Spirit flow-x, Function Reference

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Flow-X─ Function Reference
Flow-X General functions - fxAGA8_Gross
fxAGA8_Gross
Description
This function calculates the compressibility factor in accordance with the AGA-8 Gross Characterization
Method. Although the AGA-8 Gross Method is based on the Standard GERG Virial Equation Of State
(SGERG) there are slight differences in the results.
Two different methods are specified by the standard. Method 1 takes the Pressure, Temperature,
Specific Gravity (Relative Density), Carbon Dioxide content and Gross Heating Value (GHV) as inputs.
Method 2 takes the same inputs except for the Nitrogen content instead of GHV.
Compliance
AGA 8, Second edition November 1992 - 2nd printing July 1994

AGA Report No. 8, Second edition November 1992 - 2nd printing July 1994

API MPMS 14.2, Second edition November 1992 - 2nd printing July 1994
Boundaries
The AGA8 standard recommends using the Gross Characterization Method only when input conditions
lie within the following range. For conditions outside this range the standard recommends to use the
Detailed Characterization Method.
Input value Normal Range EU
Temperature 32..130 °F
Pressure 0 .. 1200 psia
Gross heating value 475 .. 1210 Btu/ft3
Relative density 0.554 .. 0.87 -
Carbon dioxide 0.00 .. 0.30 mol/mol
Nitrogen 0.00 .. 0.50 mol/mol
Function inputs and outputs
Function inputs Remark EU Range Default
Name Optional tag name, tag description and
tag group
Temperature Observed temperature °F -250..+800 60
Pressure Observed pressure psia 0..40000
Relative density Relative density at the corresponding
reference temperature and pressure - 0..2 0
RD reference
temperature Reference temperature for relative
density °F -250
..+800 60
RD reference
pressure Reference pressure for relative density psia 0..40000 14.73
Gross heating
value Gross heating value at the corresponding
reference temperature and pressure Btu/ft3 0..2500 0
GHV reference
temperature Reference temperature for gross heating
value °F -250
..+800 60
GHV reference
pressure Reference pressure for gross heating
value psia 0..40000 14.73
Nitrogen Nitrogen (N2) fraction mol/mol 0..1 0
Carbon dioxide Carbon dioxide (CO2) fraction mol/mol 0..1 0
Method Gross Characterization Method:
1: GHV, Relative Density, CO2
2: Relative Density, CO2, N2
Note: For Method 1 input ‘Nitrogen’ is not - 0