Shortcut Crude Distillation Unit (CDU)¶

DWSIM Plus

Available with a DWSIM Plus (Patreon) subscription.

Shortcut Crude Distillation Unit. Takes a single crude feed (with real components + pseudocomponents from the DWSIM assay manager / oil characterization tools) and splits it into N products defined by TBP cut-points, with a logistic overlap to emulate imperfect fractionation. Ports ───── Inlet 0 : Crude feed Outlet 0 .. N-1 : Products, light → heavy (last one is the residue)

DWSIM.UnitOperations.Refining.ShortcutCDU.ShortcutCDUUnitOperation
Assembly DWSIM.UnitOperations.Refining.dll · Object ← BaseClass ← UnitOpBaseClass ← ShortcutCDUUnitOperation

At a glance¶

Shortcut Crude Distillation Unit (CDU) in the example flowsheet

Port	Index	Connected in the example
Inlet, material	`0`	Crude
Outlet, material	`0`	Naphtha
Outlet, material	`1`	Kerosene
Outlet, material	`2`	Diesel
Outlet, material	`3`	AGO
Outlet, material	`4`	Residue

Example¶

This code runs on every build of this site, and the output below is what it printed.

Python

fs = Flowsheet.Create("CDUExample").WithCompounds("N-butane")
# Crude assay as pseudocomponents: name, NBP (K), SG, MW, mass flow (kg/s), sulfur (wt%)
crude = [("C-01", 330.0, 0.66, 85.0, 5.0, 0.01),
         ("C-02", 390.0, 0.73, 105.0, 7.0, 0.03),
         ("C-03", 440.0, 0.77, 130.0, 7.0, 0.08),
         ("C-04", 490.0, 0.80, 160.0, 8.0, 0.20),
         ("C-05", 540.0, 0.83, 200.0, 8.0, 0.60),
         ("C-06", 590.0, 0.85, 245.0, 8.0, 1.00),
         ("C-07", 640.0, 0.87, 295.0, 7.0, 1.40),
         ("C-08", 700.0, 0.90, 370.0, 10.0, 1.80),
         ("C-09", 780.0, 0.94, 480.0, 12.0, 2.40),
         ("C-10", 880.0, 1.00, 750.0, 17.0, 3.20)]
for i, (name, nbp, sg, mw, _, _) in enumerate(crude):
    CompoundExtensions.WithPseudoComponent(fs, name, Q.Kelvin(nbp), sg, mw,
                                           paraffinFrac=0.45, naphtenicFrac=0.30, aromaticFrac=0.25)
    # Give each pseudocomponent its own ID: the property package caches compounds by ID
    fs.Inner.SelectedCompounds[name].ID = -(i + 1)
fs.WithPropertyPackage(PropertyPackages.PengRobinson)

feed = fs.AddMaterialStream("Crude").At(Q.Celsius(360.0), Q.Bar(2.0)).SetCompoundMassFlow("N-butane", 1.0)
for name, _, _, _, kg_s, s in crude:
    feed.SetCompoundMassFlow(name, kg_s)                  # 89 kg/s of pseudos + 1 kg/s of butane
    ContaminantKeys.Set(feed.Object.Phases[0].Compounds[name], ContaminantKeys.WtPctSulfur, s)

# Cut points are TBP upper limits in K; the last cut takes everything heavier
cuts = [("Naphtha", 453.15), ("Kerosene", 523.15), ("Diesel", 613.15), ("AGO", 663.15), ("Residue", 0.0)]
definitions = []
for name, tbp in cuts:
    cut = CDUCutDefinition()
    cut.Name, cut.UpperTBP, cut.OutletPressure = name, tbp, 1.5e5
    definitions.append(cut)
cdu = fs.AddShortcutCDU("CDU-1").WithOverlapK(10.0).WithCuts(*definitions)
cdu.Object.CreateConnectors()                             # one outlet port per cut
products = [fs.AddMaterialStream(name) for name, _ in cuts]
cdu.ConnectFeed(feed, 0)
for port, stream in enumerate(products):
    cdu.ConnectProduct(stream, port)

fs.AutoLayout()
fs.Solve()

for cut in cdu.Object.Results.Cuts:
    print(f"{cut.Name:9s} {cut.MassFlow / cdu.Object.Results.FeedMassFlow * 100.0:5.1f} wt%   "
          f"mean NBP {cut.AverageNBP - 273.15:4.0f} C   S {cut.Contaminants.SulfurWtPct:.2f} wt%")

Output

Naphtha    20.8 wt%   mean NBP   99 C   S 0.04 wt%
Kerosene   11.4 wt%   mean NBP  213 C   S 0.23 wt%
Diesel     16.4 wt%   mean NBP  290 C   S 0.81 wt%
AGO         7.7 wt%   mean NBP  362 C   S 1.37 wt%
Residue    43.8 wt%   mean NBP  505 C   S 2.58 wt%

DWSIM 10.2.11.0, generated 2026-10-08.

Properties¶

IDs accepted by GetPropertyValue, SetPropertyValue, the sensitivity analysis, the optimizer, the Adjust block and dynamic events. Units are SI; pass another unit system to GetPropertyValue to get them converted.

All 69 properties

ID	Unit (SI)	Input
`Overlap (K)`	K	yes
`Top Pressure`	Pa	yes
`Bottom Pressure`	Pa	yes
`Number of Cuts`	NF	yes
`Feed Molar Flow`	mol/s	result
`Feed Mass Flow`	kg/s	result
`Feed Temperature`	K	result
`Feed Pressure`	Pa	result
`Pseudocomponents In Feed`	NF	result
`Cut Naphtha Sulfur (wt%)`	wt%	result
`Cut Naphtha Nitrogen (wt%)`	wt%	result
`Cut Naphtha MercaptanS (wt%)`	wt%	result
`Cut Naphtha Ni (ppm)`	ppm wt	result
`Cut Naphtha V (ppm)`	ppm wt	result
`Cut Naphtha Fe (ppm)`	ppm wt	result
`Cut Naphtha Na (ppm)`	ppm wt	result
`Cut Naphtha CCR (wt%)`	wt%	result
`Cut Naphtha Asphaltenes (wt%)`	wt%	result
`Cut Naphtha TAN (mgKOH/g)`	mgKOH/g	result
`Cut Naphtha Mass Flow`	kg/s	result
`Cut Naphtha Avg NBP`	K	result
`Cut Kerosene Sulfur (wt%)`	wt%	result
`Cut Kerosene Nitrogen (wt%)`	wt%	result
`Cut Kerosene MercaptanS (wt%)`	wt%	result
`Cut Kerosene Ni (ppm)`	ppm wt	result
`Cut Kerosene V (ppm)`	ppm wt	result
`Cut Kerosene Fe (ppm)`	ppm wt	result
`Cut Kerosene Na (ppm)`	ppm wt	result
`Cut Kerosene CCR (wt%)`	wt%	result
`Cut Kerosene Asphaltenes (wt%)`	wt%	result
`Cut Kerosene TAN (mgKOH/g)`	mgKOH/g	result
`Cut Kerosene Mass Flow`	kg/s	result
`Cut Kerosene Avg NBP`	K	result
`Cut Diesel Sulfur (wt%)`	wt%	result
`Cut Diesel Nitrogen (wt%)`	wt%	result
`Cut Diesel MercaptanS (wt%)`	wt%	result
`Cut Diesel Ni (ppm)`	ppm wt	result
`Cut Diesel V (ppm)`	ppm wt	result
`Cut Diesel Fe (ppm)`	ppm wt	result
`Cut Diesel Na (ppm)`	ppm wt	result
`Cut Diesel CCR (wt%)`	wt%	result
`Cut Diesel Asphaltenes (wt%)`	wt%	result
`Cut Diesel TAN (mgKOH/g)`	mgKOH/g	result
`Cut Diesel Mass Flow`	kg/s	result
`Cut Diesel Avg NBP`	K	result
`Cut AGO Sulfur (wt%)`	wt%	result
`Cut AGO Nitrogen (wt%)`	wt%	result
`Cut AGO MercaptanS (wt%)`	wt%	result
`Cut AGO Ni (ppm)`	ppm wt	result
`Cut AGO V (ppm)`	ppm wt	result
`Cut AGO Fe (ppm)`	ppm wt	result
`Cut AGO Na (ppm)`	ppm wt	result
`Cut AGO CCR (wt%)`	wt%	result
`Cut AGO Asphaltenes (wt%)`	wt%	result
`Cut AGO TAN (mgKOH/g)`	mgKOH/g	result
`Cut AGO Mass Flow`	kg/s	result
`Cut AGO Avg NBP`	K	result
`Cut Residue Sulfur (wt%)`	wt%	result
`Cut Residue Nitrogen (wt%)`	wt%	result
`Cut Residue MercaptanS (wt%)`	wt%	result
`Cut Residue Ni (ppm)`	ppm wt	result
`Cut Residue V (ppm)`	ppm wt	result
`Cut Residue Fe (ppm)`	ppm wt	result
`Cut Residue Na (ppm)`	ppm wt	result
`Cut Residue CCR (wt%)`	wt%	result
`Cut Residue Asphaltenes (wt%)`	wt%	result
`Cut Residue TAN (mgKOH/g)`	mgKOH/g	result
`Cut Residue Mass Flow`	kg/s	result
`Cut Residue Avg NBP`	K	result

Learn more¶

User guide
- Shortcut Crude Distillation Unit (CDU)
FluentAPI
- Refining.ShortcutCDUBuilder
- 06 — Refining Train (Plus)

API members¶

Public members declared by this class. Inherited members are documented on the base classes.

Constructors¶

ShortcutCDUUnitOperation()

C#VB.NET

public ShortcutCDUUnitOperation()

Public Sub New()

Properties¶

ComponentDescription: Gets or sets the CAPE-OPEN component description for this unit operation.

Gets or sets the CAPE-OPEN component description for this unit operation.

C#VB.NET

public override string ComponentDescription { get; set; }

Public Overrides Property ComponentDescription As String

Config: Gets or sets the CDU configuration: the list of product cuts with their TBP cut points, the logistic overlap factor...

Gets or sets the CDU configuration: the list of product cuts with their TBP cut points, the logistic overlap factor, and the column top and bottom pressures. Saved with the flowsheet.

C#VB.NET

public ShortcutCDUConfiguration Config { get; set; }

Public Property Config As ShortcutCDUConfiguration

IsRefining: Gets a value that is always true.

Gets a value that is always true. It marks this class as a refining unit operation, so the flowsheet object palettes (which read it by reflection) list it under the Refining category.

C#VB.NET

public bool IsRefining { get; }

Public ReadOnly Property IsRefining As Boolean

MobileCompatible: Gets a value indicating whether this unit operation is compatible with mobile interfaces.

Gets a value indicating whether this unit operation is compatible with mobile interfaces. Always false.

C#VB.NET

public override bool MobileCompatible { get; }

Public Overrides ReadOnly Property MobileCompatible As Boolean

ObjectClass: Gets the simulation object class category (Columns).

Gets the simulation object class category (Columns).

C#VB.NET

public override SimulationObjectClass ObjectClass { get; }

Public Overrides Property ObjectClass As SimulationObjectClass

Prefix: Gets the default name prefix for this unit operation ('CDU-').

Gets the default name prefix for this unit operation ("CDU-").

C#VB.NET

public string Prefix { get; }

Public ReadOnly Property Prefix As String

Methods¶

Calculate(object): Calculates the object.

Calculates the object.

Parameter	Type	Description
`args`	`Object`

C#VB.NET

public override void Calculate(object args = null)

Public Overrides Sub Calculate(args As Object = Nothing)

CloneXML(): Creates a deep copy of this object by round-tripping through XML serialization.

Creates a deep copy of this object by round-tripping through XML serialization.

C#VB.NET

public override object CloneXML()

Public Overrides Function CloneXML() As Object

CloseEditForm(): Closes the editor of this object, if it is open.

Closes the editor of this object, if it is open.

C#VB.NET

public override void CloseEditForm()

Public Overrides Sub CloseEditForm()

CreateConnectors(): Creates the graphic connector definitions on the flowsheet: the crude feed inlet ('Crude Feed') on the left edge and...

Creates the graphic connector definitions on the flowsheet: the crude feed inlet ("Crude Feed") on the left edge and one material outlet per configured cut on the right edge, ordered light (top) to heavy (bottom) and named after the cuts. Outlets are added or removed to match the number of cuts. The energy connector is disabled.

C#VB.NET

public void CreateConnectors()

Public Sub CreateConnectors()

DeCalculate(): Decalculates the object.

Decalculates the object.

C#VB.NET

public override void DeCalculate()

Public Overrides Sub DeCalculate()

DisplayEditForm(): Opens the editor of this object.

Opens the editor of this object. A host that has no editor for it does nothing.

C#VB.NET

public override void DisplayEditForm()

Public Overrides Sub DisplayEditForm()

Draw(object): Draws the unit operation icon on the given SkiaSharp canvas.

Draws the unit operation icon on the given SkiaSharp canvas. Draw mode 2 uses the embedded PNG image (falling back to the vector icon if the image cannot be loaded), draw mode 1 draws the vector icon as a silhouette, and any other mode draws the vector icon.

Parameter	Type	Description
`g`	`Object`	The SkiaSharp canvas (`SKCanvas`).

C#VB.NET

public void Draw(object g)

Public Sub Draw(g As Object)

GetDisplayDescription(): Returns the description string for this unit operation type.

Returns the description string for this unit operation type.

C#VB.NET

public override string GetDisplayDescription()

Public Overrides Function GetDisplayDescription() As String

GetDisplayName(): Returns the display name for this unit operation type.

Returns the display name for this unit operation type.

C#VB.NET

public override string GetDisplayName()

Public Overrides Function GetDisplayName() As String

GetIconBitmapBytes(): Returns the raw bytes of the icon image for this unit operation.

Returns the raw bytes of the icon image for this unit operation.

C#VB.NET

public override byte[] GetIconBitmapBytes()

Public Overrides Function GetIconBitmapBytes() As Byte()

GetPreferredGraphicObjectHeight(): Returns the preferred height of the flowsheet graphic object, in pixels.

Returns the preferred height of the flowsheet graphic object, in pixels.

C#VB.NET

public override double GetPreferredGraphicObjectHeight()

Public Overrides Function GetPreferredGraphicObjectHeight() As Double

GetPreferredGraphicObjectWidth(): Returns the preferred width of the flowsheet graphic object, in pixels.

Returns the preferred width of the flowsheet graphic object, in pixels.

C#VB.NET

public override double GetPreferredGraphicObjectWidth()

Public Overrides Function GetPreferredGraphicObjectWidth() As Double

GetProperties(PropertyType): Get a list of all properties of the object.

Get a list of all properties of the object.

Parameter	Type	Description
`proptype`	`PropertyType`	Type of the property.

C#VB.NET

public override string[] GetProperties(PropertyType proptype)

Public Overrides Function GetProperties(proptype As PropertyType) As String()

GetPropertyUnit(string, IUnitsOfMeasure): Gets the units of a property.

Gets the units of a property.

Parameter	Type	Description
`prop`	`String`	Property identifier.
`su`	`IUnitsOfMeasure`	Units system to use. Null to use the default (SI) system.

C#VB.NET

public override string GetPropertyUnit(string prop, IUnitsOfMeasure su)

Public Overrides Function GetPropertyUnit(prop As String, su As IUnitsOfMeasure) As String

GetPropertyValue(string, IUnitsOfMeasure): Returns the value of a named property, converting from SI to the current unit system.

Returns the value of a named property, converting from SI to the current unit system. Falls back to extra properties if the property is not found in the base implementation.

Parameter	Type	Description
`prop`	`String`	The property identifier string.
`su`	`IUnitsOfMeasure`	Optional units-of-measure system used for conversion; uses the shared SI system when `Nothing`.

C#VB.NET

public override object GetPropertyValue(string prop, IUnitsOfMeasure su)

Public Overrides Function GetPropertyValue(prop As String, su As IUnitsOfMeasure) As Object

LoadData(List<XElement>): Restores the unit operation state from a list of XML elements previously produced by SaveData.

Restores the unit operation state from a list of XML elements previously produced by SaveData.

Parameter	Type	Description
`data`	`List<XElement>`	The list of `XElement` objects containing serialized state.

C#VB.NET

public override bool LoadData(List<XElement> data)

Public Overrides Function LoadData(data As List(Of XElement)) As Boolean

PopulateEditorPanel(object): Populates the cross-platform editor panel with controls.

Populates the cross-platform editor panel with controls. Only the Avalonia editor panel (AvaloniaEditorPanel) is filled; other container types are left unchanged.

Parameter	Type	Description
`ctner`	`Object`	The editor panel (layout container) to populate.

C#VB.NET

public void PopulateEditorPanel(object ctner)

Public Sub PopulateEditorPanel(ctner As Object)

ReturnInstance(string): Creates and returns a new instance for deserialization.

Creates and returns a new instance for deserialization.

Parameter	Type	Description
`typename`	`String`	The type name to instantiate. Not used; a new `ShortcutCDUUnitOperation` is always returned.

C#VB.NET

public object ReturnInstance(string typename)

Public Function ReturnInstance(typename As String) As Object

SaveData(): Serializes the unit operation state to a list of XML elements for persistence.

Serializes the unit operation state to a list of XML elements for persistence.

C#VB.NET

public override List<XElement> SaveData()

Public Overrides Function SaveData() As List(Of XElement)

SetPropertyValue(string, object, IUnitsOfMeasure): Sets the value of a property.

Sets the value of a property.

Parameter	Type	Description
`prop`	`String`	Property identifier.
`propval`	`Object`	Property value to set at the specified units.
`su`	`IUnitsOfMeasure`	Units system to use. Null to use the default (SI) system.

C#VB.NET

public override bool SetPropertyValue(string prop, object propval, IUnitsOfMeasure su)

Public Overrides Function SetPropertyValue(prop As String, propval As Object, su As IUnitsOfMeasure) As Boolean

UpdateEditForm(): Redraws the editor of this object with the current values, if it is open.

Redraws the editor of this object with the current values, if it is open.

C#VB.NET

public override void UpdateEditForm()

Public Overrides Sub UpdateEditForm()

Fields¶

_editorForm: The classic (WinForms) editor window open for this unit operation, if any.

The classic (WinForms) editor window open for this unit operation, if any. Not saved with the flowsheet.

C#VB.NET

public FormEditorShortcutCDU _editorForm

Public _editorForm As FormEditorShortcutCDU