API MPMS 14.10-ed.2

Annotation of standard text API MPMS 14.10-ed.2 :

API MPMS 14.10, 2nd Edition, December 2021 - Manual of Petroleum Measurement Standards Chapter 14.10 Natural Gas Fluids Measurement—Measurement of Flow to Flares

General

The standard addresses measurement of flow to flares, and includes:

— application considerations;

— selection criteria and other considerations for flare meters and related instrumentation;

— installation considerations;

— limitations of flare measurement technologies;

— calibration;

— operation;

— uncertainty and propagation of error;

— calculations.

The scope of this standard does not include analytical instrumentation.

Field of Application

For safety and other considerations, it is highly undesirable to directly flare multiphase mixtures of liquids and gases. Therefore, this standard is primarily concerned with flare flow measurement in the gas or vapor phase. However, considering that fouling substances such as liquid droplets and/or mist or other contaminants may be present even in well-designed flare systems, this standard provides appropriate cautionary detail as to the effects of such contaminants that may impact flare flow measurements.

Most flare header applications are designed to operate during non-upset conditions at near-atmospheric pressure and ambient temperature, where compressibility of the mixture is near unity. Extreme conditions have been noted to be between 97.925 kPa-a (14.196 psia) and 414 kPa-a (60 psia), and between –150 °C and 300 °C (–238 °F and 572 °F). Flare gas compositions are highly variable and can range from average molecular weights approaching that of hydrogen to that of iso-pentanes and heavier. The uncertainty in flare gas density associated with varying pressure, temperature, and composition is discussed in more detail in 10.4.

Most flare headers are designed to operate at maximum velocities of 91 m/s (300 ft/s), with extremes up to 183 m/s (600 ft/s). This standard does not exclude pressures, temperatures, and velocity ranges different than those suggested above, as long as all applicable requirements are met.