Pipe

From SysCAD Documentation

Navigation: Models -> General Models

Related Links: Pipe - Dynamic Mode

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Contents 1 General Description 2 Flowchart 3 Model Theory 3.1 Pressure Drop Equations 4 Data Sections 4.1 Summary of Data Sections 4.2 Results: Flow Conditions 4.3 Connections 4.4 Requirements 4.5 EB (Flow Evaluation Block) 4.6 General Demand 4.7 FlashTrain Demand 4.8 Pressure Drop 4.9 Tear 4.10 Material Flow Sections 5 Hints and Comments

General Description

This is used to transfer material between two units in SysCAD. Each pipe can have only one source and one destination. In ProBal (Mass and Energy Balancing) mode, the pipe serves as a simple link, which requires very little configuration. However, the user will find that a large amount of information is contained in pipe.

In Dynamic mode the pipe contains additional fields relating to required flows and network configuration. Please see Pipe - Dynamic Mode for more information on this data.

Flowchart

The following shows the sequence of events if the Pipe is not simplified and any sub model options are enabled. See next heading for more information.

Model Theory

Pressure Drop Equations

Darcy Pressure Drop for slurry

where

ρ_all is density (Rho) of the complete mixture (all phases)

K can be specified or calculated as

Where

D = Diam - (2 * ScaleBuildup)

TotalLength = length (L) + Fitting Length (FitL)

FricFactor can be specified or calculated as:

Reynolds number

Re has a lower limit of 1e-9.

Viscosity has a lower limit of 1e-12.

Data Sections

The Dynamic Pipe contains additional fields relating to required flows and network configuration. Only the fields shown for ProBal are described here.

Summary of Data Sections

The pipe access window may consist of a number of sections. This number may increase or decrease, based on user configuration and / or number of species.

1. Pipe-1 - The first section, contains general information relating to material flowing through the pipe, the Source and Destination units and allows the user to enable Demand. To enable the sub models (for example Reactions or Environmental Heat Exchange) in a Pipe, the user must first disable Simplify and then the Evaluation Block (EB) will be visible.
2. Qo - This and subsequent tab pages, e.g. Qo.. and Qm, shows the properties of the outlet stream. This tab is always visible. If any sub-models have been enabled, then these values are AFTER they have been completed (see the Flowchart above).
3. Qi - This and subsequent tab pages, e.g. Qi.. and Qm, shows the properties of the inlet stream. This tab is only visible if Simplify is NOT enabled. If any sub-models have been enabled, then these values are BEFORE they have been completed (see the Flowchart above).
4. RB - Optional tab that is visible if Reactions are enabled.
5. EHX - Optional tab that is visible if Environmental Heat Exchanger is enabled.
6. VLE - Optional tab that is visible if Vapour Liquid Equilibrium is enabled.
7. MU - Optional tab, or tabs if there is more than one Makeup, that is visible if Makeups are enabled.
8. Sz & MSz - Optional tabs that are visible if Size Distribution is used.
9. Info tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
10. Links tab, only visible in SysCAD 9.2, contains a summary table for all the input and output streams.
11. Audit tab - contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.

Class: Pipe-1 The first tab page in the access window will have this name.

Tag / Symbol	Input / Calc	Description
Common First Data Section
Results: Flow Conditions
Qm	Calc	The total mass of material flowing through the pipe.
Qv	Calc	The total volumetric flow through the pipe.
NQv	Calc	The normalised volumetric flow through the pipe. The volume is calculated at Normal Temperature and Pressure (NTP), default values are 25C and 101.325kPa. This is only relevant for flows containing vapours. NTP can be specified by the user in the configuration file (see Project Configuration).
Ti	Calc	The temperature of the material flowing into the pipe.
To	Calc	The temperature of the material flowing out of the pipe.
T	Calc	The temperature of the material flowing into the pipe.
Rho	Calc	The density of the material flowing into the pipe.
NRho	Calc	The normalised density of the material flowing through the pipe. The normalised density is calculated at Normal Temperature and Pressure (NTP), default values are 25C and 101.325kPa. This is only relevant for flows containing vapours. NTP can be specified by the user in the configuration file (see Project Configuration).
Pi	Calc	The pressure into the pipe.
Po	Calc	The pressure out of the pipe.
Connections
SrcIO	Display	The tag of the source unit of the pipe, as well as the connection point, i.e. if the source is a thickener, whether the pipe is connected to the overflow or the underflow.
DstIO	Display	The tag of pipe's destination unit, as well as the connection point.
SrcTag	Display	The tag of the source unit of the pipe.
DstTag	Display	The tag of pipe's destination unit.
Requirements
Simplify	Tick Box	By default this state is enabled, causing the pipe to be a 'simple' pipe with only the Qo tabs being visible. If the user wishes to set anything in the pipe or enable reactions, heat loss, etc, then this tick box must be disabled. Additional fields will then become visible and the user may set sub-models in the pipe.
Show.Qi	Tick Box	This tickbox is only visible if Simplify is disabled. The user may enable this to view both the Qi (flow into the pipe) and Qo (flow out of the pipe) tabs, which may be useful if the user has added reactions, heat exchange, etc to the pipe.
EB (Flow Evaluation Block) Note In SysCAD 9.2 this section is only visible if Simplify is Disabled.
EvalSequence	Display	The sequence in which the sub models (which are part of the evaluation blocks) will be calculated. The user may either set the required sequence of the individual sub-models, or use the AutoSequence option to allow SysCAD to set the sequence. The autosequence is: 1st Makeup, 2nd Reactions, 3rd EHX and 4th VLE.
Makeups	Input	The number of Makeup Blocks required. Extra dropdown options Makeup1, Makeup2, etc will be added to allow these to be switched on and off and prioritised in relation to the other sub-models.
MakeupX	List	Use to enable or disable and set the sequence of the Makeup Block in relation to the other sub-models. If this is 'On' then the associated page, MUX becomes visible and may be configured. Note: This field is only visible if the entry for 'Makeups' is greater then 0. If there is one makeup then X=1. If there are two makeups, then X=1 and X=2, etc.
Reactions	List	Reaction Block (RB) - Enable or disable Reactions and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, RB becomes visible and may be configured. Note: The user does not have to configure a reaction file, even if this block is checked.
EnvironHX	List	Environmental Heat Exchanger (EHX) - Enable or disable Heat Exchange and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, EHX may become visible and may be configured. Note: The user does not have to configure an environmental heat exchange, even if this block is checked.
VLEquilibrium	List	Vapour Liquid Equilibrium (VLE) - Enable or disable Vapour Liquid Equilibrium and set the sequence in relation to the other sub-models. If this is 'On' then the associated page, VLE becomes visible and may be configured. Note: This option may automatically adjust the species make-up in Qo.
General Demand
Qm_Avail.Src	Display	The mass flow available at the source, such as a Feeder or a Flash Tank. This field is only useful when Demand mode is used, either in a Feeder or as part of the Flash Train macro model. Note This field will only be visible if ShowDemandAvail is enabled in Plant Model - Settings - Demand Configuration.
Qm_Avail.Dst	Display	The mass flow available for the destination. Note This field will only be visible if ShowDemandAvail is enabled in Plant Model - Settings - Demand Configuration.
Qm_Demand.Src	Display	The flow required at the source, ie. upstream.
Qm_Demand.Blk	Tickbox	If this is enabled, then the Demand will be Blocked from perpetrating either up or downstream. This is used to prevent demand in a recycle and also to prevent a single unit seeing two feeders with Demand enabled. (Please see Demand for further information)
Qm_Demand.Rqd	Input	The user may set a required mass flow through the pipe. This flow will filter back to the source unit and the model will attempt to satisfy this flow requirement. Note: If the pipe is connected to a Feeder, the user should enable the variable 'Demand.On' on the Feeder. The Feeder will then deliver the mass flow required by the pipe. See Demand for more information on this feature.
Qm_Demand.Dst	Display	Flow required at destination, i.e. downstream.
FlashTrain Demand
Ft.Qm_Demand.Src	Display	The vapour flow required at the source, eg. flash tank flash vapour.
Ft.Qm_Demand.Dst	Display	Flow required at destination, eg. flash vapour to the heat exchanger.
Pressure Drop Note In SysCAD 9.2 this section is only visible if Simplify is Disabled.
Press_Mode	None	There is no pressure change in the pipe.
	Fixed_Drop	The user can enter a fixed pressure drop in the pipe. The default is 0.
	Fixed_Boost	The user can enter a fixed pressure boost in the pipe. The default is 0.
	Darcy_DP	The pressure change will be calculated using the Darcy equation.
	Const_Src_P	The user can type in a fixed pressure value.
	Diameter_Velocity	The user may specify a velocity for a given pipe diameter and allow SysCAD to calculate the resulting pressure drop.
Fxd_DP	Input	Allows the user to enter a change in pressure value. This is available if either the Fixed_Drop or Fixed_Boost method is selected.
Lnk_P_Src	Input	Allows the user to specify a pressure in the pipe. This is available if the Const_Src_P method is selected.
The following is only available if the Diameter_Velocity method is selected.
Diam	Display	The estimated nominal diameter of the pipe based on the user defined Velocity.
Vel	Input	The user defined target velocity, SysCAD will estimate the required Pipe diameter needed to achieve this required velocity.
Pdrop	Calc	This is not used.
The following is only available if the Darcy_DP method is selected.
Diam	Input	The Inner diameter of the pipe.
ScaleBuildUp	Input	The build up of material inside the pipe, thus reducing the ID of pipe. For a clean pipe, this value = 0.
K_Method	Calc K	Calculate K from user denied values.
	Define_K	Calculates the pressure drop using user specified pressure drop factor.
K_Value	Input / Calc	The pressure drop factor: K = f * L/D. If the Define_K method is selected, this is an input, otherwise it is calculated.
The following fields are visible if Calc_K method is selected.
Length	Input	Sum of the actual and fitted length of the pipe.
f_Method	Calc_f	Calculate the friction factor from user defined values.
	Define_f	The user can define a friction factor (f) to be used
FricFac	Input	The Darcy friction factor (f). Please note this is equivalent to (4) times Fanning's friction factor. Visible if Define_f method is selected.
Viscosity	Input	The Viscosity of the material flowing through the pipe. Visible if Calc_f method is selected.
Pipe_Rough	Input	The Pipe Roughness value. Visible if Calc_f method is selected.
Re	Calc	The calculated Reynolds number. Visible if Calc_f method is selected.
FricFac	Calc	The calculated Darcy friction factor (f). Visible if Calc_f method is selected. Please note this is equivalent to (4) times Fanning's friction factor.
K_MinorLosses	Input	K value for minor pressure losses in the pipe.
Vel	Calc	The velocity in the pipe. Note: a warning will be given if the velocity in the pipe is too high. This is set at 100m/s for Vapour lines and 20m/s for liquid or slurry lines. These warnings are in place mainly to flag that there is excessive pressure drop in the pipe.
Tear
Priority	Normal	SysCAD determines the priority of the stream in the network and if the stream should be a tear stream and its solving order.
	First	The user may force the stream order to be first in the network.
	Last	The user may force the stream order to be last in the network.
RqdType	No Tear	No manual tear is required.
	Manual Tear	This option is used when the user does not want to use the system defined tear stream. This will force SysCAD to set this pipe as a Tear stream and the system defined tear stream in the recycle loop will be reset to have no tear.
	Break	This option is used when the user want to 'break' the stream and manually set some parameters in the stream outlet.
State	No Tear	The stream has no tears or breaks.
	Zero Flow Tear	The stream is a Tear stream with zero flow.
	System Tear	SysCAD has analysed the network and determined that the stream is a Tear stream because it is part of a recycle loop and is the most efficient stream to tear.
	Manual Tear	The user has manually set this stream as a Tear stream.
	Break	The user has manually 'broken' the stream.
Flange	Display	The relevant flange that will have the tear status. In SysCAD each pipe is connected using flanges and these will store the tear information.
AdjQmToEstQm	Tickbox	If this is enabled then the mass flow from the pipe will be forced to be equal to the estimated mass flow.
Material Flow Sections
Qi Material Flow Section
Qo Material Flow Section

Hints and Comments

1. The user must ensure that the View and Phase options will display the required variables. e.g. if the concentration of H2SO4(aq) is required, then the View would be 'CompntConc' and Phase should be 'Liquid'. If Phase is 'All', then the model calculates the acid concentration using the volume of solids, liquids and vapours.