Changing Species Models

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If additional species models are available to the user, then the species model (SpModel) can be set by the user.

Notes related to selecting and using species models in a project:

• The DEFAULT species model for the project needs to be set in the Project Configuration file (cfg).
• The default species model is used in any new unit operations inserted into SysCAD. On solve, this will be changed to the required species model based on the species models used in incoming streams.
• The species model currently in use in any pipe (Qi, Qo) or unit model stream displays (QFeed, QProd, etc.) will be displayed under tag SpModel.Used.
• In practice, only a limited number of unit models such as Feeders need to have the species models selected. This is done by selecting the required species model from the dropdown list for SpModel.Reqd. Normally Inherit is selected which will result in the default species model being used. The species model currently being used will be displayed as SpModel.Used. On solve, the species model used is propagated with material flow - from feeder to outlet pipe, to next unit model, etc.
• In the case of two different species model entering the same unit operation, SysCAD will decide what to use for it's operation and outlets. This will typically be the higher order species model, so not the Standard Species Model.
• Occasionally, the user may want to change or force the use of a species model in a pipe. For a pipe that is not simplified, the SpModel.Reqd can be set on the Qi page. The Qi and Qo pages would then report the use of separate species models. Note that there may be an enthalpy difference because different species models may calculate the mixture enthalpy differently fro the same composition and temperature.