Create and Edit a Gas Quality in the GUI

This guide provides step-by-step instructions on how to add, remove, update, and assign gas quality streams to externals supplying gas mixtures to a network within the GUI.

For more details on gas components, please refer to Add a Gas Component.

Refer to Gas quality (GQUAL) for more details on quality objects.

For details on import and export gas quality information for gas streams refer to How to Import/Export Gas Qualities.

Gas quality is a property of a stream of a gas. The user can create, modify, and delete a gas quality only when a network is available in the active project.

1. Add a gas quality stream

Use Model Explorer  Qualities and right-click for the context menu, and select Add Gas Quality (Figure 1). A new gas quality item is added to the list of "Qualities" (in the example is "QUAL_093"). Its color is grey indicating that it has not yet been associated with any external in the network. When associated, the color changes to black. Two numbers in brackets are next to the name of the quality stream. The first indicates the number of components in the stream with a molar percentage bigger than 0 %. The second indicates the total number of available components in the network. The suggested name and composition can be modified using the property editor.

assign gas quality 01
Figure 1. Example of how to add a gas quality to a network, and of a new quality stream "QUAL_093", with three components out of the four available: methane (C1) at 60 %-Mol, ethane (C2) at 20 %-Mol, and propane (C3) at 20 %-Mol. Nitrogen is absent from this quality stream.

2. Assign a gas quality stream

Once a gas quality stream is defined, the user can assign it to one or multiple supply externals. Proceed by selecting the externals either in the map view or from the model explorer, and after right-clicking, open the context menu to choose Property Editor or Multi Edit. A new window shows up, and in the section "Quality" it is possible to set the value of the variable SQSETNAME by choosing the desired quality stream from a drop-down list (Figure 2).

assign gas quality 02
Figure 2. How to assign a gas quality stream to an external supplying gas in a network using the property editor. In the example, gas quality "G_Import" is assigned to the supply point CBI_1.

3. Delete a gas quality stream

For removing a gas quality stream from the ones available in your network, just select it and right-click (Figure 3). From the context menu choose Delete Gas Quality(/)ies) and SAInt will remove it. Externals associated with the deleted stream will be reallocated to the default quality stream.

assign gas quality 03
Figure 3. How to delete a gas quality from a network.

4. Properties of a gas quality stream

The user can access and edit physical properties and energy content of a gas quality stream by opening the property editor. Figure 4 shows an example of a quality stream called "QUAL_093". By default SAInt estimates critical pressure and temperature, relative density, gross and net calorific values based on the list of components and their contribution in molar percentage.

In the section "Editing", SAInt provides a quick way to check if the sum of the molar percentage of all components in the gas mixtures equals 100 %. In case it does not, click the button AdjustMix to re-scale to add up to 100 %, and to automatically recalculate all properties. The option CalculateProperties re-estimates and updates only the mixture properties.

The user can manually specify and override the estimations for physical properties and energy content used by SAInt. The new values will be used till AdjustMix or CalculateProperties are not applied.

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Figure 4. Gas quality properties as shown by the property editor for the example "QUAL_093".

5. Turn off gas quality tracking

Gas quality tracking is a feature of a gas network object. The option is active by default when a new or saved scenario is loaded. The user can turn off the feature by adding the network event QTOFF (see Figure 5) to the list of events of the scenario. The timing of the event can be adjusted in dynamic simulations.

assign gas quality 05
Figure 5. How to turn off gas quality tracking in a scenario using the QTOFF event.