Natural gas liquids (NGLs) are composed of hydrocarbons, including ethane, propane, butane, isobutane, pentane, and higher alkanes. Although ethane cannot be readily liquefied by pressure at ambient temperature such as propane and butane (LPG) it is considered a component of NGL. There are many uses for NGLs, as summarized in Figure 12.2 . NGLs are extracted from the natural gas production stream in field processing plants, using techniques discussed related to petroleum refining operations.
NGL field production is growing in the United States, representing an important part of the supply picture.