Gas Pump

Navigation: Main Page -> Models -> Pressure Changing Models

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General Description

The gas pump model will add pressure boost to the stream or operates at a specified pressure.

Diagram

The diagram shows the default drawing of the Gas Pump, with the required connecting streams. The unit will not operate unless all of the above streams are connected.

The physical location of the connections is not important, the user may connect the streams to any position on the drawing.

Inputs and Outputs

Label	Required Optional	Input Output	Number of Connections		Description
			Min	Max.
Input	Required	In	1	1	Input stream to pump.
Output	Required	Out	1	1	Output stream from pump.

Model Theory

From the first law of thermodynamics, the energy balance is:

[math]\displaystyle{ \mathbf{\mathit{Work=Enthalpy_{in}-Enthalpy_{out}}} }[/math]

From the second law of thermodynamics:

[math]\displaystyle{ \mathbf{\mathit{Entropy_{in} = Entropy_{out}}} }[/math]

Calculating Work:

Step 1) Enthalpy and Entropy in is calculated from the inlet stream Temperature and Pressure.

Step 2) Outlet Temperature and Enthalpy is calculated based on the Entropy and outlet pressure.

Step 3) Work is calculated from the difference in enthalpy.

Assumptions

1. The process is in steady state and steady flow.
2. The process is adiabatic.
3. The change in Potential and Kinetics energy is ignored.
4. Process is reversible and adiabatic

Data Sections

The default access window consists of four sections,

1. CompGP_1 tab - Contains general information relating to the unit.
2. Optional tab Vapour Liquid Equilibrium (VLE)
3. The section, Info, fully described in Info Tab Page Section.
4. The section, Links, only visible in SysCAD 9.2, contains a summary table for all the input and output streams. See Links Table.
5. The last section is the Audit. See Model Examples for enthalpy calculation Examples.

Gas Pump Page

First Tab: CompGP_1

Tag / Symbol	Input / Calc	Options	Description/Calculated Variables
Common First Data Section
Requirements
PressMethod	List Box	None	No pressure change
		Boost	The user specifies a pressure increase. Therefore, Pout = Pin + Pboost
		Fixed	The user specifies a fixed outlet pressure from the unit.
PBoost	Input		The required pressure increase. Visible if the Boost method is selected.
PRqd	Input		The required outlet pressure. Visible if the Fixed method is selected.
VLEquilibrium	List Box	Off	Vapour Liquid Equilibrium is off.
		On	Vapour Liquid Equilibrium (VLE) is enabled. The associated section, VLE becomes visible and may be configured. Note: This option may automatically adjust the species make-up in Qo.
Results
Work	Calc		The work done.
Qm	Calc		The mass flow rate.
Ti	Calc		The inlet temperature.
To	Calc		The outlet temperature.
Pi	Calc		The inlet pressure.
dP	Calc		The pressure change.
Po	Calc		The outlet pressure.
Vfi	Calc		The inlet vapour fraction.
Vfo	Calc		The outlet vapour fraction.

Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.

	DLL:	Basic1.dll	→	Units/Links	→	Process: Piping: GasPump - General
or	Group:	Mass Transfer	→	Units/Links	→	Process: Piping: GasPump - General

See Project Configuration for more information on adding models to the configuration file.

Insert into Project

Insert Unit

→

Process

→

Piping

→

GasPump - General

See Insert Unit for general information on inserting units.