The emission of CO_2 in the coal thermal power plant is one of the most important problem for the electric utility companies. A lot of projects of CO_2 capture and storage(CCS) are planned recently in foreign countries. However, existing technologies on CCS have difficult problems, such as a great decrease of the thermal efficiency and the rise of the cost, to introduce to the power generation system. In this study, a new highly efficiency IGCC system with CO_2 capture was proposed. The system consists of a new oxygen-CO_2 blown coal gasifier and a closed gas turbine using the gas mixed oxygen with CO_2, which is recycled from exhaust gas, and the CO_2 separation system is not needed in the system. The net thermal efficiency of this system is calculated as 42%(HHV base, 1300℃ class gas turbine) with CO_2 capture and technical subjects for practical use are clarified.
