Method and apparatus for controlling temperature uniformity of the burden in a direct reduction shaft furnace

A method for controlling temperature uniformity of the burden in a furnace for the direct reduction of iron oxides comprising the steps of:

• charging particulate iron oxide material to a generally vertical shaft furnace to form a burden therein;
• injecting a hot reducing gas from a first hot reducing gas inlet means located intermediate to the ends of said furnace, wherein said reducing gas reduces the charged particulate iron oxide material;
• injecting a hot reducing gas from a second hot reducing gas inlet means into the center of said burden to offset a cooling effect of upflowing gases;
• and
• removing metallized iron product from bottom of said furnace thereby establishing a continuous gravitational flow of said burden through said furnace.

A method for controlling temperature uniformity of the burden in a furnace for the direct reduction of iron oxides comprising the steps of:

• charging particulate iron oxide material to a generally vertical shaft furnace to form a burden therein;
• injecting a hot reducing gas into said burden from at least one reducing gas inlet system, said reducing gas inlet system being located intermediate to an upper end and a lower end of said furnace;
• injecting a preheated natural gas to said burden for offsetting a cooling effect in the burden caused by upflowing gas, said natural gas being injected below the hot reducing gas inlet system;
• and
• removing metallized iron product from bottom of said furnace thereby establishing a continuous gravitational flow of said burden through said furnace.

An apparatus for controlling temperature uniformity of the burden in a furnace for direct reduction of iron oxides to a metallized iron product, comprising:

• a generally vertical shaft furnace;
• means for charging particulate iron oxide material to an upper end of said furnace to form a burden therein, and a means for removing metallized iron product from a bottom end of said furnace, whereby a continuous gravitational flow of said burden can be established through the furnace;
• at least one reducing gas inlet means comprising a bustle and tuyere through which reducing gas is injected into the burden, said reducing gas inlet means located intermediate to the ends of the furnace;
• a natural gas preheating means communicably linked to a plurality of nozzles, through which a preheated natural gas is added to said burden for offsetting a cooling effect in the burden caused by upflowing gas;
• and
• a reacted gas outlet at the upper end of said furnace.

A method for controlling temperature uniformity of the burden in a furnace for the direct reduction of iron oxides comprising the steps of:

• charging particulate iron oxide material to a generally vertical shaft furnace to form a burden therein;
• injecting a hot reducing gas from at least one hot reducing gas inlet system into said burden, said reducing gas inlet system being located intermediate the upper end and a lower end of said furnace;
• removing a portion of the upflowing gas from said burden for offsetting a cooling effect of upflowing gas by a removing means located below said at least one hot reducing gas inlet system and said bottom end of said furnace;
• scrubbing the removed upflowing gas to create a scrubbed gas;
• circulating said scrubbed gas through a plurality of pipes to said reducing gas inlet system;
• reintroducing said scrubbed gas as recycled reducing gas into said furnace through said reducing gas inlet system;
• and
• removing metallized iron products from the bottom of said furnace thereby establishing a continuous gravitational flow of said burden through said furnace.

An apparatus for controlling temperature uniformity of the burden in a furnace for direct reduction of iron oxides to a metallized iron product, comprising:

• a generally vertical shaft furnace;
• means for charging particulate iron oxide material to an upper end of said furnace to form a burden therein, and a means for removing metallized iron product from a bottom end of said furnace, whereby a continuous gravitational flow of said burden can be established through the furnace;
• a hot reducing gas inlet system through which a hot reducing gas is injected into the burden, said reducing gas system located intermediate to said upper and bottom end of said furnace;
• a removal system for collecting and removing a portion of the upflow gas to offset a cooling effect of upflowing gas, said removal system being disposed between said reducing gas inlet system and said bottom end of said furnace;
• at least one scrubber linked to said removal system for scrubbing said upflow gas;
• a plurality of pipes connected to said reducing gas inlet system for reintroduction of said upflow gas into said furnace after said gas is scrubbed;
• and
• a reacted gas outlet at the upper end of said furnace.