US 5,064,467 AGranted

Method and apparatus for the direct reduction of iron

AssigneeC.V.G. Siderurgica Del Orinoco, C.A.

InventorsOscar G. Dam G., Henry R. Bueno C.

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Abstract

A process for the direct reduction of iron-containing metal oxides to obtain iron is disclosed in which a reformed reduction gas rich in H.sub.2 and CO and having an oxidation degree in the range of from about 0.30 to about 0.35 is formed and reduction is carried out simultaneously in a single reaction zone of a reduction reactor. The reformed reduction gas is formed using a highly endothermic reaction during which a mixture of heated natural gas, recycled top gas and air, preferably oxygen enriched air, is placed into contact with heated surfaces of DRI metallized iron in the reaction zone. The resulting reformed reducing gas consists essentially of from about 45% to about 48% hydrogen, from about 32% to about 34% carbon monoxide, from about 2% to about 4% carbon dioxide, from about 1% to about 3% methane, from about 14% to about 16% nitrogen and from about 1% to about 3% water vapor.

Claims12

Dependent claims

A process for the direct reduction of metal oxides containing iron to obtain a direct reduced iron, said process consisting essentially of:

(a) providing a reforming-reduction reactor having a bed of partially metallized iron oxide material and a bed of direct reduced iron within said reforming-reduction reactor;
(b) feeding metal oxides containing iron to the reforming-reduction reactor;
(c) mixing top gas recycled from said reforming-reduction reactor with natural gas;
(d) preheating said top gas and natural gas mixture to a temperature in the range of from about 650.degree. C. to about 850.degree. C.;
(e) mixing air preheated to a temperature in the range of from about 650.degree. C. to about 850.degree. C. with said preheated top gas and natural gas mixture in a mixing chamber;
(f) partially combusting said mixture to a temperature of between 850.degree. C. to 1100.degree. C. wherein said mixture has a degree of oxidation in the range of from about 0.27 to about 0.32 and a reducing power in the range of from about 2 to 3;
(g) feeding said partially combusted mixture to said direct reduced iron in said reforming-reduction reactor so as to form a reformed reducing gas comprising H.sub.2 and CO and having an oxidation degree in the range of from about 0.05 to about 0.09 in said reforming-reduction reactor;
and
(h) contacting said iron oxide metal in said reforming-reduction reactor with said reformed reducing gas so as to effect reduction to obtain a direct reduced iron.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/455,232Filed 22 Dec 1989 · continuation in part
Priority: 25 Nov 1987
Granted: 12 Nov 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C21B 13/04
Making spongy iron or liquid steel, by direct processes: in retorts
C21B 13/00
Making spongy iron or liquid steel, by direct processes
Y02P 10/122
Reduction of greenhouse gas [GHG] emissions: by capturing or storing CO2
Y02P 10/134
Reduction of greenhouse gas [GHG] emissions: by avoiding CO2, e.g. using hydrogen