ASPEN data bank

ASPEN is supported by a versatile set of physical property correlations representing the current state-of-the-art. Physical property monitors control the property calculations in accordance with methods and models specified by the user. The user is allowed to specify different combinations of physical property calculation methods in different parts of the process. For specialized components such as coal or limestone, a collection of non-conventional property models is available. ASPEN includes data banks from which the required physical property constants and correlation parameters can be retrieved automatically at run... 

In recent years, property information systems have become widely available in computer packages. Some are available on a stand-alone basis, such as PPDS2 (1997), while others are available within the chemical process simulators, such as ASPEN PLUS, HYSYS.Plant, PRO/n, CHEMCAD, BATCH PLUS, and SUPERPRO DESIGNER. Commonly, constants and parameters are stored for a few thousand chemical species, with programs provided to estimate the property values of mixtures, and determine the constants and parameters for species that are not in the data bank using estimation methods or the regression of experimental data. Virtually all of the property systems estimate the properties of mixtures of organic chemicals in the vapor and liquid phases. Methods are also provided for electrolytes and some solids, but these are less predictive and less accurate. 

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. 

We will try different models and conpare them to data. [Note that data also needs to be checked for consistency (Barnicki, 2002 O Connel et al., 2009 Van Ness and Abbott, 1982).] First, try the IDEAL model. Before allowing you to check the VLE data. Aspen (in flowsheet mode) requires you to conplete the input information. Thus, we need to continue. Left-click on the Next button after you have selected a VLE model (IDEAL). If you get a data bank with binary parameters, left-click Next again. When you get a box that says, Required Properties Input Conplete, click either go to next required input step or modify required property specifications. Assuming you are happy with what you have, left-click on OK to go to next required input step. 

B. Explore. These components are in the Aspen Plus data bank and residue curves were generated with Aspen Plus using NRTL fFigure 11-111 (obviously, other process simulators could be used). Since there is one minimum boiling binary azeotrope between methanol (light component) and toluene (heavy) component without a distillation boundary, this residue curve map is similar to Figure 8-lla. We expect that the flowchart in either Figure 11-lQa or 11-1 Oh will do the separation. 

In the simulation, the NRTL activity coefficient model was used for the VLLE of this system. The Hayden-O Connell second virial coefficient model with association parameters was used to account for the dimerization of acetic acid in the vapor phase. The set of NRTL parameters for acetic acid, water, and isobutyl acetate is given in Table 9.3. Other NRTL parameters are obtained mostly from the Aspen Plus data bank. Four pairs... 

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