CN-116676444-B - Double-circulation system flue of steel mill

CN116676444BCN 116676444 BCN116676444 BCN 116676444BCN-116676444-B

Abstract

The invention discloses a double-circulation system flue for a steel mill, which belongs to the technical field of converters for steel mills and comprises a fixed section flue, a middle flue and a final section flue which are fixedly connected together, wherein the fixed section flue is connected with a steam drum and a water supply pump through a first descending pipe and a second ascending pipe, the middle flue is connected with the steam drum through a second descending pipe and the second ascending pipe, the final section flue is connected with the steam drum through a third descending pipe and a third ascending pipe, the final section flue is communicated with the first ascending pipe through a fourth ascending pipe, and the final section flue is communicated with an outlet main pipe of the water supply pump through the fourth descending pipe. The invention has the advantages that the phenomenon of no reduction of the outlet temperature of the cooling medium of the flue of the double-circulation system of the steel mill is avoided, the problem of overburning damage of the heated pipe is solved, and the stable operation of the rest sections of the vaporization system is ensured.

Inventors

YAN YONGXIN
LIU HAIJUN
ZHENG YUFENG
LIU ZILONG
YAN GUOFANG
FANG JIANXUN
TIAN HAITAO
MA TAO

Assignees

河北钢铁建设集团乐亭有限公司

Dates

Publication Date: 20260512
Application Date: 20230608

Claims (5)

1. The double-circulation system flue for the steel mill comprises a fixed section flue (1), a middle flue (2) and a final section flue (3) which are fixedly connected together, wherein the fixed section flue (1) is connected with a steam drum (5) and a water supply pump (4) through a first descending pipe (6) and a first ascending pipe (7), the middle flue (2) is connected with the steam drum (5) through a second descending pipe (8) and a second ascending pipe (9), and the final section flue (3) is connected with the steam drum (5) through a third descending pipe (10) and a third ascending pipe (11), and the double-circulation system flue is characterized in that the final section flue (3) is communicated with the first ascending pipe (7) through a fourth ascending pipe (13), and the final section flue (3) is communicated with an outlet main pipe of the water supply pump (4) through a fourth descending pipe (12). The interior of the lower header ring pipe (331) at the tail end of the tail section flue (3) is cut off by a first steel plate (3311) which is symmetrically distributed and is divided into a plurality of parts which are not communicated with each other, wherein a heated pipe (333) positioned in the plugging range of the first steel plate (3311) is communicated with a fourth descending pipe (12) to form an independent forced circulation branch which is parallel to the original natural circulation loop; The interior of the upper header ring pipe (332) at the upper end of the tail section flue (3) is cut off by a second steel plate (3321) which is symmetrically distributed and is separated into a plurality of parts which are not communicated with each other, wherein a heated pipe (333) positioned in the plugging range of the second steel plate (3321) is communicated with the fourth riser (13) to form an independent steam return branch corresponding to the forced circulation branch; The forced circulation branch and the independent steam return branch form a closed-loop forced circulation system which is independent of a natural circulation loop formed by the down pipe III (10) and the up pipe III (11).
2. The steel mill double circulation system flue according to claim 1, wherein a three-way pipe communicated with the fourth descending pipe (12) and the first descending pipe (6) is arranged on the main pipe at the outlet of the water feeding pump (4).
3. The dual-circulation system flue for a steel plant according to claim 1, wherein the fourth downcomer (12) comprises a newly added downcomer (121), and an electric gate valve I (122) and a flowmeter (123) which are arranged on the newly added downcomer (121).
4. The dual-circulation system flue for a steel plant according to claim 1, wherein the fourth rising pipe (13) comprises a newly added rising pipe (131), and an electric gate valve II (132) is arranged on the newly added rising pipe (131).
5. The dual cycle system flue for a steel plant as recited in claim 1 wherein said first (3311) and second (3321) plates are fixedly attached to said lower (331) and upper (332) header collars by means of welding.

Description

Double-circulation system flue of steel mill Technical Field The invention relates to the technical field of steel mill converters, in particular to a double-circulation system flue of a steel mill. Background The high-temperature flue gas in the production process of the converter is collected and cooled by the vaporization cooling flue of the converter, so that the requirements of primary dust removal and gas recovery in the next working procedure are met, the safe production of converter steelmaking is ensured, and the service life of the flue is reasonably prolonged. The vaporization cooling flue for the converter comprises three components, namely a fixed section flue, a middle flue and a final section flue. The converter flue cooling circulation system diagram of fig. 1 can be used for knowing that a fixed section flue 1 is connected with a steam drum 5 and a water supply pump 4 through a descending pipe 6 to form a forced circulation system, a medium is forced to flow along the whole flue pipe by means of pressure generated by the high-pressure water supply pump 4, a middle flue 2 is connected with the steam drum 5 through a descending pipe 8 to form a natural circulation system, a tail section flue 3 is connected with the steam drum 5 through a descending pipe 10 to form a natural circulation system with a ascending pipe 11, and heated medium in the pipe flows by means of specific gravity difference of the medium in the ascending pipe and the descending pipe and effective height of the steam drum. As can be seen from the structure diagram of the final flue in fig. 2, the dust removal mode of the steel mill is changed, the lower header ring canal 331 of the final flue is lifted up, the synchronously added spraying device 334 reduces the temperature of the flue gas at the outlet, the two changes cause the specific gravity difference of the medium in the rising pipe 11 and the falling pipe 10 of the final flue and the effective height of the steam drum to be reduced, and the natural circulation power of the final flue is insufficient due to the structural change. The flow rate of the cooling medium in the tail section flue is reduced, heat exchange is not timely, the defect of heat exchange capacity causes the overburning phenomenon at the position of the horizontal small straight section of the tail section flue 3, the heat pipe 333 is detonated to leak water, the service life of the tail section flue is greatly reduced, and the economic benefit of a steel mill is damaged. Based on the structure, the invention provides a dual-circulation system flue of a steel mill. Disclosure of Invention The invention aims to provide a dual-circulation system flue for a steel mill, which solves the problems. In order to solve the technical problems, the invention adopts the following technical scheme: The invention relates to a dual-circulation system flue of a steel mill, which comprises a fixed section flue, a middle flue and a final section flue which are fixedly connected together, wherein the fixed section flue is connected with a steam drum and a water supply pump through a first descending pipe and a second ascending pipe; the lower header ring pipe at the tail end of the tail section flue is cut off and split through a symmetrically distributed steel plate I, the heated pipe blocked by the steel plate I is communicated with the fourth descending pipe, the upper header ring pipe at the upper end of the tail section flue is cut off and split through a symmetrically distributed steel plate II, and the heated pipe blocked by the steel plate II is communicated with the fourth ascending pipe. Furthermore, a three-way pipe communicated with the fourth descending pipe and the first descending pipe is arranged on the main pipe at the outlet of the feed pump. Further, the fourth downcomer comprises a newly-added downcomer, and a first electric gate valve and a flowmeter which are arranged on the newly-added downcomer. Further, the fourth rising pipe comprises a newly-added rising pipe, and the newly-added rising pipe is provided with a second electric gate valve. Further, the first steel plate and the second steel plate are fixedly connected to the lower header ring pipe and the upper header ring pipe in a welding mode. Compared with the prior art, the invention has the beneficial technical effects that: The dual-circulation system flue of the steel mill independently supplies water to the heated pipe in the overburning range through the newly-added down pipe and the newly-added up pipe on the premise that the tail section flue is not replaced integrally, so that the water flow in the pipe is always sufficient, namely, natural circulation is changed into partial natural circulation and partial forced circulation, and the cooling capacity is enhanced. In a word, the temperature of the cooling medium outlet of the flue of the dual-circulation system of the steel mill does not drop, the problem of overburning and damage