It is known to separate a mixture comprising carbon dioxide as one of the main components by distillation. All the percentages relating to purities are molar percentages.
The mixture can comprise at least 50% of carbon dioxide, indeed even at least 70% of carbon dioxide and even at least 90% of carbon dioxide. The remainder of the gas can comprise at least one of the following gases: nitrogen, oxygen, argon or hydrogen. The mixture can originate from an oxy-combustion process in which a mixture of oxygen and fuel burns in a boiler to produce a waste gas, the mixture to be separated of the invention constitutes at least a portion of which, produced after purification.
A fluid rich in carbon dioxide can comprise at least 80% of carbon dioxide, indeed even at least 95% of carbon dioxide.
The majority of the processes of this type using distillation to purify the mixture use a distillation column, the bottom of which is heated by the mixture to be distilled.
In the case of U.S. Pat. No. 3,498,067, DE-A-3639779 and JP-A-56077673, the mixture is sent into the column and, for the documents FR-A-2 934 170, EP-A-1 953 486, US20020059807, U.S. Pat. No. 3,130,026, WO2006054008, WO2007126972, EP-A-0 965 564 and EP-A-0 994 318, the bottom liquid vaporizes against the mixture in a dedicated exchanger, separated from another larger exchanger which is used to cool the mixture.
U.S. Pat. No. 4,441,900 describes a process according to the preamble of the first independent claim.