Patent ID: 9746233
Date: 2017-08-29
CPC Classifications: F25J,Y02C

Claim:
1. A process for the separation of a feed gas rich in carbon dioxide and containing at least one component lighter than carbon dioxide, the process comprising the steps of: cooling the feed gas rich in carbon dioxide to a subambient temperature in a first heat exchanger, wherein the feed gas is partially condensed and separated to form a gaseous portion and a liquid portion; sending the liquid portion to the top of a distillation column; removing a liquid stream from the bottom of the distillation column, wherein the liquid stream is richer in carbon dioxide than the feed gas; removing a gaseous stream from the top of the distillation column and warming the gaseous stream in the first heat exchanger, wherein the gaseous stream is less rich in carbon dioxide than the feed gas, sending the gaseous portion to second heat exchanger under conditions effective to form a partially condensed stream comprising a liquid fraction and a gaseous fraction, wherein the second heat exchanger is a shell and tube heat exchanger, the tubes of which are surrounded by a bath of liquid carbon dioxide at its triple point; sending the liquid fraction or a liquid derived therefrom to the top of the distillation column; vaporizing a first portion of the liquid stream from the bottom of the distillation column outside or within the distillation column to form a gas which is subsequently separated in the distillation column; vaporizing a second portion of the liquid stream from the bottom of the distillation column in the second heat exchanger to form a vapor and warming the resulting vapor in the first heat exchanger, wherein the second portion of the liquid stream from the bottom of the distillation column is expanded before vaporization, vaporizing a third portion of the liquid stream from the bottom of the distillation column in the first heat exchanger, wherein the liquid portion of the feed gas is sent to the top of the distillation column following an expansion step, wherein the shell and tube heat exchanger operates at the triple point pressure of carbon dioxide and the triple point temperature of carbon dioxide.