Method for employing corn plant residue in the production of direct reduced iron

A method of employing biogas in the production of direct reduced iron (DRI), said method comprising the steps of:

• providing a biogas processing facility that is (a) accessible to a plurality of corn plant fields that provide corn plant residue and is (b) located upstream of and physically associated with an iron-making plant that is accessible to said plurality of corn plant fields and has a direct reduction facility for producing DRI and that comprises (i) a catalytic reformer for producing biosyngas comprising carbon monoxide and gaseous hydrogen (CO+H2) from biogas and (ii) a vertical shaft furnace that employs said biosyngas as a reducing gas to convert iron ore to DRI and that emits a top gas comprising carbon dioxide;
• subjecting said corn plant residue to processing at said biogas processing facility to form, upstream of said reformer, biogas consisting essentially of methane (CH4) and carbon dioxide (CO2), each being present in double digit percentages;
• retaining at least a major part of said carbon dioxide present in said biogas;
• and
• directing said biogas, with the retained carbon dioxide, for use at said reformer as one of a plurality of sources of carbon dioxide employed there to produce biosyngas for use as the reducing gas to convert said iron ore into iron and produce DRI, there being no provision for the removal of said carbon dioxide from said biogas.

A method of employing biogas in the production of direct reduced iron (DRI), said method comprising the steps of:

• providing an iron-making plant having a direct reduction facility, for producing DRI, and comprising a catalytic reformer and a vertical shaft furnace that receives iron ore and emits a top gas comprising carbon dioxide (CO2);
• providing a biogas that has been produced from corn plant residue at a biogas processing facility that is located upstream of said reformer, said biogas consisting essentially of methane (CH4) and carbon dioxide, each being present in double-digit percentages;
• retaining at least a major part of the carbon dioxide present in said biogas;
• introducing said biogas with the retained carbon dioxide into said reformer, for use there;
• there being no provision for the removal of said retained CO2 from said biogas;
• reacting, in said reformer, the methane from said biogas with the retained carbon dioxide from said biogas to produce a biosyngas comprising carbon monoxide and gaseous hydrogen (CH4+CO2→2CO+2H2);
• introducing said biosyngas into said vertical shaft furnace for use as reducing gas to convert said iron ore to iron and produce DRI;
• said vertical shaft furnace comprising, in descending order, from an upper end, a heating zone, a reducing zone and a transition zone, and said method further comprises:
• introducing iron ore into said vertical shaft furnace at said upper end;
• introducing reducing gas into said reducing zone;
• converting said iron ore to DRI as the iron ore descends through said vertical shaft furnace, by gravity, to produce DRI at said transition zone;
• providing said transition zone with a temperature at which methane breaks down, in the presence of a catalyst, into carbon and gaseous hydrogen (CH4→C+2H2);
• providing said transition zone with a catalyst in the form of iron from said DRI;
• and
• internally generating carbon monoxide (CO) at said transition zone by introducing, into the transition zone, said biogas with the retained CO2.

A method of employing biogas in the production of direct reduced iron (DRI), said method comprising the steps of:

• providing a biogas that has been produced from corn plant residue at a biogas processing facility, the biogas consisting essentially of methane and carbon dioxide (CH4+CO2), each being present in double-digit percentages;
• providing a direct reduction facility comprising a catalytic reformer physically associated with a vertical shaft furnace having an upper end and comprising in descending order from said upper end, a heating zone, a reducing zone, a transition zone and a cooling zone;
• retaining at least a major part of the carbon dioxide present in said biogas;
• there being no provision for the removal of said retained CO2 from said biogas;
• introducing said biogas into said catalytic reformer;
• producing biosyngas comprising carbon monoxide and gaseous hydrogen (CO+H2) in said reformer;
• introducing iron ore into said vertical shaft furnace at its upper end;
• introducing said biosyngas, as a reducing gas, into the reducing zone of said vertical shaft furnace;
• converting said iron ore to iron as the iron ore descends, by gravity, through said vertical shaft furnace, to produce direct reduced iron (DRI) in the transition zone;
• providing said transition zone with a temperature at which methane breaks down, in the presence of a catalyst, into carbon and gaseous hydrogen (CH4→C+2H2);
• providing said transition zone with a catalyst in the form of iron from said DRI;
• and
• internally generating carbon monoxide (CO) at said transition zone by introducing, into the transition zone, said biogas with the retained carbon dioxide (CO2).

In a method for producing direct reduced iron (DRI) employing a direct reduction facility comprising a catalytic reformer physically associated with a vertical shaft furnace having upper and lower ends and, in descending order from said upper end, a heating zone, a reducing zone, a transition zone and a cooling zone, wherein said method comprises the steps of:

• introducing, into said catalytic reformer, a biogas produced from corn plant residue at a biogas processing facility, the biogas consisting essentially of methane and carbon dioxide (CH4+CO2), each being present in double-digit percentages;
• retaining at least a major part of the carbon dioxide present in said biogas;
• there being no provision for the removal of said retained CO2 from said biogas;
• converting said biogas to biosyngas comprising carbon monoxide and gaseous hydrogen (CO+H2) in said reformer;
• providing said transition zone with a temperature at which methane breaks down, in the presence of a catalyst, into carbon and gaseous hydrogen (CH4→C+2H2);
• providing said transition zone with a catalyst in the form of iron from said DRI;
• introducing said biosyngas into the reducing zone of said vertical shaft furnace, for use as a reducing gas;
• introducing iron ore into said vertical shaft furnace at its upper end;
• and
• converting said iron ore to iron as the iron ore descends, by gravity, through said vertical shaft furnace to produce direct reduced iron (DRI) at said transition zone;
• the improvement comprising a process for generating carbon monoxide (CO) internally, in said transition zone, by introducing, into said transition zone, a gas consisting essentially of said biogas with the retained carbon dioxide.