Method and system for separating a gas mixture

A system for separating a starting gas mixture, which contains a first component or first component group and a second component or second component group, the system comprising:

• means for forming a first separation feed flow, using at least a part of the starting gas mixture, which contains the first component or first component group and the second component or second component group, and means for supplying the first separation feed flow to a pressure swing adsorption separation,
• means for removing a high-pressure extraction flow from the pressure swing adsorption separation at a pressure in a first pressure range, and means for removing a low-pressure extraction flow at a pressure in a second pressure range, wherein the second pressure range is below the first pressure range,
• wherein the first component or first component group is transferred from the first separation feed flow in the pressure swing adsorption separation to a greater share into the high-pressure extraction flow and to a lower share into the low-pressure extraction flow,
• wherein the second component or second component group is transferred from the first separation feed flow in the pressure swing adsorption separation to a lower share into the high-pressure extraction flow and to a greater share into the low-pressure extraction flow,
• means for subjecting at least a part of the low-pressure extraction flow to a compression at a pressure in a third pressure range to form a second separation feed flow, and subjecting the second separation feed flow to a thermal separation at the pressure in the third pressure range,
• in the thermal separation, means for subjecting at least a part of the second separation feed flow to a partial condensation by cooling at the pressure in the third pressure range to obtain a first gas phase and a first condensate,
• in the thermal separation, means for expanding at least a part of the first condensate, to form a second gas phase and a second condensate, and
• means for liquid-pressurizing a first share of the second condensate and discharging the first share of the second condensate, and means for vaporizing a second share of the second condensate and using the second share of the second condensate in the formation of the second separation feed flow.