Natural gas liquids recovery allows the processor to separate and purify heavier hydrocarbons from natural gas. Heavier hydrocarbons are more likely to condense into liquids under pressure in a pipeline, slowing the flow and increasing the wear on the piping. Extracted hydrocarbons, such as propane and butane, can be sold more profitably as separate products.
Natural gas processing equipment encompasses numerous unique processes.
- A subset of NGL, liquefied petroleum gas (LPG) focuses on propane and butane. LPG plants are used for hydrocarbon dew point control, natural gas liquids recovery, LPG production, propane recovery and butane recovery. Stabilized LPG is used worldwide for heating and transportation. LPG plant liquids are usually more valuable than the gas fractions from which they are produced. LPG plants produce acceptable heating values (HHV and LHV), which is important for downstream combustion stability.
- Dew point control plants also produce NGL and LPG but their main purpose is to eliminate hydrocarbon condensation in pipelines and downstream process units and can eliminate hydrate formation with glycol or methanol injection.
- Refrigerated gas plants recover a large fraction of propane and heavier gases without the pressure cost of a J-T plant but add the refrigeration compression HP.
- J-T plants are simpler in design and use high-pressure gas energy to liquefy heavier components by throttling. The Joule-Thomson effect is a physical principle that changes the gas entropy through pressure reduction and produces chilling and yields liquid formation.
- Turboexpanders recover a large fraction of ethane and heavier gases.