The hydrocarbon dew point is universally used in the natural gas industry as an important quality parameter, stipulated in contractual specifications and enforced throughout the natural gas supply chain, from producers through processing, transmission and distribution companies to final end users.
In the United States, the hydrocarbon dew point of processed, pipelined natural gas is related to and characterized by the term GPM which is the gallons of liquefiable hydrocarbons contained in 1,000 cubic feet (28 m3) of natural gas at a stated temperature and pressure.
When the liquefiable hydrocarbons are characterized as being hexane or higher molecular weight components, they are reported as GPM (C6+).
In such cases, when the liquefiable hydrocarbons in the raw natural gas are characterized as being ethane or higher molecular weight components, they are reported as GPM (C2+).
Similarly, when characterized as being propane or higher molecular weight components, they are reported as GPM (C3+).
GC vendors with a product targeting the HCDP analysis include Emerson,[6] ABB, Thermo-fisher, as well as other companies.
Depending on the specific method used to establish the dew point temperature, some correction calculations may be necessary.
This is due to the fact that by the time condensation had accumulated enough to be visible, the dew point had already been reached and passed.
In many instances it is important to incorporate an effective filtration system that prepares the gas for analysis.
On the other hand, filtration may alter the gas composition slightly and filter elements are subject to clogging and saturation.
Advances in technology have led to analyzers that are less affected by contaminants and certain devices can also measure the dew point of water that may be present in the gas.