الفهرس 
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Abstract
This work deals with the study of mass transfer characteristics of fluidized bed crystalizers and the role of mass transfer in the perforamance of these crystallizers. sodium chloride was chosen to perform the present study in view of its technical importance. bed fluidization was carried out by either mechanical stirring or gas stirring. variables studied were: degree of stirring , temperature and physical properties of the solution. The study revealed the following results: (1) Rate of crystallization increases with increasing degree of stirring and solution temperature.(2) The mass transfer coefficient of sodium chloride crystallize-ation was found to increase with the degree of stirring till it reaches a constant value at high degree of stirring .
(3)The effect of temperature on the mass transfer coefficient was found to obey Arrhenius equation with an activation energy of 9600 ,9800 calorie/mole for high degrees of mechanical and air stirring respectively.
(4)The study of the effect of the degree of stirring and the effect of temperature on the mass transfer coefficient of sodium chloride crystallization,have revealed that sodium chloride crystallization is a diffusion controlled process at relatively low degrees of stirring and chemically controlled at high degrees of stirring.
(5)Matheratical analysis of the mass transfer data using the method of dimensional analysis resulted in the following over-all correlations.
(6)For the same rate of crystallization, power consumed in operating gas stirred crystallizer was found to be much less than that consumed in operating mechanically stirred crystallizer.
(7)crystal size was found to decrease with increasing the degrees of stirring and temperature, the size distribution, it was found that at relacively low degress of stirring, crystal size tends to be uniform while at re-latively high degrees of stirring a wide spectrum of crystal size is obtained.