Scaling, crystal

The checkers report a yield of 50% at half-scale, crystals at 0°C melting at 23°C. 

The multicellular structure of laminar convection in small-scale crystal growth systems complicates the interpretation of the boundary layer analysis,... 

First, the role of system design on the details of convection and solute segregation in industrial-scale crystal growth systems has not been adequately studied. This deficiency is mostly because numerical simulations of the three-dimensional, weakly turbulent convection present in these systems are at the very limit of what is computationally feasible today. New developments in computational power may lift this limitation. Also, the extensive use of applied magnetic fields to control the intensity of the convection actually makes the calculations much more feasible. 

Self-assembly of arrays that could tile 3D space relied on pieces that were completely coated with lubricant (Fig. 4.20) [ref. 15]. The sequence of steps for self-assembly of these arrays is similar to that seen in molecular-scale crystallization a few blocks initially bond and form a nucleus these initial small... 

This hypothesis relates very well with the observations made by Oh et al. (22) during pilot-plant-scale crystallization and processing of palm oil in a scraped-surface heat exchanger line for margarine and shortening, as shown in Figure 2. 

Some useful experimental techniques for studying small and large-scale crystallizations and the resulting crystal forms are summarized in Table 6. 

Trends in the crystallization process development in the pharmaceutical industry is to carry out measurements at a small scale in addition to utilizing automation and high throughput systems as exemplified by the use of automated metastable zone measurement for 1 mL samples. It is expected that the future batch crystallization recipes will be designed based on the data collected from much smaller scale crystallizers than what is currently used in industry. 

O. Devos, C. Gabrielli, and B. Tribollet, "Nucleation-Growth Processes of Scale Crystallization under Electrochemical Reaction Investigated by In Situ Microscopy," Electrochemical and Solid-State Letters, 4 (2001) C73-C76. 

In a growth-dominated fluidized bed crystallizer, the interface between the fluidized bed and the mother liquors should be sharp, as the particles either grow larger or wash out at the top. Figure 11-33 shows a sight glass view of such an interface in a factory-scale crystallizer. 

A considerable amount of skepticism naturally is expressed by crystallization practitioners concerning the unbridled nse of parameters generated in well-controlled small-scale equipment to predict performance of industrial-scale crystallizers. Many factors contribute to the nonideal behavior of industrial crystallizers, and not all can be easily explained. 

Crystallized carbon with traces of Fc. SiOj, etc. Usually soft, black scales, crystals rare, d 2.09-2.23. Mohs hardness = 10. Commercial varieties usually withstand temps up to 2820°. Sol in mohen iron. 

This section provides guidance on laboratory-scale crystallization of small organic compounds. It does not deal with the more specialized area of crystallization of proteins. Crystal structure reports in journals rarely, if ever, detail crystallization information beyond the solvent used. Textbooks also tend to be limited in value because they vary so much in scope and focus. What we present here combines information gathered from textbooks with our own experience of growing single crystals for X-ray and neutron diffraction experiments, and keeps the natural products chemist very much in mind. 

Nancollas, G.H., 1983, The nucleation and growth of scale crystals, in Bryers, R.W. ed. Fouling of Heat Exchanger Surfaces. United Engineering Trustees Inc. New York. 

The scale of operation often has an overriding importance on the selection of the equipment because of the means used for heat transfer. For very small-scale crystallization work it is common to use radiation. The capacity of such equipment varies from a few liters up to several hundreds of liters per day (of solution cooled). For operation on scales up to several thousand liters per day, it is possible to use tanks with water-cooled coils and an agitator. For large-scale applications where the quantity of solution is thousands of liters per day, it is almost universal practice to use vacuum evaporation to remove the solvent this is true whether the solution is cooled by adiabatic evaporation or in equipment where crystallization occurs because of isothermal evaporation. 

A rapid examination of dimensional analysis is sufficient to convince us that, under most circumstances, the detailed dynamic behavior of a full scale crystallizer can not be captured with a geometrically similar laboratory scale experimental model. It is well known that it is impossible to achieve dynamic similarity between model and full scale of even liquid only mixing tanks and still use liquids of similar viscosity and density (Bird et al. 

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