View and edit your assay data

The Assay Preview page shows a preview of the assay data that will be used by Plan during calculations. The data shown is for a particular distillation unit selected using the Distillation Unit menu at the top of the grid.

The properties shown in the preview grid are those configured for the output streams of the selected distillation unit. Properties are configured for these streams using the Add button, or using the Outputs grid. You can edit the recut values of the properties listed using the Edit button.

Note: If you edit a value and then recut, the edit will be preserved (remaining distinct from the cut value).

Filter the assay preview grid

The Assay Preview grid supports filtering to show specific crude and property values. Type the relevant search text in the Properties and Assay Name text boxes.

Choose the distillation unit

You can choose to show assay data for a different distillation unit by choosing an option from the Distillation Unit menu.

Yields are always shown relative to the tower feed and so sum to 100%. If a tower receives material as a swing cut, this is represented as a new column.

Add properties

You can add new properties in addition to those listed in the assay table, for one or more streams of a distillation unit. Follow these steps:

1. Make sure that the correct distillation unit is shown in the Distillation Unit drop-down list.

2. Click the Add button in the toolbar at the top of the table. The Add Property dialog window opens.

   

3. Choose the property to add and select a unit of measure.

4. Select the streams for which the property should be available. If a property is already listed for a stream, the stream entry is not available.

5. Click OK. The dialog closes and the property is added to the table.

6. Enter or paste property values for the desired streams and assays.

   

To delete a previously added property from a stream, select the corresponding row in the table and click the Remove button in the toolbar at the top.

Whole crude data

The Assay Preview grid shows properties for each whole crude fed to distillation units. When a calculation or driver is added which requires the whole crude property as part of its definition then the whole crude property is automatically retrieved and displayed.

Recut vs manual assay data

Feedstock assay cutting in Plan can be performed automatically by the tool, or alternatively you may calculate and enter your own assay data. The different methods of cutting are selected using the Recutting toggle button in the top left corner of the Assay Preview page.

When the button is set to Auto, assay data is automatically recut by Plan using the fractionation parameters defined for each distillation unit. Where these units have multiple modes, the assay values for each separate mode are also automatically calculated. When distillation parameters are changed in any tower, the assay data is automatically recalculated before an optimization run.

You can force a recut at any time by clicking the Recut Assays button.

To remove all automatically generated assay data from a model, and optionally manual data as well, follow these steps:

7. In the Supply Chain Models tab of the Model Explorer, select the model from which you want to remove the assay data.

8. Click Clear Assay Data in the Model Maintenance group of the Tools ribbon tab. The Clear Assay Data dialog box opens.

   

9. Do either of the following:

   • Click Remove all recut assays to remove only the automatically generated assay data.

   • Click Remove all recut assays and associated edits to also remove manually entered property values. This includes old manual assay data corresponding to feedstocks that have since been removed from the model.

   Manual assay data in historical versions of the model are not affected in either case.

When the button is set to Manual, you are responsible for entering the necessary assay data into Plan. This can be done by copying and pasting the assay data from an external application such as Microsoft Excel into the Assay Preview page. The data in Excel could be generated in any way, but would commonly be output from an assay management tool such as Assay. Where manual data is used, you must ensure that all required cut property values for all required feedstocks are included in the assay table, including any values for swing cuts. If the distillation parameters of the distillation units change at any point, you must ensure that the relevant assay data is updated in the Assay Preview page.

If you override assay data by switching to manual and entering values, note the following:

• If you add a new crude assay, this will not be added to the assay table. You must switch to Auto to include the crude, and then switch back to Manual. This will delete the previous changes made to the assay table, so these must be repeated.

• You can only override yield by weight. Yield by volume is calculated from the weight yields and stream densities.

Assay data reset

In rare cases, the assay table in the Assay Preview page can get corrupted and prevent AVEVA Unified Supply Chain from working correctly.

In this case, a message appears at the bottom of the page. Click the Clear Assay Data and Edits link to remove all assay recut data and any manual edits. You can then proceed to rebuild the data by recutting or optimizing.