Configure a product blend

Select blending time

In the Tabular pane select the time at which blending should start and right-click the grid. Product Blends can only be made from assets which are upstream of a blender, and the blender must have product tanks after it to store the blended material. Any of the component tanks which constitute the blend can be selected to create a product blend.

Tip: If the blender is associated to a grade with a default recipe, the recipe is automatically selected when creating the product blend. Add the Grade column for the blender to the Tabular pane to see the associated grade for each row.

Choose blend name

If desired, edit the default blend name in the Name column.

Select destination assets

Click the arrow icon at the right end of the Destination Asset cell to reveal a list of available destinations. Choose the asset that will be filled during the blend activity by selecting the option button next to your chosen destination tank. Note that you have values for ullage (free space in the tank) and inventory values at the end of the blend activity shown for each destination.

Note: When you change the destination asset, the Desired Amount value is not updated automatically. Check this value after you change the destination, to ensure that the blend remains feasible.

Tip: If you have a blender feeding a pipeline which in turn feed tanks, you will see the tanks listed in the Destination column, and the pipelines feeding them listed in the Via column.

Choose product grade

Choose the Grade which will be produced during the blend activity. Only grades which are configured as products of the blender on the flowsheet can be selected (Send Streams for Sale).

Note: The grade refers to the final qualities in the destination asset after the blend activity. This is a combination of qualities provided by the blend components and the qualities of the material in the destination asset at the start of the blend.

Enter desired amount

Enter the desired amount of material that should be produced in the blend activity, and the rate, or limits on the duration of the activity if necessary.

You can enter constraints for the Flow Rate and Amount quantities if desired. Right-click on the corresponding column header and choose Show Constraints from the context menu. This shows additional columns for constraining a Min, Max or Fixed value for the selected quantity.

Note: The value in the Amount column is the amount that flows through the blender (that is, the sum of the individual component flows). This amount is combined with any inventory in the destination asset at the start of the blend.

Choose calculate option

Choose an option from the Calculate list to determine how the blend parameters are defined:

• Default: all parameters can be manually defined.

• Amount: the amount is automatically determined from the date range and rate.

• Flow rate: the flow rate is automatically determined from the date range and amount.

• Start date: the start date is automatically determined from the end date, amount and flow rate.

• End date: the end date is automatically determined from the start date, amount and flow rate.

Define initial outflow blends, if necessary

After all blend components have been sent to their destinations, there is often a small amount of material left over in the pipeline. You can define where this material is sent to using the Initial Outflow Destination column in the pipeline blend inspector, product blend inspector, and import inspector.

This is useful, for example, if the original destination of your material has now been drained, or if the material left in the pipeline is similar to the new material passing through and you just want to mix it all together.

You can also create a flush blend by using the button in the inspector. This will flush the pipe with the source you select.

Choose optimization method

You can choose among three optimization methods by clicking the Optimization labels in the top left corner of the Single Blend Inspector.

It is possible to use any combination of the optimization modes. Where more than one optimization mode is used, all optimizable variables are combined into a single objective function. Therefore any penalties and costs must be carefully defined relative to each other and their entered units of measure.

The following optimization methods are available:

• Cost. The blend is optimized in order to minimize the cost of its recipe. Cost minimization uses the entered pricing for each blending component, rather than any implied pricing back to the feedstock composition. Therefore you must enter prices for each blend component in the Blend Recipe table.

• Property Giveaway. The blend is optimized in order to minimize the amount of property giveaway, that is, to minimize the difference between the final blend properties and the specification property constraints. Each individual property constraint can be included within the optimization, but usually one or two key properties are chosen for optimization. For example, when blending gasoline the giveaway on octane would be minimized, as this is often the most difficult property to achieve, while the final blend benzene content would not be considered for minimization (but would still be used as a constraint for feasibility).

• Target Recipe. Blends may have pre-configured standard recipes. Target Recipe blending allows products to be made that deviate as little as possible from the standard recipe.

Define blend recipe

In the Blend Recipe section of the General tab, configure the recipe for the blend. You can used a previously saved recipe by selecting it from the Recipe list and clicking Apply. Otherwise you can define a new recipe as follows:

1. Select the check box in the Active column if you want the selected source to supply material to the blend.

2. If necessary, edit the Price of each blend component. This is used to calculate the total cost of material used for the blend in the Cost column.

3. For each blend component, define either a Desired Ratio relative to the other components or a Desired Flow Rate of transfer. Click the option button next to the option you want to enable.

4. If there are manifolds among the blend sources, you can configure them in the Manifold Configuration column. Click on the downward arrow icon in a cell to show an interface for controlling and targeting the manifold.

5. Enter any constraints on the quantities in the table. In the table header, a lozenge icon () next to a column name means that constraints can be set for that quantity. Right-click on the column header and choose Show Constraints from the context menu. This shows additional columns for constraining a Min, Max or Fixed value for the selected quantity.

6. Optionally, enter a Penalty for deviations from the recipe target in each row. A penalty is defined as a number of dollars for percentage deviation for barrel of transferred material. There is no difference between going under or over the recipe target.

7. You can save the final blend recipe now, or after optimizing the blend, in order to recreate the blend in future with the same composition:

   1. Enter a name for the blend activity in the Recipe field.

   2. Click the icon and choose Save, or Save as Default if you want this recipe to be the default for the selected Grade.

Note: Recipes can only be saved if the assets supplying the blender have an associated service.

Tip: A row at the bottom of the table shows the totals for various quantities over all active blend sources. Ratios, target and transfer rates and amounts are among the quantities for which a total is calculated.
This is especially useful for monitoring ratios. Suppose that you want the sum of your ratios to be 100. As you change ratios to experiment with different blend recipes, you can always make sure that their sum is correct, without having to do the calculation by hand.

Review specifications

In the Specification section of the General tab, review the specifications of the final blend and the qualities of the each of the possible components in the blend. Select and clear options in the View menu to choose what to show in the table.

Values in the Components columns show property values for each of the possible blend components. Values in the Destinations columns show property values for the destination assets after the blend activity is finished, taking into account any residual material within the destination.

Note: The default margin for property constraints is 5·10-4, that is, 0.05%. No alert is triggered if a property value exceeds a constraint by an amount smaller than the margin. For example, a maximum constraint of 1000 has an associated margin of 1000·5·10-4=0.5. Therefore, a property value of 1000.3 will not trigger an alert, but a value of 1000.6 will.

If the Property Giveaway optimization method is active, the Giveaway set of columns is visible. Giveaway is defined as a penalty in $/bbl for each unit deviation below (for a maximum) or above (for a minimum) the specification value. Enter giveaway penalties if you want the property value to be closer to one end of the allowed range. For example, you may have a density range between 0.7 and 0.8 g/cc. If you prefer the optimized value to be close to the lower limit, enter a penalty for each unit deviation above the minimum. Correspondingly, enter a penalty for each unit deviation below the maximum if you want the optimized value to be closer to the upper limit.

Enter more constraints

Go to the Constraints tab and enter any minimum, maximum or fixed constraint on the various quantities, if you haven't done so already in the General tab. Clear the check box in the Active column if you want to disable a particular set of constraints. Select the check box in the Infeasibility Breaker column if you want to associate an infeasibility breaker to a set of constraints.

Optimize the blend

Click the Optimize button to generate the product blend.

If necessary, you can tune the blend after optimization by changing the minimum and maximum transfer amounts, or by setting prices for the individual components of the blend.