Ternary system simulations

In this work, a comprehensive kinetic model, suitable for simulation of inilticomponent aiulsion polymerization reactors, is presented A well-mixed, isothermal, batch reactor is considered with illustrative purposes. Typical model outputs are PSD, monomer conversion, multivariate distritution of the i lymer particles in terms of numtoer and type of contained active Chains, and pwlymer ccmposition. Model predictions are compared with experimental data for the ternary system acrylonitrile-styrene-methyl methacrylate. 

Figure 4.83 Sulfur-iodine cycle and simulated phase behavior of the ternary system H20/Hl/I2 [132].

S 2] The result was a prediction of phase behavior of the ternary system H20/HI/I2 given in Figure 4.83 together with experimental data. The direct application of this tool to micro technology is uncritical as this simulation only considers thermodynamic and chemical model assumptions. It does not make any assumptions such as the neglect of axial heat transfer. 

The model is currently being refined to better allow for concentration related changes in the velocity of the shock waves, as well as improvements in modeling the density dependent parameters of the simulation. Work continues on the determination of adsorption and desorption isotherms for several ternary systems, as well as the thermal and mass transfer characteristics for the column and media being employed. Accurate determination of the model parameters will be required for optimization of the of the operational regime. 

Simulations of ternary systems were performed using the pure component parameters in Table I and the cross parameters for the systems acetone/ CO2 and water/C02 determined previously (fi j - 1 and 0.81 respectively). Because of expected difficulties similar to the ones mentioned for the water/C02 system, no attempt was made to simulate the system acetone/water near room temperature. Thus, we set the acetone/water interaction parameters to the values from the Lorenz-Berthelot rules with fi j-l. Direct simulations of ternary phase equilibria have not been previously reported to the best of our knowledge. 

The use of simulation software to analyze this type of process is illustrated in Example 5, which considers a simplified ternary system for illustration. The simulation of an actual aromatics extraction process is more complex and can exhibit considerable difficulty converging on a solution however. Example 5 illustrates the basic considerations involved in carrying out the calculations. For more detailed discussion of process simulation and optimization methods, see Sei-der, Seader, and Lewin, Product and Process Design Principles Synthesis, Analysis, and Evaluation, 2d ed. (Wiley, 2004) and Turton et al.. Analysis, Synthesis, and Design of Chemical Processes, 2d ed. (Prentice-Hall, 2002). 

The collective structure of aqueous IL solutions was studied by means of MD simulations [101]. Various concentrations of [C4mim][BF4] and TIP3P water were simulated at the very same size of the simulation box. For the analysis, the ternary system cation/anion/water was subdivided into binary networks. The local structure of each of these six networks and the mutual orientation of the network constituting partners were studied. Furthermore, the collective structure of the whole samples was characterized by the contribution of each species to the static dielectric constant e(co= 0) and to the Kirkwood factor [101]. 

In Section 13.5.1 we presented the data of Vogelpohl for the distillation of two ternary systems acetone-methanol-water and methanol-2-propanol-water in a bubble cap column. Krishnamurthy and Taylor (1985b) simulated these experiments using a nonequilibrium stage model similar to the one described above. The AIChE correlations were used to calculate the mass transfer coefficients. Thermodynamic properties were calculated with the models described by Prausnitz et al. (1980). 

Empirical potentials are only applicable with certainty over the range of interatomic distances used in the fitting procedure, which can lead to problems if the potential is used in a calculation that accesses distances outside this range. This can happen in defect calculations, molecular dynamics simulations or lattice dynamics calculations at high temperature and/or pressure. In addition experimental data is required and thus direct calculation is the only method available when there is no relevant experimental data. It may, of course, be possible to take potentials derived for one system and transfer them to another. This method has been successful with potentials derived for binary oxides (Lewis and Catlow, 1985 Bush et al., 1994) being transferred to ternary systems (Lewis and Catlow, 1985 Price et al., 1987 Cormack et al., 1988 Purton and Catlow, 1990 Bush et al., 1994). 

The descriptions of all ternary systems were combined in one dataset to simulate the phase equilibria in the quaternary Si-B-C-N system. The results of the thermodynamic calculations of individual systems are shown in the corresponding sections. Thermodynamic models used are the Redlich-Kister polynomial [39], extrapolations according to Muggianu et al. [40] and the compound energy formalism [41] to describe the solid solution phases )S-boron, SiBn, SiBg, SiBs and B4+ C. 

However, the availability of the Dechema collection has changed the approach to initial consideration of the feasibility step of binary solvent separations. Ten years ago one would have resorted to a computer simulation. A minor error in the data fed into such a simulation might yield a seriously incorrect answer without one having the feel for the correct VLB of an unfamiliar binary mixture or even whether an azeotrope was present. Although a few ternary systems are also included in the Dechema collection they are not as useful or as comprehensive as those for binaries. 

As illustrated throughout this section, process simulators have extensive facilities for preparing phase-equilibrium diagrams T-x-y, P-x-y, x-y,... ), and residue curve maps and binodal curves for ternary systems. In addition, related but independent packages have been developed for the synthesis and evaluation of distillation trains involving azeotropic mixtures. These include SPLIT by Aspen Technology, Inc., and DISTIL by Hyprotech (now Aspen Technology, Inc., which contains MAYFLOWER developed by M.F. Doherty and M.F. Malone at the University of Massachusetts). 

The distillation column smdied is based on a system that presents challenging design problems because of the severe nonlinearity of the phase equUibrium. The ternary system is water, acetic acid, and formic acid. The physical property package UNIQ-HOC is used in the Aspen simulations, which accounts for the dimerization of acetic acid in the vapor phase. 

We finally illustrate the behaviour of a ternary system. The parameters used in the simulation are ... 

The book, which begins with a historical perspective and an introductory chapter, includes a basic derivation for more casual readers. It is then devoted to providing new and very recent applications of FST. The first application chapters focus on simple model, binary, and ternary systems, using FST to explain their thermodynamic properties and the concept of preferential solvation. Later chapters illustrate the use of FST to develop more accurate potential functions for simulation, describe new approaches to elucidate microheterogeneities in solutions, and present an overview of solvation in new and model systems, including those under critical conditions. Expert contributors also discuss the use of FST to model solute solubility in a variety of systems. 

The examples shown for the binary system acetone-water and the ternary system benzene-cyclohexane-NMP demonstrate that the parameters used for process simulation have to be checked carefully prior to process simulation using experimental data from different sources stored in factual data banks. The verification of the binary parameters is of particular importance for systems where the separation factor shows values not far from unity. In comprehensive factual data banks, for example, the DDB, sophisticated software packages are integrated to allow the verification of all pure component properties and mixture parameters prior to process simulation. Suitable for the verification of the pure component properties and mixture parameters are in particular graphical presentations, as exemplarily shown in Figures 11.3 and 11.4. 

Fig. 2 Averaged densities across the order-disorder transition in a two-dimensional ternary system with A, B homopolymers and A-B copolymers (20% homopolymer volume fraction), as obtained from Complex Langevin simulation runs...

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