Claims
- 1. In a method for generating a reducing gas wherein sulfur-containing fuel, oxygen and a flux are injected into a molten metal bath within a pressure-tight vessel beneath the surface of the bath to produce a partially-desulfurized partial-oxidation gas having a hydrogen and carbon monoxide content of at least 80%, the molten metal bath consisting essentially of from 1.5 to 4.5 percent carbon, the balance substantially iron, the molten metal bath having a slag layer thereon, the improvement comprising:
- (a) injecting a coolant into the molten metal bath beneath the surface of the bath, said coolant being a fuel-rich gas selected from the group consisting of hydrogen, carbon monoxide, carbon dioxide lean spent top gas from a direct reduction furnace, methane, and any mixture thereof;
- (b) maintaining the temperature of the molten metal bath between 1350.degree. C. and 1600.degree. C. by monitoring the molten metal bath temperature and increasing or decreasing the coolant flow rate to lower or raise the bath temperature respectively as required;
- (c) quenching the partial-oxidation gas with carbon dioxide lean gas to produce a tempered reducing gas at a temperature between about 800.degree. and 900.degree. C.;
- (d) introducing said tempered gas into a direct reduction furnace having an iron oxide burden therein to reduce the iron oxide to metallized iron product and form a top gas;
- (e) removing the top gas from the furnace and removing a substantial portion of the carbon dioxide therefrom to form a CO.sub.2 -lean gas; and
- (f) introducing said CO.sub.2 -lean gas to the bottom of the molten metal bath as a coolant to cool the metal bath.
- 2. A method according to claim 1 wherein the flux is in the form of limestone, dolomite or calcined dolomite.
- 3. A method according to claim 1 further comprising injecting fuel rich gas into said vessel above the bath to maintain the temperature of the partial-oxidation gas between 1350.degree. and 1600.degree. C.
- 4. A method according to claim 3 wherein the fuel rich gas is directed downwardly toward the molten metal bath.
- 5. A method according to claim 1 wherein said coolant is CO.sub.2 -lean spent reducing gas produced by the direct reduction of iron oxide to metallized iron.
- 6. A method according to claim 1 further comprising introducing a sulfur acceptor into said direct reduction furnace as a portion of said burden, whereby said sulfur acceptor will desulfurize both metallized iron product and the spent top gas.
- 7. A method according to claim 6 wherein said sulfur acceptor is selected from the group consisting of lime, limestone, dolomite and calcined dolomite.
- 8. A method according to claim 1 wherein from one-fifth to one-fifteenth of the volume of coolant gas is utilized as carrier gas for introduction of the fuel into the melt.
- 9. A method according to claim 1 wherein from 40 to 300 NCM of said CO.sub.2 -lean top gas is introduced to the bottom of the molten metal bath as a coolant per ton of metallized iron product produced in the direct reduction furnace.
- 10. A method according to claim 9 wherein from 70 to 250 NCM of said CO.sub.2 -lean top gas is introduced to the bottom of the molten metal bath as a coolant per ton of metallized iron product produced in the direct reduction furnace.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part application of U.S. patent application Ser. No. 556,502, filed Dec. 1, 1983, now abandoned which is a continuation-in-part application of U.S. patent application Ser. No. 360,713, filed Mar. 22, 1982 now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2078779 |
Jan 1982 |
GBX |
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
556502 |
Dec 1983 |
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Parent |
360713 |
Mar 1982 |
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