Process and plant for avoiding metal dusting in the direct reduction of iron-oxide-containing materials
AssigneesVoest-Alpine Industrieanlagenbau GmbH, Brifer International Ltd.
InventorsGerald Kern, Werner Leopold Kepplinger, Johannes Schenk, Roy Hubert Whipp, Jr.
Life of this patent
Estimating the term…
Abstract
A direct reduction process is disclosed for iron-oxide-containing materials. Synthesis gas is mixed with top gas produced during direct reduction of the iron-oxide-containing materials and is used as reduction gas for directly reducing iron-oxide-containing materials. In order to avoid or reduce metal dusting caused by an increased CO content of the reduction gas with a simple technique and equipment, the CO/CO.sub.2 ratio of the reduction gas is set at a predetermined value from 1 to 3.
Claims21
A process for avoiding metal dusting while performing a direct reduction of iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material and reformed natural gas from vapor and natural gas in a reformer;
- (b) mixing the reformed natural gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the CO/CO.sub.2 ratio of the reducing gas to between 1/1 and 3/1, by varying the ratio of vapor/natural-gas in the reformer.
A process for avoiding metal dusting while performing a direct reduction of iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material;
- (b) mixing synthesis gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the CO/CO.sub.2 ratio of the reducing gas to between 1/1 and 3/1, by subjecting at least a partial volume of the synthesis gas to CO conversion prior to the mixing of step (b).
A process for avoiding metal dusting while performing a direct reduction of iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material;
- (b) mixing synthesis gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the CO/CO.sub.2 ratio of the reducing gas to between 1/1 and 3/1, by subjecting a partial volume of the synthesis gas to CO.sub.2 scrubbing prior to the mixing of step (b).
A process for avoiding metal dusting while performing a direct reduction of iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material;
- (b) mixing synthesis gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the reducing gas to a CO/CO.sub.2 ratio of between 1/1 and 3/1 by subjecting the synthesis gas to CO.sub.2 scrubbing prior to the mixing of step (b).
A process for avoiding metal dusting while performing a direct reduction of iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material;
- (b) mixing synthesis gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the reducing gas to a CO/CO.sub.2 ratio of between 1/1 and 3/1 by subjecting a partial volume of the synthesis gas to CO.sub.2 scrubbing prior to the mixing of step (b), wherein the degree of CO.sub.2 scrubbing is such that a varied portion of CO.sub.2 is retained in the scrubbed gas.
A process for avoiding metal dusting while performing a direct reduction of sulfur- and iron-oxide-containing material comprising:
- (a) producing top gas in the direct reduction of the iron-oxide-containing material;
- (b) mixing synthesis gas with the top gas, wherein resulting mixture is a reducing gas that contains CO, CO.sub.2 and H.sub.2 and is used for the direct reduction of the iron-oxide-containing material;
- and
- (c) adjusting the reducing gas to a CO/CO.sub.2 ratio of between 1/1 and 3/1 by supplying at least a portion of the sulfur contained in the iron-oxide-containing material to the reducing gas along with the top gas in the form of H.sub.2 S as a result of heating or direct reduction.
A plant for carrying out a process for avoiding meal dusting in performing direct reduction of iron-oxide-containing material, comprising at least one direct reduction reactor for reducing the iron-oxide-containing material, a reducing-gas supply duct leading to said direct reduction reactor and a top-gas discharge duct carrying off the direct reduction reactor the top gas forming in direct reduction, a reformer, a reformed-gas duct departing from the reformer and joining the top-gas discharge duct, the reducing gas formed of reformed gas and of top gas getting into the direct reduction reactor through the reducing-gas supply duct and both the reformed-gas duct and the top-gas discharge duct running into a CO.sub.2 scrubber, and the reducing-gas supply duct leading from the CO.sub.2 scrubber to the direct reduction reactor, wherein the reformed-gas duct, by means of a reformed-gas bypass duct to avoid CO.sub.2 scrubber, is flow-connected with the reducing-gas supply duct.
Dependencies are inferred from the claim text.