Flow-X─ Function Reference
4-85
Flow-X General functions - fxAPI_Dens15C_NGL_LPG
9.
Depending on the value of input 'Equilibrium pressure mode', either value of
input 'Equilibrium pressure value' is used or the equilibrium pressure (vapor
pressure) is calculated according to GPA TP-15. Whether the GPA TP-15 rounding
and truncation rules are applied is dictated by input ‘GPA-TP15 rounding’
10.
The compressibility factor F is calculated according to API MPMS 11.2.2M from
the density at [15
C, equilibrium pressure] and the 'Observed temperature',
with, depending on input API 11.2.2M, rounding and truncation according to the
standard.
11.
The CPL value is calculated from the compressibility factor, the equilibrium
pressure and the 'Observed pressure' input value.
12.
The new value for density at [15
C, equilibrium pressure] is calculated by dividing
the observed density by the CTL and CPL values.
13.
Steps 3 though 12 are repeated taking the density value from step 12 as the
staring value until the absolute difference between two consecutive density
values is less than the convergence limit.
To avoid convergence problems different convergence limits are applied,
depending on the whether API 11.2.2M and/or GPA TP-15 rounding is applied:
If API 11.2.2M rounding is enabled
-> Limit = 0.05 kg/m3
else if GPA TP-15 rounding is enabled -> Limit = 0.005 kg/m3
else
-> Limit = 0.00001 kg/m3
14.
If API 11.2.4 rounding is enabled, then the density at [15
C, equilibrium pressure]
is rounded to 0.1
Conversion method 2: from standard to observed conditions.
The function performs straightforward calculations to determine the density at observed conditions:
1.
When API 11.2.4 rounding is enabled, the input density and temperature values
are rounded in accordance with the standard
2.
The CTL value and the relative density at [60
F, equilibrium pressure] are
calculated according to API MPMS 11.2.4 (GPA TP-27) Table 60E from the density
at [15
C, equilibrium pressure] and the 'Observed temperature'.
3.
Depending on the value of input 'Equilibrium pressure mode', either value of
input 'Equilibrium pressure value' is used or the equilibrium pressure (vapor
pressure) is calculated according to GPA TP-15.
4.
The compressibility factor is calculated according to API MPMS 11.2.2M from the
density at [15
C, equilibrium pressure] and the 'Observed temperature'.
5.
The CPL value is calculated from the compressibility factor, the equilibrium
pressure and the 'Observed pressure' input value.
6.
If API 11.2.4 rounding is enabled, then the CTL value is rounded at [60
F,
equilibrium pressure] is rounded to 0.00001
7.
The density at the observed conditions is calculated by multiplying the density at
[15
C, equilibrium pressure] by the CTL value and the CPL value.
Summary of Contents for flow-x
Page 1: ...Function Reference Certified flow calculations Flow and batch calculations Worksheet functions...
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