Natural Gas Industry - Natural Gas Liquids (NGL) Plant - Application Note

A Natural Gas Liquids (NGL) plant consists of a series of fractionators whose purpose is to separate a mixture of light hydrocarbons into various pure products. The NGL Plant typically consists of a demethanizer, a deethanizer, a depropanizer, a debutanizer, and a butane splitter. Other arrangements of columns are possible for NGL Plants and also parallel columns may be present for higher plant processing capacity.

The feed to a NGL Plant consists of a mixture of light hydrocarbons (methane, ethane, propane, isobutane, n-butane and C5+ or gasoline components) from the Natural Gas Plant. The NGL is fed to the demethanizer where methane is removed (by fractionation) as an overhead product. The bottoms product, consisting of ethane and heavier compounds, is the feed to the deethanizer. In the deethanizer, ethane is removed as an overhead product. Propane and heavier components leaves the deethanizer as a bottoms product and fed to the depropanizer. In the depropanizer, propane is removed as an overhead product and butane and heavier compounds leaves the product and fed to a debutanizer. In the debutanizer, isobutane and normal butane are removed as an overhead product and fed to a C4 splitter. C5+ material leaves the debutanizer bottoms product. In the C4 splitter, isobutane is separated (overhead product) from the normal butane (bottoms product).