US4173465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the direct reduction of iron using gas from coal
Assignee: ZURICH BRANCH OF MIDREX INTERNATIONAL BV A NETHERLANDS Corp
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Filing: 1978-08-15
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Granted: 1979-11-06
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Expires: 1998-08-15
Abstract
Abstract A method for direct reduction of iron in a shaft reduction furnace. Spent gas from the furnace is upgraded in reductant by removal of CO2 and water to form an upgraded gas. A fossil fuel is gasified to produce a hot gas which is tempered with a first stream of upgraded gas. The mixture is desulfurized by reaction with lime to produce hot desulfurized gas. A second stream of upgraded gas is heated and mixed with the hot desulfurized gas to produce hot reducing gas.
Inventors
- 👤 David C. Meissner
- 👤 Charles W. Sanzenbacher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:35
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/0073; C21B13/02; C21B13/029; C21B2100/00; C21B2100/20; C21B2100/28; C21B2100/282; C21B2100/40; C21B2100/42; C21B2100/60; C21B2100/64; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/122; Y02P10/134
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
In a method for reducing iron oxide in a direct reduction furnace wherein hot reducing gas is introduced to said furnace to reduce the iron oxide therein to a metallized iron product and to form a CO 2 containing spent reducing gas, the improvement comprising: a. removing a substantial portion of the CO 2 from said spent reducing gas to form a reductant-rich gas; b. gasifying fossil fuel to form a hot gasifier gas; c. tempering said hot gasifier gas with a first stream of said reductant-rich gas to form a hot gas mixture; d. reacting said hot gas mixture with a sulfur acceptor to form a hot desulfurized gas; e. heating a second stream of said reductant-rich gas; and f. mixing said heated second stream of reductant-rich gas with hot desulfurized gas to form a reducing gas having a quality of at least about 8 and a temperature of from about 760° to about 900° C. for introduction to said furnace.
Claim 2
Dependent Claim
162 words
In a method for reducing iron oxide in a direct reduction furnace wherein hot reducing gas is introduced to said furnace to reduce the iron oxide therein to a metallized iron product and to form a CO 2 containing spent reducing gas, the improvement comprising: a. removing a substantial portion of the CO 2 from said spent reducing gas to form a reductant-rich gas; b. gasifying fossil fuel to form a hot gasifier gas; c. tempering said hot gasifier gas with a first stream of said reductant-rich gas to form a hot gas mixture; d. reacting said hot gas mixture with a sulfur acceptor to form a hot desulfurized gas; e. heating a second stream of said reductant-rich gas; and f. mixing said heated second stream of reductant-rich gas with hot desulfurized gas to form a reducing gas having a quality of at least about 8 and a temperature of from about 760° to about 900° C. for introduction to said furnace.
Claim 3
Dependent Claim
12 words
A method according to claim 1 wherein said sulfur acceptor is lime.
Claim 4
Dependent Claim
18 words
A method according to claim 1 wherein said gasifier gas has a quality of at least about 6.
Claim 5
Dependent Claim
29 words
A method according to claim 1 wherein a portion of the CO 2 containing spent reducing gas is used as fuel to heat said second stream of reductant-rich gas.
Claim 6
Dependent Claim
21 words
A method according to claim 1 wherein said fossil fuel is selected from the group consisting of coal, lignite and char.
Claim 7
Dependent Claim
26 words
A method according to claim 1 further comprising mixing a third stream of unheated reductant-rich gas with said desulfurized gas to control the reducing gas temperature.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-05 | 1983-05-07 | 1983-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-05 | 1987-05-07 | 1987-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-05 | 1991-05-07 | 1991-11-06 | $7700.00 | Window Closed / Lapsed |