CA1154262A - Method and apparatus for manufacturing sponge iron - Google Patents
Method and apparatus for manufacturing sponge ironInfo
- Publication number
- CA1154262A CA1154262A CA000371472A CA371472A CA1154262A CA 1154262 A CA1154262 A CA 1154262A CA 000371472 A CA000371472 A CA 000371472A CA 371472 A CA371472 A CA 371472A CA 1154262 A CA1154262 A CA 1154262A
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- CA
- Canada
- Prior art keywords
- gas
- reduction
- shaft furnace
- reducing agent
- reaction gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT
A method and apparatus for manufacturing sponge iron by the continuous reduction of iron oxides in a shaft utilizing recirculation gases. Reaction gas is removed from the shaft furnace, substantially cleaned of all CO2 and H2O, and then divided into at least two flow portions one of which is passed to a gas generator comprising a plasma burner. A reducing agent such as pit coal is injected together with a oxidant into the hot gas from the plasma burner so as to form a gas mixture mainly comprising CO and H2, which gas mixture is then mixed with the other flow portion of the cleaned reaction gas in such a proportion that the temperature of the resulting reduction gas is suitable for the reduction of iron oxides in the shaft furnace. The reduction gas is then injected into the shaft furnace and passed upwardly to reduce iron oxides contained there to form sponge iron which is then removed.
A method and apparatus for manufacturing sponge iron by the continuous reduction of iron oxides in a shaft utilizing recirculation gases. Reaction gas is removed from the shaft furnace, substantially cleaned of all CO2 and H2O, and then divided into at least two flow portions one of which is passed to a gas generator comprising a plasma burner. A reducing agent such as pit coal is injected together with a oxidant into the hot gas from the plasma burner so as to form a gas mixture mainly comprising CO and H2, which gas mixture is then mixed with the other flow portion of the cleaned reaction gas in such a proportion that the temperature of the resulting reduction gas is suitable for the reduction of iron oxides in the shaft furnace. The reduction gas is then injected into the shaft furnace and passed upwardly to reduce iron oxides contained there to form sponge iron which is then removed.
Description
~lS~ 2 DESCRIPTION
"METHOD AND APPARATUS FOR MA~UFACTURING SPO GE IRO~"
The present invention relates to a method of, and apparatus for, manufacturing sponge iron.
Despite the fact that pit coal is one of our most plentiful and cheapest energy producing raw materials, it has so far been used only to an extremely limited extent as a reducing agent in the manufacture of sponge iron. This situation persists despite the favorable relationship between price and energy content with respect to pit coal.
Conventional processes for the manufacture of sponge iron in which coal is used as a reducing agent are primarily the following:
a. The rotary furnace method in which pit coal is used together with the ore to be reduced, in an lnclined rotary furnace. The difficulty with this method is that, mainly due to kinetic energy, it is necessary to work with relatively high temperatures, preferably 1000C, which causes considerable problems with clogging and the accumulation of material in the reaction chamber.
b. The use of a shaft furnace combined with equipment for gassification of coal, which is based on partial combustion. The drawback with this known method is primarily the extremely high investment cost for the 1~5~Z~Z
gassification equipment and also the exceptionally high energy consumption.
cO The method, such as is disclosed in Swedish patent No. 73 04 332-5, of directly gassifying coa~ in solid form using a plasma generator. The drawbacks of this method are that the supply of coal must be extremely accurately adjusted and for some grades of coal there are problems in handling the ash. Moreover, the gas produced has a hydrogen content which is lower than the ideal for reduction purposes.
It has now been found that the above difficulties and drawbac~s with the known processes can be substantially eliminated according to the present invention. This invention is directed to a method and appaxatus for manufacturing sponge iron by the continuous reduction of iron oxides in a shaft furnace. The method of the present invention comprises the following steps:
1) removing reaction gas from a shaft f~rnace;
"METHOD AND APPARATUS FOR MA~UFACTURING SPO GE IRO~"
The present invention relates to a method of, and apparatus for, manufacturing sponge iron.
Despite the fact that pit coal is one of our most plentiful and cheapest energy producing raw materials, it has so far been used only to an extremely limited extent as a reducing agent in the manufacture of sponge iron. This situation persists despite the favorable relationship between price and energy content with respect to pit coal.
Conventional processes for the manufacture of sponge iron in which coal is used as a reducing agent are primarily the following:
a. The rotary furnace method in which pit coal is used together with the ore to be reduced, in an lnclined rotary furnace. The difficulty with this method is that, mainly due to kinetic energy, it is necessary to work with relatively high temperatures, preferably 1000C, which causes considerable problems with clogging and the accumulation of material in the reaction chamber.
b. The use of a shaft furnace combined with equipment for gassification of coal, which is based on partial combustion. The drawback with this known method is primarily the extremely high investment cost for the 1~5~Z~Z
gassification equipment and also the exceptionally high energy consumption.
cO The method, such as is disclosed in Swedish patent No. 73 04 332-5, of directly gassifying coa~ in solid form using a plasma generator. The drawbacks of this method are that the supply of coal must be extremely accurately adjusted and for some grades of coal there are problems in handling the ash. Moreover, the gas produced has a hydrogen content which is lower than the ideal for reduction purposes.
It has now been found that the above difficulties and drawbac~s with the known processes can be substantially eliminated according to the present invention. This invention is directed to a method and appaxatus for manufacturing sponge iron by the continuous reduction of iron oxides in a shaft furnace. The method of the present invention comprises the following steps:
1) removing reaction gas from a shaft f~rnace;
2) removing from the reaction gas su~stantially all C02 and H20,
3) dividing the reaction gas into at least two flow portions, L~) passing one of the flow portions to a gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant, heating the reaction gas with the plasma hurner and injecting into 1~54Z~Z
the heated gas solid reducing agent and oxidant to form an intermediate gas mix-ture mainly comprising CO and H2, 5) maintaining the intermedia-te gas mixture at a temperature such tha-t ash contained within the solid reducing agent forms a slag, 6) forming a reduction gas by mixing the intermediate gas mixture with at least one of the o-ther flow portions in such a proportion that the temperature of the reduction gas is suitable for the reduction of iron oxides in a shaft furnace, 7) injecting the reduction gas into the`lower portion of a shaft furnace and passing the reducti.on gas upwardly through -the shaf-t furnace to reduce iron oxides contained in the furnace and produce further reaction gas, and 8) removing reduced iron rom the furnace.
In the present method, a reduction gas is passed counter-current to the iron oxides and consists primarily of C0 and H2, the reduc-tion gas being produced from recirculation gas, i.e. reactlon gas leaving the shaft furnace, as well as an extra gas produced from solid reducing agent such as coal, preferably pi-t coal, with the help of a plasma generator. The recirculation or reaction gas is first substantially cleaned of CO2 and H2O, whereupon the gas thus cleaned is divided into a-t least two portions, one of which is passed to a gas or i~ ~2 plasma generator. The reduciny agent, together with oxidant e.g. water or oxygen, is injected into the hot gas flow leaving the plasma burner so that the oxidant is caused to react with the reducing agent to form a mixture of primarily CO and H2. The temperature level of the gas produced is kept wi-thin such a range that ash included in the solid reducing agent forms a slag. The hot CO-H2 mixture leaving the gas generator is mixed with at least some of the cleaned recirculation or reaction gas in such a proportion that the tempera-ture of the final gas mixture is suitable for the reduction process, Preferably, the temperature level of the gas produced in the gas generating shaft, i.e. the intermediate gas mixture, is adjusted to a temperature of 1300 - 1500C.
It is also preferable, before the final gas mixture is provided as reduction gas to the lower part of the shaft furnace, for its temperature to be brought to within the range 700 - lOOO~C by mixing it with the second flow portion.
The recirculation or reaction gas is preferably cleaned in a gas wash until its content of CO2 is below ~/o.
The present invention also provides an apparàtus for the manufacture of sponge iron comprising:
1) a shaft furnace for the reduction of iron oxides by a reduction gas mainly comprising CO an~ H2;
252) means connected to the upper portion of the shaft furnace for removing reaction yas from the furnace, ~ 21~
3) cleaning means for the removal of C~2 from the reaction gas,
the heated gas solid reducing agent and oxidant to form an intermediate gas mix-ture mainly comprising CO and H2, 5) maintaining the intermedia-te gas mixture at a temperature such tha-t ash contained within the solid reducing agent forms a slag, 6) forming a reduction gas by mixing the intermediate gas mixture with at least one of the o-ther flow portions in such a proportion that the temperature of the reduction gas is suitable for the reduction of iron oxides in a shaft furnace, 7) injecting the reduction gas into the`lower portion of a shaft furnace and passing the reducti.on gas upwardly through -the shaf-t furnace to reduce iron oxides contained in the furnace and produce further reaction gas, and 8) removing reduced iron rom the furnace.
In the present method, a reduction gas is passed counter-current to the iron oxides and consists primarily of C0 and H2, the reduc-tion gas being produced from recirculation gas, i.e. reactlon gas leaving the shaft furnace, as well as an extra gas produced from solid reducing agent such as coal, preferably pi-t coal, with the help of a plasma generator. The recirculation or reaction gas is first substantially cleaned of CO2 and H2O, whereupon the gas thus cleaned is divided into a-t least two portions, one of which is passed to a gas or i~ ~2 plasma generator. The reduciny agent, together with oxidant e.g. water or oxygen, is injected into the hot gas flow leaving the plasma burner so that the oxidant is caused to react with the reducing agent to form a mixture of primarily CO and H2. The temperature level of the gas produced is kept wi-thin such a range that ash included in the solid reducing agent forms a slag. The hot CO-H2 mixture leaving the gas generator is mixed with at least some of the cleaned recirculation or reaction gas in such a proportion that the tempera-ture of the final gas mixture is suitable for the reduction process, Preferably, the temperature level of the gas produced in the gas generating shaft, i.e. the intermediate gas mixture, is adjusted to a temperature of 1300 - 1500C.
It is also preferable, before the final gas mixture is provided as reduction gas to the lower part of the shaft furnace, for its temperature to be brought to within the range 700 - lOOO~C by mixing it with the second flow portion.
The recirculation or reaction gas is preferably cleaned in a gas wash until its content of CO2 is below ~/o.
The present invention also provides an apparàtus for the manufacture of sponge iron comprising:
1) a shaft furnace for the reduction of iron oxides by a reduction gas mainly comprising CO an~ H2;
252) means connected to the upper portion of the shaft furnace for removing reaction yas from the furnace, ~ 21~
3) cleaning means for the removal of C~2 from the reaction gas,
4) means for separating the cleaned reaction gas into at least two flow portions'
5) a gas generator for receiving at least one of the flow portions, said gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant into gas heated by the plasma burner thereby.
to produce an intermediate gas mixture mainly comprising C0 and ~2'
to produce an intermediate gas mixture mainly comprising C0 and ~2'
6) mixing means for the controlled mixing of the intermediate gas mixture with at least one of the other flow portions of the reaction gas to obtain a reduction gas; and
7) means for injecting the reduction gas into the lower portion of the shaft furnace.
Illustrative embodiments of the present invention will now be described, by way of example, with reference to the single figure of the accompanying drawing which illustrates diagrammatically a mode of carrying out the invention.
In the drawing, the reduction of chunks of iron oxide is performed in a reduction shaft furnace 1. The chunks of iron oxide 2 are fed through a sluice valve 3 into the shaft furnace 1 and treated by a counter-current flow of a hot reduction gas consisting primarily of carbon 1~4;Z6Z~
monoxide and hydrogen gas introduced by blowing means at the lower section L~ of the shaft furnace 1. The sponge iron product is removed throug`h an outlet 5 in the bottom 4 of the shaft furnace 1. The reaction gas, 3~/O to 5~/O of which has been reacted, is removed from the upper part of the shaft furnace 1 through an outlet 6.
The gas thus removed from the shaft furnace 1, besides containing from 50% to 70% unreacted C0 and H2, also contains the reaction products C02 and H20. Since this gas still contains relatively high percentages of CO and H2, it is re-usable in the process. However, to enable it to be re-used as reduction gas, the content of C2 and H20 should be reduced preferably to less than S%.
This is achieved by allowing the gas to pass -through a wash (CO2/H20 wash) 7. When the gas passes through this wash, not only is it freed from the reaction products CO2 and ~2' but the actual washing process enables balancing of the gas quantity so that flaring of the gas can be : avoided. The waah 7 may contain mono-ethanol~mine, for instance, as active substance and the con-tent of C02 in the gas can be suitably reduced to below 2% upon passage through the wash.
After the wash 7 the gas passes a compressor 8 to achieve a desirable pressure increase for the process 25 and is then divided into at least two flow portions 9, 10.
~1~6;~
The flow portion 9, which is at room temperature, is introduced under control into a gas generator 11 where the necessary extra gas is generated from a solid reducing agent, preferably coal, and an oxidant, preferably water.
The gas flow 9 is used as~plasma;gas in gas~generator ll and the quantity of energy necessary for~the gas ~
regenerating;process;is s~pplied in~a plasma burner~12.
The main sour~ce~of energy, whloh is ideally coal~`~dust,~
is treated wlth an~oxldant, pre~erably~water~,~and~is~
supplied to the gas~generator ll through jets 13 so that it penetrates the hot gas flow leaving the pla~ma burner 12 in such a manner that solid~reducing~agent and oxidant are brought~to~r~eact and form;CO~and~H2. In order~to ensure a sufflclent degree of reaction as well as proper handling characteristics, ~it is preferred that coal dust ~
i9 used having~ a~part}cle~size;below 20 mesh and preferably below lO0 mesh~ .S.~Standard screen~sizes~
The~supply of~energy in the gas génerator`ll is regulated~;so~that~the~ash eXls~t1ng~1n the coal dust~
is~melted to a~slag 14~which~can be~removed~from~the lower `
part of the ~as generator 11 in li~uid or solid form~.
Due to the composition of the ash, the temperature~is preferably selected to be within the~range 1300 - 1500C, The gas produced in the gas generator ll, besides 2~ containlng CO~and H2, may also contain sulphur inc~1uded~
, in the coal~ This intermediate gas mixture is therefore ~ ::
~:
:.,. ~, , : .
' ~ ~, ' " ', ~:
' , " ~.' : ~ "
~542Ei~
caused to pass a sulphur filter 15 (e.g. a dolomite filter) where the sulphur content is reduced to an acceptable level for the sponge iron process, preferably below 75 ppm.
The gas leaving the sulphur filter 15 is at a temperature substantially in excess of that required for the sponge iron process and the temperature is therefore suitably lowered by using an adjustable mixer to mix in a suitable portion of the cold, untreated,cleaned reaction gas in the flow portion 10 to yield a temperature suitable fox the process - e.g. from 700C, preferably 750C, up to 1000C, more preferably about 825C.
Substantial technical advantages are obtained utilizing the method and apparatus according to the invention. In this regard~ the gas genera-tion can take place at a temperature such that the ash forms slag which is easy to handle and which can be tapped off withou-t causing clogging problems in the process~ The hydrogen content in the reduction gas can be adjusted to an amount ; suitable for the reduction process by means of the washing process and subsequent injection of water into the gas yenerator. Furthermoxe the combination of gas washing and gas generation at increased -temperatures offers superior possibilities of balancing the quantity of gas in the system and regulating the reduction temperature.
At the same time, energy efficiency is achieved since the energy supplied by the gas or plasma generator is - g -substantially completely used in the process (i.e.
temperature adjustment is accomplished by adding cooler recycled reduction gas rather than by removing heat from the system).
In experiments on a test scale the following consumption values per ton produced sponge iron were achieved:
Electric energy: 820 kWh Coal pit powder: 172 kg Furthermore, the process according to the invention is much simpler to regulate. Simpler and more efficient regulation of the en-tire process may be achieved - in the generation of the plasma gas in a preferred embodiment by pre-mixing coal dust and added water in the correct proportions, preferably in stoichiometric proportions. Due to this pre-mixing of coal dust and water, the mixture is also easier to inject in the foYm of a coal-in-water emulsion.
Should difficulties arise in binding the ash from the solid reducing agent in a slag phase, additives affecting the properties (e.g. melting point, sulphur absorption, etc.) of the slag may be used,such as alkali compounds and chalk. These additives are preferably mixed with the solid reducing agen-t. Suitable gel-formers may be added in order to stabilize the coal-water mixture and oxygen may be supplied to the gas generator 11 in the form of oxygen gas instead of water.
,., ~
Illustrative embodiments of the present invention will now be described, by way of example, with reference to the single figure of the accompanying drawing which illustrates diagrammatically a mode of carrying out the invention.
In the drawing, the reduction of chunks of iron oxide is performed in a reduction shaft furnace 1. The chunks of iron oxide 2 are fed through a sluice valve 3 into the shaft furnace 1 and treated by a counter-current flow of a hot reduction gas consisting primarily of carbon 1~4;Z6Z~
monoxide and hydrogen gas introduced by blowing means at the lower section L~ of the shaft furnace 1. The sponge iron product is removed throug`h an outlet 5 in the bottom 4 of the shaft furnace 1. The reaction gas, 3~/O to 5~/O of which has been reacted, is removed from the upper part of the shaft furnace 1 through an outlet 6.
The gas thus removed from the shaft furnace 1, besides containing from 50% to 70% unreacted C0 and H2, also contains the reaction products C02 and H20. Since this gas still contains relatively high percentages of CO and H2, it is re-usable in the process. However, to enable it to be re-used as reduction gas, the content of C2 and H20 should be reduced preferably to less than S%.
This is achieved by allowing the gas to pass -through a wash (CO2/H20 wash) 7. When the gas passes through this wash, not only is it freed from the reaction products CO2 and ~2' but the actual washing process enables balancing of the gas quantity so that flaring of the gas can be : avoided. The waah 7 may contain mono-ethanol~mine, for instance, as active substance and the con-tent of C02 in the gas can be suitably reduced to below 2% upon passage through the wash.
After the wash 7 the gas passes a compressor 8 to achieve a desirable pressure increase for the process 25 and is then divided into at least two flow portions 9, 10.
~1~6;~
The flow portion 9, which is at room temperature, is introduced under control into a gas generator 11 where the necessary extra gas is generated from a solid reducing agent, preferably coal, and an oxidant, preferably water.
The gas flow 9 is used as~plasma;gas in gas~generator ll and the quantity of energy necessary for~the gas ~
regenerating;process;is s~pplied in~a plasma burner~12.
The main sour~ce~of energy, whloh is ideally coal~`~dust,~
is treated wlth an~oxldant, pre~erably~water~,~and~is~
supplied to the gas~generator ll through jets 13 so that it penetrates the hot gas flow leaving the pla~ma burner 12 in such a manner that solid~reducing~agent and oxidant are brought~to~r~eact and form;CO~and~H2. In order~to ensure a sufflclent degree of reaction as well as proper handling characteristics, ~it is preferred that coal dust ~
i9 used having~ a~part}cle~size;below 20 mesh and preferably below lO0 mesh~ .S.~Standard screen~sizes~
The~supply of~energy in the gas génerator`ll is regulated~;so~that~the~ash eXls~t1ng~1n the coal dust~
is~melted to a~slag 14~which~can be~removed~from~the lower `
part of the ~as generator 11 in li~uid or solid form~.
Due to the composition of the ash, the temperature~is preferably selected to be within the~range 1300 - 1500C, The gas produced in the gas generator ll, besides 2~ containlng CO~and H2, may also contain sulphur inc~1uded~
, in the coal~ This intermediate gas mixture is therefore ~ ::
~:
:.,. ~, , : .
' ~ ~, ' " ', ~:
' , " ~.' : ~ "
~542Ei~
caused to pass a sulphur filter 15 (e.g. a dolomite filter) where the sulphur content is reduced to an acceptable level for the sponge iron process, preferably below 75 ppm.
The gas leaving the sulphur filter 15 is at a temperature substantially in excess of that required for the sponge iron process and the temperature is therefore suitably lowered by using an adjustable mixer to mix in a suitable portion of the cold, untreated,cleaned reaction gas in the flow portion 10 to yield a temperature suitable fox the process - e.g. from 700C, preferably 750C, up to 1000C, more preferably about 825C.
Substantial technical advantages are obtained utilizing the method and apparatus according to the invention. In this regard~ the gas genera-tion can take place at a temperature such that the ash forms slag which is easy to handle and which can be tapped off withou-t causing clogging problems in the process~ The hydrogen content in the reduction gas can be adjusted to an amount ; suitable for the reduction process by means of the washing process and subsequent injection of water into the gas yenerator. Furthermoxe the combination of gas washing and gas generation at increased -temperatures offers superior possibilities of balancing the quantity of gas in the system and regulating the reduction temperature.
At the same time, energy efficiency is achieved since the energy supplied by the gas or plasma generator is - g -substantially completely used in the process (i.e.
temperature adjustment is accomplished by adding cooler recycled reduction gas rather than by removing heat from the system).
In experiments on a test scale the following consumption values per ton produced sponge iron were achieved:
Electric energy: 820 kWh Coal pit powder: 172 kg Furthermore, the process according to the invention is much simpler to regulate. Simpler and more efficient regulation of the en-tire process may be achieved - in the generation of the plasma gas in a preferred embodiment by pre-mixing coal dust and added water in the correct proportions, preferably in stoichiometric proportions. Due to this pre-mixing of coal dust and water, the mixture is also easier to inject in the foYm of a coal-in-water emulsion.
Should difficulties arise in binding the ash from the solid reducing agent in a slag phase, additives affecting the properties (e.g. melting point, sulphur absorption, etc.) of the slag may be used,such as alkali compounds and chalk. These additives are preferably mixed with the solid reducing agen-t. Suitable gel-formers may be added in order to stabilize the coal-water mixture and oxygen may be supplied to the gas generator 11 in the form of oxygen gas instead of water.
,., ~
Claims (19)
1. A method of manufacturing sponge iron by continuous reduction of iron oxides in a shaft furnace utilising recirculation furnace gases; which process comprises:
1) removing reaction gas from a shaft furnace, 2) removing from the reaction gas substantially all CO2 and H2O;
3) dividing the reaction gas into at least two flow portions;
4) passing one of the flow portions to a gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant, heating the reaction gas with the plasma burner and injecting into the heated gas solid reducing agent and oxidant to form an intermediate gas mixture mainly comprising CO and H2, 5) maintaining the intermediate gas mixture at a temperature such that ash contained within the solid reducing agent forms a slag, 6) forming a reduction gas by mixing the intermediate gas mixture with at least one of the other flow portions in such a proportion that the temperature of the reduction gas is suitable for the reduction of iron oxides in a shaft furnace;
7) injecting the reduction gas into the lower portion of a shaft furnace and passing the reduction gas upwardly through the shaft furnace to reduce iron oxides contained in the furnace and produce further reaction gas;
and 8) removing reduced iron from the furnace.
1) removing reaction gas from a shaft furnace, 2) removing from the reaction gas substantially all CO2 and H2O;
3) dividing the reaction gas into at least two flow portions;
4) passing one of the flow portions to a gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant, heating the reaction gas with the plasma burner and injecting into the heated gas solid reducing agent and oxidant to form an intermediate gas mixture mainly comprising CO and H2, 5) maintaining the intermediate gas mixture at a temperature such that ash contained within the solid reducing agent forms a slag, 6) forming a reduction gas by mixing the intermediate gas mixture with at least one of the other flow portions in such a proportion that the temperature of the reduction gas is suitable for the reduction of iron oxides in a shaft furnace;
7) injecting the reduction gas into the lower portion of a shaft furnace and passing the reduction gas upwardly through the shaft furnace to reduce iron oxides contained in the furnace and produce further reaction gas;
and 8) removing reduced iron from the furnace.
2. A method according to claim 1 wherein the oxidant is water or oxygen.
3. A method according to claim 2 wherein, in step 5), the intermediate gas mixture is maintained at 1300° to 1500°C.
4. A method according to claim 3 wherein, in step 6), the intermediate gas mixture is mixed with at least one other flow portion in such a proportion that the temperature of the resulting reduction gas prior to injection into the shaft furnace is 700°C to 1000°C.
5. A method according to claim 4 wherein the temperature of the reduction gas prior to injection into the shaft furnace is approximately 825°C.
6. A method according to claim 1 wherein, in step 2), CO2 and H2O is removed from the reaction gas by means of a gas wash until the content of CO2 is less than 2%.
7. A method according to claim 1 wherein the reducing agent is coal.
8. A method according to claim 7 wherein the reducing agent is coal dust.
9. A method according to claim 8 wherein the reducing agent is pit coal dust.
10. A method according to claim 8 wherein the reducing agent is coal dust having a particle size below 20 mesh.
11. A method according to claim 10 wherein the reducing agent is coal dust having a particle size below 100 mesh.
12. A method according to any one of claims 1 to 3 wherein the intermediate gas mixture is passed through a sulphur filter.
13. Apparatus for the manufacture of sponge iron by the continuous reduction of iron oxides comprising:
1) a shaft furnace for the reduction of iron oxides by a reduction gas mainly comprising CO and H2;
2) means connected to the upper portion of the shaft furnace for removing reaction gas from the furnace, 3) cleaning means for the removal of CO2 from the reaction gas, 4) means for separating the cleaned reaction gas into at least two flow portions;
5) a gas generator for receiving at least one of the flow portions, said gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant into gas heated by the plasma burner thereby to produce an intermediate gas mixture mainly comprising CO and H2;
6) mixing means for the controlled mixing of the intermediate gas mixture with at least one of the other flow portions of the reaction gas to obtain a reduction gas, and 7) means for injecting the reduction gas into the lower portion of the shaft furnace.
1) a shaft furnace for the reduction of iron oxides by a reduction gas mainly comprising CO and H2;
2) means connected to the upper portion of the shaft furnace for removing reaction gas from the furnace, 3) cleaning means for the removal of CO2 from the reaction gas, 4) means for separating the cleaned reaction gas into at least two flow portions;
5) a gas generator for receiving at least one of the flow portions, said gas generator comprising a plasma burner and means for injecting solid reducing agent and oxidant into gas heated by the plasma burner thereby to produce an intermediate gas mixture mainly comprising CO and H2;
6) mixing means for the controlled mixing of the intermediate gas mixture with at least one of the other flow portions of the reaction gas to obtain a reduction gas, and 7) means for injecting the reduction gas into the lower portion of the shaft furnace.
14. Apparatus according to claim 13 wherein the cleaning means comprises a CO2 wash.
15. Apparatus according to claim 13 wherein the CO2 wash contains mono-ethanolamine as the active agent.
16. Apparatus according to claim 13, 14 or 15 including a compressor located between the cleaning means and the means for separating the cleaned reaction gas.
17. Apparatus according to claim 13, 14 or 15 wherein the gas generator is provided with means for removing slag.
18. Apparatus according to claim 13, 14 or 15 including a sulphur filter between the gas generator and the mixing means.
19. Apparatus according to claim 13, 14 or 15 wherein the means for injecting solid reducing agent and oxidant has an injection area immediately in front of the plasma burner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000371472A CA1154262A (en) | 1981-02-23 | 1981-02-23 | Method and apparatus for manufacturing sponge iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000371472A CA1154262A (en) | 1981-02-23 | 1981-02-23 | Method and apparatus for manufacturing sponge iron |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1154262A true CA1154262A (en) | 1983-09-27 |
Family
ID=4119263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000371472A Expired CA1154262A (en) | 1981-02-23 | 1981-02-23 | Method and apparatus for manufacturing sponge iron |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1154262A (en) |
-
1981
- 1981-02-23 CA CA000371472A patent/CA1154262A/en not_active Expired
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