Topics: Heat, Evaporation, Water Pages: 9 (2922 words) Published: April 11, 2013
In this experiment,we use a microwave dryer to dry the wet sand . We choose to use a mixture of sand and water because we believe that sand is a solid which possesess both regular and irregular crystal lattice structure , therefore making the movement of water particle easy and decrease faster ,leading to a short drying time. The measurement of the moisture content is based on the weight sample which is inversely proportional with the temperature and time , though the temperatue is kept constant throughout the experiment .Thus we can determine the drying rate of the sample based on the data obtained from the experiment ,the mass and moisture content is decreasing with time whereas the drying rate is varying rapidly with time.

Table of content
List of tables
List of symbols
List of figures
CHAPTER ONE: 1.1 Introduction
1.2 Aims and Objectives 1.3 Significance of experiment CHAPTER TWO: 2.0 Theoretical principles
CHAPTER THREE: 3.0 Description of apparatus
3.1 Experimental procedure CHAPTER FOUR: 4.0 Experimental result
4.1 Discussion of result CHAPTER FIVE: 5.0 Conclusion
5.1 Recommendation

Drying is a thermal process which involves the final removal of volatile constituent from a substance to reduce the content of the residual liquid to an acceptable low value .Drying of a material is often the final step in a series of operation in manufacturing process, carried out immediately prio to packaging or dispatch. Excluding the partial drying of a solid by mechanical means (e.g centrifuges) for example ,by squeezing all drying operation depends upon the application of heat to vaporize the volatile constituent either completely or partially .Generally, it is cheaper to remove liquid mechanically than thermally.When a wet solid is subjected to thermal drying , two processes occur simultaneously; First is the transfer of energy ,mostly as heat from the surrounding environment to evaporate the surface moisture and second is the transfer of internal moisture to the solid and its subsequent due to first process.The liquid content of a dried product varies from product to product. In a case when the product contains no liquid it is called BONE-DRY.. Drying is a relative term and means merely that there is a reduction in liquid content from an initial value to some acceptable final value. The solid to be dried may be in different form (flakes, powders, granules, slabs, crystals or continuous sheets) and may have widely differing properties. The liquid to be vaporized may be on the surface of the solid , as in dried salt; it may be entirely inside the solid, or partly outside and inside. Consequently a multitude of types of dryer are on market for commercial drying. They differ chiefly in the way the solid are moved through the drying zone and the way heat is been transferred. There is no simple way of classifying drying equipment,because several types of dryer are used in different fields.Some dryers are: Batch drying: Wet material is inserted in drying equipment and removed after an appropriate amount of time.

Continuous drying: Wet material is continuously introduced and “dry” material withdrawn after a contacting period.
Some dryers are agitated while some are unagitated.Operation under vacuum drying can be carried out in two phases: 1. Dryers in which the solid is directly exposed to the hot gas and they are called Adiabatic or Direct Dryers.They are heated by either dielectric,radiant or microwave energy. Here the solids are exposed to the gas in the following ways: a. Air is blow across the surface of a bed or slab of solids which is referred to as cross- circulation drying....
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