Stock Mixture Properties Dialog: Composition Tab

This tab is part of the Stock Mixture Properties Dialog.

The properties of a mixture are currently limited to its composition, density, and purchase price.

●      Composition
The composition of a mixture is defined on a mass or mole %, or a concentration basis (Target Concentration Calculator Dialog). A mixture can be composed of pure components as well as of other stock mixtures.

●      Density [g/L or kg/m³]
Used in converting between mass and volumetric flowrates, and calculating the concentration of species in streams. The density is assumed to apply for either the liquid or the solid phase (whichever the component appears in the process file).
It is estimated using the formula:

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If the mixture is in vapor phase, the system uses the ideal gas law to estimate its density.

●      Purchase Price [$/kg]
Used in economic calculations. It can be either provided by the user or calculated from the mixture’s ingredients as the weighted average of their purchasing price.

The most important of the mixture properties is the composition. Notice that you can bring into the composition table either a pure component or another stock mixture, by clicking on the respective radio button. This feature is very powerful since it allows you to describe a stock mixture as a mixture of other mixtures and/or pure components. In case you have a mixture whose composition is described by one or more other mixtures, you may want to view the component composition of that mixture (that is the composition of this mixture in terms of pure components only). In order to do that, simply click on the View Composition () button. This will bring up the Component Composition Dialog, where you see the list of all the pure components that constitute the stock mixture. The mixture may contain other stock mixtures but this dialog shows only the pure components.

Notice that the list of pure components and/or stock mixtures that is available to you for defining (or editing) the composition table of a mixture depends on whether you are editing the properties of a registered mixture or a databank mixture. If you are editing the properties of a registered mixture, then you may select to include ingredients which are registered in the process (From Registered button) or ingredients from the databases (From Database button). The From Database option allows the user to select the preferred database (Designer, User, DIPPR or PPDS if available). If you are editing the properties of a mixture in the stock mixture databank, then the list will include any other stock mixture and/or pure components already residing in the corresponding databank.