Fluid technological background

This chapter introduces the important topics of fluid flow, properties of gases, heat and mass transfer, and physical/chemical characteristics of contaminants. The aim is to assist all engaged in industrial air technology in understanding the physical background of the issues involved. 

By now, nearly every chemist has had some introduction to the subject of supercritical extraction in one form or another, and it would seem that after scores of papers, newsreleases, and trade journal articles, only so much can be said about the background and early findings, the thermodynamic interactions between dissolved solutes and high pressure gases, the equations of state that can correlate and predict solubility behavior, the many applications of the technology (some of which are in flavors), the full scale coffee and hops extraction plants now in operation, etc. What, then, can a paper entitled "Supercritical Fluids - Overview and Specific Examples in Flavors Applications" give that s new -hopefully, a different development of the historical perspective... 

Figure 1.3. A 40-nm wide logo for NIST (National Institute of Standards and Technology), made by the manipulation of Co atoms on a Cu(lll) surface. The ripples in the background are due to electrons in the fluid-like layer at the copper surface, bouncing off the cobalt atoms — much hke the patterns produced when pebbles are dropped in a pond. Image provided courtesy of J. A. Strosdo and R. J. Celotta (NIST,...

The focus of this entry is limited to the design of aerobic fermenters, i.e., stirred tank and concentric tube airlift fermenters, which are commonly utilized in the bioprocessing industries. Design principles and the basic calculations are described with a couple of industrial examples. Readers with a limited background in mixing technology are referred to the gas-liquid contactor entry of this encyclopedia for a more comprehensive understanding of fluid flow and mass transfer characteristics in stirred tank reactors and bubble columns. 

The mass mi corresponds to the rubber compound before extracting, and it is the sum of the mass of the bonded rubber part Rf the mass of the soluble rubber part and filler, m2 is the mass of the rubber-filler gel, which is the sum of the bonded rubber part and filler, is the mass concentration of filler in the single rubber mixture or binary blends. 1 is the mixing time in an internal mixer. The difference between the terms rubber layer L and bound rubber, which has been commonly used in rubber technology, was discussed in our previous work. To understand the physical background of the rubber layer L, we correlated the wetting behaviour determined from our extraction experiment with the infiltration behaviour reported in the literature." In a capillary flow of a Newtonian fluid in a small gap between two parallel plates, the position x of the liquid-air interface at time t is given by Equation (6.27) ... 

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