METHOD AND APPARATUS FOR REMOVING NITROGEN FROM A CRYOGENIC HYDROCARBON COMPOSITION

摘要

Nitrogen is removed from a cryogenic hydrocarbon composition. A least a first portion of the cryogenic hydrocarbon composition is fed to a nitrogen stripper column. The nitrogen stripper column operates at a stripping pressure. A stripping vapour is passed into the nitrogen stripper column, comprising at least a stripping portion of a compressed process vapour that has been produced from the nitrogen-stripped liquid which has been depressurized after drawing it from the nitrogen stripper column. Reflux is generated involving partially condensing overhead vapour of the nitrogen stripper column by passing heat from the overhead vapour to an auxiliary refrigerant stream at a cooling duty. An off gas consisting of a, non-condensed, vapour fraction from the overhead vapour is discharged. The cooling duty is adjusted to regulate a heating value of the vapour fraction being discharged.