Blast furnace empty stockline blowing-out gas purification device and method

Abstract

The invention relates to a blast furnace empty stockline blowing-out gas purification device and method, and belongs to the technical field of ironmaking devices and methods. According to the technical scheme, an outlet of a clean gas pipeline (8) is connected with a gas pipe network (1), a clean gas outlet eye valve (6) and a clean gas outlet butterfly valve (7) are arranged at the outlet end of the clean gas pipeline (8), and a grid-connected butterfly valve (2) and a grid-connected eye valve (3) are arranged at the inlet end of the gas pipe network (1); and the diffusion butterfly valve (4), the diffusion eye valve (5) and the gas igniter (9) are arranged between the grid-connected eye valve (3) and the clean gas outlet eye valve (6). According to the invention, coal gas can meet the requirement of quiet combustion through cloth bag dust removal, and a large amount of dust cannot be discharged in an unorganized manner as before; the short-flame combustion can be realized by adopting the gas ignition device, so that the gas is completely combusted at the outlet of the bleeder and is not discharged into the atmosphere in an unorganized manner, thereby realizing the short-flame combustion and ensuring the safety of the system.

Description

Technical Field

[0001] The present invention relates to a blast furnace empty stockline blow - down gas purification device and method, belonging to the technical field of iron - making devices and methods. Background Art

[0002] There are two ways to blow down a blast furnace, one is the material filling method, and the other is the empty stockline method. Among them, the empty stockline method means that no material is charged into the furnace during the blow - down process, and the top temperature of the furnace is controlled by spraying water on the top. When the material surface drops to near the tuyere, the blast is stopped. The advantage of this method is that the amount of material removed in the furnace after blow - down is reduced, and the blow - down process is accelerated, saving time for major and medium repairs. The disadvantage is that the furnace wall is prone to collapse during the blow - down process, and special attention needs to be paid to gas safety. Therefore, when the blast furnace undergoes major or medium repairs or treats furnace body accretion, the commonly used method is the method of lowering the material surface to blow down the furnace.

[0003] Here, what needs to be mentioned is the improved method of recovering gas during the empty stockline blow - down of the blast furnace, which is often used nowadays. In the early days of the empty stockline blow - down, generally, gas was not recovered and was discharged into the atmosphere through the top gas - discharging valve. This not only polluted the environment with gas mixed with dust and noise, but also required the furnace to be stopped with normal pressure and slow blast due to insufficient gas - discharging capacity. Recovering gas during blow - down means that gas is continuously recovered during the blow - down process, which is not only safe but also speeds up the blow - down process. Baotou Steel in China was the first factory to adopt gas - recovery blow - down. In June 1983, Angang learned from Baotou Steel and adopted gas - recovery blow - down in blast furnaces with a volume of more than 1000 m³. The blow - down time was shortened to 8 hours and 47 minutes, achieving safe, economical, and rapid blow - down.

[0004] In the modern method of recovering gas during blow - down, during the blow - down process of a blast furnace with a volume of about 2500 m³, the general blow - down time is about 12 - 15 hours, of which the gas recovery time is about 6 - 8 hours, accounting for 55% of the entire blow - down time. So far, blast furnace operators have opened the top gas - discharging valve when the material surface reaches the furnace waist and is close to the furnace belly, switched to normal - pressure gas - discharging, and during the period of lowering the material surface to blow down the furnace for about 6 - 8 hours under normal pressure, a large amount of gas and dust are discharged into the atmosphere in an unorganized manner, and the noise pollution is serious. Summary of the Invention

[0005] The purpose of the present invention is to provide a blast furnace empty stockline blow - down gas purification device and method. Through bag - type dust removal, the gas can meet the requirements of quiet combustion, and a large amount of dust will not be discharged in an unorganized manner as in the past; by using a gas ignition device, short - flame combustion can be achieved, so that the gas burns out at the outlet of the gas - discharging pipe, and the gas will not be discharged into the atmosphere in an unorganized manner, thereby realizing short - flame combustion and ensuring system safety, effectively solving the above problems existing in the background art.

[0006] The technical solution of the present invention is: a blast furnace empty stockline blowdown gas purification device, which includes a gas pipeline network, a grid-connected butterfly valve, a grid-connected spectacle valve, a blowdown butterfly valve, a blowdown spectacle valve, a clean gas outlet spectacle valve, a clean gas outlet butterfly valve, a clean gas pipeline and a gas igniter. The outlet of the clean gas pipeline is connected to the gas pipeline network. The clean gas outlet spectacle valve and the clean gas outlet butterfly valve are arranged at the outlet end of the clean gas pipeline. The grid-connected butterfly valve and the grid-connected spectacle valve are arranged at the inlet end of the gas pipeline network. The blowdown butterfly valve, the blowdown spectacle valve and the gas igniter (9) are arranged between the grid-connected spectacle valve and the clean gas outlet spectacle valve.

[0007] The sum of the blowdown areas of the blowdown butterfly valve, the blowdown spectacle valve and the gas igniter is equal to the total blowdown area of the bag filter housing, and the differential pressure of the bag filter housing is 3 kPa - 5 kPa.

[0008] The opening degree of the blowdown butterfly valve matches the size of the required combustion flame.

[0009] A blast furnace empty stockline blowdown gas purification method includes the following steps: (1) Add a blowdown butterfly valve, a blowdown spectacle valve and a gas igniter between the clean gas outlet spectacle valve and the grid-connected spectacle valve; (2) When the stockline reaches the predetermined position and the oxygen content in the gas increases due to the gradually thinning material layer after the inflection point, open the blowdown spectacle valve and the blowdown butterfly valve in sequence; (3) When gas appears at the blowdown outlet, open the blowdown valve of the bag filter housing, and close the grid-connected butterfly valve and the grid-connected spectacle valve in sequence; (4) After the gas output is stable, close the blowdown valve of the bag filter housing and open the gas igniter.

[0010] The sum of the blowdown areas of the blowdown butterfly valve, the blowdown spectacle valve and the gas igniter is equal to the total blowdown area of the bag filter housing, and the differential pressure of the bag filter housing is 3 kPa - 5 kPa.

[0011] In step (4), the gas flow rate of the blowdown gas is controlled by adjusting the opening degree of the blowdown butterfly valve, so as to indirectly control the size of the combustion flame.

[0012] The beneficial effects of the present invention are: through bag dust removal, the gas can meet the requirements of quiet combustion, and there will be no unorganized emission of a large amount of dust as in the past; the use of a gas ignition device can achieve short-flame combustion, so that the gas burns out at the outlet of the blowdown pipe, and the gas will not be unorganized emitted into the atmosphere, thus realizing short-flame combustion and ensuring system safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural schematic diagram of the present invention; In the figure: gas pipeline network 1, parallel connection butterfly valve 2, parallel connection spectacle valve 3, blow-off butterfly valve 4, blow-off spectacle valve 5, clean gas outlet spectacle valve 6, clean gas outlet butterfly valve 7, clean gas pipeline 8, gas igniter 9. Detailed implementation manners

[0014] In order to make the objectives, technical solutions and advantages of the embodiments of the invention clearer, the following will, in conjunction with the accompanying drawings in the embodiments, clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a small part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0015] A blast furnace empty stockline blowdown gas purification device includes a gas pipeline network 1, a parallel connection butterfly valve 2, a parallel connection spectacle valve 3, a blow-off butterfly valve 4, a blow-off spectacle valve 5, a clean gas outlet spectacle valve 6, a clean gas outlet butterfly valve 7, a clean gas pipeline 8 and a gas igniter 9. The outlet of the clean gas pipeline 8 is connected to the gas pipeline network 1. The clean gas outlet spectacle valve 6 and the clean gas outlet butterfly valve 7 are arranged at the outlet end of the clean gas pipeline 8. The parallel connection butterfly valve 2 and the parallel connection spectacle valve 3 are arranged at the inlet end of the gas pipeline network 1. The blow-off butterfly valve 4, the blow-off spectacle valve 5 and the gas igniter 9 are arranged between the parallel connection spectacle valve 3 and the clean gas outlet spectacle valve 6.

[0016] The sum of the blow-off areas of the blow-off butterfly valve 4, the blow-off spectacle valve 5 and the gas igniter 9 and the total blow-off area of the bag filter housing is equal to the large blow-off area at the top of the furnace, and the differential pressure of the bag filter housing is 3 kPa - 5 kPa.

[0017] The opening degree of the blow-off butterfly valve 4 matches the size of the combustion flame required.

[0018] A blast furnace empty stockline blowdown gas purification method includes the following steps: (1) A blow-off butterfly valve, a blow-off spectacle valve and a gas igniter are added between the clean gas outlet spectacle valve and the parallel connection spectacle valve; (2) When the stockline reaches the predetermined position and after the inflection point, as the material layer gradually thins and the oxygen content in the gas increases, the blow-off spectacle valve and the blow-off butterfly valve are opened in sequence; (3) When gas appears at the blow-off outlet, the blow-off valve of the bag filter housing is opened, and the parallel connection butterfly valve and the parallel connection spectacle valve are closed in sequence; (4) After the gas output is stable, the blow-off valve of the bag filter housing is closed, and the gas igniter is opened.

[0019] The sum of the blow-off areas of the blow-off butterfly valve, the blow-off spectacle valve and the gas igniter and the total blow-off area of the bag filter housing is equal to the large blow-off area at the top of the furnace, and the differential pressure of the bag filter housing is 3 kPa - 5 kPa.

[0020] In step (4), the amount of the released gas passing through is controlled by adjusting the opening degree of the release butterfly valve, thereby indirectly controlling the size of the combustion flame.

[0021] In practical applications, in the present invention, on the clean gas pipeline 8, between the clean gas outlet eye valve 6 and the grid connection eye valve 3, a gas release and ignition device is added, which includes a release butterfly valve 4, a release eye valve 5, and a gas igniter 9. Since the total release area of the newly added gas release and ignition device plus the total release area of the bag filter housing is equal to the large release area at the top of the furnace, and the differential pressure of the bag filter housing is 3 kPa - 5 kPa, it can fully meet the pressure relief level during the past normal pressure release. Moreover, the clean gas after bag dust removal can be directly burned, which is safe and environmentally friendly.

[0022] When the stock line reaches the predetermined position, the indirect reduction reaction gradually decreases. The inflection point indicates that the indirect reduction reaction during the furnace shutdown process is basically over, and CO2 drops to the lowest point, about 3% - 5%, and the relative position is near the furnace waist. After the inflection point, since the material layer gradually becomes thinner and the oxygen content in the gas increases: open the release eye valve 5 → open the release butterfly valve 4 → (when both valves are fully opened and gas appears at the release outlet) open the release valve of the bag filter housing → close the grid connection butterfly valve 2 → close the grid connection eye valve 3 → (after the gas output is stable) close the release valve of the bag filter housing → open the gas igniter 9. By controlling the opening degree of the release butterfly valve 4, the amount of the released gas passing through can also be controlled to indirectly control the size of the combustion flame.

[0023] The main design of the present invention is in the stage when the stock line reaches the furnace waist and the furnace belly during the shutdown of the blast furnace. When the oxygen content in the gas increases, the gas supply to the gas pipeline is stopped, and the clean gas after bag dust removal is quietly burned through the gas release and ignition device of the present invention. The gas after bag dust removal can meet the requirements of quiet combustion, and it will not cause a large amount of dust to be emitted without organization as in the past. The gas igniter can achieve short-flame combustion, enabling the gas to burn out at the outlet of the release pipe and preventing the gas from being emitted into the atmosphere without organization, thereby achieving short-flame combustion and ensuring the safety of the system.

Claims

1. A blast furnace empty line shutdown gas purification device, characterized in that: The invention comprises a gas network (1), a grid-connected butterfly valve (2), a grid-connected eye valve (3), a release butterfly valve (4), a release eye valve (5), a clean gas outlet eye valve (6), a clean gas outlet butterfly valve (7), a clean gas pipeline (8) and a gas igniter (9), wherein the outlet of the clean gas pipeline (8) is connected to the gas network (1), the clean gas outlet eye valve (6) and the clean gas outlet butterfly valve (7) are arranged at the outlet end of the clean gas pipeline (8), the grid-connected butterfly valve (2) and the grid-connected eye valve (3) are arranged at the inlet end of the gas network (1), and the release butterfly valve (4), the release eye valve (5) and the gas igniter (9) are arranged between the grid-connected eye valve (3) and the clean gas outlet eye valve (6).

2. A blast furnace empty line shutdown gas purification device according to claim 1, characterized in that: The sum of the venting areas of the venting butterfly valve (4), the venting eye valve (5) and the gas igniter (9) and the total venting area of ​​the bag box is equal to the large venting area of ​​the furnace top, and the pressure difference of the bag box is 3kpa-5kpa.

3. A blast furnace empty line shutdown gas purification device according to claim 1, characterized in that: The opening degree of the diffusion butterfly valve (4) matches the size of the required combustion flame.

4. A method for purifying gas from shutdown of an empty blast furnace line, characterized in that The following steps are involved: (1) Install a relief butterfly valve, relief eye valve and gas igniter between the clean gas outlet eye valve and the grid-connected eye valve; (2) When the material line reaches the predetermined position, after the inflection point, as the material layer gradually becomes thinner and the oxygen content in the gas increases, the diffuser eye valve and the diffuser butterfly valve are opened in sequence; (3) When gas appears at the discharge outlet, open the bag box discharge valve and close the grid-connected butterfly valve and grid-connected eye valve in turn; (4) After the gas output is stable, close the bag box release valve and turn on the gas igniter.

5. A blast furnace empty line shutdown gas purification method according to claim 4, characterized in that: The sum of the venting areas of the venting butterfly valve, venting eye valve and gas igniter and the total venting area of ​​the bag box is equal to the large venting area of ​​the furnace top, and the pressure difference of the bag box is 3kpa-5kpa.

6. A blast furnace empty line shutdown gas purification method according to claim 4, characterized in that: In the step (4), the amount of gas released is controlled by adjusting the opening of the release butterfly valve, thereby indirectly controlling the size of the combustion flame.

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