Method and apparatus for producing molten iron

Abstract

A system for producing molten iron from iron ores, including a direct reduction shaft furnace, a melting zone in a melting furnace having a coke bed in its lower portion and a charging and preheating chamber in its upper portion, and at least one reducing gas generation zone in communication with said melting zone.

1 . A system for producing molten iron from iron ores, comprising: 
 (1) a direct reduction shaft furnace;    (2) a melting zone in a melting furnace having a coke bed in its lower portion and a charging and preheating chamber in its upper portion; and    (3) at least one reducing gas generation zone communicating with said melting zone, wherein said system: 
 (a) produces a reduced intermediate product with a predetermined degree of metallization and carburization in said reduction furnace by reaction of said ores with a high-temperature reducing and carburizing gas;  
 (b) charges said reduced intermediate product into said melting furnace upon said coke bed, whereby said reduced intermediate product is melted by contact with said high-temperature reducing gas;  
 (c) produces a reducing gas in said reducing gas generation zone by partial combustion of a hydrocarbon fuel with an oxygen-containing gas; and  
 (d) transfers said reducing gas into said melting furnace preventing any free oxygen from contacting said coke bed in said melting furnace.  
   
   
   
       2 . The system for producing molten iron from iron ores according to  claim 1 , wherein said reducing gas is produced in a partial combustion chamber so that the hydrocarbon fuel, and oxygen-containing gas react an combust to substantially eliminate the presence of any free oxygen before contacting said coke bed.  
   
   
       3 . The system for producing molten iron from iron ores according to  claim 2 , wherein said hydrocarbon fuel is natural gas.  
   
   
       4 . The system for producing molten iron from iron ores according to  claim 3 , wherein the ratio of the volumetric flow rate of the oxygen-containing gas to the flow rate of said natural gas is in the range from about 0.86 to about 1.04.  
   
   
       5 . The system for producing molten iron from iron ores according to  claim 2 , wherein said hydrocarbon fuel is liquid.  
   
   
       6 . A system for producing molten iron from iron ores according to  claim 2 , wherein said hydrocarbon fuel is pet-coke.  
   
   
       7 . A system for producing molten iron from iron ores according to  claim 2 , wherein said hydrocarbon fuel is coal.  
   
   
       8 . The system for producing molten iron from iron ores according to  claim 1 , wherein said system: 
 (e) withdraws reacted reducing gas from said reduction furnace;    (f) regenerates the reducing potential of said withdrawn reducing gas by cooling and removing at least a portion of its water content;    (g) heats a portion of said regenerated withdrawn reducing gas to a temperature above 800° C.; and    (h) feeds said heated regenerated withdrawn reducing gas to the reduction furnace.    
   
   
       8 . The system for producing molten iron from iron ores according to  claim 1 , wherein said reducing gas is produced in a single partial combustion chamber and fed to said PATENT  120194 - 4420 . 1  melting furnace through a plurality of inlet ports formed and located in the refractory lining of said melting furnace.  
   
   
       9 . The system for producing molten iron from iron ores according to  claim 1 , wherein said reducing gas being is produced in a plurality of partial combustion chambers connecting to said melting furnace through a plurality of inlet ports formed through the wall of said melting furnace.  
   
   
       10 . The system for producing molten iron from ores according to  claim 1 , wherein said inlet ports are located in said melting furnace so that the high-temperature reducing gas is fed to contact said coke and ascend through a portion of said coke bed and through said preheating chamber of said melting furnace.  
   
   
       11 . The system for producing molten iron according to  claim 10 , wherein said iron-containing material is DRI produced in a location remote from said melting furnace.  
   
   
       12 . The system for producing molten iron according to  claim 11 , wherein said reducing gas effluent from said melting furnace is further used as fuel, power generation or synthesis gas in other chemical processes.  
   
   
       13 . The system for producing molten iron according to claims  8 , wherein the length of said partial combustion chamber is at least about 0.6 m.  
   
   
       14 . The system for producing molten iron according to claims  8 , wherein the length of said partial combustion chamber is at least about 0.8 m.  
   
   
       15 . The system for producing molten iron according to  claim 1 , wherein said melting furnace is located at a remote distance from said direct reduction shaft furnace, wherein said system: 
 (a) withdraws effluent gases from said melting furnace;    (b) cools and cleans said effluent gases;    (c) separates CO 2  from said cooled effluent gases;    (d) heats said cooled effluent gases to a temperature above about 600° C.; and    (e) recycles said heated reducing gases to said melting furnace.    
   
   
       16 . The system for producing molten iron according to  claim 15 , wherein a portion of said cooled and cleaned effluent gases from said melting furnace are utilized as fuel for heating said recycled gases.