ABSTRACT
In all gas-based Direct reduction (DR) processes, a reducing gas containing carbon monoxide and hydrogen obtained by reforming natural gas with atmospheric oxygen, water vapor or carbon dioxide (produced in the reduction process itself) is used. It is also theoretically possible to utilize waste gases from other processes as well as the reducing agent. In Nippon Steel Corporation's DR process also, reactor top gas is recycled into the furnace. Iron ore is continuously charged into the furnace where high pressure is maintained. Reducing gas (produced by steam reforming of natural gas or partial oxidation of liquid fuel oil) is injected into the lower section of the furnace, and reduced iron (DRI) is produced. Carbon dioxide absorption systems: optimum utilization of reducing gases is achieved by eliminating carbon dioxide from the gas to be recycled to the reactor after water has been separated by quenching. Thus, only the reducing gases (hydrogen and carbon monoxide) are recycled back to the reactor.
