller
- 13. RADIAL-FLOWIMPELLERS Those impellers that generate currents an a radial or tangential direction are calle d radial flow impellers. Radial-flow
- 14. Three main types of impellers for low-to moderate viscosity liquids are. TYPES OF IMPELLERS
- 15. PROPELLERS A propeller is an axial-flow, high speed impeller for liquids of low viscosity. Small propellers turn at full speed either 1,150 or 1,750 rpm. Larger propellers turn at 400 to 800 rpm.
- 16. PROPELLERS (cont…..) The ratio of distance to the propeller diameter is known as pitch of the propeller. A propeller with a pitch 1.0 is said to have square pitch. Propellers rarely exceeds 18 inch in diameter.
- 17. TURBINES There are 4 types of turbine impeller The straight-blade turbine Disc turbine Concave blade CD-6 disc turbine Pitched-blade turbine
- 18. The straight-blade turbine The simple pushes the liquid radially and tangentially with almost no vertical motion at the impeller. The current it generate travel outward to the vessel wall and then flow either upward or downward. Such impellers sometimes called paddle s. straight-blade turbine
- 19. Disc turbine The disc turbine with multiple straight blades mounded on a horizontal disc. Useful for dispersing a gas in a liquid.
- 20. Concave blade CD-6 disc turbine It is also used for gas dispersion. Consists of six concave blades.
- 21. Pitched-blade turbine Used when good overall circulation important. Because it provides some axial flow in addition to the radial flow.
- 22. HIGHEFFICENCY IMPELLERS The high efficiency impeller HE-3 has three slanted blades that are crimped to decrease the blade angle near the tip. The A31 0 fluid fo ilim pe lle r uses air foil shaped blades with taper so that they are narrower at the tip than their edges. Used to mix low-or moderate- viscosity liquids.
- 23. CONCLUSION In the whole it is concluded that during agitation or mixing process “ Impellers agitators are widely used to circulate the liquid through the vessel in which the dispersion of liquids and gases into other liquids like mixing of stiff paste, elastomers and dry solids powders takes place.”