Product design particle formation

Tailoring of the particle size of the crystals from industrial crystallizers is of significant importance for both product quality and downstream processing performance. The scientific design and operation of industrial crystallizers depends on a combination of thermodynamics - which determines whether crystals will form, particle formation kinetics - which determines how fast particle size distributions develop, and residence time distribution, which determines the capacity of the equipment used. Each of these aspects has been presented in Chapters 2, 3, 5 and 6. This chapter will show how they can be combined for application to the design and performance prediction of both batch and continuous crystallization. 

Why does painting metallic objects that contain 2. How might particle size of reactants be varied iron help prevent formation of rust to promote the sale of a product designed to... 

Since the properties of these particulate materials are basically determined by their mean size, size distribution, external shape, internal structure, and chemical composition, the science in the mechanistic study of particle formation and the fundamental technology in their synthesis and characteristic control may constitute the background for the essential development of colloid science and pertinent industries. Scientists have now learned how to form monodispersed fine particles of different shapes of simple or mixed chemical compositions, and, as a result, it is now possible to design many powders of exact and reproducible characteristics for a variety of uses. These achievements are especially important in the manufacture of high-quality products requiring stringent specification of properties. 

Despite the details of gel-particle formation inside a micro-reactor channel having been reported previously by Zhan et al. [23], the continuous production of such particles was first described by Sugiura et al. [31]. For this, the design of a special reactor was described, that employed micro-hthographically prepared micro-nozzles (Figure 14.23). These nozzles ensured that the droplets were formed... 

In many processing sequences a filter is preceded by a particle formation unit such as a crystalliser or precipitator, the product from which can have a profound effect on filter cycle performance. While the effects of particle size on washing and deliquoring are explicit in the equations, correlations and design charts relating to those processes, the effects on cake formation need to approximated for the purpose of simulation. Although ideally the variation of specific resistance and porosity with particle size would be assessed experimentally, for the current purpose approximations... 

Soaps have often been incorporated in detergents to control levels of foam, especially in the context of products designed to be used in foam-intolerant washing machines. Utility as antifoam additives in this context alone invites attention with respect to their mode of action. We therefore explore the possibility that they function as hydrophobic particles according to the principles outlined here. Of particular interest is the possibility that formation of highly insoluble calcium soaps represent the key to their mode of action. 

Suspension polymerization of VDE in water are batch processes in autoclaves designed to limit scale formation (91). Most systems operate from 30 to 100°C and are initiated with monomer-soluble organic free-radical initiators such as diisopropyl peroxydicarbonate (92—96), tert-huty peroxypivalate (97), or / fZ-amyl peroxypivalate (98). Usually water-soluble polymers, eg, cellulose derivatives or poly(vinyl alcohol), are used as suspending agents to reduce coalescence of polymer particles. Organic solvents that may act as a reaction accelerator or chain-transfer agent are often employed. The reactor product is a slurry of suspended polymer particles, usually spheres of 30—100 pm in diameter they are separated from the water phase thoroughly washed and dried. Size and internal stmcture of beads, ie, porosity, and dispersant residues affect how the resin performs in appHcations. 

Continuous Cake Filters Continuous cake filters are apphcable when cake formation is fairly rapid, as in situations in which slurry flow is greater than about 5 L/min (1 to 2 gal/min), shiny concentration is greater than 1 percent, and particles are greater than 0.5 [Lm in diameter. Liquid viscosity below 0.1 Pa s (100 cP) is usually required for maintaining rapid liquid flow through the cake. Some designs of continuous filters can compromise some of these guidelines by sacrificial use of filter aid when the cake is not the desired product. 

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