Single homogeneous

Early ia the development of chemical reaction engineering, reactants and products were treated as existing ia single homogeneous phases or several discrete phases. The technology has evolved iato viewing reactants and products as residing ia interdependent environments, a most important factor for multiphase reactors which are the most common types encountered. 

Continuous processes may be used for the production of yeast biomass. Raw Hquid feed is added continuously to the fermentor and an equal volume of fermentor Hquid is removed to harvest the yeast ceUs. These may be a single homogeneous fermentation in a stirred fermentor or two fermentors in series. Growth rates are high a typical dilution rate in the production of C. utilis on sulfite waste Hquor is 0.25, ie, one-fourth of the fermentor volume is harvested hourly. 

The simplest element is a single homogeneous. stream. The variables necessary to define it are ... 

DEF. When the constitution point lies in a single-phase region, the alloy consists of a single, homogeneous, phase. Its composition must (obviously) be that of the alloy. The phase composition and the alloy composition coincide in single-phase fields. 

Consider a single homogeneous phase of one eomponent of unehang-ing eomposition. If it undergoes an isothermal reversible ehange and does work, then from the first law of thermodynamies ... 

Because flashing steam-condensate lines represent two-phase flow, with the quantity of liquid phase depending on die system conditions, these can be designed following the previously described two-phase flow methods. An alternate by Ruskin [28] uses the concept but assumes a single homogeneous phase of fine liquid droplets dispersed in the flashed vapor. Pressure drop was calculated by the Darcy equation ... 

Binder is the material used in the FCC catalyst to bind the matrix and zeolite components into a single homogeneous particle. 

All gas mixtures are homogeneous hence all gas mixtures are solutions. Air is an example. There is only one phase—the gas phase—and all the molecules, regardless of the source, behave as gas molecules. The molecules themselves may have come from gaseous substances, liquid substances, or solid substances. Whatever the source of the constituents, this gaseous solution, air, is a single, homogeneous phase. As with other solutions, the constituents of air are separated by phase changes. 

Equilibrium Compositions for Single Reactions. We turn now to the problem of calculating the equilibrium composition for a single, homogeneous reaction. The most direct way of estimating equilibrium compositions is by simulating the reaction. Set the desired initial conditions and simulate an isothermal, constant-pressure, batch reaction. If the simulation is accurate, a real reaction could follow the same trajectory of composition versus time to approach equilibrium, but an accurate simulation is unnecessary. The solution can use the method of false transients. The rate equation must have a functional form consistent with the functional form of K,i,ermo> e.g., Equation (7.38). The time scale is unimportant and even the functional forms for the forward and reverse reactions have some latitude, as will be illustrated in the following example. 

On some occasions, the body does not behave as a single homogeneous compartment, and multicompartment pharmacokinetics are required to describe the time course of drug concentrations. In other instances certain pharmacokinetic processes may not obey first-order kinetics and saturable or nonlinear models may be required. Additionally, advanced pharmacokinetic analyses require the use of various computer programs, such as those listed on the website http //www.boomer.org/pkin/soft.html. 

The Wagner-Nelson method of calculation does not require a model assumption concerning the absorption process. It does require the assumption that (a) the body behaves as a single homogeneous compartment and (b) drug elimination obeys first-order kinetics. The working equations for this calculation are developed next. 

Lumping compartments 1, 2, and 3 into a single homogeneous tissue compartment implies the blood flow-limited model. The tissue mass balance equation for a noneliminating organ is... 

Many reactions take place in heterogeneous systems rather than in a single homogeneous phase. These reactions often occur at the interface between the two phases. In such cases it is appropriate to define the reaction rate in terms of the interfacial area (S ) available for reaction. 

Coupling Between Mass Transfer and a Single Homogeneous Irreversible Reaction... 

With19 D(Ni-Ni) = 55 kcal.mole-1 and assuming the average Ni-CO bond dissociation energy in Ni(CO)2 is the same (35.2 kcal.mole-1)20 as in Ni(CO)4, reaction (8) would be endothermic by approximately 85 kcal.mole-1. It is therefore unlikely that this reaction occurs by a single homogeneous step. It might proceed by reaction (9)... 

The value of S0 decreases with increasing elevation. Zao, the interface between air and the LNAPL phase, may or may not coincide with Zu, the upper boundary of the aquifer. Typically, the saturation of the LNAPL phase extends over two distinct regions (see Figure 5.10). These are (1) water and LNAPL phase zone, and (2) water, LNAPL phase, and air zone. When a single homogeneous stratum is considered, O can be assumed constant. In a stratified medium, however, saturation discontinuities generally exist due to the variation in soil characteristics, and the determination of LNAPL volume based on Equation 6.22 may become much more involved. 

Two compounds which mix together to give a single, homogeneous liquid phase. 

When all the species remain in a single homogeneous phase, the mole fractions in the phase are given by... 

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