Blending

Blend streams into products

To configure which streams can be blended into particular blender products, navigate to Blending > Blend Matrix, then:

1. Select the required blending pool using the Blender drop-down menu.

2. For the stream row in the grid, select the check box in the column where the stream can be pooled into that product.

Type a value into a cell in the Blending Matrix tab to have Plan target this blend percentage during optimization. This is indicated by a padlock icon, as shown by the following image. Other streams are adjusted to meet the required percentage. If this is not possible, a diagnostic message indicates that the blend is infeasible.

Blending pools

Final products are often made from different streams which are blended either to a recipe, or the blend of which is optimized to meet a set of material specifications. When a product is made of different pooled streams, it may be convenient to add a Blending Pool to the flowsheet. A blending pool is a blender with all the different possible input feeds directed to it as inputs, and the output of the blender directed to one or more saleable products.

Example: Most refineries have a gasoline blending pool where the possible blending components (such as light naphtha, reformate, isomerate and so on) are pooled for blending to meet the gasoline requirements of the refinery. This gasoline pool will take the input feeds and blend them (for example, to make 93 RON gasoline and 97 RON gasoline) as required by the sales of the case.

Blender units included in the flowsheet are listed on the Blend Matrix. If the output from a blender is a saleable product, then the output pipe carrying the stream should be directed to sales (by selecting Send To > Sales from the pipe context menu). By default, the blend matrix shows the input streams to the blender down the left side of the grid, and the products the output streams of the grid are associated with across the top of the grid.

The different blending pools available in the flowsheet are accessed using the Blender menu.

Create a blend recipe

Some products are blended to particular recipes, rather than to meet particular material specifications. For example, LPG may often be blended to have a fixed ratio of propane and butane. You can define the recipes of these products by entering the relative amount of each product in the blend matrix.

To create a recipe for a blended product:

3. Ensure the blended product is the output from a blending unit in the flowsheet.

4. Select the producing blender using the Blender menu.

5. Type the relative ratio of each blender input in the blend matrix.

Solution values can be locked during subsequent runs. This means that a solution value will not change in any subsequent run, even if other input to the run is changed.

Example: The flow of naphtha from a crude could be locked, and in subsequent runs it would not be able to change. Therefore, if a fixed swing cut point was changed and the model re-run, the crude blend would have to change in order to match the fixed flow rate.

Locking a solution value acts in a similar way to fixing the value. The advantage over fixing a value is that the lock can be clearly seen in the user interface, so it is simpler to distinguish true fixed values from those which are temporarily locked.

To lock one or more solution values, select the corresponding rows in the table and do either of the following:

• Click Lock Solution in the Behaviour group of the Home ribbon tab.

• Right-click on the table and choose Locking > Lock from the context menu.

To unlock one or more solution values, select them and either click Unlock Solution in the ribbon or choose Locking > Unlock from the context menu.

Limit the number of components in a blend

You can limit the maximum number of components in a blend by setting a Component Limit in the Blending > Blend Matrix grid. The Component Limit column is only present in the All View.

Add grades to your case

Product grades should normally be defined in the Global Reference Data within the main Model Explorer. However, grades can also be added on a case level, in which situation they will only be available for use in the current Supply Chain Model. To add a grade to the current Supply Chain Model, navigate to the Blending > Specifications page, then:

6. Click Add Grade in the Specifications group of the Home ribbon tab. The Add Grade dialog box opens.

7. Enter a Name for the new grade, optionally a Description, and the Share to store the grade.

8. If required, choose an existing grade to copy the specifications from.

9. Choose a Material Type for the grade.

10. Either create a new traded material with the same name as the grade, or choose an existing traded material to associate with the grade.

11. Click OK. The new grade is added to the tab. A new sale for the grade is added to the Products tab of the Sales page.

A new grade must be connected with a pipe on the flowsheet before it can actually be sold from the plant (see: Send Streams for Sale).

Identify property specifications

The Configuration column in the Blending > Specifications page helps you identify which properties are for which particular RFG or CARB Specifications. You can also use the filter search bar to find such properties.

Report on properties

You may want to output a property value for a traded material, without actually constraining the value for that property. In this situation, you can set the Report on Property option in the Blending > Specifications page. To set reporting for a particular stream property:

12. Select the required property for the required stream.

13. Right-click and select Report on this Property from the context menu.

After setting a property to be reported on, your cell will contain a blue R.

Warning: To report on a property, all the component streams for that product must have a value for that property. When these are crude streams, this value will come from the assay; for other streams, the value must be predicted by relevant process models.

View the composition of a blend

The Blend Composition tab displays a flow diagram for the chosen blender, showing how flows from the blender inputs contribute to the blend products. The thickness of each band in the diagram is proportional to the flow rate.

Configure the diagram in the following ways:

• Select the blender from the Blender list.

• Select a blend input from the Component list. The default is to show all components.

• Select a blend output from the Product list. The default is to show all products.

• Select a unit of measure for the flows from the UoM list.

Additional information is available via tooltips by hovering your mouse pointer over various parts of the diagram:

• On a component label: the flow toward each product the component contributes to, in absolute and percentage terms, plus the total component flow.

• On a coloured band: the corresponding flow rate.

• On a product label: the flow contribution from each relevant component, in absolute and percentage terms.

  Tip: Optimization results for the case must be available for the flow diagrams to appear. Optimize the case if the Blend Composition tab does not show any content.