Heating device for heating hydrogen to high temperature and use method thereof

Abstract

The invention relates to the field of sponge iron or liquid steel smelting in a shaft furnace through a direct reduction method, in particular to a heating device for heating hydrogen to high temperature and a using method of the heating device. The heating device for heating the hydrogen to the high temperature comprises a gas-based shaft furnace (2), and is characterized by further comprising a re-heating device (1), a tubular heating furnace (3) and a preheating device (4), the hydrogen outlet end of the tubular heating furnace (3) is connected with the hydrogen inlet end of the re-heating device (1) through a hydrogen conveying pipe (51), the re-heating device (1) is further provided with an oxygen inlet end, the oxygen inlet end of the re-heating device (1) is connected with an oxygen conveying pipe (53), and the preheating device (4) is connected with the gas-based shaft furnace (2). And the gas outlet end of the re-heating device (1) is connected with the gas inlet end of the gas-based shaft furnace (2) through a gas conveying pipe (54). The using method of the heating device for heating the hydrogen to the high temperature is characterized by being implemented according to the following steps in sequence: S1, preheating; s2, initial heating; and S3, reheating. The heating temperature is high, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of direct reduction smelting of sponge iron or liquid steel in a vertical shaft furnace, specifically to a heating device for heating hydrogen to a high temperature and its method of use. Background Technology

[0002] Hydrogen-based vertical shaft furnaces have gained attention and popularity in the global steel industry as a green metallurgical technology. However, due to limitations such as high-temperature hydrogen heating equipment and the cost of hydrogen production, there are still no successful commercial operation cases at home and abroad.

[0003] Chinese Patent Publication No. 113388708A, published on September 14, 2021, discloses a hydrogen heating system, including a convection section and a radiation section connected to each other. The radiation section contains a mixing heating furnace tube for heating hydrogen. The convection section contains independently installed fuel gas furnace tubes, combustion air furnace tubes, supplementary hydrogen furnace tubes, and circulating hydrogen furnace tubes. The supplementary hydrogen furnace tubes and the circulating hydrogen furnace tubes are both connected to the mixing heating furnace tube. The fuel gas furnace tube and the combustion air furnace tube are both connected to the radiation section, where they mix and burn to heat the hydrogen inside the mixing heating furnace tube. Patent 113388708A uses radiant heating as an external heat source to heat the hydrogen inside the metal tube to 850℃~1000℃. However, in the metallurgical field, hydrogen is mainly used as a reducing agent for iron oxides. The reduction of iron oxides by hydrogen is an endothermic reaction, and pure hydrogen needs to reach a temperature above 1000°C when used as a reducing agent. Patent 113388708A cannot meet this temperature range requirement. Furthermore, Chinese patent publication number 116123730A, published on May 16, 2023, discloses a device and method for direct-heating rapid electric heating of hydrogen in pure hydrogen metallurgy, and Chinese patent publication number 116287519A, published on June 23, 2023, discloses an electric heating device and method for reducing high-temperature hydrogen in a vertical shaft furnace. Both patents use electric heating to raise the hydrogen temperature to above 1000°C, but electric heating methods are affected by many factors such as heating efficiency, equipment size, and investment, and are only at the industrial experimental stage. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art and provide a smelting equipment with high heating temperature and improved production efficiency, this invention discloses a heating device for heating hydrogen to a high temperature and its usage method.

[0005] The present invention achieves its objective through the following technical solution: A heating device for heating hydrogen to a high temperature includes a gas-based vertical furnace with a hydrogen inlet. The device further includes a reheating device, a tubular heater, and a preheating device. The hydrogen inlet and flue gas outlet of the preheating device are connected to the hydrogen supply pipe and the flue gas supply pipe, respectively. The hydrogen outlet and flue gas inlet of the preheating device are connected to the hydrogen inlet and flue gas outlet of the tubular heater through the hydrogen supply pipe and the flue gas supply pipe, respectively. The hydrogen outlet of the tubular heater is connected to the hydrogen inlet of the reheating device through the hydrogen supply pipe. The reheating device is also equipped with an oxygen inlet. The oxygen inlet of the reheating device is connected to the oxygen supply pipe. The gas outlet of the reheating device is connected to the gas inlet of the gas-based vertical furnace through the gas supply pipe.

[0006] The heating device for heating hydrogen to a high temperature is characterized in that: there are at least two reheating devices, which are connected in series. When connected in series, two adjacent reheating devices are respectively connected to the gas outlet of one reheating device and the hydrogen inlet of the other reheating device through a gas supply pipe.

[0007] The heating device for heating hydrogen to a high temperature is characterized in that: an oxygen inlet nozzle is provided at the oxygen inlet end of the reheating device. When there is only one oxygen inlet of the reheating device, the hydrogen inlet and gas outlet of the reheating device are respectively located at the top and bottom of the reheating device, and the oxygen inlet of the reheating device is located at the top of the reheating device. When there is more than one oxygen inlet in the reheating device, the hydrogen inlet and gas outlet of the reheating device are respectively located at both ends of the reheating device and are both located on the central axis of the reheating device. Each of the oxygen inlet ends is evenly arranged around the central axis of the reheating device, and the oxygen outlet of each oxygen inlet nozzle is on a plane perpendicular to the central axis of the reheating device.

[0008] The heating device for heating hydrogen to a high temperature is characterized in that the oxygen inlet nozzle is arranged in any one of the following i to iii: i. The oxygen inlet nozzle is L-shaped. The lower section of the oxygen inlet nozzle is connected to the oxygen inlet end of the reheating device in a manner perpendicular to the central axis of the reheating device, and the upper section of the oxygen inlet nozzle is located outside the reheating device in a manner parallel to the central axis of the reheating device. ii. The oxygen inlet nozzle is obtuse-angled. The lower section of the oxygen inlet nozzle is connected to the oxygen inlet end of the reheating device at an angle to the central axis of the reheating device, and the upper section of the oxygen inlet nozzle is located outside the reheating device in a manner parallel to the central axis of the reheating device. iii. The oxygen inlet nozzle is Z-shaped. The lower and upper sections of the oxygen inlet nozzle are parallel and perpendicular to the middle section. The oxygen inlet nozzle passes through the middle section and is installed inside the oxygen inlet end of the reheating device. The lower section of the oxygen inlet nozzle is located inside the reheating device and is parallel to the central axis of the reheating device. The upper section of the oxygen inlet nozzle is located outside the reheating device and is parallel to the central axis of the reheating device.

[0009] The heating device for heating hydrogen to a high temperature is characterized in that: the oxygen inlet nozzle includes an oxygen inlet central pipe and an oxygen inlet outer ring pipe, the oxygen inlet central pipe is sleeved inside the oxygen inlet outer ring pipe and the central axes of the two coincide, the oxygen inlet central pipe is connected to an oxygen delivery pipe, and the oxygen inlet outer ring pipe is connected to a hydrogen delivery pipe.

[0010] The heating device for heating hydrogen to a high temperature is characterized in that: the reheating device is lined with a refractory material layer that can withstand high temperatures of not less than ℃, and the reheating device is provided with explosion-proof holes.

[0011] The method of using the heating device for heating hydrogen to a high temperature is characterized by the following steps being performed sequentially: S. Preheating: The hot flue gas generated by the combustion of fuel outside the tubes of the tubular heater is fed into the preheating device to heat the hydrogen in the preheating device into preheated hydrogen. The hot flue gas is discharged from the preheating device. S. Initial heating: The preheated hydrogen is input into the furnace tube of the tubular heater, and the fuel combustion outside the furnace tube heats the preheated hydrogen in the furnace tube to ℃~℃ to become the initial heating hydrogen. S. Reheating: The initial heating hydrogen is fed into the reheating device through a hydrogen supply pipe. Oxygen is injected into the reheating device to make the volume ratio of oxygen flow rate to hydrogen flow rate in the reheating device less than %. The temperature of the initial heating hydrogen is raised to above ℃ to become secondary heating gas. The secondary heating gas is fed into the gas-based vertical furnace as reducing gas through the outlet of the reheating device.

[0012] The method of using the heating device for heating hydrogen to a high temperature is characterized in that: in step S, the volume ratio of oxygen flow rate to hydrogen flow rate in the reheating device is less than %, and the temperature of the initially heated hydrogen is heated to above ℃ to become a secondary heated gas.

[0013] The method of using the heating device for heating hydrogen to a high temperature is characterized in that it is used for the preparation of reducing gas in a hydrogen-based vertical shaft furnace.

[0014] The present invention has the following beneficial effects: By using a staged oxygenation and heating method, the pure hydrogen gas is heated to over 1000°C, thereby increasing the thermal energy carried by the hydrogen into the gas-based vertical shaft furnace. This solves the problem of needing supplemental heating when hydrogen is used as a reducing agent in the gas-based vertical shaft furnace; it also increases the reduction rate of iron oxides in the gas-based vertical shaft furnace, improving production efficiency; and it addresses the issue of needing to increase the amount of circulating hydrogen to meet thermal energy requirements due to insufficient hydrogen temperature, thus reducing overall energy consumption. In this invention, "pure hydrogen gas" refers to the raw material gas with a hydrogen content greater than 90%. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 2This is a schematic diagram of the structure of the present invention, where the oxygen inlet nozzle adopts an obtuse angle type. Figure 3 This is a schematic diagram of an obtuse-angled oxygen inlet nozzle. Figure 4 This is a schematic diagram of the Z-type oxygen inlet nozzle. Figure 5 This is a schematic diagram of the structure of the present invention, where the oxygen inlet nozzle is L-shaped. Figure 6 This is a schematic diagram of an L-shaped oxygen inlet nozzle. Figure 7 This is a schematic diagram of the structure of the present invention, consisting of three reheating devices connected in series. Figure 8 This is a schematic diagram of the reheating device in this invention. Figure 9 This is a schematic diagram of the oxygen inlet nozzle in this invention. Detailed Implementation

[0016] The present invention will be further illustrated below through specific embodiments. Example

[0017] A heating device for heating hydrogen to a high temperature includes a reheating device 1, a gas-based vertical furnace 2, a tubular furnace 3, and a preheating device 4, such as... Figures 1-3 As shown, the specific structure is: The gas-based vertical furnace 2 is equipped with a hydrogen inlet end; The hydrogen inlet and the flue gas outlet of the preheating device 4 are connected to the hydrogen supply pipe 51 and the flue gas supply pipe 52, respectively. The hydrogen outlet and the flue gas inlet of the preheating device 4 are connected to the hydrogen inlet and the flue gas outlet of the tubular heater 3 through the hydrogen supply pipe 51 and the flue gas supply pipe 52, respectively. The hydrogen outlet of the tubular heater 3 is connected to the hydrogen inlet of the reheating device 1 through the hydrogen supply pipe 51. The reheating device 1 is also provided with an oxygen inlet. The oxygen inlet of the reheating device 1 is connected to the oxygen supply pipe 53. The gas outlet of the reheating device 1 is connected to the gas inlet of the gas-based vertical furnace 2 through the gas supply pipe 54. The oxygen inlet of the reheating device 1 is equipped with an oxygen inlet nozzle 12. The reheating device 1 has more than one oxygen inlet. In this embodiment, two are used as an example. The hydrogen inlet and gas outlet of the reheating device 1 are respectively located at both ends of the reheating device 1 and are both located on the central axis of the reheating device 1. Each of the oxygen inlet ends is evenly arranged around the central axis of the reheating device 1, and the oxygen outlet of each oxygen inlet nozzle 12 is on a plane perpendicular to the central axis of the reheating device 1.

[0018] In this embodiment, as Figure 2 and Figure 3 As shown: The oxygen inlet nozzle 12 is configured as follows: The oxygen inlet nozzle 12 is obtuse-angled. The lower section of the oxygen inlet nozzle 12 is connected to the oxygen inlet end of the reheating device 1 at an angle to the central axis of the reheating device 1. The upper section of the oxygen inlet nozzle 12 is located outside the reheating device 1 in a manner parallel to the central axis of the reheating device 1.

[0019] When using this embodiment, follow these steps in sequence: S1. Preheating: The hot flue gas generated by the combustion of fuel outside the tube of the tubular heating furnace 3 is input into the preheating device 4 to heat the hydrogen in the preheating device 4 into preheated hydrogen, and the hot flue gas is discharged from the preheating device 4. S2. Initial heating: The preheated hydrogen is input into the furnace tube of the tubular heater 3. The combustion of fuel outside the furnace tube of the tubular heater 3 heats the preheated hydrogen in the furnace tube to 750°C to 980°C, which becomes the initial heating hydrogen. S3. Reheating: The initial heating hydrogen is fed into the reheating device 1 through a hydrogen supply pipe. Oxygen is injected into the reheating device 1 to make the volume ratio of oxygen flow rate to hydrogen flow rate in the reheating device 1 less than 4%. The temperature of the initial heating hydrogen is raised to above 1000°C to become a secondary heating gas. The secondary heating gas is fed into the gas-based vertical furnace 2 as a reducing gas through the outlet of the reheating device 1. Example

[0020] A heating device for heating hydrogen to a high temperature includes a reheating device 1, a gas-based vertical furnace 2, a tubular furnace 3, and a preheating device 4, such as... Figure 1 and Figure 4 As shown, the specific structure is: The oxygen inlet nozzle 12 is configured as follows: The oxygen inlet nozzle 12 is Z-shaped. The lower and upper sections of the oxygen inlet nozzle 12 are parallel and perpendicular to the middle section. The oxygen inlet nozzle 12 passes through the middle section and is installed inside the oxygen inlet end of the reheating device 1. The lower section of the oxygen inlet nozzle 12 is located inside the reheating device 1 and is parallel to the central axis of the reheating device 1. The upper section of the oxygen inlet nozzle 12 is located outside the reheating device 1 and is parallel to the central axis of the reheating device 1.

[0021] All other structures are the same as in Example 1.

[0022] When using this embodiment, follow these steps in sequence: S1. Preheating: The hot flue gas generated by the combustion of fuel outside the tube of the tubular heating furnace 3 is input into the preheating device 4 to heat the hydrogen 7 in the preheating device 4 into preheated hydrogen, and the hot flue gas is discharged from the preheating device 4. S2. Initial heating: The preheated hydrogen is input into the furnace tube of the tubular heater 3. The combustion of fuel outside the furnace tube of the tubular heater 3 heats the preheated hydrogen in the furnace tube to 750°C to 980°C, which becomes the initial heating hydrogen. S3. Reheating: The initial heating hydrogen is fed into the reheating device 1 through a hydrogen supply pipe. Oxygen is injected into the reheating device 1 to make the volume ratio of oxygen flow rate to hydrogen flow rate in the reheating device 1 less than 1%. The temperature of the initial heating hydrogen is raised to above 1050°C to become a secondary heating gas. The secondary heating gas is fed into the gas-based vertical furnace 2 as a reducing gas through the outlet of the reheating device 1. Example

[0023] A heating device for heating hydrogen to a high temperature includes a reheating device 1, a gas-based vertical furnace 2, a tubular furnace 3, and a preheating device 4, such as... Figure 1 , Figure 5 and Figure 6 As shown, the specific structure is: The oxygen inlet nozzle 12 is configured as follows: The oxygen inlet nozzle 12 is L-shaped. The lower section of the oxygen inlet nozzle 12 is connected to the oxygen inlet end of the reheating device 1 in a manner perpendicular to the central axis of the reheating device 1, and the upper section of the oxygen inlet nozzle 12 is located outside the reheating device 1 in a manner parallel to the central axis of the reheating device 1.

[0024] There are at least two reheating devices 1. In this embodiment, two are used as an example. Each reheating device 1 is connected in series. When connected in series, two adjacent reheating devices 1 are connected to the gas outlet of one reheating device 1 and the hydrogen inlet of the other reheating device 1 through the gas supply pipe 54.

[0025] All other structures are the same as in Example 1.

[0026] The usage steps are the same as in Example 2. Example

[0027] A heating device for heating hydrogen to a high temperature includes a reheating device 1, a gas-based vertical furnace 2, a tubular furnace 3, and a preheating device 4, such as... Figure 7 As shown, the specific structure is: The gas-based vertical furnace 2 is equipped with a hydrogen inlet end; The hydrogen inlet and the flue gas outlet of the preheating device 4 are connected to the hydrogen supply pipe 51 and the flue gas supply pipe 52, respectively. The hydrogen outlet and the flue gas inlet of the preheating device 4 are connected to the hydrogen inlet and the flue gas outlet of the tubular heater 3 through the hydrogen supply pipe 51 and the flue gas supply pipe 52, respectively. The hydrogen outlet of the tubular heater 3 is connected to the hydrogen inlet of the reheating device 1 through the hydrogen supply pipe 51. The reheating device 1 is also provided with an oxygen inlet. The oxygen inlet of the reheating device 1 is connected to the oxygen supply pipe 53. The gas outlet of the reheating device 1 is connected to the gas inlet of the gas-based vertical furnace 2 through the gas supply pipe 54. The oxygen inlet of the reheating device 1 is equipped with an oxygen inlet nozzle 12. The reheating device 1 has one oxygen inlet, and the hydrogen inlet and gas outlet of the reheating device 1 are respectively located at the top and bottom of the reheating device 1. The oxygen inlet of the reheating device 1 is located at the top of the reheating device 1. There are at least two reheating devices 1. In this embodiment, three are used as an example. Each reheating device 1 is connected in series. When connected in series, two adjacent reheating devices 1 are connected to the gas outlet of one reheating device 1 and the hydrogen inlet of the other reheating device 1 through the gas supply pipe 54.

[0028] In this embodiment, the oxygen inlet nozzle 12 is as follows: Figure 8 As shown: The oxygen inlet nozzle 12 includes an oxygen inlet central pipe 121 and an oxygen inlet outer ring pipe 122. The oxygen inlet central pipe 121 is fitted inside the oxygen inlet outer ring pipe 122 and the central axes of the two coincide. The oxygen inlet central pipe 121 is connected to the oxygen delivery pipe 53, and the oxygen inlet outer ring pipe 122 is connected to the hydrogen delivery pipe 51.

[0029] In this embodiment, the reheating device 1 is as follows: Figure 9 As shown: The reheating device 1 comprises a shell 11, an oxygen inlet 12, a hydrogen inlet 13 for initial heating 6, and a gas outlet 14 for secondary heating 8. The shell 11 is lined with a refractory material layer 15 that is resistant to high temperatures of not less than 2000℃.

[0030] This embodiment employs three reheating devices 1 connected in series. Each reheating device 1 is connected to a dual-channel oxygen inlet nozzle 12. Without affecting the overall oxygen flow rate, the ratio of hydrogen to oxygen flow in a single reheating device 1 is further reduced, ensuring the safety of the all-hydrogen oxygenation device. The series connection ensures that the volume ratio of oxygen flow to hydrogen flow in a single reheating device 1 is less than 1%. The initial heating temperature of the hydrogen entering the reheating device 1 is 750–900°C, and the temperature at the gas outlet 14 after secondary heating is 1010–1050°C. The usage steps are the same as in Example 2.

Claims

1. A heating device for heating hydrogen to a high temperature, comprising a gas-based shaft furnace (2) provided with a hydrogen inlet end, characterized in that: The re-warming device (1), the tubular heating furnace (3) and the preheating device (4) are further included, The hydrogen inlet end and the smoke outlet end of the preheating device (4) are connected with the hydrogen conveying pipe (51) and the smoke conveying pipe (52) respectively, the hydrogen outlet end and the smoke inlet end of the preheating device (4) are connected with the hydrogen inlet end and the smoke outlet end of the tubular heating furnace (3) through the hydrogen conveying pipe (51) and the smoke conveying pipe (52) respectively, the hydrogen outlet end of the tubular heating furnace (3) is connected with the hydrogen inlet end of the re-warming device (1) through the hydrogen conveying pipe (51), the re-warming device (1) is further provided with an oxygen inlet end, the oxygen inlet end of the re-warming device (1) is connected with the oxygen conveying pipe (53), and the gas outlet end of the re-warming device (1) is connected with the gas inlet end of the gas-based shaft furnace (2) through the gas conveying pipe (54).

2. The heating device for heating hydrogen gas to a high temperature according to claim 1, wherein: The number of the re-warming device (1) is at least two, and each re-warming device (1) is connected in series, when connected in series, the gas outlet end of one re-warming device (1) and the hydrogen inlet end of another re-warming device (1) are connected through the gas conveying pipe (54).

3. The heating apparatus for heating hydrogen gas to a high temperature according to claim 2, wherein: The oxygen inlet end of the re-warming device (1) is provided with an oxygen inlet nozzle (12), When the number of the oxygen inlet end of the re-warming device (1) is one, the hydrogen inlet end and the gas outlet end of the re-warming device (1) are arranged at the top and the bottom of the re-warming device (1) respectively, and the oxygen inlet end of the re-warming device (1) is arranged at the top end of the re-warming device (1); When the number of the oxygen inlet end of the re-warming device (1) is more than one, the hydrogen inlet end and the gas outlet end of the re-warming device (1) are arranged at both ends of the re-warming device (1) and on the central axis of the re-warming device (1), each oxygen inlet end is arranged averagely around the central axis of the re-warming device (1), and the oxygen outlet end of each oxygen inlet nozzle (12) is on a plane perpendicular to the central axis of the re-warming device (1).

4. The heating apparatus for heating hydrogen gas to a high temperature according to claim 3, wherein: The oxygen inlet nozzle (12) is arranged in any one of the following i-iii: i. The oxygen inlet nozzle (12) is L-shaped, the lower section of the oxygen inlet nozzle (12) is connected with the oxygen inlet end of the re-warming device (1) in a manner perpendicular to the central axis of the re-warming device (1), and the upper section of the oxygen inlet nozzle (12) is arranged outside the re-warming device (1) in a manner parallel to the central axis of the re-warming device (1); ii. The oxygen inlet nozzle (12) is obtuse-angled, the lower section of the oxygen inlet nozzle (12) is connected with the oxygen inlet end of the re-warming device (1) in a manner oblique to the central axis of the re-warming device (1), and the upper section of the oxygen inlet nozzle (12) is arranged outside the re-warming device (1) in a manner parallel to the central axis of the re-warming device (1); iii. The oxygen inlet nozzle (12) is Z-shaped, the lower section and the upper section of the oxygen inlet nozzle (12) are parallel and both perpendicular to the middle section, the oxygen inlet nozzle (12) is arranged in the oxygen inlet end of the re-warming device (1) through the middle section, the lower section of the oxygen inlet nozzle (12) is arranged in the re-warming device (1) and parallel to the central axis of the re-warming device (1), and the upper section of the oxygen inlet nozzle (12) is arranged outside the re-warming device (1) and parallel to the central axis of the re-warming device (1).

5. The heating apparatus for heating hydrogen gas to a high temperature according to claim 4, wherein: The oxygen inlet nozzle (12) comprises an oxygen inlet central pipeline (121) and an oxygen inlet outer ring pipeline (122), the oxygen inlet central pipeline (121) is sleeved in the oxygen inlet outer ring pipeline (122) and the central axes of the two coincide, the oxygen inlet central pipeline (121) is connected with the oxygen conveying pipeline (53), and the oxygen inlet outer ring pipeline (122) is connected with the hydrogen conveying pipeline (51).

6. The heating apparatus for heating hydrogen gas to a high temperature according to claim 5, wherein: The reheating device (1) is lined with a refractory layer (15) with a high-temperature resistance of not less than 2000 DEG C, and an explosion-proof hole is arranged on the reheating device (1).

7. The method of claim 1 to 6, wherein the heating apparatus for hydrogen gas is used for heating to a high temperature, characterized in that: The following steps are sequentially implemented: S1. Preheating: the hot flue gas generated by the combustion of fuel outside the furnace tube of the tubular heating furnace (3) is input into the preheating device (4) to heat the hydrogen in the preheating device (4) into preheated hydrogen, and the hot flue gas is discharged from the preheating device (4); S2. Initial heating: the preheated hydrogen is input into the furnace tube of the tubular heating furnace (3), and the preheated hydrogen in the furnace tube is heated to 750 DEG C to 980 DEG C by the combustion of fuel outside the furnace tube of the tubular heating furnace (3) to become primary heated hydrogen; S3. Reheating: the primary heated hydrogen is input into the reheating device (1) through the hydrogen conveying pipeline, oxygen is sprayed into the reheating device (1), the volume ratio of the oxygen flow and the hydrogen flow in the reheating device (1) is less than 4%, the temperature of the primary heated hydrogen is increased to more than 1000 DEG C to become secondary heated gas, and the secondary heated gas is used as reducing gas and is input into the gas-based shaft furnace (2) through the gas outlet of the reheating device (1).

8. The method of claim 7, wherein the heating apparatus is heated to a temperature of at least 1000 °C. In step S3, the volume ratio of the oxygen flow and the hydrogen flow in the reheating device (1) is less than 1%, the temperature of the primary heated hydrogen is heated to more than 1050 DEG C to become secondary heated gas.

9. The method of using a heating device for heating hydrogen gas to an elevated temperature according to any one of claims 1 to 6, wherein: Preparation of reducing gas for a full-hydrogen gas-based shaft furnace (2). Preparation of reducing gas for a full-hydrogen gas-based shaft furnace (2).

Images