Fluid Catalytic Cracking (FCC) Unit¶

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Shortcut Fluid Catalytic Cracker. Feed: 1 VGO/residue stream. Products: 5 material outlets (dry gas, LPG, gasoline, LCO, slurry). Coke is reported (not streamed) and its combustion heat is emitted via the energy connector (regenerator duty). Product composition: the four light outlets (dry gas, LPG, gasoline, LCO) are emitted as moles of a single surrogate compound each (see FCCConfiguration.*Surrogate), with molar flow sized so the outlet's mass equals the computed lump mass yield. The slurry outlet keeps the feed pseudocomponents, scaled to its mass yield. This lets the shortcut synthesise representative light molecules without a full reaction network. Contaminants are partitioned by the user-configured fractions and written to each outlet's ExtraProperties.

DWSIM.UnitOperations.Refining.FCC.FCCUnitOperation
Assembly DWSIM.UnitOperations.Refining.dll · Object ← BaseClass ← UnitOpBaseClass ← FCCUnitOperation

At a glance¶

Fluid Catalytic Cracking (FCC) Unit in the example flowsheet

Port	Index	Connected in the example
Inlet, material	`0`	VGO
Inlet, energy	`1`	Riser-duty
Outlet, material	`0`	Dry-gas
Outlet, material	`1`	LPG
Outlet, material	`2`	Gasoline
Outlet, material	`3`	LCO
Outlet, material	`4`	Slurry

Example¶

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

Python

# The light products leave as one surrogate compound each: methane (dry gas),
# propane (LPG), isooctane (gasoline) and n-hexadecane (LCO).
fs = Flowsheet.Create("FCCExample").WithCompounds("Methane", "Propane", "2,2,4-trimethylpentane", "N-hexadecane")
# Vacuum gas oil as three pseudocomponents: name, NBP (K), SG, MW.
# The paraffin/naphthene/aromatic split shifts the conversion and the coke yield.
vgo = [("VGO-1", 650.0, 0.89, 330.0), ("VGO-2", 720.0, 0.91, 420.0), ("VGO-3", 790.0, 0.93, 520.0)]
for name, nbp, sg, mw in vgo:
    CompoundExtensions.WithPseudoComponent(fs, name, Q.Kelvin(nbp), sg, mw,
                                           paraffinFrac=0.55, naphtenicFrac=0.20, aromaticFrac=0.25)
fs.WithPropertyPackage(PropertyPackages.PengRobinson)

feed = fs.AddMaterialStream("VGO").At(Q.Celsius(250.0), Q.Bar(3.0))
for name, *_ in vgo:
    feed.SetCompoundMassFlow(name, 20.0)                 # kg/s each, 60 kg/s in total
    comp = feed.Object.Phases[0].Compounds[name]
    ContaminantKeys.Set(comp, ContaminantKeys.WtPctSulfur, 0.4)
    ContaminantKeys.Set(comp, ContaminantKeys.CCR_wt_pct, 0.5)

products = [fs.AddMaterialStream(tag) for tag in ("Dry-gas", "LPG", "Gasoline", "LCO", "Slurry")]
riser_duty = fs.AddEnergyStream("Riser-duty")

fcc = (fs.AddFCC("FCC-1")
       .WithYieldMethod(FCCYieldMethod.Slate)
       .WithReactorTemperature(Q.Celsius(520.0))
       .WithReactorPressure(Q.Bar(2.5))
       .WithCatalystOilRatio(7.0)
       .WithTargetConversion(0.75)
       .ConnectFeed(feed, 0)
       .ConnectEnergyFeed(riser_duty, 1))
for port, stream in enumerate(products):
    fcc.ConnectProduct(stream, port)

fs.AutoLayout()
fs.Solve()

r = fcc.Object.Results
print(f"Conversion        = {r.Conversion * 100.0:.1f} wt%")
print(f"Gasoline yield    = {r.Gasoline.MassYield * 100.0:.1f} wt% ({products[2].MassFlowKgPerSecond:.1f} kg/s)")
print(f"LPG yield         = {r.LPG.MassYield * 100.0:.1f} wt%")
print(f"Coke yield        = {r.CokeMassFlow / r.FeedMassFlow * 100.0:.1f} wt% ({r.CokeMassFlow * 3.6:.1f} t/h burned)")
print(f"Regenerator heat  = {r.RegeneratorDuty / 1e6:.1f} MW")
print(f"Riser duty        = {riser_duty.EnergyFlowKW / 1000.0:.1f} MW")

Output

Conversion        = 75.1 wt%
Gasoline yield    = 48.1 wt% (28.9 kg/s)
LPG yield         = 18.0 wt%
Coke yield        = 5.4 wt% (11.7 t/h burned)
Regenerator heat  = 103.9 MW
Riser duty        = 60.0 MW

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.

ID	Unit (SI)	Input
`Yield Method`	NF	yes
`Reactor Temperature`	K	yes
`Reactor Pressure`	Pa	yes
`Catalyst/Oil Ratio`	NF	yes
`Riser Residence Time (s)`	s	yes
`Target Conversion`	NF	yes
`Feed Mass Flow`	kg/s	result
`Conversion`	NF	result
`Dry Gas Yield`	NF	result
`LPG Yield`	NF	result
`Gasoline Yield`	NF	result
`LCO Yield`	NF	result
`Slurry Yield`	NF	result
`Coke Yield`	NF	result
`Coke Mass Flow`	kg/s	result
`Regenerator Duty`	kW	result
`Ni Deposited`	kg/s	result
`V Deposited`	kg/s	result
`Feed xP`	NF	result
`Feed xN`	NF	result
`Feed xA`	NF	result

Learn more¶

User guide
- Fluid Catalytic Cracking (FCC) Unit
FluentAPI

API members¶

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

Constructors¶

FCCUnitOperation()

C#VB.NET

public FCCUnitOperation()

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 FCC configuration: yield method, riser temperature, pressure, catalyst-to-oil ratio and residence...

Gets or sets the FCC configuration: yield method, riser temperature, pressure, catalyst-to-oil ratio and residence time, target conversion, Weekman kinetic parameters, sulfur and nitrogen partition fractions per product, coke combustion heat and the surrogate compounds used for the light products. Saved with the flowsheet.

C#VB.NET

public FCCConfiguration Config { get; set; }

Public Property Config As FCCConfiguration

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 (Reactors).

Gets the simulation object class category (Reactors).

C#VB.NET

public override SimulationObjectClass ObjectClass { get; }

Public Overrides Property ObjectClass As SimulationObjectClass

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

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

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 material feed inlet ('Feed') on the left edge, the...

Creates the graphic connector definitions on the flowsheet: the material feed inlet ("Feed") on the left edge, the regenerator duty energy port ("Regen. Duty") on the bottom edge, and five material outlets on the right edge ("Dry Gas", "LPG", "Gasoline", "LCO", "Slurry"). The standard 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 `FCCUnitOperation` 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 FormEditorFCC _editorForm

Public _editorForm As FormEditorFCC