Streams with Spiral Assay Data

This window is used to select the crude from the Spiral Assay database and specify its rate and composition. The stream phase can be liquid, vapor, or a mixture of liquid and vapor. Spiral Assay must be installed on your computer to use this option.

Usage

To open this window, in the Stream Data Window, select Spiral Assay from the Stream Type list and click Flowrate and Crude Selection button.

Select a Crude flowrate specification and enter the appropriate values for crude composition or crude flow rates.

Crude Flowrate Specification

Crude flowrate specification can either be the Total Blend Flowrate or the Individual Crude Flowrates. If you select Total Blend Flowrate, enter its value in the data entry field available next to it. The flowrate must be in weight or liquid volume units. The dimensional unit can be changed by using the Convert Unit of Measure window, which appears when you click UOM on the Toolbar.

Crude Table

The Crude Name and Crude Reference columns of the table contain the names and reference IDs of crudes that are selected from the Assay Database. Click the Browse button of the table to go to the Crude Selection window.  Enter the required values (composition or flow rates) for the crudes you have selected.

Depending on the option you have selected for the Crude Flowrate Specification, enter appropriate values for the individual crudes selected. The various possibilities are:

If Total Blend Flowrate has been selected

• Enter the individual composition values for all the crudes that are selected. The basis by which the compositions are entered can be changed through the Convert Unit of Measure Window, which appears when you click UOM on the Toolbar. The default basis is "Liquid Volume".

• The individual crude compositions must add up to 1.00, 100.0, or the total blend flowrate, within a tolerance of 1%. If this tolerance is not met, an error message will be generated upon clicking the OK button. Selecting "Normalize Crude Compositions" option scales the individual compositions and avoids this error.

 If Individual Component Flowrate has been selected

Enter the individual Crude flowrate values for all the crudes that are selected. There is no restriction on the flowrate sum for this option.

Crude Selection

Click the Browse button to open the Crude Selection window. All the crudes are segregated under different libraries in the Data Sets section of the window. When you click a library its corresponding crudes are displayed in the bottom section of the window. The fields displayed are Name, Reference, Origin and Density API of the crude.

When the Browse button is clicked, by default, a crude is selected and its properties are displayed in the Currently Selected Crude group box.  Each time you click a new crude this group box displays the properties for the latest selection.

PRO/II provides Sort and Filter option to the users for easy navigation and selection of the required crudes.

You can filter each of the fields, or multiple fields, by entering either the initial string or an embedded string in the Search String field. Range field will filter all the crudes whose Density API are equal to or between the values entered. For PRO/II to filter the required field, enter both the values.

Sort Name, Reference, Origin and Density API  in ascending or descending order by clicking the repective buttons. Range field is sorted from light to heavy crudes by clicking up arrow and heavy to light crudes by clicking down arrow.

Cutset Specification

The Cutset Specification group box allows the user to define the boiling points of the individual cuts.  These cutsets are defined as they are defined in conventional PRO/II assays on the Cutpoints and Characterization DEW (Data Entry Window). This cutset name cannot be shared with any other Crude Blend or Assay Blend id. You can override the default cutset by selecting the Secondary Cutset radio button and then selecting the required cutpoint set from the drop-down list.

Clear Crude Compositions

Click Clear Crude Compositions button to remove all the composition or crude flowrate data entered into the table.

Normalize Flowrate

If the total blend flowrate has been entered, you may select the option of normalizing the composition of the individual crudes to the Total Blend Flowrate. Since the composition values are normalized, no error condition arises when the required tolerances are not met.

Note: Normalization is performed during calculations to solve and converge the flowsheet. It is not performed during input data processing.

Spiral Crude Processing

Once the crude blend is selected in the Spiral Stream DEW and the OK button is clicked, the Spiral pseudo cuts are generated based on the CUTSET information provided. The process of Spiral pseudo cut generation also involves finding the light end components available in the selected Spiral Crude Blend Stream and adding them to the PRO/II flow sheet, if they haven't already been added to the flow sheet from the PRO/II Library. Though a Spiral Crude Blend Stream can have several light end components, at present, PRO/II considers only the limited number of components. The properties of all these light end components are retrieved from the PRO/II Library only.

Till PRO/II v10.0, only 16 components were considered as Lightends from Spiral crude, but from PRO/II v10.1, 59 components are considered as Lightends. User is provided with option either to choose old list of Lightends or extended list of Lightends. This options are provided in Assay Cutpoints and Characterization DEW. By default Short list or 16 components are treated as Lightends. The list of components supported as Lightends is provided in the section Supported Lightends for Spiral Crude Sets.

After generating the Spiral pseudo cuts, PRO/II gets the following seven fixed properties for all the pseudo cuts from the Spiral database: molecular weight, NBP, critical temperature, critical pressure, critical volume, acentric factor, and standard density. All the other fixed properties and temperature dependent properties are calculated using the petro characterization methods selected in PRO/II.

Following is the comparison of fixed property names in PRO/II with those in Spiral.

Once the Spiral stream is created in PRO/II, the refinery inspection properties are associated with each pseudo cut and stored in PRO/II data base as input component refinery inspection properties.

Following is the comparison of Refinery Inspection Property names in PRO/II with those in Spiral.

Related Topics

Streams - Technical Information

Stream Data Window

Petroleum Assay Streams

Reference Streams

Toolbar

OK and Cancel Buttons

Supported Lightends for Spiral Crude Sets