Process for separating hydrocarbon gas constituents utilizing a fractionator

摘要

A process for separating the gas components contained in liquified natural gas wherein a small amount of heavier reflux liquid (propane, butane, pentane, iso-butane and iso-pentane) is recycled to the top of a demethanizer column. This alters its chemical equilibrium causing methane to vaporize in large quantities and to separate from the liquified feed stream. A fractionator receives the heavier demethanized liquid end product from the demethanizer column and through distillation separates the lighter ethanes and propanes from the heavier reflux liquid, a portion of the latter being recycled to the demethanizer column.