US 5,335,504 A · Carbon dioxide recovery process

Abstract

A process for recovering CO.sub.2 from a mixture of light hydrocarbons, e.g. light hydrocarbons produced from a CO.sub.2 injection enhanced oil recovery. The mixture is distilled in a distributive zone with CO.sub.2 produced overhead and in the bottoms. The overhead and bottoms produced from the distributive zone are then fed to first and second concentrating distillation zones, respectively. The first concentrating zone produces a bottoms product rich in CO.sub.2 and an overhead product rich in methane and lean in CO.sub.2. The second concentrating zone is refluxed with lean oil and produces a CO.sub.2 distillate and a CO.sub.2 -lean bottoms product. In various embodiments, at least a section of each of the concentrating zones are placed in a single column, the CO.sub.2 product streams are taken as a side draw, vapor from the first concentrating zone is used in an open cycle heat pump to heat the second concentrating zone, the distributive zone is thermally coupled with one or both of the concentrating zones, and the distributive zone and certain sections of the concentrating zones are physically integrated into a single column.

Claims22

Dependent claims

A process for recovering CO.sub.2 from a mixture of light hydrocarbons, comprising the steps of:

feeding the mixture to a distributive distillation zone to distill the mixture into a CO.sub.2 containing overhead stream enriched in methane and a CO.sub.2 -containing bottoms stream enriched in propane and heavier hydrocarbons;
feeding the overhead stream from the distributive zone to a first concentrating distillation zone;
withdrawing a bottoms product CO.sub.2 stream from a stripping section of the first concentrating zone;
obtaining a CO.sub.2 -lean, methane enriched distillate from a rectifying section of the first concentrating zone;
feeding the bottoms stream from the distributive zone to a second concentrating distillation zone;
refluxing a lean oil stream to an enriching section of the second concentrating zone;
withdrawing a CO.sub.2 distillate stream from the enriching section of the second concentrating zone;
and
obtaining a CO.sub.2 -lean bottoms product from a stripping section of the second concentrating zone.

6 more elements

A process for recovering CO.sub.2 from a mixture of light hydrocarbons, comprising:

feeding the mixture to a CO.sub.2 distributive distillation zone to produce a CO.sub.2 -containing overhead vapor enriched in methane and a CO.sub.2 -containing bottoms liquid enriched in propane and heavier hydrocarbons;
compressing the overhead vapor from the distributive zone and vapor from a stripping section of a first concentrating zone;
cooling the compressed vapors in heat exchange with a stripping section of a second CO.sub.2 concentrating zone;
feeding the cooled, compressed vapors to the bottom of a rectifying section of the first concentrating zone;
recovering a methane-rich overhead product from the rectifying section of the first concentrating zone;
expanding liquid from the rectifying section of the first concentrating zone;
refluxing the expanded liquid from said rectifying section to the distributive zone and to the stripping section of the first concentrating zone;
recovering a liquid CO.sub.2 bottoms product from the stripping section of the first concentrating zone;
introducing the bottoms liquid from the distributive zone to an upper part of the stripping section of the second concentrating zone;
introducing a lean oil feed to an upper region of an enriching section of the second CO.sub.2 concentrating zone;
recovering a CO.sub.2 vapor product from the enriching section of the second concentrating zone above the lean oil feed;
supplying vapor from the stripping section of the second CO.sub.2 concentrating zone to a lower region of the distributive zone;
recovering a bottoms product from the stripping section of the second concentrating zone comprising propane and heavier hydrocarbons.

10 more elements

Dependencies are inferred from the claim text.

Carbon dioxide recovery process

Life of this patent

Carbon dioxide recovery process

Life of this patent

Abstract

Claims22