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How does lean oil separate heavier hydrocarbons from a natural gas stream?

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natural gas The Troll A natural gas production platform in the North Sea, 80 km (50 miles) northwest of Bergen, Norway. Troll A, the largest movable structure ever built, rests on the seafloor some 300 metres (990 feet) below the surface and rises more than 100 metres (330 feet) above the sea. The platform regulates the recovery of gas from 40 wells located on the seafloor.

In the processing of natural gas, lean oil is used to extract heavier hydrocarbons through an absorption process. The compressed raw gas is mixed with the lean oil in an absorber column, where the heavier components of the gas stream are absorbed into the liquid oil.1

As the gas passes through the column, the lighter components—primarily methane—remain in the gaseous phase and are discharged from the top as residue gas. The heavier hydrocarbons, now dissolved in the oil, exit the bottom of the column as a mixture known as rich oil. This rich oil is subsequently sent to a distillation or stripping tower, where it is heated to separate the absorbed hydrocarbons from the oil. The recovered lean oil is then recycled back to the absorption tower for reuse, while the extracted components are further processed into products such as ethane, propane, and butane.12