| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1989: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
With development in highly advanced technology, the deman for purity, shape and size of crystallized products have become severe more and more. The traditional theory of industrial crystallization, however, depends on experience very much, and cannot meet these demands. The main reasons for this situation are ; (1) that the microscopic crystallizing processes at the interface between crystal and solution phases are not enough investigated, (2) that the relation between the factors in the microscopic phenomena and the macroscopic operational condition has not be clarified yet, (3) that the macroscopic dynamical behavior of the crystal particles in a crystallizer is not considered sufficiently.
In this investigation, we have made the new industrial crystallization theory to overcome these difficulties (2) and (3), With this theory, we have developed the new operation of crystallization that is able to control the crystal particle size distribution and to product highly pure and less strai
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nedcrystals.
As the flow field in the crystallizer, we have adopted Benard convection whose velocity and temperature fields are well investigated, and that contains a stable circulating flow and a stable temperature gradient. This crystallizer has two characteristics ; (1) it has less unknown factors because it has no mechanically movable parts, (2) we can obtain the crystals that contain less impurity and less strain because they circulate through the supersaturated and unsaturated regions alternatively.
In the theoretical analysis, we considered the dynamical motion of crystal particles in the new phase space that is constituted of the dimensions of real space and the additional dimension of particle diameter. With this theory, we can clarify the relation between the crystal particles' motion in the crystallizer and the dissolution and/or crystallization rates, and we can calculated the particle size distribution. The determination of operational conditions that product the crystal particles with both of the desired mean diameter and the desired size distribution, has become easy by using this analytical model. This model that uses actively the computer simulation to analyze the industrial crystllization can apply to study the traditional crystallizer. By its application, we expect the new insights about the industrial crystallization phenomena. Less
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