Method for the purification of a gas containing CO2

A method for the purification of a feed gas stream, comprising;

• introducing a feed gas stream comprising CO2, water and at least one impurity chosen from the group consisting of nitrogen, oxygen, argon, rare gases, SOx, CS2, H2S, NOx, HCN, HCl, CHCl3, HF, volatile organic compounds, and the following metals:
• mercury, arsenic, iron, nickel, tin, lead, cadmium, vanadium, molybdenum and selenium and compounds derived from these metals,
• a) pretreating the feed gas stream, thereby eliminating, at least partially, at least one of the impurities;
• b) compressing the pretreated gas stream to a pressure of between 10 and 50 bar;
• reducing the temperature of the compressed, pretreated gas steam to a temperature of <5° C.;
• c) eliminating at least one impurity present in the compressed gas stream with the aid of exchangers combined with separators, the impurity selected from the group consisting of nitrogen, oxygen, argon and the rare gases;
• d) recovering a purified gas stream enriched in CO2 in the liquid, gaseous or supercritical state;
• wherein, between steps a) and c), a purification step is carried out enabling water contained in the gas stream to be at least partially eliminated, and at least partially eliminating at least one other impurity chosen from the group consisting of nitrogen, oxygen, argon, the rare gases, SOx, CS2, H2S, NOx, HCN, HCl, CHCl3, HF, volatile organic compounds, the following metals, mercury, arsenic, selenium, cadmium, iron, and nickel, and compounds derived from these metals, wherein between steps a) and c), a purification step is carried out enabling water contained in the gas stream to be at least partially eliminated, and at least partially eliminating at least partially SOxx and wherein the compression step b comprises successive compression phases and in that the purification step is carried out between two successive compression phases of said compression step b).