Multi-plant models

You can create multi-plant models only with a valid Spiral Network license.

For more information about checking for installed licenses, see the Configure your Licenses topic. Contact AVEVA support (spiral.support@aveva.com) for information about obtaining new licenses.

Configure a multi-plant model

After creating a network model, follow these steps to configure it as a multi-plant model, that is, a model in which all nodes are of type Plant.

1. Create the plant nodes

   

   In the network environment, go to the Nodes page and add as many nodes of type Plant as there are plants in the model.

   

2. Define the periods

   

   Go to the Periods page and define at least one period.

3. Match plants with nodes

   

   Go to the Plants page, which will list the plants you added when creating the model. For each plant, choose the corresponding node from the lists in the Node column.

   If you have created more than one period, change the values in the Start and End columns so that each plant is active during the desired periods.

4. Define the supplies and demands

   You can create supplies and demands in two ways:

   • By reusing the existing purchases and sales included in plant definitions.

   • By creating supplies and demands manually and adding them as separate network structure.

     It is possible to have supplies and demands created in both ways in the same multi-plant model.

     

     To reuse purchases and sales from plants as supplies and demands, go to the Plants page and select the corresponding check boxes under the Purchases and Sales columns.

     Warning: You cannot use grouping for supplies and demands created from plant purchases and sales.

     To create new supplies and demands:

   1. Add necessary Supply and Demand nodes.

   2. Add necessary transport links between the supply and demand nodes and the plants.

   3. Create supplies and demands of the relevant feedstocks and grades at the respective nodes.

Configure inter-plant material transfers

Material transfers are created by Network when it detects a sale of a traded material from one plant, and a matching import of the same traded material at another plant within a multi-plant model. Therefore, to allow a transfer of material between plants it is necessary to follow these steps:

5. Configure necessary traded materials, grades and feedstocks

   

   Before a material can be transferred between plants the necessary product grade and its associated traded material must be defined, along with a feedstock with an identical traded material.

   The feedstock needs to have all of the properties required in the single-plant model for its use. For example, if the feedstock were alkylate, and its final use as part of gasoline blending, it would need to have a density value, octane number, benzene content and so on. These must be entered for the single-plant model to optimize correctly. During a multi-plant optimization the bulk feedstock properties are replaced by the calculated values for the feedstock derived during the optimization calculations.

   The grade does not need to have any final property specifications. If the property specifications are left empty, the material as produced in the source plant can be transferred no matter what its qualities. If you do enter values for the grade specifications, then the produced material, even if it is not a finished product, must meet the entered requirements.

   Warning: Transferring intermediate distillation products between plants in a multi-plant model is not supported. An intermediate distillation product is an output of a distillation unit and a feed to another, such as atmospheric residue. In the unsupported configuration, the intermediate distillation product would be produced by one distillation unit at the origin plant and then processed by another distillation unit at the destination plant.
   If you need to create a model with this topology, please contact AVEVA Support (spiral.support@aveva.com) to discuss a suitable workaround.

6. In the source plant add the grade sale

   

   The plants where the material is produced must have the grade add as a sale from the appropriate blender, tank or process unit.

   You must also enter a sale price for the grade. This is the selling price for the grade, not the transfer cost, which is added during creation of the actual multi-plant model. For intra-company transfers the sale price may often be set to zero.

7. In the destination plant add the feedstock purchase

   

   The plants where the material is received must have the feedstock added as a feed (see: Manage your Feedstocks and Feedstocks).

   

   Note: The Feedstock must have exactly the same traded material as the product grade, and this traded material must be unique for this transfer.

   

   You must also enter a purchase price for the grade. This is the price that the receiving plant buys the material for. It is not the transfer cost, which is added separately during creation of the multi-plant model. For intra-company transfers the purchase price may often be set to zero.

   Warning: If you do enter a purchase price of zero, within the single plant model ensure the purchase amount is limited so it is not possible to buy an infinite amount of the material. If no purchase limit is applied, it may not be possible for the optimizer to converge correctly. When creating a multi-plant model, the purchase limit can be overridden to enable the inter-plant transfer.

8. Create the multi-plant model and add the transfer cost

   Create the new multi-plant model and add a transport link between the plants. The origin must be the source plant and the destination the receiving plant. By default the transport link carries any material, so if more than one transfer is available between plants they will all flow down this link. If necessary enter a cost for the material transfer.

   Tip: You may wish to create transport links for each transferred traded material. For example, if you transfer alkylate and isomerate you could have two links, each one limited to the specific traded material. This allows you to have different transfer costs. Alternatively you can have a single link which carries any material, but these will all be transported for the same fee. In reporting you will see a breakdown of the amount of each traded material transferred by the link.