US3902844A - Method for operating a hot blast stove - Google Patents
Method for operating a hot blast stove Download PDFInfo
- Publication number
- US3902844A US3902844A US478499A US47849974A US3902844A US 3902844 A US3902844 A US 3902844A US 478499 A US478499 A US 478499A US 47849974 A US47849974 A US 47849974A US 3902844 A US3902844 A US 3902844A
- Authority
- US
- United States
- Prior art keywords
- regenerator
- air
- heat
- combustion gas
- hot blast
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000000567 combustion gas Substances 0.000 claims abstract description 29
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 20
- 239000011593 sulfur Substances 0.000 claims abstract description 20
- 239000000446 fuel Substances 0.000 claims abstract description 17
- 239000002253 acid Substances 0.000 claims abstract description 13
- 238000010438 heat treatment Methods 0.000 claims description 15
- 238000007664 blowing Methods 0.000 claims description 7
- 238000012546 transfer Methods 0.000 claims description 5
- 230000003134 recirculating effect Effects 0.000 claims description 2
- 230000007797 corrosion Effects 0.000 abstract description 9
- 238000005260 corrosion Methods 0.000 abstract description 9
- 239000007789 gas Substances 0.000 description 7
- 238000003723 Smelting Methods 0.000 description 4
- 239000011449 brick Substances 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 3
- 230000008929 regeneration Effects 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000000295 fuel oil Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B9/00—Stoves for heating the blast in blast furnaces
- C21B9/14—Preheating the combustion air
Definitions
- ABSTRACT A method for operating a hot blast stove in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to heat up the regenerator and air subsequently is blown through the regenerator and is heated by heat-exchange with the heat built up in the regenerator, the improvement comprising preheating the air to a temperature above the acid dew point of the combustion gas whereby corrosion of the regenerator by sulfur is prevented.
- This invention relates to a method for operating a hot blast stove in which a sulfur-containing fuel is burned.
- this invention relates to a method for operating a hot blast stove without causing corrosion of the regenerator structure.
- a fuel is burned in a combustion furnace which is separate from a regenerator, and then, the combustion gas is passed through the regenerator to transfer the heat of the combustion gas to the regenerator, with the combustion gas being passed through the regenerator for about 30 to 55 minutes to achieve a wall temperature of about 250 to 350C.
- air at room temperature is introduced into the regenerator generally from the side of the outlet of the combustion gas from the regenerator and is brought into contact with the regenerator to recover the heat as hot blast. In this case, the temperature of the section of the regenerator near the air inlet of the regenerator drops to about 50C.
- the amount of corrosion of a steel material in general. for example, is to 50 mg/dm Hr. If the lifetime of a hot blast stove can be calculated on this basis, a hot blast stove should be renewed every eight years when it is operated in the conventional method. This is about half of the inherent lifetime. Generally speaking. the inherent lifetime of a hot blast stove is about yearsv In order to avoid this, fuels containing large quantities of sulfur have not been employed as a heat source.
- .it is an object of this invention to remove these defects of the conventional methods, and to provide a method for operating a hot blast stove which permits the use of a fuel having a high sulfur content which could not be used previously.
- the present invention provides a method for operating a hot blast stove of the type in which a combustion gas of asulfurcontaining fuel is passed through a regenerator and the regenerator heated up, followed by the blowing of air through the regenerator to heat the air using the heat built up in the regenerator, comprising preheating the air to be blown through the regenerator to a temperature above the acid dew point of the combustion gas prior to blowing the air through the regenerator.
- the hot blast stove is operated so that the temperature of every part of the regenerator is not below the acid dew point of the combustion gas.
- the air to be blown for about 35 to 60 minutes through the regenerator generally at 500 to 650 Nm"/min, for producing the hot blast is pre-heated toa temperature above the acid dew point. preferably at least about C above the acid dew point, so that upon blowing the pre-heated air through the regenerator, the temperature of the regenerator is maintained always at a temperature above the acid dew point.
- the range of acid dew point of the exhaust gas can not be unequivocably defined.
- the acid dew point is dependent upon the sulfur content of the fuel, and the water content in the exhaust gas. Therefore, the heating temperature for the blast air is determined by the fuel used. Generally, a pre-heating temperature of about 200C to about 250C is sufficient.
- the preheating of the air blast can be by any known method, but a method for heating using steam, or a method of heating by circulating a part of the high temperature hot blast is preferred.
- EXAMPLE A hot blast stove which was used to provide a feed hot blast to a smelting furnace for smelting a copper ore and which had a regenerating capacity of 6,700,000 Kcal per hour was used.
- a heavy oil containing 2 percent of sulfur was burned at a rate of 1,000 liters per hour, and the burning was stopped when the temperature of the brick at the outlet of the combustion exhaust gas of the hot stove reached 350C.
- air was pre-heated to 200C with superheated steam, and then fed to the hot blast stove at a rate of 500 Nm per minute.
- the supply of the blast was stopped when the hot blast temperature fed to the smelting furnace could not be maintained at 900C, and the operation was switched over to one for regeneration.
- the time required for regeneration was about minutes, and the time for supplying the hot blast was about minutes.
- the regenerator can be heated to the desired temperature even if the combustion time is shorter than in conventional method.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Air Supply (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
A method for operating a hot blast stove in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to heat up the regenerator and air subsequently is blown through the regenerator and is heated by heat-exchange with the heat built up in the regenerator, the improvement comprising preheating the air to a temperature above the acid dew point of the combustion gas whereby corrosion of the regenerator by sulfur is prevented.
Description
United States Patent Higashi Sept. 2, 1975 [75] Inventor: Masaru Higashi, Hitachi. Japan [73] Assignee: Nippon Mining Co., Ltd., Tokyo.
Japan [22] Filed: June 12, 1974 [21] Appl. No.: 478,499
[52] US. Cl 432/30; 432/214 [51] Int. Cl. F2411 7/00 [58] Field of Search 432/30, 214, 217, 218
[56] References Cited UNITED STATES PATENTS 1,880,229 10/1932 Andrews ct a1 1. 432/30 2,171,596 9/1939 Parker 432/30 X 3.061.292 10/1962 Kinncy 432/30 Primary E \'uminer.lohn J. Camby Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn and Macpeak 5 7 ABSTRACT A method for operating a hot blast stove in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to heat up the regenerator and air subsequently is blown through the regenerator and is heated by heat-exchange with the heat built up in the regenerator, the improvement comprising preheating the air to a temperature above the acid dew point of the combustion gas whereby corrosion of the regenerator by sulfur is prevented.
4 Claims, N0 Drawings METHOD FOR OPERATING A HOT BLAST STOVE BACKGROUND OF THE INVENTION 1. Field of the Invention g This invention relates to a method for operating a hot blast stove in which a sulfur-containing fuel is burned.
with the heat of the combustion gas being stored in-a regenerator, and with the air to be heated by the regenerator being brought into contact with the regenerator for heat exchange. More specifically. this invention relates to a method for operating a hot blast stove without causing corrosion of the regenerator structure.
2. Description of the Prior Art It is customary to introduce a hot blast into a smelting furnace in order to smelt ores. Various methods are available to generate heat for the hot blast. Generally, however. prior techniques have employed a method in which an iron blast furnace gas is used, or a method in which a fuel is burned and the sensible heat of the exhaust gas is utilized. The sensible heat of the exhaust I gas is stored generally in a heat-receiving device constructed of bricks, by passing the exhaust gas through the heat-receiving device. This heat-receiving device is generally called a regenerator. ln operation, when the temperature of the regenerator has reached a fixed level, the flow of the combustion gas is stopped, and then air is blown in an opposite direction to the combustion gas flow, so that air is heated with the heat stored in the regenerator. As a result of this operation air is heated to a fixed temperature and usually. all of this equipment is called a hot blast stove.
Thus, in a hot blast stove operation. a fuel is burned in a combustion furnace which is separate from a regenerator, and then, the combustion gas is passed through the regenerator to transfer the heat of the combustion gas to the regenerator, with the combustion gas being passed through the regenerator for about 30 to 55 minutes to achieve a wall temperature of about 250 to 350C. Then, in order to use the stored heat for a desired purpose, air at room temperature is introduced into the regenerator generally from the side of the outlet of the combustion gas from the regenerator and is brought into contact with the regenerator to recover the heat as hot blast. In this case, the temperature of the section of the regenerator near the air inlet of the regenerator drops to about 50C.
However, in such a method for operating a hot blast stove, a sulfur free heat source is required. When the sulfur content of the fuel is less than 0.2 percent, S which is a main cause of corrosion is scarcely formed, and therefore, no consideration on the corrosion of the stove due to the sulfur is needed. However when the sulfur content is higher, corrosion of the regenerator in contact with the combustion gas occurs, and the regenerator can be damaged or destroyed.
It is said that when a heavy oil containing 2% of sulfur is used as a fuel, the amount of corrosion of a steel material in general. for example, is to 50 mg/dm Hr. If the lifetime of a hot blast stove can be calculated on this basis, a hot blast stove should be renewed every eight years when it is operated in the conventional method. This is about half of the inherent lifetime. Generally speaking. the inherent lifetime of a hot blast stove is about yearsv In order to avoid this, fuels containing large quantities of sulfur have not been employed as a heat source.
SUMMARY or THE- INVENTION Accordingly, .it is an object of this invention to remove these defects of the conventional methods, and to provide a method for operating a hot blast stove which permits the use of a fuel having a high sulfur content which could not be used previously.
The present invention provides a method for operating a hot blast stove of the type in which a combustion gas of asulfurcontaining fuel is passed through a regenerator and the regenerator heated up, followed by the blowing of air through the regenerator to heat the air using the heat built up in the regenerator, comprising preheating the air to be blown through the regenerator to a temperature above the acid dew point of the combustion gas prior to blowing the air through the regenerator.
DETAILED DESCRIPTION OF THE INVENTION According to this process, the hot blast stove is operated so that the temperature of every part of the regenerator is not below the acid dew point of the combustion gas. In order to achieve this, the air to be blown for about 35 to 60 minutes through the regenerator, generally at 500 to 650 Nm"/min, for producing the hot blast is pre-heated toa temperature above the acid dew point. preferably at least about C above the acid dew point, so that upon blowing the pre-heated air through the regenerator, the temperature of the regenerator is maintained always at a temperature above the acid dew point.
The range of acid dew point of the exhaust gas can not be unequivocably defined. The acid dew point is dependent upon the sulfur content of the fuel, and the water content in the exhaust gas. Therefore, the heating temperature for the blast air is determined by the fuel used. Generally, a pre-heating temperature of about 200C to about 250C is sufficient. The preheating of the air blast can be by any known method, but a method for heating using steam, or a method of heating by circulating a part of the high temperature hot blast is preferred.
The following example illustrates the method of this invention more specifically. Unless otherwise indicated all parts, and percents are by weight.
EXAMPLE A hot blast stove which was used to provide a feed hot blast to a smelting furnace for smelting a copper ore and which had a regenerating capacity of 6,700,000 Kcal per hour was used. A heavy oil containing 2 percent of sulfur was burned at a rate of 1,000 liters per hour, and the burning was stopped when the temperature of the brick at the outlet of the combustion exhaust gas of the hot stove reached 350C. After regeneration, using a heat exchanger separately provided, air was pre-heated to 200C with superheated steam, and then fed to the hot blast stove at a rate of 500 Nm per minute. The supply of the blast was stopped when the hot blast temperature fed to the smelting furnace could not be maintained at 900C, and the operation was switched over to one for regeneration. The time required for regeneration was about minutes, and the time for supplying the hot blast was about minutes. These operations were repeated alternately. After a lapse of about 6 months, scarcely any appreciable corrosion or damage of the stove was observed.
Since the damage of the regenerator by corrosion can be prevented by operating the hot blast stove in accordance with the method of this invention. fuels having a slightly higher sulfur content, e.g., up to about 3 percent and higher as desired, can also be utilized. Thus,
use of such a higher sulfur content has not been possible with prior approaches as set forth above. The shortened lifetime of the stove, estimated at about 8 years in the conventional method, can be obviated. Rather, since the pre-heating of air to be supplied also causes a decrease in the periodical change in thermal expansion, it is expected that the brick collapsing of the hot blast stove due to thermal stresses on the brick can be prolonged.
Furthermore, because of the air pre-heating, the regenerator can be heated to the desired temperature even if the combustion time is shorter than in conventional method.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
What is claimed is:
l. A method of operating a hot blast stove of the type in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to transfer the heat of the combustion gas to the regenerator, and subsequently air is blown through the regenerator to heat the air and utilize the heat stored in the regenerator, the improvement comprising pre-heating the air to be passed through the regenerator to a temperature above the acid dew point of said combustion gas prior to blowing the air through the regenerator, said pre-heating taking placing by recirculating a portion of the air passed through the regenerator.
2. The method of claim 1, wherein said pre-heating is to a temperature of at least about 200C.
3. The method of claim 1, wherein the passing of combustion gas through the regenerator and the passing of air is conducted alternately.
4. A method for operating a hot blast stove of the type in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to transfer the heat of the combustion gas to the regenerator and subsequently air is blown through the regenerator to heat the air and utilize the heat stored in the regenerator, the improvement comprising pre-heating the air to be passed through the regenerator to a temperature above the acid dew point of said combustion gas prior to blowing the air through the regenerator, said preheating taking place by using steam.
UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION Q PATENT NO. 3, 902, 844
DATED September 2, 1975 INVENTOR(5) I Masaru HIGASHI It is certified that error appears in the abcve-identified patent and that said Letters Patent q are hereby corrected as shown below:
IN THE HEADING: I
The CTaimed Priority Data was omitted: Should read; --June 12, 1973 Japa.n----'-----65363/73 Signed and Sealed this twenty-fourth Day of February 1976 Q [SEAL] Arrest: i r RUTH c. MASON c. MARSHALL DANN AIM-Wing ff ('mnmissiuru'r uj'Parenrs and Trademarks
Claims (4)
1. A method of operating a hot blast stove of the type in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to transfer the heat of the combustion gas to the regenerator, and subsequently air is blown through the regenerator to heat the air and utilize the heat stored in the regenerator, the improvement comprising pre-heating the air to be passed through the regenerator to a temperature above the acid dew point of said combustion gas prior to blowing the air through the regenerator, said pre-heating taking placing by recirculating a portion of the air passed through the regenerator.
2. The method of claim 1, wherein said pre-heating is to a temperature of at least about 200*C.
3. The method of claim 1, wherein the passing of combustion gas through the regenerator and the passing of air is conducted alternately.
4. A method for operating a hot blast stove of the type in which a combustion gas of a sulfur-containing fuel is passed through a regenerator to transfer the heat of the combustion gas to the regenerator and subsequently air is blown through the regenerator to heat the air and utilize the heat stored in the regenerator, the improvement comprising pre-heating the air to be passed through the regenerator to a temperature above the acid dew point of said combustion gas prior to blowing the air through the regenerator, said pre-heating taking place by using steam.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP48065363A JPS5014506A (en) | 1973-06-12 | 1973-06-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3902844A true US3902844A (en) | 1975-09-02 |
Family
ID=13284789
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US478499A Expired - Lifetime US3902844A (en) | 1973-06-12 | 1974-06-12 | Method for operating a hot blast stove |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US3902844A (en) |
| JP (1) | JPS5014506A (en) |
| CA (1) | CA1080211A (en) |
| PH (1) | PH10883A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4022573A (en) * | 1974-09-20 | 1977-05-10 | S.A. Des Anciens Etablissements Paul Wurth | Hot blast stove and method of operation |
| US4145033A (en) * | 1974-09-20 | 1979-03-20 | S.A. Des Anciens Etablissements Paul Wurth | Hot blast stove and method of operation |
| CN101634529B (en) * | 2008-07-25 | 2012-09-05 | 上海雷林工程技术有限公司 | Preheating system of plate heat exchanger of hot blast furnace |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5837108A (en) * | 1981-08-28 | 1983-03-04 | Ishikawajima Harima Heavy Ind Co Ltd | Preventing method for dew point corrosion of checker bracket by sulfuric acid in hot stove |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1880229A (en) * | 1928-03-22 | 1932-10-04 | Brassert & Co | Air heating |
| US2171596A (en) * | 1934-09-11 | 1939-09-05 | George M Parker | Continuous process of gas making |
| US3061292A (en) * | 1959-06-22 | 1962-10-30 | Kinney Eng Inc S P | Blast heating system for blast furnaces and method of operating the same |
-
1973
- 1973-06-12 JP JP48065363A patent/JPS5014506A/ja active Pending
-
1974
- 1974-06-04 CA CA201,650A patent/CA1080211A/en not_active Expired
- 1974-06-11 PH PH15931A patent/PH10883A/en unknown
- 1974-06-12 US US478499A patent/US3902844A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1880229A (en) * | 1928-03-22 | 1932-10-04 | Brassert & Co | Air heating |
| US2171596A (en) * | 1934-09-11 | 1939-09-05 | George M Parker | Continuous process of gas making |
| US3061292A (en) * | 1959-06-22 | 1962-10-30 | Kinney Eng Inc S P | Blast heating system for blast furnaces and method of operating the same |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4022573A (en) * | 1974-09-20 | 1977-05-10 | S.A. Des Anciens Etablissements Paul Wurth | Hot blast stove and method of operation |
| US4145033A (en) * | 1974-09-20 | 1979-03-20 | S.A. Des Anciens Etablissements Paul Wurth | Hot blast stove and method of operation |
| CN101634529B (en) * | 2008-07-25 | 2012-09-05 | 上海雷林工程技术有限公司 | Preheating system of plate heat exchanger of hot blast furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1080211A (en) | 1980-06-24 |
| PH10883A (en) | 1977-09-30 |
| JPS5014506A (en) | 1975-02-15 |
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