Method for producing pig iron in a shaft furnace

Abstract

A method of producing pig iron in a shaft furnace is provided. The shaft furnace is charged in an upper region with raw materials which fall within the shaft furnace under the influence of gravity. A portion of the raw materials is melted and/or partly reduced under the action of the atmosphere that exists within the shaft furnace. A hot gas stream which is introduced in a lower region of the shaft furnace flows through and influences the atmosphere that exists within the shaft furnace in terms of chemical composition and temperature. A cold gas stream is fed to a heat exchanger in which the cold gas stream is heated to a temperature higher than 700° C. to give a hot gas stream. The cold gas stream comprises a CO 2 component of at least 5% by volume. The cold gas stream may contain, air and/or pure oxygen as residual component.

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         11 . A method of producing pig iron in a shaft furnace which is charged in an upper region of the shaft furnace with raw materials which fall within the shaft furnace under the influence of gravity, wherein a portion of the raw materials is at least one of melted and at least partly reduced under the action of the atmosphere that exists within the shaft furnace, and a hot gas stream which is introduced in a lower region of the shaft furnace flows through and influences the atmosphere that exists within the shaft furnace in terms of chemical composition and temperature, wherein a cold gas stream is fed to at least one heat exchanger in which the cold gas stream is heated to a temperature higher than 700° C. to give a hot gas stream, wherein the cold gas stream, before being introduced into the at least one heat exchanger, comprises a CO 2  component of at least 5% by volume, wherein the cold gas stream contains, aside from impurities, at least one of air and pure oxygen as residual component. 
     
     
         12 . The method as claimed in  claim 11 , wherein the cold gas stream contains CO 2 , air and pure oxygen in addition to impurities, where the proportion of air is limited to not more than 50% by volume. 
     
     
         13 . The method as claimed in  claim 11 , wherein the cold gas stream contains CO 2  and pure oxygen in addition to impurities, wherein the proportion of CO 2  is at least 70% by volume. 
     
     
         14 . The method as claimed in  claim 12 , wherein the CO 2  is provided from a CO 2  separation. 
     
     
         15 . The method as claimed in  claim 14 , wherein hydrogen is additionally introduced in the lower region of the shaft furnace. 
     
     
         16 . The method as claimed in  claim 15 , wherein pure oxygen is additionally introduced in the lower region of the shaft furnace. 
     
     
         17 . The method as claimed in  claim 16 , wherein carbon is additionally introduced in the lower region of the shaft furnace. 
     
     
         18 . The method as claimed in  claim 17 , wherein the hydrogen is produced and provided from electrolysis, and the pure oxygen from an air fractionation plant. 
     
     
         19 . The method as claimed in  claim 12 , wherein at least the air component of the cold gas stream, before being combined with the other components, is compressed to a pressure above the ambient pressure before being combined with the other components and before the cold gas stream is introduced into the at least one heat exchanger. 
     
     
         20 . The method as claimed in  claim 12 , wherein the cold gas stream is compressed to a pressure above the ambient pressure before the cold gas stream is introduced into the at least one heat exchanger.