Program ReteGas  

Gas networks design
(low, medium and hight pressure)

• methane distribution networks  (low and medium pressure),
• methane transport networks (hight pressure),
• thecnical gasses (nitrogen, CO2 ..) and vapours networks.

In detail, program calculates pressures and composition in all the nodes and flow rates in all the elements.

Defining the network
The network is described by a directed graph in which:

• arcs are the elements of the net,
• nodes are the points of junction of two or more elements.

:Possible elements are:

• sources (feeds to the net),
• demands (concentraded in the nodes or distributed along the pipes), 
• pipes,
• booster stations,
• pressure relief valves,
• interception valves,
• minor losses.

Applied formulas
We recommend using Fergusson’s formula.
These others are inserted only for completeness:

• Splitzglass,
• medium pressure Renouard's formula,
• low pressure Renouard's formula.

Gas compressibility factor z is calculated according to Redlich-Kwong's formula.
Physical gas characteristics (specific weight, viscosity... ) are calculated according to temperature, pressure and gas composition.

Contemporaneity coefficient
Families demands are strongly intermittent.
The more are the families supplied, the less is probable that all flow rates have the maximum value at the same time.
Contemporaneity coefficient  is defined as the ratio between maximum theoretical demand and real demand; where maximum theoretical demand is the product of family maximum demand by the number of supplied families.

Contemporaneity coefficient changes along the network.
To design correctly a gas network it is necessary to apply the contemporaneity coefficient to every pipe flow rate, according to the number of families supplied by the pipe.
.
For more details see chapter 4.10 of book "Steady  state calculation of a gas network (low, medium and hight pressure)" joined to the program.
Chapter 4.10 Download  (utgasin.zip)

Cheks
Program checks inputs values and verifies the network behaviour. 

• as a stand alone program,
• connected to a cartographic system.

In this second point the program only calculates the steady state and save results.

These companies supply cartographic systems including program ReteGas:

Entrprise edition restriction

• maximum number of nodes  10000,
• maximum number of pipes   10000,
• maximum number of sources    200,
• maximum number of booster stations  200,
• maximum number of relief valves        200,
• maximum number of minor losses       200,
• maximum number of interception valves  400,
• maximum number of gas mixture components  12.

Light edition restriction: the maximum number of nodes is  400.

Steady state calculation of a gas network
(low, medium and hight pressure)
 - program ReteGas, release 3.2/A -

• describes, in detail, all the equations utilized,
• explains how to use the program.

 PROGRAM FEATURES

    1.   PHISICAL QUANTITIES AND UNITS
       1.1   Density
       1.2   Weight density
       1.3   Specific gravity
       1.4   Internal energy
       1.5   Enthalpy
       1.6   Specific heat
       1.7   Pressure
       1.8   Flow rates
       1.9   Viscosity 
     1.10   Compressibility

    2.   GAS CHARACTERISTICS
       2.1   Density
       2.2   Molecular weight
       2.3   Dynamic viscosity
       2.4   State equation
           2.4.1   Van der Wals' law
           2.4.2   Gas compressibility factor
       2.5   Viriale eqution
       2.6   Acentric factor
       2.7   Pitzer's correlation
       2.8   Residual funcions
       2.9   Real gas enthalpy

    3.  GAS FLOW
       3.1   Hydrostatic pressure
       3.2   Laminar flow and turbolent flow
       3.3   Flow fundamental equations
       3.4   Pressure leaks
       3.5   Fergusson's equation
       3.6   Pipes with distributed demands

    4.   DEFINING THE NETWORK
       4.1    Sources
           4.1.1   Setting a node pressure
           4.1.2   Setting source flow rate
       4.2    Pipes
           4.2.1   Fergusson's formula
           4.2.2   Spitzglass's formula
           4.2.3   Medium pressure Renouard's formula
           4.2.4   Low pressure Renouard's formula
       4.3    Pressure relief valves
           4.3.1   Temperature lowering
       4.4    Booster stations
       4.5    Minor losses
           4.5.1   Equivalent pipe fixed lenght
           4.5.2   Equivalent lipe calculated lenght
       4.6    Interception valves
       4.7    Concentrated and distributed demands
       4.8    Nodes
           4.8.1   Pressure check
           4.8.2   External pressure
       4.9    Gas composition
     4.10    Conptemporaneity coefficient 
           4.10.1   Fixed demands
           4.10.2   Family demands
           4.10.3   Pipse compensation flows
           4.10.4   Nodes compensation flows
           4.10.5   Sources compensationn flows

USER MANUAL

    5.   INSTALLATION
       5.1   Typical working session

    6.   FORMS LIST
       6.1   Main menù
       6.2   Files
       6.3   Parameters and formulas
       6.4   Gas composition
       6.5   Network description       
       6.6   Solving
       6.7   Results
       6.8   Reports
       6.9   Setting
     6.10   Example

    7.   LINKING TO A CARTHOGRAPHIC SYSTEM
       7.1   Executing program ReteGas
       7.2   Structure of input/output data

    8.   APPENDIX    
        8.1   Some gas physical characteristics
        8.2  Methane specific heat (constant pressure)
        8.3  Surface roughness
        8.4  Relations between units

     9.   SYMBOLOGY

     10.   BIBLIOGRAPHY      

Light edition
Program ReteGas + book:    400 euro +  80 (taxes)   = 480 euro.

Program description download