Method for producing liquid pig iron or liquid steel intermediate products from fine-particled material containing iron oxide

Abstract

A method for producing liquid pig iron or liquid steel intermediate products from fine-particled material containing iron oxide. The fine-particled material is prereduced in at least one prereduction stage and reduced in a final reduction stage to sponge iron. The sponge iron is melted in a melt-down gasification zone, with carbon carriers and oxygen-containing gas supplied. A CO- and H2-containing reduction gas is generated and introduced into the final reduction stage, is converted there, is drawn off and introduced into at least one prereduction stage, converted there and drawn off. A first quantity fraction of the fine-particled material containing iron oxide is introduced into a melt-down gasification zone via at least one prereduction stage and one final reduction stage, and a further quantity fraction of the fine-particled material containing iron oxide is introduced into the melt-down gasification zone directly or together with the carbon carriers and the oxygen-containing gas.

1 . A plant for producing liquid pig iron or liquid steel intermediate products from fine-particled material containing iron oxide comprising;
 at least two fluidized bed reactors, first conveying lines connecting the reactors in series one behind the other and operable such that fine-particled material containing iron oxide is guided from each of the fluidized bed reactors via the first conveying lines in one direction;   reduction gas connecting lines operable such that reduction gas is guided from one of fluidized bed reactors to a next one of the fluidized bed reactors via the reduction gas connecting lines in the opposite direction from the one direction;   a melt-down gasifier, a second conveying line operable for guiding the sponge iron out of the fluidized bed reactor that is arranged last in the direction of flow of the fine-particled material containing iron oxide,   a supply line to the gasifier for carbon carriers, and a supply line to the gasifier for oxygen-containing gases, taps from the gasifier for the pig iron and/or steel intermediate material and slag;   a reduction gas discharge line, issuing into the fluidized bed reactor that is arranged last in the direction of flow of the material containing iron oxide operable for discharging reduction gas formed in the melt-down gasifier;   a first branch conveying line operable for conveying a quantity fraction of the fine-particled material containing iron oxide, and further conveying lines from fluidized bed reactor to fluidized bed reactor and a subsequent conveying line to the melt-down gasifier; and   a second branch conveying line for conveying a further quantity fraction of the fine-particled material containing iron oxide including a connecting conveying line form a feed device into the melt-down gasifier.   
     
     
         2 . The plant as claimed in  claim 1 , wherein the second branch conveying line for the further quantity fraction of the fine-particled material containing iron oxide comprises a connecting conveying line from a feed device to the supply line for carbon carriers and comprises a connecting line for oxygen-containing gases to the melt-down gasifier. 
     
     
         3 . The plant as claimed in  claim 1 , wherein the second branch conveying line is operable for conducting 10% to 15% of the overall quantity of the fine-particled material containing iron oxide which is used. 
     
     
         4 . The plant as claimed in  claim 1 , further comprising a hot-dedusting plant connected into the reduction gas discharge line;
 a temperature measurement device operable for detecting the reduction gas temperature arranged in the reduction gas discharge line; and   a blast furnace gas line issuing on the outlet side of a CO2 removal plant; and   an inflow-quantity regulation device operable for setting the reduction gas temperature in the reduction gas discharge line leading to the fluidized bed reactor of the final reduction stage.   
     
     
         5 . The plant as claimed in  claim 1 , further comprising in addition to the reduction gas connecting lines leading from each fluidized bed reactor to next fluidized bed reactor and in addition to the reduction gas discharge line leading to the fluidized bed reactor, individual reduction gas connecting lines between the reduction gas discharge line and the at least one fluidized bed reactor of the prereaction stage, and quantity regulation devices for the individual reduction gas connecting lines for the metered admixing of reduction gas. 
     
     
         6 . The plant as claimed in  claim 1 , wherein the last of the series-connected fluidized bed reactors of the series thereof is connected to a first conveying line for the transfer of sponge iron into the melt-down gasifier;
 an additional conveying line for extracting a part quantity of the sponge iron; and   a cooling device to which the additional conveying line.