Graphical Kvalue Correlations
As discussed in Sec. 4, the K value of a species is a complex function of temperature, pressure, and equilibrium vapor- and liquid-phase compositions. However, for mixtures of compounds of similar molecular structure and size, the K value depends mainly on temperature and pressure. For example, several major graphical K-value correlations are available for light-hydrocarbon systems. The easiest to use are the DePriester charts Chem. Eng. Prog. Symp. Ser. 7, 49, 1 1953 , which cover 12...
C Wep
FIG. 13-33 Typical construction for a sidestream showing the intersection of the two operating lines with the q line and with the x - y diagonal. a Liquid sidestream near the top of the column. b Vapor sidestream near the bottom of the column. FIG. 13-34 Illustration of how equilibrium stages can be located on the x-y diagram through the alternating use of the equilibrium curve and the operating line. FIG. 13-34 Illustration of how equilibrium stages can be located on the x-y diagram through...
Reactive Distillation
Introduction Reactive distillation is a unit operation in which chemical reaction and distillative separation are carried out simultaneously within a fractional distillation apparatus. Reactive distillation may be advantageous for liquid-phase reaction systems when the reaction must be carried out with a large excess of one or more of the reac-tants, when a reaction can be driven to completion by removal of one or more of the products as they are formed, or when the product recovery or...
Insideout Methods
The BP, SR, and SC methods described above expend a large percentage of their computational effort during each iteration in the calculation of K values, enthalpies, and derivatives thereof. An algorithm designed to significantly reduce that effort was developed by Boston and Sullivan Can. J. Chem. Engr., 52, 52 1974 . The MESH equations are solved in an inner loop using simple, approximate equations for K values and enthalpies. The empirical constants in these equations are determined and...
Simultaneouscorrection Procedures
The BP and SR tearing methods are generally successful only when applied respectively to the distillation of mixtures having a narrow boiling range and to absorbers and strippers. Furthermore, as shown earlier, specifications for these two tearing methods are very restricted. If one wishes to treat distillation of wide-boiling mixtures and other operations shown in Fig. 13-7 such as rectification, reboiled stripping, reboiled absorption, and refluxed stripping, it is usually necessary to...
Thielegeddes Stagebystage Method For Simple Distillation
Prior to the availability of digital computers, the most widely used manual methods for rigorous calculations of simple distillation were those of Lewis and Matheson LM Ind. Eng. Chem., 24, 496 1932 and Thiele and Geddes TG Ind. Eng. Chem., 25, 290 1933 , in which the equilibrium-stage equations are solved one by one by using tearing techniques. The former is a design method, in which the number of stages is determined for a specified split between two key components. Thus, it is a rigorous...
Design Procedures
Two general procedures are available for designing fractionators that process petroleum, synthetic crude oils, and complex mixtures. The first, which was originally developed for crude units by Packie Trans. Am. Inst. Chem. Eng. J., 37, 51 1941 , extended to main fractionators by Houghland, Lemieux, and Schreiner Proc. API, sec. III, Refining, 385 1954 , and further elaborated and described in great detail by Watkins op. cit. , utilizes material and energy balances, with empirical correlations...
Batch Distillation
Simple Batch Batch Distillation with Approximate Calculation Procedures for Binary Mixtures 13-97 Operating Batch Rectification at Constant Batch Rectification at Constant Overhead Other Operating Effect of Column Shortcut Methods for Multicomponent Batch Calculational Rigorous Computer-Based Calculation Example 10 Calculation of Multicomponent Batch Distillation . . . . 13-102 Rapid Solution
Rigorous Methods For Multicomponent Distillationtype Separations
Thiele-Geddes Stage-by-Stage Method for Simple Distillation 13-40 Example 3 Calculation of TG Equation-Tearing Procedures Using the Tridiagonal-Matrix Tridiagonal-Matrix BP Method for Example 4 Calculation of the BP Certain portions of this section draw heavily on the work of Buford D. Smith, editor of this section in the fifth edition. SR Method for Absorption and Example 5 Calculation of the SR Simultaneous-Correction Naphtali-Sandholm SC Example 6 Calculation of Naphtali-Sandholm SC Method...
Enhanced Distillation
Residue Curve Maps and Distillation Region Applications of RCM and Extension to Batch Azeotropic Exploitation of Homogeneous Exploitation of Pressure Exploitation of Boundary Exploitation of Azeotropy and Liquid-Phase Immiscibility 13-73 Design and Operation of Azeotropic Distillation Columns 13-75 Extractive Solvent Effects in Extractive Extractive Distillation Design and Solvent Screening and Extractive Distillation by Salt Reactive Simulation, Modeling, and Design Mechanical Design and...