Supercritical carbon dioxide power generation system including dry gas seal and method of operating the same

A supercritical carbon dioxide power generation system including a dry gas seal, comprising:

• a turbine;
• a cooler;
• a compressor;
• a heater;
• a carbon dioxide injecting portion injecting carbon dioxide as a working fluid from a carbon dioxide tank into an intake side of the compressor;
• a heater flow path provided in the heater and configured to introduce and heat the carbon dioxide received from the compressor and then to discharge the carbon dioxide to the turbine;
• a seal gas flow path diverged from the heater flow path and guiding at least part of the carbon dioxide heated on the heater flow path to be injected into a dry gas seal portion of the compressor and to be used as a seal gas;
• a seal gas valve installed on the seal gas flow path and opening/closing of the seal gas flow path;
• and
• a controller controlling an amount of an opening degree of the seal gas valve according to temperature of the carbon dioxide heated by the heater,
• wherein the seal gas flow path comprises:
• a low-temperature seal gas flow path diverged from the heater flow path;
• and
• a high-temperature seal gas flow path diverged from a downstream side of the heater flow path compared to the low-temperature seal gas flow path, and
• wherein the seal gas valve comprises:
• a low-temperature seal gas valve installed on the low-temperature seal gas flow path;
• and
• a high-temperature seal gas valve installed on the high-temperature seal gas flow path.