Concept and Design of Continuous Crystallizers

There are many variations of how the above fonctions are incorporated into the design. The following discussion outlines concepts and design considerations that are useful in both design and troubleshooting of continuous crystallizers. 

The concept behind the design of the oscillator shown in Fig. 22 ensures continuous measurement and automatic compensation of the parallel capacitance Cq, while the quartz crystal is simultaneously and independently driven at its zero-phase frequency [47,48]. Provided that the capacitance compensation is effective, the zero-phase frequency is always equal to the sensor series resonance frequency/s, irrespective of the load. 

Concepts of plants can be divided into solid layer and suspension crystallization. Furthermore, these two techniques can be split into continuous and batchwise as well as into static and dynamic (stagnant or flowing melt) operating modes. A detailed overview of the different designs of existing and commercially available plants in solid layer as well as suspension crystallization is provided in Chapter 16. In the Sections... 

There are numerous examples of purified materials by the above-mentioned two types of suspension crystallization process designs some of them are acetic acid, caprolactam, methacrylic acid, and phenol. The two discussed suspension crystallization concepts, shown in the Figures 17.9 and 17.10, count to the continuous packed column with mechanical forced transport. 

It was shown in Chapter 3 that the ideal continuous MSMPR crystallizer could be analysed using the population balance approach coupled with mass balances and crystallization kinetics to yield equations describing crystallizer performance in terms of the crystal size distribution, solids hold up etc. These concepts will now developed further to yield methods for continuous crystallizer design. Firstly, however, it is useful to consider how crystallization kinetics and crystallizer performance interact. 

The role of continuous-cooling transformation diagrams in the heat treatment and control of microstructure was presented (for iron-carbon alloys) in Chapter 10. We discussed in this chapter how this type of diagram is employed in designing heat treatments to crystallize glass-ceramics. The following concept map represents this relationship for processing these materials. 

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