Configure your distillation units

A configuration is a way of operating a process unit, and may be closely associated with a mode for that unit. During the scheduling period, a unit may have one or more configurations, or may be inactive. When a unit is operating it must have an associated configuration. A unit can only have one active configuration at a time.

The configuration defines the operating parameters for a process unit, and the time window for which these parameters are in use.

The configurable parameters depend on the asset you are working with. For example, for a distillation unit the parameters include the cut points and fractionation indices.

Within a configuration it is possible to manually set all the details of the operating state, or alternatively it is possible to target particular details.

Use the Configuration Inspector to set up or edit a configuration for your distillation units.

Note: There must always be an active configuration; it may be necessary to split an active configuration in order to change the start or end date of a configuration and edit the configuration parameters for a limited duration (Changing Configuration Duration).

Tip: In the Simulation Settings window you can configure how assays are recut when distillation parameters are changed.

Distillation targeting

Targeting allows the input or the output of the unit to be targeted so that the asset properties are manipulated during simulation to try and meet the configured target.

To set a unit target, open the Configuration Inspector, then:

1. Define the operating timespan for the configuration by editing the Start Date and End Date fields in the General tab.

2. Select the unit stream to target by double clicking the stream at the top of the Targeting tab. The stream can be a feed or a product.

3. Write the target in the Target Value field. This might be an absolute number, a new calculation or a new time-based parameter.

4. In the Sources pane, configure the sources that will be manipulated during targeting. For each source, choose the operating parameter to control, set how it will be controlled in terms of rate or percentage and so on, and choose the order of priority in which sources are evaluated.

   

The Sources section allows the flow from the sources to the unit to be controlled. Upstream assets such as manifolds must have at least one free available ratio output to use for diverting excess material (Target the Flows of your Manifold).

You can set the Control value to any of the following:

• None: No control is attempted on the flow from this asset.

• Sequential: The tank is emptied completely before material is drawn from the following asset. Select the Respect Working Min check box to avoid emptying the tank below its working minimum. The Sequential option is not available for manifolds.
  The simulation draws material in turn from all tanks marked as Sequential before returning to the first tank.

• Simultaneous: Draw material from this asset at the same time as from other assets.

• Simultaneous (Max Rate): Same as Simultaneous, but you can define an absolute maximum flow rate in the Value and UoM columns.

• Simultaneous (Max %): Same as Simultaneous, but you can define the maximum flow rate in the Value column as a percentage of the overall flow rate to the unit.

Select the Status check box under Respect Tank to make sure that no material is drawn from a tank until its state is set to Available.

In the Tabular pane you can add multiple columns showing target rates for the feed and all the outputs in your distillation unit. This is useful if you set targets for different flow rates in different parts of the scheduling period.

Note: Only tanks and manifolds are supported upstream target assets.