# Pump 2

Navigation: Models ➔ Pressure Changing Models ➔ Pump 2

## General Description

The Pump 2 model is mainly used in dynamic projects with Transfer mode, normally as part of the Piping System Model. It allows users to set the pump speed or the pressure boost. The pump will NOT control the flow, but the user can use the pressure boost results to set the flow through the Piping System Model.

The Pump has two main operating modes:

1. Simple - the user may NOT control the Pump speed, it acts as fixed pressure boost unit only.
2. Controlled - The user may control the Pump speed and the pressure boost from the Pump will vary accordingly.

The user may select a number of methods within these two modes for calculating the pressure boost:

1. Simple:
• Fixed Boost - the pressure boost from the Pump is a fixed value, irrespective of flow;
• Fixed Exit Pressure - the exit pressure from the Pump is a fixed value, irrespective of flow;
• Fixed Atmospheric Pressure - the exit pressure from the Pump = Atmospheric pressure, irrespective of flow; and
• Boost proportional to mass flow through the Pump - a simple linear function relating pressure boost to mass flow will be used. This method does not allow the user to set the Pump speed.
2. Controlled:
• Boost proportional to Pump speed - a simple linear function relating pressure boost to Pump speed will be used;
• Head proportional to Pump speed - a simple linear function relating Pump head to speed will be used; and
• Pump Curves - The user may emulate pump curves where head is a function of flow.
3. Pump curve options are:
• Simple Quadratic - Centrifugal pump curve specified by cut off head (at zero flow) and flow at zero head;
• Points Quadratic - Centrifugal pump curve specified by cut off head (at zero flow), flow at zero head and head at half of zero flow head;
• Points Cubic - Centrifugal pump curve specified by cut off head (at zero flow), flow at run out head, and heads values at one thirds and two thirds of the flow at run out;
• User Cubic - Centrifugal pump curve specified by cut off head (at zero flow), together with coefficients calculated by the user;
• Positive Displacement - Operating characteristics of a positive displacement pump specified by flow at maximum speed and maximum head as limited by the pump Pressure Relief Valve.

## Diagram

The diagram shows the default drawing of the 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 RequiredOptional InputOutput 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:

$\displaystyle{ \mathbf{\mathit{Work = Enthalpy_{in} - Enthalpy_{out}}} }$

From the second law of thermodynamics:

$\displaystyle{ \mathbf{\mathit{Entropy_{in} = Entropy_{out}}} }$

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. The process is reversible and adiabatic

## Data Sections

### Summary of Data Sections

1. Pump2 tab - Allows the user to set the Pump Speed (if the appropriate operating mode has been chosen) and displays the calculated results.
2. Settings Tab - Allows the user to specify the Pump method and enter the required data.
3. QFeed - Available from Build 139. Optional tab, visible if ShowQFeed is enabled. This and subsequent tab pages, e.g. QFeed.. and Sp, shows the properties of the feed stream. The tags in the QFeed tab are valid even when the ShowQFeed option is not selected.
4. QProd - Available from Build 139. Optional tab, visible if ShowQProd is enabled. This and subsequent tab pages, e.g. QProd.. and Sp, shows the properties of the product stream. The tags in the QProd tab are valid even when the ShowQProd option is not selected.
5. Info tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
6. Links tab, contains a summary table for all the input and output streams.
7. Audit tab - contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.

### Pump2 Page

Unit Type: Pump2 - The first tab page in the access window will have this name.

Tag (Long/Short) Input / Calc Description/Calculated Variables / Options
Tag Display This name tag may be modified with the change tag option.
Condition Display OK if no errors/warnings, otherwise lists errors/warnings.
ConditionCount Display The current number of errors/warnings. If condition is OK, returns 0.
GeneralDescription / GenDesc Display This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here.
If this field is blank, then SysCAD will display the UnitType or SubClass.

Requirements

On Tick Box This allows the user to disable the Pump. If the Pump is Off then the pressure boost from the Pump = 0.

### Control

This is only visible if the method chosen allows the Pump to be controlled.

Speed.Reqd Input The required Pump speed. Any value between 0 and 100%.
Speed.Actual Display The actual Pump speed. This is normally equal to the required speed. However, if the user has specified a stroke time, then the actual speed will lag the required speed by the stroke time.
RPM.Actual Display Visible when Settings tab - OpType = xxxx (Controlled) and WithRPM = on. The actual Pump speed in RPM.
Run Pump Button Clicking on this button will start the Pump at the required speed.
Stop Pump Button Clicking on this button will stop the pump (set the required speed to 0%).
Running Tick Box If this is True then the Pump is running.
RunningMax Tick Box If this is True then the Pump is running at 100%.
Stopped Tick Box If this is True then the Pump is stopped.
Position.Changing Tick Box If this is True then the Pump speed is changing. Visible as part of piping system.
Options
ShowQFeedTickbox Available from Build 139. When selected, the QFeed and associated tab pages (e.g. Sp) will become visible, showing the properties of the feed stream. See Material Flow Section. Tags in the QFeed tab can be used for controllers (e.g.: PGM files) and reports even when this option is not selected.
ShowQProdTickbox Available from Build 139. When selected, the QProd and associated tab pages (e.g. Sp) will become visible, showing the properties of the product stream. See Material Flow Section. Tags in the QProd tab can be used for controllers (e.g.: PGM files) and reports even when this option is not selected.

### Results

DensityIn / Rhoin Calc The density of material at the inlet of the pump.
TemperatureIn / Ti Calc The inlet temperature to the Pump.
PressureIn / Pi Calc The inlet pressure to the Pump.
PressChange / dP Calc The total pressure change across the Pump.
PressureOut / Po Calc The outlet pressure from the Pump.
EquivHead Calc The calculated equivalent head from the pump.
ActualWork Calc The actual work done.
IdealWork Calc The ideal work done.
Total
Pump.dP Calc The total pressure change across the Pump.
dP Calc The total pressure change across the overall unit.
PBoost Calc The total pressure boost from the Pump.
DiamUsed Calc
Stream In and Out Summary
PressChange / dP Calc The total pressure change across the Pump.
ActualWork Calc The actual work done.
IdealWork Calc The ideal work done.
MassFlow / Qm Calc The total mass of material flowing through the pump.
TemperatureIn / Ti Calc The temperature of material at the inlet of the pump.
TemperatureOut / To Calc The temperature of material at the outlet of the pump.
PressureIn / Pi Calc The actual pressure at the inlet of the pump.
PressChange / dP Calc The pressure change in the pump.
PressureOut / Po Calc The actual pressure at the outlet of the pump.
VolFlowIn / Qvi Calc The volume flow into the pump.
VolFlowOut / Qvo Calc The volume flow out of the pump.
DensityIn / Rhoi Calc The density of material at the inlet of the pump.
DensityOut / Rhoo Calc The density of material at the outlet of the pump.
VapourFracIn / Vfi Calc Vapour Mass Fraction at the inlet of the pump.
VapourFracOut / Vfo Calc Vapour Mass Fraction at the outlet of the pump.

## Adding this Model to a Project

Add to Configuration File

Sort either by DLL or Group:

 DLL: Piping2.dll → Units/Links → Piping: Pump(2) or Group: Mass Transfer → Units/Links → Piping: Pump(2)

See Model Selection for more information on adding models to the configuration file.

Insert into Project Flowsheet

 Insert Unit → Piping → Pump(2)

See Insert Unit for general information on inserting units.