Downstream processing physical characteristics

Thus, methods are now becoming available such that process systems can be designed to manufacture crystal products of desired chemical and physical properties and characteristics under optimal conditions. In this chapter, the essential features of methods for the analysis of particulate crystal formation and subsequent solid-liquid separation operations discussed in Chapters 3 and 4 will be recapitulated. The interaction between crystallization and downstream processing will be illustrated by practical examples and problems highlighted. Procedures for industrial crystallization process analysis, synthesis and optimization will then be considered and aspects of process simulation, control and sustainable manufacture reviewed. 

Many of the physical characteristics of the atmosphere, such as wind, temperature, cloud cover, humidity, and precipitation, are easily perceived. Sometimes, chemicals in the atmosphere also can be observed, as in smoke plumes and smog, and their physical transport tracked downwind just as downstream transport of substances in a river can be measured. Other atmospheric processes are less apparent to the unaided observer, however, occurring either on the microscopic scale of a chemical reaction, or on a global scale, or at high altitudes. Such processes may be detected only by instrumentation on satellites or some high-altitude aircraft. 

Physical and chemical properties of the wet feed as well as the product desired (specifications) expected variability in feed characteristics Upstream and downstream processing operations... 

Polyhydroxyalkanoate(s) (PHA) have gained rapid interest worldwide. The structural diversity of hydroxyalkanoates has resulted in materials with a wide range of physical and thermal characteristics. In addition, the variety of characteristics are significantly impacted by every aspect of upstream processing, as well as recovery during downstream processing. The diversity and versatility of PHA have opened up various opportunities for exploitation as many possibilities are yet to be discovered and evaluated in various applications. 

Hydrographs for locations downstream of a gauging station can be constmcted by a process known as flood routing which incorporates a stream flow model and the equation of continuity to predict flow rates. The stream flow model must incorporate physical characteristics of the channel. A number of routing models are available as computer software packages. 

The quality characteristics of the oil produced by the enzyme-assisted aqueous extraction process is comparable to that of conventional extraction procedures except in its phosphorus content (Table 12.5). The enzymatic process yields oil with less phosphorus which requires no or limited degumming. The crude oil from this process can be physically refined without further treatment (Laiho et al., 1991). Despite this improved quality of the crude oil which is an apparent cost saving in subsequent downstream processing, the enzymatic process has not been commercially exploited due to problems with yields. Considerable degree of emulsification occurs during the process. Approximately 18-25% of the available oil in the seed remains unrecovered in a standard operation. The discovery that the versatile protein, oleosin, binds approximately 20% of the oil in oil-bearing seeds (Tzen et al., 1990) has implicated this protein in the low yields associated with this process. Thus, the recoveries could be improved by the use of proteases. It has, however, been observed that successful application of proteases to improve oil recovery produces excessively bitter meals, repressing the potential utilization of the meal as feed or food. 

As the basic component of medical textile materials, the structures and properties of the constituent polymers have a significant effect on the biodegradability, biocompatibility, absorbency, antimicrobial property, and other functional performances of the final medical textile products. Functional modifications of polymers have far-reaching effects on the fibers, yams, fabrics, and textile materials that are processed in a series of downstream operations. In order to generate the desired product performance characteristics for their diverse applications such as hygiene, protection, therapeutic, nonimplantable or implantable materials, extracorporeal devices, etc., the chemical and physical structures of the relevant polymers should be engineered to suit their required specifications. 

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