Patent ID: 11952638
Assignee: MIDREX TECHNOLOGIES, INC.
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  Y | IPC C

Claim 0:
1. A direct reduction method, comprising:
adding via separate streams variable amounts of natural gas, hydrogen, and a carbon-free oxidizing gas to a feed gas stream upstream of a reformer, and a preheater disposed upstream of the reformer, wherein the stream of the variable amount of hydrogen is operable to replace 20-90% of the natural gas by fuel value;
reforming the feed gas stream in the reformer to form a reformed gas stream, and
delivering the reformed gas stream to a shaft furnace, where the reformed gas stream is used to reduce a metallic ore material to a direct reduced metallic material
wherein the carbon-free oxidizing gas comprises steam, and the direct reduction method further comprises controlling a steam flow rate of the steam to maintain a maximum k-factor value of the feed gas stream of 0.74 or lower, defined by an equation wherein xi is the respective mol fraction of the gas i in the gas composition:, k
   -
   factor
  
  =
  
   
    
     
      x
      CO
     
     ⁢
     
      x
      
       H
       2
      
     
    
    
     x
     
      
       H
       2
      
      ⁢
      O
     
    
   
   .