Direct reduction system utilizing hydrogen

Abstract

A process for the production of direct reduced iron (DRI), with or without carbon, using hydrogen, where the hydrogen is produced utilizing water generated internally from the process. The process is characterized by containing either one or two gas loops, one for affecting the reduction of the oxide and another for affecting the carburization of the DRI. The primary loop responsible for reduction recirculates used gas from the shaft furnace in a loop including a dry dedusting step, an oxygen removal step to generate the hydrogen, and a connection to the shaft furnace for reduction. In the absence of a second loop, this loop, in conjunction with natural gas addition, can be used to deposit carbon. A secondary carburizing loop installed downstream of the shaft furnace can more finely control carbon addition. This loop includes a reactor vessel, a dedusting step, and a gas separation unit.

1 - 11 . (canceled) 
     
     
         12 . A system for the direct reduction of iron, comprising:
 a process loop using hydrogen as a chemical carrier for removal of oxygen from iron ore and regenerating resulting steam by electrolysis;   a deduster operable for deducting top gas from a shaft furnace of the process loop without condensing steam in the top gas;   wherein no liquid water is added to the process loop; and   an electrolyzer operable for producing the hydrogen using water vapor present in the top gas from the shaft furnace and forming a portion of the process loop.   
     
     
         13 . The system of  claim 12 , wherein the electrolyzer comprises a solid oxide electrolyzer. 
     
     
         14 . The system of  claim 12 , further comprising one or more of:
 a compressor operable for compressing the top gas without cooling at a temperature above 100° C.;   an oxygen injector operable for adding oxygen to the hydrogen before introducing the hydrogen to the shaft furnace to reduce the iron ore;   a carburizing gas injector operable for depositing carbon on direct reduced iron formed from the iron ore via the introduction of carburizing gas into the shaft furnace, wherein the carburizing gas is injected directly into the shaft furnace below a bustle thereof; and   a purge stream integrated with a fired heater operable for heating bustle gas introduced into the shaft furnace.   
     
     
         15 . The system of  claim 12 , wherein a carburizing zone below a reduction zone of the shaft furnace is used to increase a direct reduced iron carbon percentage and the hydrogen is separated and delivered to the process loop, thereby forming a secondary gas loop comprising:
 solid material entering the carburization zone via gravity and interacting with a gas to add carbon to the direct reduced iron;   a gas stream then exiting the carburizing zone and entering the dedusting step to remove solid particulates;   hydrogen being removed from the gas using a gas separation unit and being returned to the process loop;   natural gas or another carburizing gas being introduced into the gas; and   a compressor being used to increase the pressure of the gas to provide motive force for gas circulation and separation;   wherein the carburization zone is implemented one of in the shaft furnace and in a separate vessel distinct from the shaft furnace.   
     
     
         16 . (canceled)