103.adwait pharmaceutical engineering EMC

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1. Equilibrium moisture content Name : Adwait Mandar Sinkar Roll no: 103 Subject : Pharmaceutical Engineering College Name: Shri D D Vispute College Of Pharmacy and Research Center

2. Definition of equilibrium moisture content: Equilibrium moisture content (EMC) is the point at which a material is neither gaining nor losing moisture when surrounded by air. It is the amount of water present in the solid which exerts a vapour pressure equal to the vapour pressure of the atmosphere surrounding it. The moisture which is more difficult to remove in practice is the equilibrium moisture content. This moisture content is retained by the solid under steady conditions. This water does not vapourize and does not produce vapour pressure e quilibrium moisture content in wet mass.

3. Measurement of emc : The solid samples are placed in a series of closed chambers such as desiccators. Each chamber consists f solution , which maintains a fixed relative humidity n the enclosed air spaces. " In other words , the solid samples are exposed to several humidity conditions. The exposure is continued until the material attains a constant weight. The difference in the final and initial weights gives the moisture content.

4. Graph of emc , cmc and fmc

5. Applications of equilibrium moisture content: The EMC curve permits the selection of the experimental condition to be used for drying the product. Drying should be stopped when the moisture content reaches the level of the EMC under the exposed conditions. Over drying can be avoided, because over -dried solid quickly regain the moisture from the ambient conditions.