Thermophysical Property Data

When the data are assembled, graphs are often prepared with curves positioned to provide a good representation, especially for experimental data with scatter. Alternatively, the coefficients of equations, theoretical or empirical, are computed using regression analysis programs. This is especially common for thermophysical property data, such as the vapor pressure, P as a function of the temperature, T, and vapor-liquid equilibrium data, as discussed later in this section. 

If molecular structure design is previously carried out, as discussed in Chapter 2, most of the pertinent data will have been collected. This is especially the case for protein pharmaceuticals where automated lab benches are often employed, permitting hundreds and thousands of cell clones to be evaluated experimentally in parallel, as discussed in Section 2.1. 

Because phase equilibria are important in most chemical processes, design teams usually spend considerable time assembling data, especially vapor-liquid and liquid-liquid equilibrium data. Over the years, thousands of articles have been published in which phase equilibria data are provided. These can be accessed by a literature search, although the need to search the literature has largely been negated by the extensive compilation provided in 

Vapor-Liquid Equilibrium Data Collection (Gmehling et al., 1980). In this DECHEMA data bank, which is available both in more than 20 volumes and electronically, the data from a large fraction of the articles can be found easily. In addition, each set of data has been regressed to determine interaction coefficients for the binary pairs to be used to estimate liquid-phase activity coefficients for the NRTL, UNIQUAC, Wilson, etc., equations. This database is also accessible by process simulators. For example, with an appropriate license agreement, data for use in ASPEN PLUS can be retrieved from the DECHEMA database over the Internet. For nonideal mixtures, the extensive compilation of Gmehling (1994) of azeotropic data is very useful. 

Clearly, data regression is needed to obtain a rigorous design for the distillation. Furthermore, in this case, the UNIQUAC equation represents the nonidealities of this polar mixture quite well. When the Peng-Robinson (Reid et al., 1987) equation is used instead, as shown on the multimedia CD-ROM, the data are not represented as well after the data regression is completed.  

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This database provides thermophysical property data (phase equilibrium data, critical data, transport properties, surface tensions, electrolyte data) for about 21 000 pure compounds and 101 000 mixtures. DETHERM, with its 4.2 million data sets, is produced by Dechema, FIZ Chcmic (Berlin, Germany) and DDBST GmhH (Oldenburg. Germany). Definitions of the more than SOO properties available in the database can be found in NUMERIGUIDE (sec Section 5.18). 

NIST also maintains a website called the NIST Chemistry WebBook (http //webbook. nist.gov), which provides access to a broad array of data compiled under the Standard Reference Data Program. This site allows a search for thermochemical data for more than 7000 organic and small inorganic compounds, reaction thermochemistry data for over 8000 reactions, IR spectra for over 16,000 compounds, mass spectra for over 15,000 compounds, UV/VIS spectra for over 1600 compounds, electronic and vibrational spectra for over 5000 compounds, spectroscopic constants of over 600 diatomic molecules, ion energetics data for over 16,000 compounds, and thermophysical properties data for 74 selected fluids. The site allows general searches by formula, name, CAS registry number, author, and stracture and also a few specialized searches by properties like molar mass and vibrational energies. 

Like the first edition, the second edition contains five chapters and several appendices, particularly a compilation of thermophysical property data needed for the solution of problems. Changes are made in those chapters presenting heat and mass transfer correlations based on theoretical results or experimental findings. They were adapted to the most recent state of our knowledge. Some of the worked examples, which should help to deepen the comprehension of the text, were revised or updated as well. The compilation of the thermophysical property data was revised and adapted to the present knowledge. 

In spite of their practical importance, the precise mechanisms by which cryo- and lyoprotectants work are not well understood. Protectant formulations are often conceived through a trial-and-error process. Moreover, the thermophysical property data required to formulate protectant solutions rationally and to design cryopreservation and lyophilization protocols are rarely available. As discussed in this proposal, it is of particular interest to understand how protectants interact with cell membranes. Over the last several years we have conducted a systematic study of the structure, thermod)mamic and transport properties of model cell membranes in liquid and glassy solutions of protectant molecules. Our two-pronged theoretical and experimental approach comprises the development of novel and powerful methods for molecular simulation of complex fluids near the... 

Major Sources of Thermophysical Property Data for Pure Fluids and Mixtures... 

Some of the compilers of the DECHEMA Chemistry Data Series expanded their work into a comprehensive data bank for thermophysical property data. The Dortmund Data Bank (DDB) historically concentrated on mixtnre data, and it contains tens of thousands of datasets both for mixtnre phase eqnilibria (inclnding electrolytes) and for excess properties of mixing. In recent years, a large amonnt of pnre-component property data has also been added. 

For readers interested in collection of thermophysical properties data may want to have a look at [150-154] for pure metals, for commercial alloys at [74], or consult the literature sources mentioned in each section. 

The NIST Chemistry WebBook contains thermochemical data, reaction thermochemistry data, spectra, spectroscopic data, ion energetics data, thermophysical property data [150]. Several compilations of enthalpies of vaporization and sublimation measured by different means can be foxmd in the literature [3,151-154]. A compilation of bond dissociation energies of organic compounds has recently been published by Luo [155]. 

For the manufacture of vinyl chloride, assemble a preliminary database. This should include thermophysical property data, MSDSs for each chemical giving toxicity and flammability data, and the current prices of the chemicals. 

Process as well as model development -either predicting or even only interpolating -requires multitudinous amounts of reliable thermophysical property data for electrolytes and electrolyte solutions. Among the most important property types are ... 

Semiempirical modification SUPERTRAPP As will be shown in the next section, the modified TRAPP is very successful for the majority of fluids tested the exception is that the viscosity prediction for cyclic compounds and some highly branched alkanes is not satisfactory. To correct this and slightly improve the overall representation of the data, a further modification is proposed. It is semiempirical and requires thermophysical property data as input. If these data are not available, however, the modified procedure will revert to TRAPP. The modifications are implemented in a computer program SUPERTRAPP (Ely Huber 1990) and are as follows ... 

In addition to estimating individual properties, LOADER-2 checks whenever possible that the thermodynamic consistency between properties is maintained. For example, the liquid heat capacity will be compatible with the enthalpy of vaporization and liquid enthalpy. The ideal-gas thermal conductivity will be compatible with the ideal-gas specific heat capacity. By fitting well-behaved representative equations to each property, the program produces a self-contained set of thermophysical property data, which can be used with the main PPDS system. 

Imperial College Thermophysical Properties Data Centre,... 

JF Ely, JW Magee. Experimental measurement and prediction of thermophysical property data of carbon dioxide rich mixtures. Proceedings of the 68th GPA Convention, 1989 89. 

In early studies, ie, approximately before 1990, a peak in thermal conductivity was not taken into account. Later, this peak was well established (see Fig. A3.6(b) for water and Fig. A3.15 for carbon dioxide) and included into thermophysical properties data and software. The peak in thermal conductivity diminishes at about 25.5 MPa for water (see Fig. A3.6(b) and Table A3.3) and at about 8.4 MPa for carbon dioxide (see Fig. A3.15 and Table A3.3). 

Recommended Thermophysical Property Data for Silicon System... 

Haynes, W.M., Kidnay, A.J., Olien, N.A., Hiza, ML States of thermophysical properties data for pure fluids and mixtures of cryogenic interest. Adv. Cryog. Eng. 29,919 (1983)... 

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