American Petroleum Institute

Manual of Petroleum Measurement Standards Chapter 11—Physical Properties Data Section 2, Part 4—Temperature Correction for the Volume of NGL and LPG Tables 23E, 24E, 53E, 54E, 59E, and 60E - First Edition
 N MPMS 11.2.4 ERTA

Annotation

The actual Standard represented by this report consists of the explicit implementation procedures. Sample tables, flow charts, and specific examples created from a computerized version of these implementation procedures are presented within. The examples are to provide guides and check points to those who wish to implement a computerized procedure to represent the Standard, however these are not a part of the actual Standard.

This Standard covers a 60°F relative density range of 0.3500 to 0.6880 which nominally equates to a density at 15°C of 351.7 to 687.8 kg/m3 and a density at 20°C of 331.7 to 683.6 kg/m3. The temperature range of this Standard is –50.8 to 199.4°F (–46 to 93°C). At all conditions, the pressure is assumed to be at saturation conditions (also known as bubble point or saturation vapor pressure).

The calculation method was developed from GPA RR-148 "Volume Correction Factors for Natural Gas Liquids – Phase II"[11] and API/ASTM/GPA Technical Publication, TP-25, September, 1998[10]. The implementation procedures for Tables 23 and 24 are entirely consistent with those presented in TP-25. Supporting data can be found in GPA RR-147 "Density Measurements on Natural Gas Liquids"[12]. GPA RR-133 "Volume Correction Factors for Natural Gas Liquids – Phase I"[13] should no longer be used, as GPA RR-148 completely replaced it.

The implementation procedures describe how to:

1) calculate the CTL given an appropriate density factor at the basis temperature and an observed temperature, and