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Unformatted text preview: ABSTRACT In this exp. Dissolution of solid-liquid was studied. The idea of the Exp. Was to put three solid sugar spheres in a vessel containing water and steer the water at different speeds and through the use of two different impellers and measure the different lose in the weight of the sugar balls at different times. The liq-solid mass transfer coefficient Kls was calculated for different speeds and types of impellers as 16.35e-5, 16.39e-5, 16.33e-5, and 26.288e-5 for 3 b (110rpm), 3 b (200 rpm) ,6 b (110rpm) and 6 b(200rpm) respectively. Also , some discussion about the mass transfer and comparing the effect of both speed and number of impellers on mass transfer are included. The error in the KLs values was very high due to reasons that will be discussed later. The error was around 95%. INTRODUCTION Solid liquid mass transfer is important in some in industrial applications such as crystallisation, dissolution, and solid liquid extraction. Because of the effectiveness in suspended solid particles and good transfer rate, agitated vessels are usually used. The mass transfer between liquid and solid is very much affected by agitation. In this experiment we were using two types of impellers: the 3-bladed and 6-bladed impeller. The speed of each impeller was changed during the experiment. The use of the agitated vessel is very efficient in calculating mass transfer because of the large area they have especially for the type of suspending solids experiments. Furthermore, the use of sour balls is efficient since these solids have a very high solubility in water that leads to good results. In this experiment, some physical assumptions were made to help us solving the differential equations and in making affixed model for the experiment. First, we assumed that the solids are perfectly spheres and their spherical shape was retained during the process of dissolution in the same rate throughout the experiment....
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This note was uploaded on 12/30/2010 for the course CHEMICAL E CHE 309 taught by Professor M.elgaily during the Fall '09 term at King Fahd University of Petroleum & Minerals.
- Fall '09