Electric power requirements are defined by the user or calculated by the program for every operation that may need power to be carried out. Auxiliary power can also be specified for each operation (from the Operations Dialog: Labor etc. Tab) to account for needs not accounted for by the operations models. Additional power demand may be assigned to a section directly (from the Operating Cost Adjustments Dialog: Utilities Tab) without directly associating the consumption with any particular process step. At the section level one can define additional power consumed by unlisted equipment (skids, storage units etc) as well as power due to the general load of the plant. By default the program will use the standard power type to represent the demand in power, but the user may define his own types of power.
Power may also be generated from certain procedures. The procedures that are capable of producing power are the following:
● Power Generation in a Straight Flow Steam Turbine-Generator Procedure
● Power Generation in an Extraction Steam Turbine-Generator Procedure
● Power Generation in a Gas Expander-Generator Procedure
SuperPro Designer keeps track of the instantaneous as well as cumulative demand or production of power types.
The ‘SuperPro (User)’ database contains the entire definition of the power type databank and currently it contains just a few entries. To review the properties of the standard power type, select Databanks }Power Types from the main menu. This will bring up the Power Types Databank Dialog. From the same interface the user may introduce new power types in the ‘SuperPro (User)’ database. Changes made in the power databank do not affect existing process files or other parts of the databank even if the edited power types are used as the basis for power declared in sites.
The application registers in the process file by default the standard power type (‘Std Power’) for use in operations or sections. If other types of power are required, you can choose them from a list of generic power types defined in the power types databank or, for operations belonging to allocated sections (see Section Allocation), from the corresponding site’s available options for power types. Power types currently consumed (or produced) can then be inspected from the List of Power Types Currently Consumed by the Process or List of Power Types Currently Generated by the Process accessed by selecting Edit } Process Options } Resources } Power or Tasks } Other Resources } Power from the main menu. From here you may edit the properties of a power type (see Power Type Properties).
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If the process does not contain any power generating unit procedures then you may only see the power types currently consumed. As soon as a unit procedure that can produce power is introduced in the process then there are two menu options available in the Edit }Process Options }Resources and Tasks }Other Resources. These are the Power Consumed and the Power Generated options. Also power consumed and generated differ by their properties too. |
If at any time the user wishes to change the Power type used in the process with another power, instead of visiting all the locations the power is used and replacing it, the Replace Resources Dialog can be used to perform a global switch of resource(s) with another resource(s).
To add, edit or delete power declared as utilities in sites, select Databanks } Sites and Resources from the main menu. From the Sites & Resources Databank Dialog that appears, you can select the desired site from the left pane (site tree) and the Power node on the right pane and you may add new, edit, or delete power by clicking on the appropriate button from the toolbar.
When adding a new site power you will be presented with a dialog which displays all currently available power types in the databank. From there you can select one or more power types that you want to include in the site.
Once a new power type is added to a site as a site power then you cannot delete it from the power type databank; first you must remove the power type from the site.
If a section is allocated to a site, then available to operations of this section are not only power of this site but of its parent sites as well. This implies that if there is a central power plant in a site then all produced types of power are available to all sub-facilities within that site.
Changes made in site power (i.e. power types associated with sites) will not affect existing process files that contain sections that use them. SuperPro Designer will not automatically adjust any files even if they are currently not open. However, you can check consistency of resource definitions (power or any other) between what’s contained in a process model and what is defined in a process site (in the database) by invoking the Reconcile with Site DB Dialog (File } Check Consistency with Site DB...). From that interface, you can propagate all changes done in the site-power databank to a process model file or force the de-allocation (i.e. substitution with generic-type power) when needed to maintain consistency. Such changes could affect economic results so re-doing economic calculations might be needed for all affected process files.
For more details, see Adding or Deleting a Power Type.
The parameters of a power type as shown in the power types databank are the default parameters that are used the first time any of the processing steps in your process file employs that power type. If you decide to use different values for your specific process file, then you can adjust those parameters without affecting the default values of the power type in the databank, by bringing up the Power Types dialog that appears when you select the Edit } Process Options } Power Types option from the main menu, or just the Resources } Power Types option from the flowsheet context menu. The dialog that pops up displays a list with all power types currently employed by the process file.
To view or edit the properties of a power, you should click on the power type’s index column to select it and then press the View/Edit Properties button (
). Alternatively you can double-click on the power. The dialog that appears contains the selected power types data organized in three tabs. Changes made through this dialog will only affect the current process file; they will not be stored in the power types databank. If you want the power type in this process file to take up the properties of the power type in the databank (in case they are different) select the power by clicking on the power’s index column and press the Update Properties from DB Record button (
). If you want to update the databank's record (power type properties) based on the current process file record press on the Update Properties in DB button (
). If you wish to deposit the selected power type to the databank, then click on the Deposit Record in DB (
) button.
The properties for a power type that is consumed or generated are:
● Voltage: the voltage of electricity may be different from country to country, the default is 110V for USA.
● Purchasing Price: how much does the electricity cost to purchase per unit basis (default in kWh)
● Selling Price: the selling price of the power which is produced if any.
As prices of utilities tend to fluctuate in time, if your company regularly updates values in the ‘SuperPro (User)’ database, you may decide to bring all prices in your SuperPro Designer model up-to-date. This can be easily done by invoking the Update Resource Prices from SuperPro (User) DB Dialog (select Tasks } Update Resource Cost Data... from the main menu of the application).
Other properties which are only available in this process file (do not exist in the power types databank) and are exclusive to power produced from the process are the following:
● Revenue vs Credit: the generated power may be considered as revenue or as a credit to the whole operation of the plant. If a power type is a revenue it is included in the total annual revenues, and if it is a credit it may reduce the total annual operating cost of the plant.
● Recycling: the generated power can also be reused in the same process therefore reducing the cost of the total power consumed in a plant. The extent of power recycled can be set by setting a percentage in the relevant edit box.
The Availability Limits tab lets you define bounds on consumption of this power type. There are two types of limits: rate limits (instantaneous or time-averaged over a user-defined time span) and cumulative limits over a user-defined time span. Upon request, these limits will be plotted on the resource consumption charts (see Power Demand & Power Generation Chart) so that you can compare them against the actual consumption.
Note that, for site power, data in the Properties and Availability Limits Tab are not editable through the Power Currently in Use dialog. The reason is that site power could be shared by different process files and only through the site databank their properties can be modified. To edit those values, you will need to visit the sites databank through the Databanks } Sites & Resources menu item as explained before.
The locations (Consumption or Production) where a selected power is currently utilized in the process can be viewed by clicking on the button 
.This can be in operations or sections.
For more details on the interfaces please see:
● List of Power Types Currently Consumed by the Process
● List of Power Types Currently Generated by the Process
● Power Type Properties Dialog
