Add input properties parameters

Each model may be driven by several input properties. These are the stream properties of the feed for the unit and these properties affect the properties of the output streams from the unit. For example the final properties of the output streams from a hydrotreater would depend on the sulphur content of the input feed.

When input properties require a blending index for typical use then Process Model Manager Reference Manual will automatically use the standard blending index for that property. Standard blending indices are shown for each property in the Property Manager. During regression of the data the indexed value will be used.

To add a new Input property for the Generator Case:

1. Click the button to the right of the properties grid.

2. Select the Stream for which you want to add the property.

3. Select the name of required property from the list of available properties (to include the complete list of Process Model Manager Reference Manual properties and not just the short common list select All from the Show properties drop-down menu).

4. Select the required unit for the property.

5. Click OK to add the property.

Indexed Properties

When adding an input property it is possible to add the property as its indexed value, rather than the real value. That is, the input value and its changes will occur in the scale and unit of measure of the property once converted to its index value using its associated blend rule ("Blend Rules" on page 102).

To use an input in its indexed value the property must already have a blend rule associated with it. When this is true, the Indexed check box for the property is enabled and may be selected; when this option is selected, the indexed property is used as the input rather than the real property value. The real property value is included in the Data Grid for reference, but this is not included in the actual process model.

If the property is marked as indexed, then the base and delta value for the property must also be expressed in indexed units as measure, as the base delta calculation is performed in this space, and then converted back to real units of measure using the inverse of the index.