A direct reduction vertical furnace top gas temperature raising and tempering system and method

Abstract

The present invention discloses a direct reduction vertical furnace top gas temperature raising and tempering system, which belongs to the field of iron and steel metallurgy technology, and includes a receiving system, a loosening device, an oxygen injection valve, a heat recovery system and a control system. The receiving system is arranged above the vertical furnace body, and the loosening device and the heat recovery system are both arranged inside the vertical furnace body. The loosening device is used to loosen the raw materials received by the receiving system, and the heat recovery system includes a gas heat exchanger, and an online gas analyzer is arranged on the pipeline of the gas heat exchanger. The gas composition signal in the pipeline is collected by the online gas analyzer, and the gas composition signal is transmitted to the control system, and the opening degree of the oxygen injection valve is adjusted by the control system. The present invention can improve the primary reaction rate of the reducing gas after reforming, strengthen the smelting intensity, improve the utilization coefficient of the vertical furnace, and optimize the system energy efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and particularly relates to a direct reduction shaft furnace top gas temperature raising and tempering system and method. Background Art

[0002] Gas-based direct reduced iron (DRI) is a process in which a high-temperature reducing gas (pure H2 or CO+H2≥90%, H2 / CO≥1.5) with a temperature of more than 950°C is blown in from the air inlet nozzle in the middle of the furnace body at a certain pressure. The iron ore block or pellet is reduced to sponge iron with a metallization rate of more than 90% under solid conditions. The reduction product can be used as a pure raw material for smelting high-quality steel and special steel, and can also be used as an iron-containing raw material for casting, ferroalloy, powder metallurgy and other processes. The direct reduction process does not require the use of coke. The raw materials can be cold-pressed pellets, pellet blocks or lump ore, and sintered ore is not required. It is a high-quality, low-carbon, low-pollution new steel metallurgical process and one of the cutting-edge technologies in the world of steel metallurgy. The DRI gas-based reduction technology requires the use of a reforming furnace or a tubular heating furnace to process natural gas into H2 and CO after reforming and heating. The reducing gas is heated and blown into a vertical furnace for solid-gas reduction reaction. The ore and the reducing gas flow in reverse, and sponge iron (full iron TFe≥90%) is obtained after reduction. DRI has the common characteristics of ordinary sponge iron: high purity, low harmful impurity content, which is conducive to the production of high-quality steel. If pure hydrogen is used for smelting, CO2 can achieve zero emissions.

[0003] Since the reaction of H2 and FeOX is a strong endothermic reaction, the temperature of the 950℃ furnace gas will drop to about 800℃ after the reaction. Going further up, the temperature of the gas in the furnace will drop to 600℃, reaching the furnace top outlet, where the airflow and the block material at the feed port will exchange mass and energy, and the temperature will drop to below 450℃ before being discharged from the furnace, purified and decarbonized, and recycled. This process has temperature changes, a primary gas utilization rate of about 30%, and a reverse reaction will occur, resulting in an increase in the CH4 content of the circulating gas discharged from the furnace top. How to increase the primary reaction rate of the reducing gas after reforming, strengthen the smelting intensity, and at the same time reduce the purification and treatment energy of the circulating cooling gas on the furnace top, thereby reducing the energy consumption of the subsequent reducing gas manufacturing process, improving production efficiency, improving the utilization factor of the vertical furnace, optimizing the system energy efficiency, and reducing the overall cost, the improvement of the DRI vertical furnace process is of great practical significance. Summary of the invention

[0004] The object of the present invention is to provide a direct reduction vertical furnace top gas temperature raising and tempering system and method, which can improve the primary reaction rate of the reducing gas after reforming, strengthen the smelting intensity, and at the same time reduce the purification treatment energy of the furnace top circulating cooling gas, thereby reducing the energy consumption of the subsequent reducing gas manufacturing process, improving production efficiency, improving the vertical furnace utilization factor, and optimizing the system energy efficiency.

[0005] To achieve the above-mentioned purpose, the present invention provides a direct reduction vertical furnace top gas temperature raising and tempering system, comprising a receiving system, a loosener, an oxygen injection valve, a heat recovery system and a control system, wherein the receiving system is arranged above the vertical furnace body, the loosener and the heat recovery system are both arranged inside the vertical furnace body, the loosener is used to loosen the raw materials received by the receiving system, the oxygen injection valve is arranged on one side of the loosener, the heat recovery system comprises a gas heat exchanger, an online gas analyzer is arranged on the pipeline of the gas heat exchanger, the gas composition signal in the pipeline is collected by the online gas analyzer, and the gas composition signal is transmitted to the control system, and the opening degree of the oxygen injection valve is adjusted by the control system.

[0006] Furthermore, the material loosener is driven by a DC motor.

[0007] Furthermore, the material loosener is connected by a connecting rod, so that the material loosener can rotate 180 degrees horizontally.

[0008] Furthermore, the material loosener is in the shape of a cylinder as a whole, and a plurality of air supply holes are provided in the lower half of the cylinder.

[0009] Furthermore, the plurality of air supply holes are divided into three rows and evenly distributed, and the interval angle between each row is 30°.

[0010] Furthermore, an oxygen delivery pipeline is provided inside the loosening device, and the oxygen delivery pipeline is used to deliver the oxygen input through the plurality of air supply holes.

[0011] Furthermore, the system also includes: a purification and decarburization system, which is arranged outside the vertical furnace body. The purification and decarburization system is used to purify and decarburize the gas discharged from the vertical furnace body, and then return the purified and decarburized gas to the vertical furnace body as reducing gas.

[0012] The present invention also provides a method for heating and tempering the gas at the top of a direct reduction shaft furnace, which uses the direct reduction shaft furnace top gas heating and tempering system as claimed in any one of claims 1 to 7, and comprises the following steps:

[0013] S1. The solid raw material is fed into a receiving system. After being processed by the receiving system, the solid raw material is fed into a vertical furnace body. The control system controls the oxygen injection valve according to data obtained by a pressure detection instrument in the vertical furnace body to control the amount of oxygen introduced.

[0014] S2, feeding high-temperature reducing gas from the reducing gas inlet of the vertical furnace body, so that the high-temperature reducing gas is mixed with the oxygen introduced in step S1;

[0015] S3. During the mixing process of the raw materials, in the feed preheating section, the raw materials are loosened by a loosening device;

[0016] S4. Spray oxygen evenly through the air supply holes on the loosener.

[0017] Furthermore, in step S3, the feed preheating section is set in a certain temperature range, and the reduction rate is on a downward trend within the temperature range.

[0018] Furthermore, the temperature range is 650-680°C.

[0019] Compared with the prior art, according to the direct reduction vertical furnace top gas temperature raising and tempering system and method of the present invention, a loosener is arranged above the area where the reduction reaction gas is injected into the vertical furnace body, in a certain low temperature zone (650-680°C) and where the reduction rate decreases, that is, the feed preheating section. The loosener is driven by a DC motor and connected by a connecting rod. It can rotate 180° horizontally to the left and right. An air supply hole is opened on the lower semi-cylinder of the loosener, and an oxygen delivery pipeline is arranged in the middle of the loosener to evenly spray oxygen to the area of ​​650-680°C. In this temperature range, because it is higher than the ignition temperature of the reducing gas (coke oven gas: 560°C; methane: 537°C), this injection position has a higher safety. The present invention can not only make the oxygen diffuse more evenly in this area inside the vertical furnace, but also cool and protect the loosener.

[0020] On the other hand, before oxygen enters the oxygen delivery pipeline of the loosener in the vertical furnace body, it is fully exchanged with the top gas out of the vertical furnace and waste heat is recovered through the top gas heat recovery system. The gas composition signal is fed back through the vertical furnace online gas analyzer to adjust the opening degree of the oxygen injection valve and control the oxygen injection amount to prevent excessive oxygen consumption and avoid overheating and energy loss caused by excessive temperature. Through the flexible and precise modulation of the control system online analysis coupling, the production of the vertical furnace can be adjusted according to the grade of the pellets entering the furnace and the composition of the top gas, ensuring the quality of the finished product and stabilizing the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 2 is a schematic diagram of the operation of a gas temperature raising and tempering system at the top of a direct reduction shaft furnace according to an embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of a material loosening device according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the function of the installation structure of the material loosener according to one embodiment of the present invention;

[0024] Figure 4It is a schematic diagram of the relationship between the temperature rise of the methanation furnace and the concentration of CO and CO2 in the inlet gas according to one embodiment of the present invention.

[0025] Description of main reference numerals:

[0026] ① Reduction reaction gas, ② Reduction gas after adding top return gas, ③ Top gas, ④ Oxygen entering the buffer tank ⑤ Quantitative oxygen to be injected, ⑥ Top gas purification and decarburization system, ⑦ Purified gas, ⑧ Receiving system, ⑨ Direct reduced iron, ⑩ Online gas analyzer, Oxygen injection valve, Feeder. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0028] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0029] like Figure 1 As shown, a direct reduction vertical furnace top gas temperature raising and tempering system according to a preferred embodiment of the present invention comprises a receiving system 8, a loosening device 12, an oxygen injection valve 11, a heat recovery system and a control system, wherein the receiving system is arranged above the vertical furnace body, the loosening device and the heat recovery system are both arranged inside the vertical furnace body, the loosening device is used to loosen the raw materials received by the receiving system, the oxygen injection valve is arranged on one side of the loosening device, and the heat recovery system comprises a gas heat exchanger, an online gas analyzer 10 is arranged on the pipeline of the gas heat exchanger, the gas composition signal in the pipeline is collected by the online gas analyzer 10, and the gas composition signal is transmitted to the control system, and the opening degree of the oxygen injection valve 11 is adjusted by the control system. The purpose of the present invention is to propose a gas-based DRI direct reduction vertical furnace top gas further quality raising and temperature adjusting process technology method with low carbon emission and adaptability to dual carbon environment, when the working gas blown into the vertical furnace body adopts natural gas or coke oven gas, it needs to be reformed and the direct reduction gas 1 is heated to 950°C before being blown into the reactor to provide the energy required for the reaction. The temperature of the reducing gas is heated to above 950°C. Since the reduction reaction of rich hydrogen and FeOX is endothermic, the temperature of the reduction zone can be reduced to about 820°C, which not only ensures the reduction reaction but also avoids the sticking of pellets.

[0030] As the reducing gas moves upwards in the vertical furnace, after heat exchange and reduction reaction with the pellets, when the temperature of the mixed gas after the reaction drops to about 600°C, a methanogenic reaction will occur to generate CH4 due to the presence of three gases: H2, CO2, and CO. Due to the occurrence of the methanogenic reaction (see the following reaction equations 1-1, 1-2), the chemical process of the effective gas (CO+H2) required for the reduction reaction in the vertical furnace is "back-mixed", which in turn increases the energy consumption of the subsequent reducing gas manufacturing process and reduces the gas utilization rate in the vertical furnace. The most ideal reaction result in the vertical furnace is to convert all the "carbon" into carbon dioxide and all the "hydrogen" into water, so that the reduction capacity of carbon and hydrogen elements is fully utilized.

[0031] The thermal effect of the methanation reaction is a highly exothermic reaction, and its reaction formula is as follows:

[0032]

[0033]

[0034] Through the analysis of the top gas composition, it can be known that the top gas after reduction has a lower temperature. Methane reforming is a reversible reaction, and a methanogenic reaction will occur at this time, commonly known as "backmixing". In an environment where the temperature drops to about 600°C, the effective gas (CO+H2) coming from the reaction area in the vertical furnace undergoes a methanogenic reaction in this temperature range. This increases the methane concentration, and the average level is maintained at about 12-15%, which is higher than the CH4 content in the reducing gas blown into the reaction vertical furnace after reforming. The composition of typical natural gas and coke oven gas used as reducing gas to produce DRI and the composition when discharged from the top are shown in Table 1 below.

[0035] Table 1 Composition of natural gas and coke oven gas process and top exhaust

[0036]

[0037] The general process uses the top gas to recover waste heat through the waste heat boiler, enter the top gas washing system for dust removal, cool to room temperature and enter the decarbonization system for decarbonization. The decarbonized gas circulates into the reducing gas heating / reforming system. In this process, the effective gas undergoes methanation reaction in the low temperature area. Even if it is an exothermic reaction, it is difficult to obtain full economical recycling due to the low temperature and poor energy grade. In addition, the methane circulated back to the reducing gas manufacturing system needs to consume high-grade heat for reforming reaction. Therefore, the methanation of the mixed gas (CO2, CO, H2) components is a typical chemical "backmixing" and is the source of consumption of effective gas and high-grade energy.

[0038] Practice shows that the adiabatic temperature rise for every 1% CO conversion is 72°C, and the adiabatic temperature rise for every 1% CO2 conversion is 60°C. The total temperature rise of the reactor can be calculated by the following formula:

[0039] ΔT=72·[CO] 入 +60 [CO2] 入 (1)

[0040] In formula (1), ΔT is the temperature rise of the reactor, °C; [CO]in, [CO2]in are the concentrations of CO and CO2 in the air inlet, respectively, in volume %

[0041] Figure 4 The relationship between the temperature rise of the methanogenization furnace and the concentration of CO and CO2 in the inlet gas is shown. The operating conditions of the methanogenization are known using the figure and formula (1).

[0042] In some embodiments, the material loosener is driven by a DC motor, and the material loosener is connected by a connecting rod, so that the material loosener can rotate horizontally by 180°.

[0043] In some embodiments, the material loosener is cylindrical as a whole, and a plurality of air supply holes are opened in the lower half of the cylinder. The plurality of air supply holes are divided into three rows and evenly distributed, and the interval angle between each row is 30°.

[0044] In some embodiments, an oxygen delivery pipeline is disposed inside the loosener, and the oxygen delivery pipeline is used to deliver oxygen input through the plurality of air supply holes.

[0045] In some embodiments, the system further comprises a purification and decarburization system, which is arranged outside the vertical furnace body. The purification and decarburization system is used to purify and decarburize the gas discharged from the vertical furnace body, and then return the purified and decarburized gas to the vertical furnace body as reducing gas.

[0046] Therefore, the present invention is to set a feed preheating section above the area where the reduction reaction gas is injected into the vertical furnace, in a certain low temperature zone (650-680°C) and where the reduction rate decreases. The feeder is driven by a DC motor, connected by a connecting rod, and rotated 180° horizontally to the left and right. An air delivery hole is opened on the lower semi-cylinder of the feeder, and an oxygen delivery pipeline is set in the middle of the feeder to evenly spray oxygen to the area of ​​650-680°C. In this temperature range, because it is higher than the ignition temperature of the reducing gas (coke oven gas: 560°C; methane: 537°C), the injection position has a higher safety. It can not only make the oxygen diffuse more evenly in this area inside the vertical furnace, but also enable the feeder to be cooled and protected. The oxygen diffused into the vertical furnace and the reducing gas components with lower reducing ability undergo a reforming conversion reaction under the catalysis of iron element.

[0047] The complex system mainly consists of CH4, CO, CO2, H2O, H2, and O2. It is a typical carbon-one chemical system, and the main reaction network includes the following basic reaction equations:

[0048]

[0049] Before oxygen enters the vertical furnace loosening pipe, it is fully exchanged with the top gas out of the vertical furnace through the top gas heat recovery system and waste heat is recovered, so that the temperature of the oxygen heat recovery device is controlled at 200°C, and the gas composition signal is fed back through the vertical furnace online gas analyzer to adjust the opening degree of the oxygen injection valve and control the oxygen injection amount to prevent excessive oxygen consumption and avoid overheating and energy loss caused by excessive temperature. Real-time data transmission and feedback are achieved through the control system retention interface, and the online analysis coupling is flexibly and accurately adjusted. The production of the vertical furnace can be adjusted according to the grade of the pellets entering the furnace and the composition of the top gas, ensuring the quality of the finished product and stabilizing the system operation.

[0050] According to the CH4 content in the gas of the 650℃~680℃ zone of the vertical furnace, the oxygen injection amount is controlled at about 10% of the gas volume flow in the furnace. The oxygen preheated at 200℃ can make the reforming reaction occur again in the vertical furnace, and the temperature of the generated reducing gas is controlled at about 950℃, reaching the temperature and energy grade of the reducing gas entering the furnace, while avoiding carbon deposition of the gas at about 700℃, which is coated on the surface of the pellets and hinders the rapid reduction diffusion reaction. Finally, the preheating section becomes a pre-reduction section with higher utilization efficiency, expanding the reduction reaction range, resulting in a higher grade of pellets entering the reduction section, requiring a shorter reduction residence time, and the production capacity per unit furnace capacity is greatly improved, and the primary utilization rate of the reducing gas is increased from the original 35% to more than 50%. Under the condition of a certain equipment volume and production capacity, the production capacity is increased by 20%, thereby reducing the overall cost.

[0051] Figures 2 to 3 Shown is a schematic diagram of the structure of the loosener and a schematic diagram of its installation function. The loosener is driven by a DC motor and adopts a connecting rod connection so that the loosener can rotate horizontally 180°. The loosener is cylindrical as a whole, and a plurality of air supply holes are provided in the lower half of the cylinder. The plurality of air supply holes are divided into 3 rows and evenly distributed, and the interval angle between each row is 30°. An oxygen delivery pipeline is also provided inside the loosener, and the oxygen delivery pipeline is used to transport oxygen input by the plurality of air supply holes.

[0052] The main function of the loosener is to cool and transport oxygen while stirring. The loosener is embedded across the 650℃~680℃ area of ​​the vertical furnace, with sealing flanges at both ends. Support bases are installed on the platforms on both sides of the vertical furnace. A water cooling jacket is added to the loosener, and the middle layer is used as an oxygen channel. Oxygen is only opened in the lower semicircle of the loosener column, and the holes are divided into 3 rows at 30° intervals and 15° intervals as shown in the planing diagram AA above.

[0053] exist Figure 3In the figure, tube 1 is the main stirring tube, with stirring blades welded on the upper end, which rotates at a low speed in the furnace to stir the materials. Tube 2 is a cooling tube, which is sealed with a plugging plate 2 on one side and open on the other side. There is a certain gap between tubes 1 and 2, which are supported by several support blocks. Cooling water enters from the open side, fills the tube, and then overflows from the cooling tube to enter the gap between tubes 1 and 2, cooling the wall of tube 1. Tube 3 is an oxygen delivery pipeline, which is processed from a half tube and welded to tube 1. Both ends are sealed with plugging plates 3 to form an independent cavity, and the oxygen enters the furnace body through the bottom pores.

[0054] The oxygen and water inlet consists of a hydraulic drive shaft and a support frame, wherein the hydraulic drive shaft is connected to pipe 1, and the drive device drives the drive shaft and the stirring pipe to rotate at a low speed. The support frame and the bracket support the stirring pipe, and the inner wall of the support and the outer wall of the pipe are filled with flexible materials such as polyurethane foam. The opening of the furnace body is sealed with a stuffing box to ensure that the material in the furnace will not leak from the flange when pipe 1 rotates. The oxygen supply pipe and the cooling water pipe are connected to the flange with threads, and the thread tightening range is adjusted according to the stirring range to ensure that the flange will not be locked when rotating.

[0055] A method for heating and tempering the gas at the top of a direct reduction shaft furnace according to a preferred embodiment of the present invention uses the above-mentioned system for heating and tempering the gas at the top of a direct reduction shaft furnace, comprising the following steps:

[0056] S1. The solid raw material is fed into a receiving system. After being processed by the receiving system, the solid raw material is fed into a vertical furnace body. The control system controls the oxygen injection valve according to data obtained by a pressure detection instrument in the vertical furnace body to control the amount of oxygen introduced.

[0057] S2, feeding high-temperature reducing gas from the reducing gas inlet of the vertical furnace body, so that the high-temperature reducing gas is mixed with the oxygen introduced in step S1;

[0058] S3. During the mixing process of the raw materials, in the feed preheating section, the raw materials are loosened by a loosening device;

[0059] S4. Spray oxygen evenly through the air supply holes on the loosener.

[0060] In some embodiments, in step S3, the feed preheating section is set to a low temperature zone and a position where the reduction rate decreases, and the temperature range of the low temperature zone is 650-680°C.

[0061] The reducing gas ① of the working reducing gas heating / reforming unit is mixed with oxygen ② before entering the shaft furnace and heated up before entering the reduction section of the shaft furnace. After the reforming reaction occurs in the shaft furnace, the reducing reaction occurs with the solid pellets; the endothermic nature of the reaction causes the rising steam flow to cool down to about 600℃. According to the amount of CH4 generated by the methanation reaction, a certain amount of oxygen needs to be injected from ⑤ to promote the secondary reforming reaction, reduce the CH4 content, increase the H2 and CO concentrations, and increase the temperature to about 950℃ to ensure the continuous reduction reaction of the reducing gas and the pellets. Finally, it is discharged through the furnace top gas ③, and enters the gas purification and decarbonization process after cooling. The decarbonized gas enters the reducing gas ① again for recycling. When the certain amount of oxygen ⑤ needs to be injected, a loosening device is set in this section. The furnace body is connected with two sealing flanges. The oxygen delivery pipeline is set inside the loosening device to spray oxygen evenly, which can make the oxygen diffuse more evenly inside the shaft furnace and cool the loosening device. The oxygen diffused into the shaft furnace and the reducing gas components with low reducing ability undergo reforming conversion reaction under the catalysis of iron element. In this temperature range, the injection position has a higher safety because it is higher than the auto-ignition point of the reducing gas.

[0062] Table 1 shows that when the CH4 content is 12.5%, after O2 is blown in, the concentration drops to 0.0268%, and the concentrations of H2 and CO are converted from 40% and 11% of the instant content to 56.71% and 24.17% respectively, ensuring that H2 / CO is 2.35 and H2+CO is 80.88%, meeting the basic requirements of direct reduction reaction and promoting further reaction.

[0063] Table 1 is the material balance of the furnace gas at 600℃ with CH4 content of 12.5% ​​and after O2 injection

[0064]

[0065] Table 2 shows that when the CH4 content is 15.0%, after O2 is blown in, the concentration drops to 0.035%, and the concentrations of H2 and CO are converted from 40% and 11% of the immediate content to 62.84% and 26.73% respectively, ensuring that H2 / CO is 2.35 and H2+CO is 89.57%, meeting the basic requirements of direct reduction reaction and promoting further reaction.

[0066] Table 2 is the material balance of the furnace gas at 600℃ with CH4 content of 15.0% and after O2 injection

[0067]

[0068] Table 3 is the material balance of the furnace gas at 600℃ with CH4 content of 10.0% and after O2 injection

[0069]

[0070]

[0071] forward

[0072] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A direct reduction shaft furnace top gas temperature raising and tempering system, characterized in that: It includes a receiving system, a loosening device, an oxygen injection valve, a heat recovery system and a control system. The receiving system is arranged above the vertical furnace body. The loosening device and the heat recovery system are both arranged inside the vertical furnace body. The loosening device is used to loosen the solid raw materials received by the receiving system. The oxygen injection valve is arranged on one side of the loosening device. The heat recovery system includes a gas heat exchanger. An online gas analyzer is arranged on the pipeline of the gas heat exchanger. The gas composition signal in the pipeline is collected by the online gas analyzer, and the gas composition signal is transmitted to the control system. The opening degree of the oxygen injection valve is adjusted by the control system. The loosening device is arranged above the area where the reduction reaction gas is injected into the vertical furnace, in a low temperature area of ​​650-680°C and where the reduction rate decreases; An oxygen delivery pipeline is arranged in the middle of the loosener to spray oxygen evenly to the area with a temperature of 650-680°C.

2. The direct reduction shaft furnace top gas temperature raising and tempering system according to claim 1, characterized in that: The material loosener is driven by a DC motor.

3. The direct reduction shaft furnace top gas temperature raising and tempering system according to claim 1, characterized in that: The material loosener is connected by a connecting rod, so that the material loosener can rotate 180 degrees horizontally.

4. The direct reduction shaft furnace top gas temperature raising and tempering system according to claim 1, characterized in that: The material loosener is in the shape of a cylinder as a whole, and a plurality of air supply holes are provided in the lower half of the cylinder.

5. The direct reduction shaft furnace top gas temperature raising and tempering system according to claim 4, characterized in that: The plurality of air supply holes are divided into three rows and evenly distributed, and the interval angle between each row is 30°.

6. The direct reduction shaft furnace top gas temperature raising and tempering system according to claim 1, characterized in that: The system further comprises: a purification and decarburization system, which is arranged outside the vertical furnace body and is used for purifying and decarburizing the gas discharged from the vertical furnace body, and then returning the purified and decarburized gas to the vertical furnace body as reducing gas.

7. A method for heating and tempering the gas at the top of a direct reduction shaft furnace, characterized in that: The direct reduction shaft furnace top gas temperature raising and tempering system according to any one of claims 1 to 6 is used, comprising the following steps: S1. The solid raw material is fed into a receiving system. After being processed by the receiving system, the solid raw material is fed into a vertical furnace body. The control system controls the oxygen injection valve according to data obtained by a pressure detection instrument in the vertical furnace body to control the amount of oxygen introduced. S2, feeding high-temperature reducing gas from the reducing gas inlet of the vertical furnace body, so that the high-temperature reducing gas is mixed with the oxygen introduced in step S1; S3, in the process of mixing the high-temperature reducing gas with the oxygen introduced into S1, in the feed preheating section, the solid raw material of S1 is loosened by the loosening device; S4. Spray oxygen evenly through the air supply holes on the loosener.

8. The method for increasing temperature and tempering gas at the top of a direct reduction shaft furnace according to claim 7, characterized in that: In step S3, the feed preheating section is set as a low temperature zone and a position where the reduction rate decreases, and the temperature range of the low temperature zone is 650-680°C.

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