Coal is stably low in value, large in amount of deposit that can be mined, small in uneven distribution among districts, and stable in properties of sources. For such reasons, it is expected that coal will be a main primary energy up to the future, and the use thereof will be enlarged the economic growth all over the world in the future.
In the enlargement of the use of coal, advanced nations of the EU countries, North America, Australia, and Japan have been setting an innovative mid-term and long-term CO2-reducing target for global warming. In order to enlarge the use of coal, which is larger in CO2 discharge per unit electric energy than other primary energies, it is indispensable to reduce amount of the CO2 discharge.
Thus, as a new technique capable of reducing the amount of the CO2 discharge, Patent Documents 1 and 2 disclose a coal-used technique having a plant structure in which a coal gasification combined power plant IGCC (integrated coal gasification combined cycle) is combined with CO2 separation and recovery equipment CCS (carbon dioxide capture and storage).
In this plant, steam is added to a coal gasified gas (CO rich gas) obtained by mixing coal and oxygen with each other and combusting the mixture in a coal gasifying furnace, thus converting CO to CO2 and H2. In addition, an absorption liquid which has absorbed CO2 is regenerated to separate and recover the CO2. The recovered CO2 is compressed to be liquefied, and the liquefied CO2 is transported and stored. Hydrogen-rich gas, which is obtained after the CO2 is recovered, is used as a gas turbine fuel. Accordingly, the plant can be made high in efficiency as a whole.