By entering the composition of the natural gas into a recognized equation of state, the theoretical HCDP can be calculated for any pressure as well as the
cricondentherm (the highest dew point temperature at any pressure).
NGSA had asked FERC for three new standards: a minimum safe harbor national
cricondentherm hydrocarbon dew point (CHDP) of 15 degrees Fahrenheit, new interchangeability specifications for pipelines, and implementation by pipelines of new tariff language requiring the non-discriminatory use of aggregation, blending and pairing.
The graph above shows the
cricondentherm dew point reduction after processing.
The sample pressure should be at the approximate cricondentherm of the specific gas or the contract pressure.
* Controlling Measurement Pressure--The derivation of the word cricondentherm is critical condensation thermal curve--also called the "phase envelope." The cricondentherm is the point on this curve where pressure and temperature indicate that the maximum HCDP is to be found (diagram).
The cricondentherm pressure is not as critical as may be anticipated.
Hydrocarbon dewpoint calculations from compositional data allow us to get the whole phase envelope including
cricondentherm which is the maximum temperature at which hydrocarbon liquids may exist.
NGSA had asked FERC for three new standards: a minimum safe harbor national
cricondentherm hydrocarbon dew point (CHDP) of 15 degrees Fahrenheit, new interchangeability specifications for pipelines and implementation by pipelines of new tariff language requiring the non-discriminatory use of aggregation, blending and pairing.