Depressuring Unit Vessel Data Window
This window is used to define the configuration of the depressuring unit. You must select one choice from Sphere, Horizontal Cylinder, Vertical Cylinder, or Unspecified Shape to model the depressuring vessel.
For Horizontal Cylinder and Vertical Cylinder, different types of heads are supported. You can select one of the following heads from the list box: Spherical Segment, Hemispherical, Ellipsoidal, and Flat. By default, Spherical Segment is selected.
Diameter
You must enter a value for the diameter of the vessel for Sphere, Horizontal Cylinder, and Vertical Cylinder geometries. There is no default value.
Length
For the Horizontal Cylinder vessel geometry, you must enter the tangent to tangent length. There is no default values. The value entered here is used in conjunction with the Diameter to calculate the total vessel volume.
Height
For the Vertical Cylinder, you must enter the tangent to tangent height. There is no default values. The value entered here is used in conjunction with the Diameter to calculate the total vessel volume.
Liquid Height
You may enter a value for the height of the holdup liquid in a Sphere, Horizontal Cylinder, or Vertical Cylinder. The holdup volume is than calculated from the value entered and the volume of the vessel. By default, the holdup liquid is saturated liquid of the combined feed composition at initial conditions. The remaining vessel volume contains vapor in equilibrium with this liquid.
Volume
For a vessel of Unspecified Shape, you must enter a value for the total vessel volume.
Liquid Holdup
For a vessel of Unspecified Shape, you may specify the quantity of holdup liquid, on either a mole, weight, or actual volume basis. Moles are the default. You can enter a weight unit for either mole or weight basis. For the volume basis, the units are liquid volume at the initial conditions. By default, the holdup liquid is saturated liquid of the combined feed composition at initial conditions. The remaining vessel volume contains vapor in equilibrium with this liquid.
Vessel Weight
For any vessel configuration selected, you may enter the total weight of the vessel material of construction. If a value is entered here, you must also enter a value for the Vessel Specific Heat. The overall heat balance includes the vessel heat capacity only when these entries appear. This entry is required if the Blowdown model has been selected on the Depressuring Heat Input Window.
Vessel Density and Vessel Thickness
Vessel Density and Vessel Thickness data act as an alternative to the Vessel Weight data. For known vessel shapes, such as Spherical, Horizontal, and Vertical, Vessel Weight can be calculated by using Vessel Density and Vessel Thickness. If you have entered a value for Vessel Density and Vessel Thickness, enter a value for the Vessel Specific Heat as well. Either Vessel Density and Vessel Thickness or Vessel Weight is required if the Blowdown model has been selected on the Depressuring Heat Input Window.
Vessel Specific Heat
You may enter a value for the specific heat for the vessel material of construction. If a value is entered here, you must also enter a value for the Vessel Weight. This entry is required if the Blowdown model has been selected on the Depressuring Heat Input Window.
Volume Correction Factor
For a vessel geometry of Sphere, Horizontal Cylinder, or Vertical Cylinder, you may enter a value for this correction factor, which corrects the calculated vessel volume for pipes, fittings and end plates. The default value is 1.0.
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