Method for safely and quickly treating coal gas during blowing out of empty stockline of large blast furnace

Abstract

The invention relates to a method for safely and quickly treating coal gas during blow-out of a large blast furnace empty stockline. The method comprises the following steps: S1, determining the position of the empty stockline: the empty stockline is located in a tuyere area or an area above the tuyere; and S2, performing targeted gas treatment according to different stockline positions. The corresponding coal gas treatment method is specifically designed according to different stockline positions, coal gas can be rapidly treated, conditions are created for rapid reblowing production, meanwhile, safety is guaranteed, the distance between empty stocklines can be reduced, and a large amount of metallurgical coke is saved.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a method for the safe and rapid handling of gas during shutdown of a large blast furnace empty charge line. Background Technology

[0002] Currently, most blast furnace empty charge lines require empty charge surface operations when replacing cooling walls or spraying furnace linings. When the charge surface is empty to the predetermined target, the blast furnace is shut down. After the shutdown, the blast furnace gas needs to be treated to create conditions for construction.

[0003] During empty material line operations, the location of the empty material line varies depending on the production needs and the location of the construction work (e.g., ...). Figure 1 and Figure 2 As shown in the diagram, the usual method for handling blast furnace gas is to shut down the entire air supply system, block the tuyeres, stop the blowers, and then, based on experience (approximately 16 hours), determine that the gas composition inside the furnace is acceptable (below the explosive concentration: CO ≤ 5%, H2 ≤ 3%). Then, the gas system is purged, and finally, the steam at the furnace top is stopped before ignition. However, these methods rely on experience, and to ensure safety, the waiting time is often long, leading to extended shutdown times and project delays. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a method for the safe and rapid handling of gas during shutdown of a large blast furnace empty charge line. By treating the gas according to different locations of the empty charge line, the gas can be processed quickly, creating favorable conditions for rapid resumption of production while ensuring safety.

[0005] The technical solution adopted in this invention is as follows:

[0006] The present invention proposes a method for the safe and rapid handling of gas during shutdown of a large blast furnace empty charge line, comprising the following steps: S1. Determine the location of the empty material line: It should be located in the air vent area or above the air vent. S2. Process according to different material line positions as follows: If the empty material line is located in the tuyere area, handle it as follows: (1) Stop water pumping and shut down the blast furnace according to the normal shutdown procedure; (2) Install an air pump in the static pressure hole at the bottom of the furnace body, connect the air pump to the blast furnace gas online analyzer, and analyze the gas composition in the furnace online; (3) If the gas composition is qualified, open the inspection hole and the large cover, and the gas in the furnace will ignite on its own; (4) After the gas combustion in the furnace is stable, disassemble the entire air supply system and install blind plates on the air supply straight section of each tuyere; at the same time, set up three coke oven gas torches in different directions at a distance of 0.4-0.6 meters from the tuyere in the furnace; (5) After the gas system finishes purging the gas, open the furnace top inspection hole and set up coke oven gas torches on the manhole on the side of the ignition gun; (6) After the blind plates are installed on the air supply straight section, stop the blower.

[0007] If the empty material line is located above the tuyere, it shall be handled in the following manner: (1) Stop water pumping and shut down the tuyere according to the normal shutdown procedure; (2) Open 2 / 3 of the tuyere sight glass. After the negative pressure is formed in the tuyere area of ​​the furnace, remove all the straight air supply pipes, plug the tuyere with refractory mud, and stop the blower after the hot blast stove backflows; (3) After the normal shutdown, install the suction pump in the static pressure hole at the bottom of the furnace body. Connect the suction pump to the blast furnace gas online analyzer to analyze the composition of the gas in the furnace online; (4) When the composition of the gas in the furnace is qualified and the gas system finishes purging the gas, open the inspection hole at the top of the furnace and carry out the furnace top ignition operation; (5) After the furnace top ignition, seal the tuyere and install the blind plate on the straight section corrugated pipe; (6) Cut the furnace skin; (7) Put three long-burning torches into the material surface from the furnace skin cutting position.

[0008] Furthermore, the qualified indicators for the gas composition are CO≤5% and H2≤3%.

[0009] Furthermore, in step S2, when the empty material line is located above the air outlet, after stopping water supply, the cold air regulating valve and the cold air gate need to be closed, the air pressure drops to 0.01MPa, and then the normal shutdown procedure is followed.

[0010] Compared with the prior art, the present invention has the following advantages: 1. Installing a gas extraction pump can detect the composition of the gas, ensuring that the gas composition is qualified when the furnace is ignited at the top, thus guaranteeing safety. This avoids the safety hazard of gas explosion when the furnace is shut down because no gas can be collected and the gas composition cannot be determined.

[0011] 2. Installing coke oven gas torches for accompaniment or continuous torches can ensure that the gas generated on the material surface continues to burn after the blast furnace is shut down and restarted, thus avoiding the safety accident of gas poisoning.

[0012] 3. Saves gas processing time: Judging whether the gas composition is qualified based on experience takes about 16 hours, while online analyzers monitor the gas composition in real time and can determine whether the gas is qualified in just 2-3 hours, saving about 13 hours and effectively improving the blast furnace operating rate.

[0013] 4. Because the above methods ensure the safe handling of coal gas, it is not necessary to empty the material line to the tuyere every time. The distance of the material line is shortened by 5-8 meters, saving about 200t-240t of coke from burning this part. This breaks through the traditional operation of "emptying the material line to the tuyere area". The shortening of the material line directly reduces the amount of coke used.

[0014] In summary, the present invention has a simple process and is easy to operate. It can ensure safe production while reducing the downtime of the blast furnace. Moreover, it eliminates the need for empty material lines to reach the tuyeres, thus saving a significant amount of coke consumption. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the area from the empty material line to the air outlet. Figure 2 This is a schematic diagram of the area from the empty material line to above the air vent. Figure 3 This is a schematic diagram showing the connection between the air extraction pump and the online blast furnace gas analyzer when the empty material line reaches the tuyer area. Figure 4 A schematic diagram showing the coke oven gas torch burning during the transition from the empty feed line to the tuyeres area; Figure 5 A schematic diagram showing the connection between the extraction pump and the online blast furnace gas analyzer when the area is from the empty material line to the tuyere; Figure 6 This is a schematic diagram of cutting the furnace lining when the material line reaches the area above the tuyeres; Figure 7 This diagram illustrates the placement of a torch on the material surface at the furnace lining cutting location when the material line extends to the area above the tuyeres. Detailed Implementation

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] The present invention proposes a method for the safe and rapid handling of gas during shutdown of a large blast furnace empty charge line, comprising the following steps: S1. Determine the location of the empty material line: located in the air vent area (e.g., ... Figure 1 (as shown) or the area above the vent (such as) Figure 2 (as shown) S2. Process according to different material line positions as follows: If the empty material conveyor is located in an air vent area, handle it as follows: (1) When the material line is lowered to the tuyere area, water injection is stopped, and the blast furnace is shut down according to the normal shutdown procedure (but without backflow). Stopping water injection is to avoid a sharp drop in furnace temperature, which could lead to furnace cracking and continued generation of explosive gases. Shutting down the blast furnace means disconnecting it from the hot blast stove.

[0018] (2) Install an air extraction pump at the static pressure hole at the bottom of the furnace body. Connect the air extraction pump to an online blast furnace gas analyzer to analyze the composition of the gas in the furnace online, such as... Figure 3 As shown. Replacing the traditional method of judging by experience, it accurately measures the composition of coal gas in real time, and can determine whether it meets the standards (CO≤5%, H2≤3%) in 2-3 hours, improving efficiency and ensuring safety.

[0019] (3) If the gas composition is qualified (CO≤5%, H2≤3%), open the inspection port and the large cover. The gas in the furnace will ignite on its own. Introduce air so that the qualified gas can be burned by the residual heat in the furnace, thereby eliminating the risk of gas toxicity and explosion.

[0020] (4) After the combustion of the gas in the furnace (hearth) stabilizes in about 1.5-2.5 hours, organize personnel to dismantle the entire air supply system and install blind flanges on the straight sections of the 32 tuyeres. Simultaneously, set up three coke oven gas torches in different directions at a distance of about 0.4-0.6 meters from the tuyeres inside the furnace for accompaniment combustion. Figure 4 As shown. The upper blind flange of the straight section further isolates the connection between the blast furnace and the hot blast stove, preventing residual gas generated in the blast furnace from entering the cold air duct, thus preparing for the next step of shutting down the blast furnace blower. The coke oven gas torch accompaniment ensures that the gas generated on the blast furnace burden surface continues to burn, thereby preventing poisoning after the gas is extinguished.

[0021] (5) After the gas system finishes purging the gas, open the inspection hole on the top of the furnace and set a coke oven gas torch to burn alongside the manhole on the side of the ignition gun. This will ensure that the gas produced by the blast furnace can still be ignited instantly after the ignition gun is extinguished, thus avoiding poisoning after the gas is extinguished.

[0022] (6) After the blind flange is installed on the air supply section, the blower is stopped. The blind flange further isolates the blast furnace from the blower and hot blast stove, preventing the gas generated by the blast furnace from entering the blower through the hot blast pipe (the pipe will be under negative pressure after the blower is stopped).

[0023] If the empty material line is located above the air vent, it shall be handled as follows: (1) When the material line is lowered to the predetermined position, stop water pumping, close the cold air regulating valve and the cold air gate, and reduce the air pressure to 0.01MPa; shut down the blast furnace according to the normal shutdown procedure. Stopping water pumping is to avoid a sharp drop in furnace temperature, which could lead to furnace cracking and continued generation of explosive gases. Closing the cold air regulating valve and the cold air gate disconnects the blast furnace from the hot blast stove.

[0024] (2) Open 2 / 3 of the tuyeres sight glass. After 2-3 hours, a negative pressure will form in the tuyeres area of ​​the furnace (no flames will be emitted from the tuyeres). Remove all the straight air supply pipes, plug the tuyeres with refractory mud, and turn off the hot blast stove after the flow is reversed. Opening the sight glass allows air to enter the furnace to burn the gas, eliminating the toxicity and explosion risk of the gas. Pluging the tuyeres with refractory mud further disconnects the blast furnace from the hot blast stove and the blower, preventing residual gas generated in the blast furnace from entering the cold air pipes. This ensures that a negative pressure is generated after the blast furnace blower is stopped, drawing the blast furnace gas to the blower.

[0025] (3) After normal shutdown, install an air extraction pump at the static pressure hole at the bottom of the furnace body. Connect the air extraction pump to an online blast furnace gas analyzer to analyze the composition of the gas in the furnace online, such as... Figure 5As shown. Replacing the traditional method of judging by experience, it accurately measures the composition of coal gas in real time, and can determine whether it meets the standards (CO≤5%, H2≤3%) in 2-3 hours, improving efficiency and ensuring safety.

[0026] (4) When the composition of the gas in the furnace is qualified and lower than the explosion concentration (CO≤5%, H2≤3%), after the gas system has finished purging the gas, open the inspection hole on the top of the furnace and carry out the furnace top ignition operation. The composition of the gas during the furnace top ignition operation must be lower than the detonation concentration.

[0027] (5) After the furnace is ignited, the tuyeres are sealed and the upper blind flange of the straight corrugated pipe is installed. The tuyeres are sealed to reduce the amount of air entering the blast furnace, thus reducing the combustion of coke and the amount of gas produced. The upper blind flange of the straight corrugated pipe further disconnects the blast furnace from the hot blast stove and the blower. (6) Construction workers cut open the furnace lining (a section of the cooling wall above the replacement part), such as Figure 6 As shown. The furnace lining is cut open for hoisting equipment used in operations inside the blast furnace.

[0028] (7) Place three long-burning torches on the material surface at the location where the furnace skin has been cut open, such as Figure 7 As shown, the three torches on the blast furnace charge surface are there to ensure that the gas produced on the charge surface continues to burn, preventing poisoning if the gas is extinguished.

[0029] The logical principle of this invention is as follows: Addressing the problems of traditional processes such as "reliance on experience, inaccurate material line location, and high energy consumption," this invention utilizes sampling from the static pressure holes at the bottom of the furnace body combined with online analysis to determine the gas quality (CO≤5%, H2≤3%) within 2-3 hours, replacing the traditional experience-based approach. Differential processing allows the material line to extend above the tuyeres, shortening the distance by 5-8 meters and saving 30%-40% of coke. Simultaneously, gas ignition safety is ensured, guaranteeing safe construction.

[0030] This invention pioneers differentiated processing of material lines and designs processes in different areas, which can shorten the time of a single process by 2-3 hours; it establishes a time control system of "monitoring + combustion", which can reduce the total time from 20-24 hours to 8-10 hours, breaks through the limitation of each empty material line to the tuyeres, and saves coke significantly; it installs a vacuum pump to safely detect coal gas, which saves time while ensuring the safety of coal gas processing.

[0031] All matters not covered in this invention are common knowledge.

[0032] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for the safe and rapid handling of gas during shutdown of a large blast furnace empty charge line, characterized in that, The method includes the following steps: S1. Determine the location of the empty material line: It should be located in the air vent area or above the air vent. S2. Process according to different material line positions as follows: If the empty material line is located in the tuyere area, handle it as follows: (1) Stop water pumping and shut down the blast furnace according to the normal shutdown procedure; (2) Install an air pump in the static pressure hole at the bottom of the furnace body, connect the air pump to the blast furnace gas online analyzer, and analyze the gas composition in the furnace online; (3) If the gas composition is qualified, open the inspection hole and the large cover, and the gas in the furnace will ignite on its own; (4) After the gas combustion in the furnace is stable, disassemble the entire air supply system and install blind plates on the air supply straight section of each tuyere; at the same time, set up three coke oven gas torches in different directions at a distance of 0.4-0.6 meters from the tuyere in the furnace; (5) After the gas system finishes purging the gas, open the furnace top inspection hole and set up coke oven gas torches on the manhole on the side of the ignition gun; (6) After the blind plates are installed on the air supply straight section, stop the blower. If the empty material line is located above the tuyere, it shall be handled in the following manner: (1) Stop water pumping and shut down the tuyere according to the normal shutdown procedure; (2) Open 2 / 3 of the tuyere sight glass. After the negative pressure is formed in the tuyere area of ​​the furnace, remove all the straight air supply pipes, plug the tuyere with refractory mud, and stop the blower after the hot blast stove backflows; (3) After the normal shutdown, install the suction pump in the static pressure hole at the bottom of the furnace body. Connect the suction pump to the blast furnace gas online analyzer to analyze the composition of the gas in the furnace online; (4) When the composition of the gas in the furnace is qualified and the gas system finishes purging the gas, open the inspection hole at the top of the furnace and carry out the furnace top ignition operation; (5) After the furnace top ignition, seal the tuyere and install the blind plate on the straight section corrugated pipe; (6) Cut the furnace skin; (7) Put three long-burning torches into the material surface from the furnace skin cutting position.

2. The method for safe and rapid handling of gas during shutdown of a large blast furnace empty charge line according to claim 1, characterized in that: The acceptable composition of the gas is defined as CO ≤ 5% and H2 ≤ 3%.

3. The method for safe and rapid handling of gas during shutdown of a large blast furnace empty charge line according to claim 1, characterized in that: In step S2, when the empty material line is located above the air outlet, after stopping water supply, the cold air regulating valve and the cold air gate need to be closed, the air pressure drops to 0.01MPa, and then the normal shutdown procedure is followed.

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