Rate targeting in simulation

Some assets support rate targeting of their operations:

• Base Delta Targeting

• Manifold Targeting

If an asset is being targeted during simulation, Schedule attempts to meet the rate target based on the input flow to that asset.

Rate targeting is left to right on the flowsheet, that is, the assets are evaluated in the order they receive feed, and adjust their targets independently. If a downstream asset cannot meet its rate targets because of an upstream target, it is not possible for the downstream asset to adjust the upstream unit's target.

As rate targets are evaluated left-to-right, downstream targets override any upstream targets.

Example: An HGO manifold may target a flow to an FCC feed pool of 10 kbbl/d, while the FCC feed pool itself has a target of 30 kbbl/d with the HGO manifold being available for control. If the FCC feed pool flow drops below 30 kbbl/d, the HGO manifold will have more flow taken (above 10 kbbl/d) to satisfy this target (because the FCC is after the HGO manifold and so takes precedence in the order of evaluation).

Rate targeting requires the asset to have upstream sources that have flexibility in their operation; this flexibility may be split ratio or inventory. As such, only upstream manifolds and upstream tanks can be target sources. To meet the target, an upstream manifold's split ratio may be adjusted, or material may be taken from buffer tanks.

Tip: In the Simulation Settings window you can configure options for rate targeting calculations.