King Saud University Engineering College Department of Chemical Engineering 403 Che Drying Dr.

1. King Saud University Engineering CollegeDepartment of Chemical Engineering 403 CheDrying Dr. /Malek Al-Aahmed

2. Introduction Drying is the removal of small amounts of water form the wet materials (solid). also used to removed of other organic liquids, such as benzene or organic solvent from solid. There are two different processes are used in drying: Batch processes. Continuous process.

3. Theory

4. Theory where : R: drying rate in kg H2O /h.m2 Ls : weight of dry solid in kg A : exposed surface area in m2 dx : change in water content in kg H2O/kg dry solid dt : change in time in hour x: water content in kg H2O/kg dry solid Xt : Moisture content at time t (kg water/kg dry solid). W : Weight of water (kg water). X* : is equilibrium water contents Ws: Weight of dry solid (kg)

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6. Schematic Diagram:

7. Electrically Heated Insulated Enclosure for Hot Wax Coating

8. High Efficiency Hot Air Drying System

9. Hot Air Annealing Oven for Polycarbonate Bottles

10. Results

13. Discussion Free water content Vs time : The free water content (x) is decreasing with time increasing. The (rate Vs Water contents) must be contains two regions : Constant rate period. Falling rate period. In result and computation we can see the weight of dry sand before drying is more than weight of dry sand after drying, because the surroundings humidity. Drying rate can be effected by : Velocity of hot air used drying. Surroundings humidity and temperature. Exposed surface area.

14. Recommendations A non-porous granular solid such as a fraction of sand sieved to approximately 500 microns should be used for the material to be tested. A stop clock will be required for this experiment. The laboratory must be well ventilated to ensure that warm moist air discharged from the drier does not effect the original inlet conditions over the period of the experiment.

15. Summary The objective of this experiment is : to investigate the influence of particle size on the drying behavior of a wet solid in air. to produce drying and drying rate curves for a wet solid being dried with air. to investigate the influence of air velocity on the drying rate of a wet solid in air, all in fixed temperature and humidity. Also to investigate the influence of air temperature on the drying rate of wet solid in air at a fixed velocity.

16. References Chirstie J.Geankoplis, ( Transport Process and Unit Operation ), 3rd edition. University of Minnesota. Aziz M. Abu-Khalaf, ( Chemical Engineering Education, CHE 403 ), King Saud University 1998. Some of web sites like: http://www.process-heating.com http://www.ChemicalProcessing.com http:// www.process-equipment.globalspec.com

17. Thank you�