C254 – API MPMS/GPA TP-27 Ctl Calculation
Description
This calculates the temperature correction factor for the volume of natural gas liquids and liquefied petroleum gases according to the TP-27 specification.
References
GPA Technical Publication TP-27, ASTM MPMS 11.2.4 – Temperature Correction for the Volume of NGL and LPG Tables 23E, 24E, 53E, 54E 59E and 60E
Kelton calculation reference C254
This calculation is used by:
F064/K213 – API MPMS/GPA TP-27:2007 Density Referral
Options
Standard Temperature
- 15°C
- 20°C
- 60°F
This option allows the user to select which standard conditions they are using as a reference.
Solve For
- Density
- Standard density
This option is used to select the desires output of the calculation.
Precision
- Full precision
- Rounding
Density Input
- Enter Density as Relative Density
Constants
Density of water at 60°F ρw60 = 999.016 kgm-3
Table 1: Reference Fluid Parameters
| Fluid Name | γ60 | Zc | Tc | ρc | k1 | k2 | k3 | k4 |
|---|---|---|---|---|---|---|---|---|
| EE(68/32) | 0.325022 | 0.279980 | 298.11 | 6.250 | 2.54616855327 | -0.058244177754 | 0.803398090807 | -0.745720314137 |
| Ethane | 0.355994 | 0.282200 | 305.33 | 6.870 | 1.89113042610 | -0.370305782347 | -0.544867288720 | 0.337876634952 |
| EP(65/35) | 0.429277 | 0.280600 | 333.67 | 5.615 | 2.20970078464 | -0.294253708172 | -0.405754420098 | 0.319443433421 |
| EP(35/65) | 0.470381 | 0.279300 | 352.46 | 5.110 | 2.25341981320 | -0.266542138024 | -0.372756711655 | 0.384734185665 |
| Propane | 0.507025 | 0.276260 | 369.78 | 5.000 | 1.96568366933 | -0.327662435541 | -0.417979702538 | 0.303271602831 |
| i-Butane | 0.562827 | 0.283260 | 407.85 | 3.860 | 2.04748034410 | -0.289734363425 | -0.330345036434 | 0.291757103132 |
| n-Butane | 0.584127 | 0.275360 | 425.16 | 3.920 | 2.03734743118 | -0.299059145695 | -0.418883095671 | 0.380367738748 |
| i-Pentane | 0.624285 | 0.270260 | 460.44 | 3.247 | 2.06541640707 | -0.238366208840 | -0.161440492247 | 0.258681568613 |
| n-Pentane | 0.631054 | 0.272350 | 469.65 | 3.200 | 2.11263474494 | -0.261269413560 | -0.291923445075 | 0.308344290017 |
| i-Hexane | 0.657167 | 0.267060 | 498.05 | 2.727 | 2.02382197871 | -0.423550090067 | -1.152810982570 | 0.950139001678 |
| n-Hexane | 0.664064 | 0.267620 | 507.35 | 2.704 | 2.17134547773 | -0.232997313405 | -0.267019794036 | 0.378629524102 |
| n-Heptane | 0.688039 | 0.263120 | 540.15 | 2.315 | 2.19773533433 | -0.275056764147 | -0.447144095029 | 0.493770995799 |
Calculation
The Ctl is calculated by using an iterative process unless the standard temperature is 60°F. The iterative regime converts the standard density to the relative density at 60°F. The calculation works by referencing this relative density value against the properties of 2 reference fluids at a standard temperature of 60°F. An algorithm determines which reference fluids should be used according to the relative density of the input fluid. A further algorithm then calculates the Ctl from a series of relationships stemming from the reference fluid parameters.
| Where | ||
|---|---|---|
| h | = | Scaling factor |
| δ | = | Interpolation variable |
| X | = | Interpolating factor |
| ρsat601 | = | Saturation density of reference fluid 1 at 60°F |
| ρsat602 | = | Saturation density of reference fluid 2 at 60°F |
| ρsatx1 | = | Saturation density of reference fluid 1 at reduced observed temperature |
| ρsatx2 | = | Saturation density of reference fluid 2 at reduced observed temperature |