Separations generic separation process

Advancing the field of process engineering. Important generic goals for research include the development of separation processes for complex and fragile bioproducts the design of bioreactors for plant and mammalian tissue culture and the development of detailed, continuous control of process parameters by rapid, accurate, and noninvasive sensors and instruments. 

This chapter introduces the reader to elementary concepts of modeling, generic formulations for nonlinear and mixed integer optimization models, and provides some illustrative applications. Section 1.1 presents the definition and key elements of mathematical models and discusses the characteristics of optimization models. Section 1.2 outlines the mathematical structure of nonlinear and mixed integer optimization problems which represent the primary focus in this book. Section 1.3 illustrates applications of nonlinear and mixed integer optimization that arise in chemical process design of separation systems, batch process operations, and facility location/allocation problems of operations research. Finally, section 1.4 provides an outline of the three main parts of this book. 

We consider a generic class of reaction-separation process systems, such as the one in Figure 3.1, consisting of N units (modeled as lumped parameter systems) in series, with one material recycle stream. 

Figure 4.3 A generic reactor-separator process system with recycle and purge.

Figure 5.1 A generic reaction-separation process system with material recycle and purge.

In a UCST system, when the temperature is reduced to a final value 7/ that is below the critical temperature Tc, a mixture with a concentration 0 not too far from the critical composition phase separate into two phases whose compositions lie on the opposite sides of the binodal envelope line of Fig. 9-1. The dynamics of the separation process of a single phase into these two phases is controlled by Tf, the composition , the rate of the quench dT/dt, the viscous (or viscoelastic) properties of the phases formed, and the interfacial tension F between the two phases. Although a variety of different kinds of behavior can occur, there are two generic types of phase separation, namely, spinodal decomposition (SD) and nucleation and growth (NG). SD occurs when the mixture is quenched into a part of the phase diagram where the mixture is unstable to small variations in composition, leading to immediate growth of phase-separated domains. When the quenched... 

Three generic adsorptive process schemes have been commercialized to serve most of the applications shown in Table 1. They include 1) temperature swing adsorption (TSA) 2) pressure swing adsorption (PSA) and 3) concentration swing adsorption (CSA).P The fluid mixture (feed) to be separated is passed over a regenerated adsorbent (contained in an adsorber vessel) to produce a stream enriched in the less strongly adsorbed components of the mixture. 

Figure 2.1 Generic unit operation for a separation process.

The analysis of equilibrium-stage operations is normally performed on the basis of counter-current flow between two phases. Because most separation processes, whether described in terms of equilibrium or mass transfer rates, operate in this flow scheme, it is useM to compare countercurrent to cocurrent flow. Figure 2.2 illustrates cocurrent and counter-current operation. Assuming mass transfer across a barrier between the two fluid phases, generic concentration profiles can be drawn for each case (Figure 2.3). 

Referring to the generic separation schematic (Figure 3.28), assume that it represents a single stage of an equilibrium-based process for the separation of a binary feed mixture. 

Generic pharmaceutical companies sometimes do employ organic chemists as process chemists. To appreciate this situation, imagine that a Fipco s compoimd patent expires, depriving a valuable medicine of further composition-of-matter protection. Also suppose that a separate process patent still protects the originator s commercial synthesis. In these circumstances, the generic firm wishing to sell this medicine is free to do so if its... 

After the first patents of the coated cellulose- and amylose-type CSPs expired in 2006 a series of generic CSPs have been introduced into the market. The main arguments for choosing one of these phases for a preparative separation process should be the loadability and stability of the stationary phase beside the price per... 

This leads to the definition of a Second Law efficiency (77) for the generic steady state separation process depicted in Fig. 2.3 as the ratio of the minimum work to the actual work ... 

Sorbex is the generic name used by UOP for their simulated countercurrent sorption process which has been successfully developed for a variety of large-scale commercial separations. All Sorbex processes in current operation operate in the liquid phase, but in principle the process could also be applied to a vapor phase system. In order to understand the Sorbex process it is simplest to consider a true isothermal countercurrent displacement desorption system, as sketched in Figure 12.11. Such a system is similar in its essential features to the Hypersorption system but without the additional complexity of the thermal swing. 

The most simple, generic model of a separation process is a single equilibrium flash unit. Applying the usual assumptions (i.e. negligible vapor holdup, equilibrium, perfect stirred liquid phase, no chemical reactions) and assuming a constant molar holdup in the vessel, the model equations for the general dynamic case relating the distribution functions F (, ) and F (, t) of the vapor and liquid phase read as follows ... 

Investigation of the details of this system indicate that at low metal-ion loading the extractant dependence from (1 M lactic acid-0.05 M DTPA) is lowered to 2.1-2.9, dependent on the metal ion. Concentration isotherms for the extraction of lanthanum from lactic acid solutions, with and without DTPA present, indicate that saturation occurs at 1.5 equivalents of lanthanum per mol of extractant monomer, interpreted by the authors as indicative of the extraction of one mol of lactate per extracted metal ion. This observation is supported by actual measurement of extracted lactate concentration. Lactic acid is not extracted by HDEHP in the absence of lanthanum. This separation process has acquired the acronym TALSPEAK (trivalent-actinide/lanthan-ide separation by phosphorus reagent extraction from aqueous komplexes). The generic applicability of the concept is demonstrated by the work of Baybarz (1965), who finds only slightly reduced efficiency upon substitution of 2-ethyl(hexyl)phenylphos-phonic-acid/diethyl benzene for HDEHP/DIPB. 

Simulated moving-bed (SMB) processes have been widely nsed for difficult, liquid-phase separations (Ruthven, 1984 Humphrey and Keller, 1997 Juza et al 2000). Sorbex is the generic name used by UOP for these processes. The most important application is the separation of the xylene isomers, named the Parex process. Other commercialized SMB separations include n-paraffins/isoparaffins (Molex), olefins/paraffins (Olex), fructose/glucose (Sarex), and chiral SMB separations (Juza et al., 2000). A host of other separations have been demonstrated (Humphrey and Keller, 1997), although the commercial status of these applications is unknown. These demonsffated separations include separation of hydroxyparaf-finic dicarboxylic acids from olefinic dicarboxylic acids removal of thiophene, pyridine, and phenol from naphtha separation of unsaturated fatty acid methyl esters from saturated fatty acid methyl esters and separation of saturated fatty acids from unsaturated fatty acid (Humphrey and Keller, 1997). 

These density differences can be used to separate plastics into different generic types as well as to separate out non - plastic contaminants. Figure 3 shows a schematic of such a separation process [11]. 

Solvent based processes can be used to separate plastics into different generic type groups, to separate plastics from non - plastic materials or even to remove fillers which have been incorporated in plastic. The solvent base separation processes are based on... 

The example in the previous section illustrates the importance of equilibrium in partition and separation processes. Before delving in detail into specific sample preparation considerations, a review of the more important of these in the forensic context is worthwhile. The generic expression of equilibrium for a reaction lA + bB —> cC + dD is... 

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