PURPOSE: To expand width of utilized hydrocarbon, to manufacture reduced gas at a low cost and easily, and to realize high temperature reduction, by placing in series a spare reducing furnace of a fluid layer system, a reducing furnace and a gas reforming furnace, and making iron ore grains and hydrocarbon flow through in order.
CONSTITUTION: Iron ore grains are heated by a heater 1, and after that, are fed to a spare reducing furnace 2, and are brought into contact with hydrocarbon preheated to such an extent as it is not decomposed, by a preheater 5, and circulating gas containing oxidizing gas such as CO2, H2O, etc., which has passed through a heater 21 from a line 12. Subsequently, a part of the hydrocarbon is decomposed and becomes reduced gas, and a part by-produces C and sticks onto the surface of iron ore grains, and the iron ore grains are prereduced. The C stuck grains are fed to a reducing furnace 3, contacts with high temperature reduced gas from a line 16, and becomes reduced iron. Decomposed gas of the furnace 2 is made to pass through a purifying device 18, also a part of reduced iron of the furnace 3 is fed to a gas reforming furnace 4, and its decomposed gas is reformed to reduced gas mainly consisting of CO and H2. This gas is made to pass through a heater 22, also reduced iron is fed to the furnace 3 through a line 5, and its waste gas is fed to the furnace 2.
MORI KENJI
NARITA KIICHI
KANEKO DENTAROU
KAMIMURA NOBUO
MIYAZAKI KAZUHIRO
