Co2 separation system

A CO2 separation system, comprising:

• first CO2 separation equipment;
• second CO2 separation equipment;
• a first pipe;
• low-concentration CO2 gas discharge equipment;
• and
• gas reflux equipment including a second pipe and a high-concentration CO2 gas discharge apparatus, wherein
• the first CO2 separation equipment includes a cryogenic separation apparatus configured to separate CO2 from gas to be treated by cryogenic separation treatment,
• the first pipe supplies gas discharged from the first CO2 separation equipment to the second CO2 separation equipment,
• the second CO2 separation equipment includes an adsorption separation apparatus including rubber as a CO2 adsorbent,
• the low-concentration CO2 gas discharge equipment discharges gas containing low concentration CO2 from the second CO2 separation equipment,
• the high-concentration CO2 gas discharge apparatus discharges gas containing CO2 having a concentration higher than the low concentration from the second CO2 separation equipment, in the gas reflux equipment, at least a part of the gas discharged from the high-concentration CO2 gas discharge apparatus is returned to the first CO2 separation equipment through the second pipe, and
• the first CO2 separation equipment performs cryogenic separation treatment for separating CO2 from the gas returned by the gas reflux equipment.