CN110643772A - Online cutting process for flue gas pipeline in waste heat recovery area of blast furnace hot blast stove - Google Patents
Online cutting process for flue gas pipeline in waste heat recovery area of blast furnace hot blast stove Download PDFInfo
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- CN110643772A CN110643772A CN201910320542.XA CN201910320542A CN110643772A CN 110643772 A CN110643772 A CN 110643772A CN 201910320542 A CN201910320542 A CN 201910320542A CN 110643772 A CN110643772 A CN 110643772A
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- flue gas
- preheater
- gas
- air
- hot blast
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B9/00—Stoves for heating the blast in blast furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B9/00—Stoves for heating the blast in blast furnaces
- C21B9/10—Other details, e.g. blast mains
Abstract
The invention relates to an online cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove, which comprises the following process steps: step one, enabling an air preheater and a gas preheater to exit a hot blast stove waste heat recovery system; turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater; thirdly, manually opening outlet valves of the two flue gas preheater, introducing nitrogen, driving internal gas, and completely pumping the mixed gas out of the flue gas preheater under the action of the suction force of a chimney; and fourthly, stopping introducing nitrogen, and enabling air to enter the flue gas preheater from the manhole under the action of suction force of the chimney, so that safe cutting can be realized. The cutting of the flue gas pipeline in the waste heat recovery area can be completed before the blast furnace is shut down, the shut down time of the transformation of the blast furnace matched with the preheater is greatly shortened, and the influence on the production of the blast furnace is reduced.
Description
Technical Field
The invention belongs to the technical field of treatment processes of blast furnace hot blast stove equipment, and relates to an online cutting process of a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove.
Background
In the transformation process of the waste heat recovery area preheater of the blast furnace hot blast stove, if the flue gas blind plate valve on the inner side of the electric butterfly valve of the flue fails, the flue pipe on the inner side of the electric butterfly valve needs to be cut and welded with a blind plate, and the blind plate is thoroughly separated from the flue gas system of the original hot blast stove. The heat insulation of the inner wall of the flue pipeline adopts the prior construction technology of anchoring parts and spraying coating layers: after the blast furnace damping down hot blast stove stops burning (blowing), the flue pipeline is cut and a blind plate is welded. The process is slow in field construction, and the recovery of production of the blast furnace on time is often severely restricted.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides the online cutting process for the flue gas pipeline in the waste heat recovery area of the blast furnace hot blast stove, the cutting of the flue gas pipeline in the waste heat recovery area can be completed before the blast furnace stops blowing down, the blowing down time of the blast furnace in cooperation with the transformation of a preheater is greatly shortened, and the influence on the production of the blast furnace is reduced.
The technical scheme adopted by the invention for solving the technical problems is as follows: an on-line cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove comprises the following process steps:
firstly, opening a bypass valve of flue gas, air and coal gas of a hot blast stove, then closing a butterfly valve of an inlet and an outlet of the flue gas, the air and the coal gas, manually confirming the closing on site, and enabling an air preheater and a coal gas preheater to exit a waste heat recovery system of the hot blast stove;
turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater;
manually opening outlet valves of the two flue gas preheaters by 10-20%, simultaneously opening all manholes in the flue gas preheaters, binding the gas alarm on a rod, extending into the flue gas preheaters for confirmation again, extending a nitrogen rubber pipe into the flue gas preheaters from the manholes, introducing nitrogen, driving internal gas, and completely pumping the mixed gas away from the flue gas preheaters under the action of the suction force of a chimney;
and fourthly, stopping introducing nitrogen after 20-30 minutes, and allowing air to enter the flue gas preheater from the manhole to replace the original residual mixed gas under the action of the suction force of the chimney, wherein the flue gas pipeline has the condition of safe cutting in advance after 10-20 minutes.
In the second step, if atmospheric air is pumped inwards, the interior of the flue gas preheater can be determined to be in a negative pressure state; the gas concentration is displayed as 0 PPm, and the fact that no gas leaks or residual gas exists in the smoke preheater can be determined.
Because of carrying out flue gas pipeline on-line cutting operation under the normal production condition of hot-blast furnace, the prerequisite of this technique implementation: detecting the content of CO in the flue gas of the hot blast stove to be qualified; the inlet butterfly valve of the flue gas preheater has good sealing condition after being closed.
Introducing nitrogen to the tail end of the flue header pipe before cutting to dilute and protect the flue gas; during the process of starting the hot blast stove, the air-fuel ratio is regulated to prevent a large amount of unburned gas from entering a flue main pipe.
The invention has the positive effects that:
under the normal production condition of the hot blast stove, the cutting of the flue pipeline is completed in advance, the damping down time of the transformation of the blast furnace matched with the preheater is greatly shortened, and the influence on the production of the blast furnace is reduced. The method is safe and controllable, can be popularized to the modification process of large, medium and small blast furnaces in hot blast stove preheaters in the same industry, and the flue gas blind plate valve is invalid, so that the flue pipe needs to be cut.
Drawings
FIG. 1 is a schematic view of example 1.
In the figure: 1-first flue gas inlet valve, 2-second flue gas inlet valve, 3-gas outlet valve, 4-thermometer, 5-gas bypass valve, 6-inspection manhole, 7-gas outlet valve, 8-first flue gas outlet valve, 9-second flue gas outlet valve, 10-combustion air inlet valve, 11-air bypass valve, 12-combustion air outlet valve, 13-flue gas bypass valve, 14-first flue gas preheater, 15-second flue gas preheater, 16-chimney, 17-gas preheater, 18-air preheater and 19-hot blast stove.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1
Referring to FIG. 1, 3200m at a company3The application in the transformation process of the preheater of the blast furnace hot blast stove comprises the following technical processes:
firstly, opening a flue gas bypass valve 13, an air bypass valve 11 and a coal gas bypass valve 5 of a hot blast stove 19, then closing a flue gas inlet valve 1, a flue gas inlet valve 2, a flue gas outlet valve 8, a flue gas outlet valve 9, a combustion air inlet valve 10, a combustion air outlet valve 12, a coal gas inlet valve 7 and a coal gas outlet valve 3, manually confirming on site, and enabling an original air preheater 18 and a coal gas preheater 17 to exit a waste heat recovery system of the hot blast stove 19.
And secondly, turning on thermometers 4 on the two flue gas preheaters to confirm the internal conditions of the flue gas preheaters. If the airflow is pumped inwards, the negative pressure state inside the first flue gas preheater 14 and the second flue gas preheater 15 can be determined; the gas concentration is displayed as 0 PPm, and the fact that no gas leaks or residual gas exists in the smoke preheater can be determined.
And thirdly, manually opening the first flue gas outlet valve 8, the first flue gas outlet valve 9 and the combustion air inlet valve 10 by about 10-20% on site, and opening an inspection manhole 6 on the flue gas preheater. And binding the gas alarm on the stick to go deep into the first flue gas preheater 14 and the second flue gas preheater 15 for confirmation again. The nitrogen rubber pipe is deeply arranged in the smoke preheater 1 and the smoke preheater 2 from the manhole to drive the internal gas, and the mixed gas is completely pumped out of the smoke preheater 1 and the smoke preheater 2 under the action of the suction force of the chimney.
And fourthly, closing the nitrogen after 20-30 minutes, and replacing the original residual mixed gas by allowing the atmosphere to enter the flue gas preheater 1 and the flue gas preheater 2 from the manhole under the action of the suction force of the chimney, wherein the flue gas pipeline has an early cutting condition after 10-20 minutes.
Because of the on-line action under the normal production condition of the hot blast stove 19, the technology has the following implementation preconditions: the CO content in the flue gas of the hot blast stove 19 is qualified; the inlet butterfly valve of the flue gas preheater has good sealing condition after being closed.
And (3) matched protection measures: before cutting, namely in the welding process, nitrogen at the tail end of a main flue pipe is opened to dilute and protect the flue gas; during the process of heating the hot blast stove 19, attention is paid to the air-fuel ratio adjustment to prevent a large amount of unburned gas from entering the flue header.
The mixing time of the blast furnace blowing down in this case is shortened from the original 26 hours to 17 hours. The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. An on-line cutting process for a flue gas pipeline in a waste heat recovery area of a blast furnace hot blast stove is characterized by comprising the following process steps:
firstly, opening a bypass valve of flue gas, air and coal gas of a hot blast stove, then closing a butterfly valve of an inlet and an outlet of the flue gas, the air and the coal gas, manually confirming the closing on site, and enabling an air preheater and a coal gas preheater to exit a waste heat recovery system of the hot blast stove;
turning on two thermometers positioned in the flue gas preheater to serve as air suction ports of the flue gas preheater, and confirming the condition of air sucked in the flue gas preheater;
manually opening outlet valves of the two flue gas preheaters by 10-20%, simultaneously opening all manholes in the flue gas preheaters, binding the gas alarm on a rod, extending into the flue gas preheaters for confirmation again, extending a nitrogen rubber pipe into the flue gas preheaters from the manholes, introducing nitrogen, driving internal gas, and completely pumping the mixed gas away from the flue gas preheaters under the action of the suction force of a chimney;
and fourthly, stopping introducing nitrogen after 20-30 minutes, and allowing air to enter the flue gas preheater from the manhole to replace the original residual mixed gas under the action of the suction force of the chimney, wherein the flue gas pipeline has the condition of safe cutting in advance after 10-20 minutes.
2. The blast furnace hot blast stove waste heat recovery area flue gas pipeline on-line cutting process according to claim 1, characterized in that: in the second step, if atmospheric air is pumped inwards, the interior of the flue gas preheater can be determined to be in a negative pressure state; the gas concentration is displayed as 0 PPm, and the fact that no gas leaks or residual gas exists in the smoke preheater can be determined.
3. The blast furnace hot blast stove waste heat recovery area flue gas pipeline on-line cutting process according to claim 1, characterized in that: because of carrying out flue gas pipeline on-line cutting operation under the normal production condition of hot-blast furnace, the prerequisite of implementation: detecting the content of CO in the flue gas of the hot blast stove to be qualified; the inlet butterfly valve of the flue gas preheater is closed and then the sealing condition is good; introducing nitrogen to the tail end of the flue header pipe before cutting to dilute and protect the flue gas; during the process of starting the hot blast stove, the air-fuel ratio is regulated to prevent a large amount of unburned gas from entering a flue main pipe.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910320542.XA CN110643772B (en) | 2019-04-20 | 2019-04-20 | Online cutting process for flue gas pipeline in waste heat recovery area of blast furnace hot blast stove |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910320542.XA CN110643772B (en) | 2019-04-20 | 2019-04-20 | Online cutting process for flue gas pipeline in waste heat recovery area of blast furnace hot blast stove |
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| CN110643772B CN110643772B (en) | 2021-06-25 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1618991A (en) * | 2004-11-12 | 2005-05-25 | 马鞍山钢铁股份有限公司 | Exchange technology of hot air furnace hot air short pipe |
| CN103615628A (en) * | 2013-11-20 | 2014-03-05 | 内蒙古包钢钢联股份有限公司 | Operating method of gas pipeline with gas |
| CN104593536A (en) * | 2015-01-12 | 2015-05-06 | 山西太钢不锈钢股份有限公司 | Method for replacing hot air furnace blast furnace gas cut-off valve on line |
-
2019
- 2019-04-20 CN CN201910320542.XA patent/CN110643772B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1618991A (en) * | 2004-11-12 | 2005-05-25 | 马鞍山钢铁股份有限公司 | Exchange technology of hot air furnace hot air short pipe |
| CN103615628A (en) * | 2013-11-20 | 2014-03-05 | 内蒙古包钢钢联股份有限公司 | Operating method of gas pipeline with gas |
| CN104593536A (en) * | 2015-01-12 | 2015-05-06 | 山西太钢不锈钢股份有限公司 | Method for replacing hot air furnace blast furnace gas cut-off valve on line |
Non-Patent Citations (3)
| Title |
|---|
| 丁启圣等: "《新型实用过滤技术（第4版）》", 31 December 2017, 冶金工业出版社 * |
| 刘振均等: "热风炉热状态下内衬耐火材料外观状态的检查与判断", 《炼铁》 * |
| 马琼: "《高炉炼铁生产》", 31 August 2014, 北京理工大学出版社 * |
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