Hydrogen-based shaft furnace device for directly reducing iron

Abstract

The invention belongs to the technical field of ferrous metallurgy, and provides a hydrogen-based shaft furnace device for directly reducing iron, which comprises a furnace body, the interior of the furnace body is sequentially divided into a sealing head area, a reaction area and a cooling area from top to bottom, and the sealing head area, the reaction area and the cooling area are sequentially communicated; a first reaction zone and a second reaction zone are sequentially arranged in the reaction zone from top to bottom, and gas-solid contact units are respectively arranged in the first reaction zone and the second reaction zone; the sealing head area is communicated with the cooling area through the gas-solid contact unit in the first reaction area and the gas-solid contact unit in the second reaction area. The internal structure of the hydrogen-based shaft furnace is simplified, the metallization ratio can be increased, and energy consumption can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a hydrogen-based vertical furnace device for direct reduction of iron. Background Art

[0002] Hydrogen metallurgy technology is to use CO or H2 to replace coke to reduce iron oxide in iron ore, which is one of the important ways to reduce carbon in the steel industry. Hydrogen-based shaft furnace direct reduction is the most feasible way for hydrogen metallurgy at this stage. Projects such as EU ULCOS, South Korea COOLSTAR, Germany SALCOS, and Voestalpine H2FUTURE all cover hydrogen-based shaft furnace processes. The steel industry has a huge production scale, and large-scale implementation of hydrogen metallurgy requires reliable hydrogen-based shaft furnace processes.

[0003] The Chinese patent "High-efficiency reduction vertical furnace and reduction process for oxidized pellets" with patent number CN113046508A discloses a structure of a reduction vertical furnace, including a heating section, a reduction section and a cooling section. The reduction section includes an annular reduction chamber, and an outer heat storage chamber and an inner heat storage chamber are respectively arranged inside and outside the reduction chamber. The outer heat storage chamber and the inner heat storage chamber are interconnected through a multi-layer heat-conducting connecting pipe. The top of the heating section is connected to a gas purification cooling circulation system, and the output pipe of the gas purification cooling circulation system is connected to the lower part of the cooling section to form a gas circulation cycle. Although the discharge efficiency is improved, the reduction effect of the process device is difficult to ensure, and the content of reduced iron is not high.

[0004] The Chinese patent "A coal-based hydrogen metallurgical vertical furnace with high-efficiency reduction" with patent number CN218026186U discloses a hydrogen metallurgical vertical furnace, which is provided with an external combustion chamber and a plurality of roasting tanks. By arranging a central combustion chamber in the roasting tank of the hydrogen metallurgical vertical furnace, the metallurgical gas produced during the heating and reduction process of the coal-ore mixture passes through the high-temperature material layer during the top-down flow process to achieve the reduction of iron oxides. The reduction effect is difficult to guarantee, fluctuates greatly, and has high energy consumption. Summary of the invention

[0005] The object of the present invention is to provide a hydrogen-based vertical furnace device for direct reduction of iron to solve the above problems, thereby simplifying the internal structure of the vertical furnace, improving the metallization rate and reducing energy consumption.

[0006] To achieve the above object, the present invention provides the following solution: a hydrogen-based vertical furnace device for direct reduction of iron, comprising:

[0007] A furnace body, wherein the interior of the furnace body is divided into a head zone, a reaction zone and a cooling zone from top to bottom, and the head zone, the reaction zone and the cooling zone are connected in sequence;

[0008] The reaction zone is provided with a first reaction zone and a second reaction zone from top to bottom, and a gas-solid contact unit is provided in the first reaction zone and the second reaction zone respectively. The head zone is connected with the cooling zone through the gas-solid contact unit in the first reaction zone and the gas-solid contact unit in the second reaction zone.

[0009] Preferably, the gas-solid contact unit in the first reaction zone comprises a plurality of top conical tubes and a plurality of bottom conical tubes, the large-diameter ends of the plurality of top conical tubes and the bottom conical tubes are arranged upward, the small-diameter end openings of the plurality of top conical tubes are respectively connected with the large-diameter end openings of the plurality of bottom conical tubes, gaps are arranged between the plurality of bottom conical tubes, and the gas in the first reaction zone enters the head zone upward through the plurality of top conical tubes;

[0010] The large-diameter end of the top conical tube in the second reaction zone is communicated with the small-diameter end of the bottom conical tube in the first reaction zone.

[0011] Preferably, a deflection cone is coaxially arranged inside the top conical tube, the tip of the deflection cone is facing, and the deflection cone is arranged close to the large diameter end of the top conical tube.

[0012] Preferably, the small diameter ends of several of the bottom conical tubes in the first reaction zone and the small diameter ends of several of the bottom conical tubes in the second reaction zone are respectively connected to a first rotary seal unloader, and the second reaction zone is connected to the cooling zone through several of the first rotary seal unloaders.

[0013] Preferably, a feed zone and a transition zone are also provided in the furnace body from top to bottom, the feed zone is located at the bottom of the head zone and is connected to the head zone, and the transition zone is located at the bottom of the first reaction zone and is connected to the first reaction zone.

[0014] Preferably, a plurality of first reaction zone reducing gas inlets and a plurality of second reaction zone reducing gas inlets are arranged on the circumferential side wall of the furnace body, and the plurality of first reaction zone reducing gas inlets are respectively arranged close to the small diameter end of the bottom conical tube in the first reaction zone, and the plurality of second reaction zone reducing gas inlets are respectively arranged close to the small diameter end of the bottom conical tube in the second reaction zone.

[0015] Preferably, a cooling zone nitrogen inlet and a cooling zone nitrogen outlet are also connected on the circumferential side wall of the furnace body, and the cooling zone nitrogen inlet and the cooling zone nitrogen outlet are respectively connected to the cooling zone, and the cooling zone nitrogen inlet and the cooling zone nitrogen outlet are symmetrically arranged about the axis of the furnace body, and the cooling zone nitrogen inlet is located below the cooling zone nitrogen outlet.

[0016] Preferably, an air outlet channel and a plurality of feed channels are provided in the head area, and the air outlet channel and the plurality of feed channels are respectively connected to the feed area.

[0017] Preferably, a discharge area is further provided in the furnace body, the discharge area is connected to the bottom of the cooling area, the bottom of the discharge area is connected to a discharge channel, and the discharge channel is connected to a second rotary seal discharger.

[0018] Preferably, nitrogen sealing valves are respectively provided in the feed channel and the discharge channel.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects: the hydrogen-based vertical furnace device of the present invention can use hydrogen-rich reducing gas to directly reduce iron, the internal structure of the device is simple, the flow field is adjustable, the resistance is small, the reduction reaction is divided into zones, the reaction is sufficient, and a metallization rate ≥ 92% can be achieved. The reducing gas is introduced into the first reaction zone and the second reaction zone separately, and the temperature and pressure are adjusted separately according to the reduction effect, thereby achieving energy-saving effects, avoiding the pollution and high carbon emissions of traditional long-process blast furnace ironmaking, achieving pollution reduction and substantial carbon emission reduction at the source, promoting the development of green and low-carbon metallurgical technology of "replacing carbon with hydrogen" in the ironmaking process, and helping the green transformation and upgrading of the steel industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the internal structure of the hydrogen-based vertical furnace device of the present invention;

[0022] Among them, 1. head area; 2. feed area; 3. transition area; 4. first reaction zone; 5. second reaction zone; 6. cooling zone; 7. unloading area; 8. reducing gas inlet of the first reaction zone; 9. reducing gas inlet of the second reaction zone; 10. gas outlet channel; 11. feed channel; 12. discharge channel; 13. nitrogen inlet of the cooling zone; 14. nitrogen outlet of the cooling zone; 15. first rotary sealed unloader; 16. deflector cone; 17. top conical tube; 18. bottom conical tube; 19. second rotary sealed unloader. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Embodiment 1:

[0026] Reference Figure 1 The present invention provides a hydrogen-based vertical furnace device for direct reduction of iron, comprising:

[0027] The furnace body, the interior of the furnace body is divided into a head zone 1, a reaction zone and a cooling zone 6 from top to bottom, and the head zone 1, the reaction zone and the cooling zone 6 are connected in sequence;

[0028] The reaction zone is provided with a first reaction zone 4 and a second reaction zone 5 from top to bottom, and a gas-solid contact unit is provided in the first reaction zone 4 and the second reaction zone 5 respectively. The head zone 1 is connected with the cooling zone 6 through the gas-solid contact unit in the first reaction zone 4 and the gas-solid contact unit in the second reaction zone 5.

[0029] The first reaction zone 4 and the second reaction zone 5 are separately arranged, and the air intake can be controlled separately, and the temperature, pressure, etc. can be adjusted separately according to the reduction effect; the main function of the gas-solid contact unit is to control the descending speed of the pellet raw material and the height of the material layer, and to make the pellet raw material contact with the reducing gas in countercurrent, so that the reducing gas can efficiently reduce the pellet raw material into metallized pellets; the main function of the cooling zone 6 is to exchange heat with the reduced metallized pellets, recover the sensible heat in the furnace body, and achieve energy saving and emission reduction. On the whole, the hydrogen-based vertical furnace of the present invention can use hydrogen-rich reducing gas to directly reduce iron, the internal structure of the furnace body is simple, the resistance is small, the reduction reaction is divided into zones, the reaction is sufficient, and the metallization rate can be achieved ≥ 92%. The reducing gas of the first reaction zone and the second reaction zone is separately introduced, and the temperature and pressure can be adjusted separately according to the reduction effect, which is helpful to achieve energy saving and emission reduction.

[0030] Further optimizing the scheme, the gas-solid contact unit in the first reaction zone 4 includes a plurality of top conical tubes 17 and a plurality of bottom conical tubes 18, the large diameter ends of the plurality of top conical tubes 17 and the bottom conical tubes 18 are arranged upward, the small diameter end openings of the plurality of top conical tubes 17 are respectively connected with the large diameter end openings of the plurality of bottom conical tubes 18, and gaps are arranged between the plurality of bottom conical tubes 18, and the gas in the first reaction zone 4 enters the head zone 1 upward through the plurality of top conical tubes 17;

[0031] The large-diameter end of the top conical tube 17 in the second reaction zone 5 is connected to the small-diameter end of the bottom conical tube 18 in the first reaction zone 4 .

[0032] like Figure 1 As shown, in the first reaction zone 4, the large diameter end edges of two adjacent top tapered tubes 17 are connected to each other and form a sealing surface. At the same time, the large diameter end edges of several top tapered tubes 17 close to the inner wall of the furnace body are respectively connected to the inner wall of the furnace body and form a sealing surface, so that the reducing gas in the first reaction zone 4 can only flow to the head zone 1 through the top tapered tube 17 after passing through the gaps between several bottom tapered tubes 18 from bottom to top. Similarly, several top tapered tubes 17 in the second reaction zone 5 are connected to each other and to the inner wall of the furnace body to form a sealing surface, so that the reducing gas in the second reaction zone 5 can only enter the first reaction zone 4 through the top tapered tube 17.

[0033] After the pellet raw material enters the first reaction zone 4 from the head zone, it will slowly descend in the top conical tubes 17 under the influence of the conical structure, and fall into the bottom conical tube 18, and slowly descend in the bottom conical tube 18, and fall into the top conical tube 17 in the second reaction zone 5, and finally fall into the cooling zone 6 through the bottom conical tube 18 in the second reaction zone 5. While descending in the top conical tube 17, the pellet raw material is countercurrently contacted with the upward-flowing reducing gas and is reduced to metallized pellets.

[0034] A further optimized solution is that a deflection cone 16 is coaxially arranged inside the top conical tube 17 , the tip of the deflection cone 16 is facing, and the deflection cone 16 is arranged close to the large diameter end of the top conical tube 17 .

[0035] like Figure 1 As shown, the main function of the deflector cone 16 is to make the flow field in the top conical tube 17 uniform.

[0036] To further optimize the solution, the small diameter ends of several bottom conical tubes 18 in the first reaction zone 4 and the small diameter ends of several bottom conical tubes 18 in the second reaction zone 5 are respectively connected to the first rotary sealed unloader 15, and the second reaction zone 5 is connected to the cooling zone 6 through the several first rotary sealed unloaders 15.

[0037] like Figure 1 As shown, the main function of the first rotary sealed discharger 15 is to control the amount of metallized pellets falling into the cooling zone 6 , thereby controlling the height of the material layer in the first reaction zone 4 and the second reaction zone 5 .

[0038] To further optimize the solution, a feed zone 2 and a transition zone 3 are provided in the furnace body from top to bottom. The feed zone 2 is located at the bottom of the head zone 1 and is connected to the head zone 1. The transition zone 3 is located at the bottom of the first reaction zone 4 and is connected to the first reaction zone 4.

[0039] To further optimize the solution, a plurality of first reaction zone reducing gas inlets 8 and a plurality of second reaction zone reducing gas inlets 9 are arranged on the circumferential side wall of the furnace body, and the plurality of first reaction zone reducing gas inlets 8 are respectively arranged close to the small diameter end of the bottom conical tube 18 in the first reaction zone 4, and the plurality of second reaction zone reducing gas inlets 9 are respectively arranged close to the small diameter end of the bottom conical tube 18 in the second reaction zone 5.

[0040] like Figure 1 As shown, a plurality of first reaction zone reducing gas inlets 8 are connected to the bottom of the first reaction zone 4 , and a plurality of second reaction zone reducing gas inlets 9 are connected to the bottom of the second reaction zone 5 .

[0041] A further optimization scheme is that a cooling zone nitrogen inlet 13 and a cooling zone nitrogen outlet 14 are also connected on the circumferential side wall of the furnace body. The cooling zone nitrogen inlet 13 and the cooling zone nitrogen outlet 14 are respectively connected to the cooling zone 6. The cooling zone nitrogen inlet 13 and the cooling zone nitrogen outlet 14 are symmetrically arranged about the axis of the furnace body, and the cooling zone nitrogen inlet 13 is located below the cooling zone nitrogen outlet 14.

[0042] like Figure 1 As shown, the nitrogen used for cooling enters the cooling zone 6 through the cooling zone nitrogen inlet 13, flows upward from the bottom of the metallized pellets accumulated in the cooling zone 6, and finally flows out from the cooling zone nitrogen outlet 14 to achieve heat exchange with the metallized pellets, so as to recover the sensible heat in the furnace body and achieve energy-saving production.

[0043] According to a further optimization scheme, a gas outlet channel 10 and a plurality of feed channels 11 are provided in the head area 1 , and the gas outlet channel 10 and the plurality of feed channels 11 are respectively connected to the feed area 2 .

[0044] like Figure 1 As shown, the pellet raw materials enter the furnace body through the feed channel 11 , and the reducing gas in the furnace body flows upward and is finally discharged from the gas outlet channel 10 .

[0045] According to a further optimization scheme, a discharge area 7 is further provided in the furnace body. The discharge area 7 is connected to the bottom of the cooling area 6 . The bottom of the discharge area 7 is connected to a discharge channel 12 . The discharge channel 12 is connected to a second rotary sealed discharger 19 .

[0046] like Figure 1 As shown, the second rotary sealed discharger 19 mainly functions to control the discharge of the metallized pellets in the furnace body. At the same time, the amount of the metallized pellets accumulated in the cooling zone 6 can be controlled by the second rotary sealed discharger 19 .

[0047] The rotary seal unloader is a conventional device in the field, and its structure and working principle are not described in detail.

[0048] To further optimize the solution, nitrogen sealing valves (not shown in the figure) are respectively provided in the feed channel 11 and the discharge channel 12.

[0049] The main function of the nitrogen sealing valve is to prevent gas leakage during material inlet and outlet.

[0050] To further optimize the solution, the furnace body is a pressure vessel, the outer shell is made of carbon steel, the inner wall is built with refractory bricks, and the outer wall is paved with insulation material.

[0051] The working process of this embodiment is as follows: the pellet raw material enters the feed zone 2 in the device from the feed channel 11 at the top of the hydrogen-based vertical furnace device, flows downward, contacts and reacts with the reducing gas entering from the reducing gas inlet 8 of the first reaction zone in the first reaction zone 4, and then contacts and reacts again with the reducing gas entering from the reducing gas inlet 9 of the second reaction zone through the second reaction zone 5. The reduced metallized pellets enter the cooling zone 6, perform heat exchange with the low-temperature nitrogen entering from the nitrogen inlet 13 of the cooling zone in the cooling zone, and finally enter the unloading zone 7, and are discharged from the hydrogen-based vertical furnace through the discharge channel 12 and the second rotary sealed unloader 19 to obtain metallized pellets.

[0052] in:

[0053] Coke oven gas or natural gas or other hydrogen-rich gas is used as reducing gas, which is introduced into the first reaction zone 4 and the second reaction zone 5 through the first reaction zone reducing gas inlet 8 and the second reaction zone reducing gas inlet 9. The total sulfur content (including organic sulfur and inorganic sulfur) in the reducing gas is ≤0.1 mg / m 3 , H2+CO content ≥90%;

[0054] The ratio of the reducing gas intake volume of the first reaction zone 4 to the second reaction zone 5 is controlled at 1:(0.45-0.66); the reducing gas intake temperature in the first reaction zone 4 is 900°C-1020°C, and the intake pressure is 0.84Mpa-1.1Mpa, and the reducing gas intake temperature in the second reaction zone 5 is 450°C-560°C, and the intake pressure is 0.84Mpa-1.1Mpa;

[0055] The pressure in cooling zone 6 is controlled at 0.7 MPa to 0.9 MPa.

[0056] Embodiment 2:

[0057] The only difference between this embodiment and the first embodiment is that a number of reaction zones connected in sequence from top to bottom can be added to the furnace body according to needs, for example, a third reaction zone and a fourth reaction zone connected at the top and bottom can be added, and the newly added reaction zone has the same structure as the first reaction zone 4 and the second reaction zone 5, and is connected between the second reaction zone 5 and the cooling zone 6 to fully improve the reduction rate of the pelletizing raw materials.

[0058] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0059] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A hydrogen-based vertical furnace device for direct reduction of iron, characterized in that: include: A furnace body, wherein the interior of the furnace body is divided into a head zone (1), a reaction zone and a cooling zone (6) from top to bottom, and the head zone (1), the reaction zone and the cooling zone (6) are connected in sequence; The reaction zone is provided with a first reaction zone (4) and a second reaction zone (5) in order from top to bottom, and a gas-solid contact unit is provided in the first reaction zone (4) and the second reaction zone (5), respectively. The head zone (1) is connected to the cooling zone (6) via the gas-solid contact unit in the first reaction zone (4) and the gas-solid contact unit in the second reaction zone (5).

2. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 1, characterized in that: The gas-solid contact unit in the first reaction zone (4) comprises a plurality of top conical tubes (17) and a plurality of bottom conical tubes (18), the large-diameter ends of the plurality of top conical tubes (17) and the bottom conical tubes (18) are arranged upward, the small-diameter end openings of the plurality of top conical tubes (17) are respectively connected to the large-diameter end openings of the plurality of bottom conical tubes (18), and gaps are arranged between the plurality of bottom conical tubes (18), and the gas in the first reaction zone (4) enters the head zone (1) upward through the plurality of top conical tubes (17); The large diameter end of the top conical tube (17) in the second reaction zone (5) is connected to the small diameter end of the bottom conical tube (18) in the first reaction zone (4).

3. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 2, characterized in that: A deflection cone (16) is coaxially arranged inside the top conical tube (17), the tip of the deflection cone (16) is facing, and the deflection cone (16) is arranged close to the large diameter end of the top conical tube (17).

4. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 2, characterized in that: The small diameter ends of the plurality of bottom conical tubes (18) in the first reaction zone (4) and the small diameter ends of the plurality of bottom conical tubes (18) in the second reaction zone (5) are respectively connected to a first rotary seal unloader (15), and the second reaction zone (5) is connected to the cooling zone (6) via the plurality of the first rotary seal unloaders (15).

5. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 1, characterized in that: A feed zone (2) and a transition zone (3) are also provided in the furnace body from top to bottom, wherein the feed zone (2) is located at the bottom of the head zone (1) and is connected to the head zone (1), and the transition zone (3) is located at the bottom of the first reaction zone (4) and is connected to the first reaction zone (4).

6. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 2, characterized in that: A plurality of first reaction zone reducing gas inlets (8) and a plurality of second reaction zone reducing gas inlets (9) are arranged on the circumferential side wall of the furnace body. The plurality of first reaction zone reducing gas inlets (8) are arranged close to the small diameter end of the bottom conical tube (18) in the first reaction zone (4), and the plurality of second reaction zone reducing gas inlets (9) are arranged close to the small diameter end of the bottom conical tube (18) in the second reaction zone (5).

7. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 1, characterized in that: The circumferential side wall of the furnace body is also connected with a cooling zone nitrogen inlet (13) and a cooling zone nitrogen outlet (14); the cooling zone nitrogen inlet (13) and the cooling zone nitrogen outlet (14) are respectively connected with the cooling zone (6); the cooling zone nitrogen inlet (13) and the cooling zone nitrogen outlet (14) are symmetrically arranged about the axis of the furnace body, and the cooling zone nitrogen inlet (13) is located below the cooling zone nitrogen outlet (14).

8. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 5, characterized in that: An air outlet channel (10) and a plurality of feed channels (11) are provided in the head area (1), and the air outlet channel (10) and the plurality of feed channels (11) are respectively connected to the feed area (2).

9. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 8, characterized in that: A discharge area (7) is also provided in the furnace body, the discharge area (7) is connected to the bottom of the cooling area (6), the bottom of the discharge area (7) is connected to a discharge channel (12), and the discharge channel (12) is connected to a second rotary seal discharger (19).

10. A hydrogen-based vertical furnace device for direct reduction of iron according to claim 9, characterized in that: The feed channel (11) and the discharge channel (12) are respectively provided with nitrogen sealing valves.

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