Physical Property Methods

In addition to the chemical and spectroscopic methods that are applied to the identification of strnc-tural types in coal, it is also possible to make an evalnation of varions structural parameters by application of varions formulae derived from the physical property data. These particular techniques have received wide application to nonvolatile petroleum fractions becanse of the wider range 

FIGURE 10.11 Variation of vitrinite density with carbon content. (From Davis, A., Scientific Problems of Coal Utilization, B.R. Cooper, Ed., United States Department of Energy, Washington, DC, 1978a.) 

The molar volume is determined by summation of the single-bonded atomic volumes per gram atom minus a term to allow for unsaturation  

The terms C, H, N, O, S represent the numbers of carbon, hydrogen, nitrogen, oxygen, and sulfur atoms per molecule, respectively. 

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The following reference numbers, some of which have been cited previously, are good sources for lists of simple enamines, their physical properties, methods of preparation or references thereto, and yields I, 9, 18,19, 24,35,36,36a, and 37. They provide a reasonable starting place for a research scientist who requires this kind of information. 

As computers become more pervasive and increasingly powerful, specialized programs and databases are being developed to assist in a wide variety of research efforts. This is true in the search for solvent alternatives, and in this section we review the application of computers to solvent substitution studies and cover computer-aided molecular design of new solvents, methods developed for the prediction of physical properties, methods for predicting less precise chemical characteristics such as toxicity and carcinogenicity, and computer-aided design of alternative synthetic pathways. 

However, when the carboxyl groups are closer together the possibilities for interaction increase we shall be interested primarily in such acids. A number of important dicarboxylic acids are listed in Table 18-4 together with their physical properties, methods of manufacture, and commercial uses. 

Identification of the constituents of complex materials such as coal may proceed in a variety of ways but generally can be classified into three methods (1) spectroscopic techniques, (2) chemical techniques, and (3) physical property methods whereby various structural parameters are derived from a particular property by a sequence of mathematical manipulations. It is difficult to completely separate these three methods of structural elucidation, and there must, by virtue of need and relationship, be some overlap. Thus, although this review is more concerned with the use of spectroscopic methods applied to the issues of coal structure, there will also be reference to the other two related methods. 

Figure 2.40 (a) Selection physical property method (b) Chao-Seader method chosen. 

Aspen Properties. Physical Property Methods and Models. Version 10.2,... 

For this example, you choose the hrst column in the process shown in Figure 5.4. In Aspen Plus you use the module DSTWU for the shortcut method you also use RK-Soave as the physical property method, because it is a good one for hydrocarbons. The feed is 100 lb mol/h propane, 300 lb mol/h /-butane, and the other chemicals as listed in Table 6.1, at 138 psia and 75°F. The column operates at 138 psia with a reflux ratio of 10 (a wild guess initially, confirmed because the column worked). Remember, the minimum number of stages goes together with infinite reflux, so if your column does not work, increase the reflux ratio. 

Click and then the box on the left (in the Data Browser option). The part of the process represented by that box is then described. You can also click on the box and then the FI key to obtain the same information. The Help menu provides detailed help in all areas. For example, the Help/Physical Property Methods/Choosing a Property Method gives advice about which thermodynamic model is recommended for different applications. The Guidelines for Choosing a Property Method and Guidelines for Choosing an Activity Coefficient Method are sub-menus that outline decision trees to guide your choice. 

Riddick, J.A. "Organic Solvents Physical Properties, Methods of Purification" Wiley-Interscience New York 1970. 

Boyce R.E., 1973. Appendix I. Physical properties -Methods. In Edgar NT, Sanders JB et al (eds) Initial Reports of the Deep Sea Drilling Project 15, Washington, US Government Printing Office, pp 1115-1127... 

The integrated system includes both all-purpose flowsheeting system, and specialised packages. Different packages communicate via specific files, but share the same physical property methods and data. Here we mention only the major components. More complete and updated list can be found by consulting the website. 

The observant reader may have noticed in Figure 1.3 that the physical property method specified for the VLB calculations in the benzene/toluene example was Chao-Seader. This method works well for most hydrocarbon systems. 

One of the most important issues involved in distillation calculations is the selection of an appropriate physical property method that will accurately describe the phase equilibrium of the chemical component system. The Aspen Plus library has a large number of alternative methods. Some of the most commonly used methods are Chao-Seader, van Laar, Wilson, Unifac, and NRTL. 

In most design situations, there is some type of data that can be used to select the most appropriate physical property method. Often VLB data can be found in the literature. The multivolume DECHBMA data books provide an extensive source of data. 

If operating data from a laboratory, pilot-plant, or plant column are available, it can be used to determine what physical property method fits the column data. There could be a problem in using column data because the tray efficiency is also not known, and the VLB parameters cannot be decoupled from the efficiency. 

Federal Test Method Standard No. 175B for physical properties Methods 4032.1,4041.1, and 4051.1. 

B. Hartmann, in R. A. Fava, ed.. Polymers, Part C Physical Properties, (Methods of Experimental Physics, Vol. 16) Academic Press, New York, 1980, pp. 59-90. 

Physical properties method grades clarity grades... 

The ternary system containing isopropanol, water, and cyclohexane is used as an example to show how to obtain the prediction of azeotropes in Aspen Plus. After inputting components and the physical property method, the following route is selected Tools Conceptual... 

Note that selecting a proper physical property method is extremely important for obtaining reliable simulation results of a process flowsheet. Aspen Physical Property System gives the recommended classes of property methods for different applications. The phase equilibrium behavior predicted by the selected physical property method should be compared to experimental data for validation purpose. The experimental data that can typically be found in literamre includes the Txy and yx data binary and ternary LLE data VLLE data and azeotropic information. For details of how to validate the prediction of the selected physical property method, please refer to Chapter 2. 

The next steps arc entering components and selecting physical property methods as in previous Sections 3.1.2 and 3.1.3. Notice that only NRTL, UNIQUAC, or UNIFAC should be selected because we need to describe LLE in this decanter operation. 

BS 6070-0 1981 (2005) Methods of Sampling and Test for Sodium Carbonate for Industrial Use - General introduction and Determination of Pouring Density BS 5551 Part 3, Section 3.1 (1993). Replaced by BS EN 11236 1995 Fertilisers. Physical Properties Method for the Determination of Bulk Density (Loose)... 

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