Method for separating CO 2 from a gas stream based on chemical absorption, comprising the following steps: a) absorbing the CO 2 coming from the gas stream to be treated at a temperature of between 40 °C and 60 °C and a pressure in a range of between 1 and 1.5 bar, by means of putting said stream in contact in an absorber with an absorbent solution in which the CO 2 will be retained; b) recirculating into the absorber up to 75 % of the stream comprising the CO 2 -rich absorbent solution coming from step a); c) desorbing CO 2 in a regenerator from the stream comprising the CO 2 -rich absorbent solution coming from step a) not recirculated to step b) at a temperature of between 80 °C and 120 °C a pressure of between 1.5 and 5 bar and a steam stripping flow rate of between 10 and 90 % by volume with respect to the desorbed CO 2 flow rate, characterized in that the stream comprising the CO 2 -rich absorbent solution is split into at least two streams by means of a set of heat exchangers, prior to the inlet of the regenerator, wherein the at least two streams are a primary stream and a secondary stream, wherein both are directed to an upper part and to an intermediate bed of the regenerator, respectively, and wherein a heating of the primary stream is carried out in internal heat exchangers (24, 25, 26) of the set of heat exchangers and the secondary stream is obtained from inner streams (13A, 13B, 13C) which are removed at the outlet of each of the internal exchangers (24, 25, 26); and d) recovering the absorbent solution resulting from step c) from the absorber of step a), wherein the stream of the stripped regenerated absorbent solution resulting from step c) is in turn split into different substreams (21A, 21B, 21C) which enter each of the internal heat exchangers (24, 25, 26). a) absorbing the CO 2 coming from the gas stream to be treated at a temperature of between 40 °C and 60 °C and a pressure in a range of between 1 and 1.5 bar, by means of putting said stream in contact in an absorber with an absorbent solution in which the CO 2 will be retained; b) recirculating into the absorber up to 75 % of the stream comprising the CO 2 -rich absorbent solution coming from step a); c) desorbing CO 2 in a regenerator from the stream comprising the CO 2 -rich absorbent solution coming from step a) not recirculated to step b) at a temperature of between 80 °C and 120 °C a pressure of between 1.5 and 5 bar and a steam stripping flow rate of between 10 and 90 % by volume with respect to the desorbed CO 2 flow rate, characterized in that the stream comprising the CO 2 -rich absorbent solution is split into at least two streams by means of a set of heat exchangers, prior to the inlet of the regenerator, wherein the at least two streams are a primary stream and a secondary stream, wherein both are directed to an upper part and to an intermediate bed of the regenerator, respectively, and wherein a heating of the primary stream is carried out in internal heat exchangers (24, 25, 26) of the set of heat exchangers and the secondary stream is obtained from inner streams (13A, 13B, 13C) which are removed at the outlet of each of the internal exchangers (24, 25, 26); and d) recovering the absorbent solution resulting from step c) from the absorber of step a), wherein the stream of the stripped regenerated absorbent solution resulting from step c) is in turn split into different substreams (21A, 21B, 21C) which enter each of the internal heat exchangers (24, 25, 26).