Process and system for producing direct reduced iron by using coke oven gas

Abstract

The invention discloses a process and system for producing direct reduced iron by using coke oven gas, and the process comprises the following steps: S1, mixing pressurized coke oven gas with circulating furnace top gas to form mixed gas, and then feeding the mixed gas into a heat accumulating type gas heating furnace for heating, in the heating process, the mixed gas is subjected to high-temperature reforming to obtain high-temperature reformed gas; s2, blending the high-temperature reforming gas and circulating furnace top gas to serve as shaft furnace reducing gas to enter a shaft furnace, reducing the iron ore into DRI pellets, and discharging the DRI pellets from the furnace top of the shaft furnace to obtain furnace top gas; and S3, carrying out dust removal and dehydration treatment on the furnace top gas to obtain the circulating furnace top gas. The coke oven gas can be directly used, deep purification of the coke oven gas is not needed, oxygen does not need to be added to sacrifice effective components of the coke oven gas to heat the coke oven gas to the high temperature, and efficient and low-cost ironmaking is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and more specifically, to a process and system for producing direct reduced iron using coke oven gas. Background Art

[0002] The hydrogen-based vertical furnace combined with the electric furnace short-process steel smelting process is a green and low-carbon manufacturing and CO 2 It is an important technical path for emission reduction and also a key technical innovation direction for research and development, testing and application of carbon neutrality at home and abroad. Currently, green hydrogen is difficult to obtain on a large scale and is costly, and the full hydrogen vertical furnace is not yet technically mature. Therefore, the full hydrogen vertical furnace is still some distance away from industrial application.

[0003] At present, all industrial gas-based direct reduction in the world uses natural gas as the raw material, and the annual output of direct reduced iron (DRI) is approaching 100 million tons. At present, there are a large number of coking plants in my country, which produce a large amount of coke oven gas as a by-product every year. At present, most of the coke oven gas is used for combustion power generation and low-quality use. Some independent coking plants even release a large amount of coke oven gas, causing a lot of losses. Studies have found that using coke oven gas as a gas source to produce direct reduced iron is also a feasible technical path for low-carbon ironmaking. Compared with the direct reduction process that uses natural gas as the raw material gas, which is currently widely popular abroad, its carbon emission intensity is lower.

[0004] As shown in Table 1, due to the high impurity content of coke oven gas, even after preliminary purification in the factory, it still contains a lot of tar, benzene, toluene, xylene, etc., and the existing direct reduction process uses metal furnace tubes to heat the gas, that is, burning gas to heat the metal furnace tube, and the high-temperature metal furnace tube transfers heat to the high-pressure gas in the tube. The impurities in the coke oven gas are very easy to precipitate carbon during the heating process, causing the metal furnace tube to become dusty and lose strength, which poses a safety hazard. Therefore, it is difficult for the existing direct reduction gas heating process to directly use coke oven gas as a raw gas source in large quantities. In order to use coke oven gas as a gas source to produce direct reduced iron, all current direct reduction processes require deep purification of coke oven gas to remove tar, naphthalene and BTX; for example, the direct reduction iron project of Zhongjin Taihang Mining in my country is the first gas-based direct reduction iron production line built in my country, and it is also the world's first industrial device that uses coke oven gas as a supplementary gas source; although its process configuration is equipped with more purification devices, the purified coke oven gas still cannot meet the process requirements, resulting in the project being unable to operate normally. Hesteel's direct reduction process uses a large amount of equipment for coke oven gas purification, which has high operating costs.

[0005] Table 1 Coke oven gas after preliminary purification and deep purification Impurity content

[0006] project <![CDATA[BTX(g / m 3 )]]> <![CDATA[C 10 H 8 Naphthalene (mg / m 3 )]]> <![CDATA[Tar content (mg / m 3 )]]> Initial purification in the plant 2～2.5 ＜100 ＜20 Deep purification ＜0.05 ＜1 ≤1

[0007] In addition, the current metal furnace tube heating method can only heat the gas to 980°C at most. Under this temperature condition, the gas and CO 2 The reforming effect is poor and carbon deposition is easy. Usually, the CO in the top gas needs to be 2 After removal, water vapor and CH 4 In wet reforming, pure oxygen needs to be blown into the vertical furnace to raise the gas temperature to 1050°C, sacrificing the effective components of the gas, and it is also necessary to separate the top gas CO 2 , the process is complicated and the manufacturing cost is high. Summary of the invention

[0008] In view of the problem that coke oven gas cannot be directly utilized in the prior art, the present invention aims to provide a process and system for producing direct reduced iron using coke oven gas, which can directly use coke oven gas without deep purification of coke oven gas and without removing CO in the furnace top gas. 2 When carrying out coal gas reforming, there is no need to add oxygen and sacrifice the effective components of coke oven gas to heat the coke oven gas to a high temperature, thus achieving efficient and low-cost ironmaking.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] A first aspect of the present invention provides a process for producing direct reduced iron using coke oven gas, comprising the following steps:

[0011] S1, mixing the pressurized coke oven gas with the circulating furnace top gas to form a mixed gas, which is then heated in a regenerative gas heating furnace. During the heating process, the mixed gas undergoes high-temperature reforming to obtain a high-temperature reformed gas;

[0012] S2, high-temperature reforming gas is blended with high-pressure and low-temperature circulating furnace top gas and then enters the vertical furnace as vertical furnace reduction gas, reducing the iron ore into DRI pellets and then discharged from the top of the vertical furnace to obtain furnace top gas;

[0013] S3, the furnace top gas is treated with dust removal and dehydration to obtain circulating furnace top gas.

[0014] Preferably, in step S1, according to CH 4 :CO 2 +H 2 O molar ratio to supplement water vapor, ensuring that CH 4 :CO 2 +H 2 The molar ratio of O is 1 to 1.1:1.

[0015] Preferably, in step S1, at least two regenerative gas heating furnaces are provided, and when one regenerative gas heating furnace delivers high-temperature reformed gas to the vertical furnace, the other regenerative gas heating furnaces are in the stage of burning or stewing and waiting for gas delivery;

[0016] The regenerative gas heating furnace adopts circulating furnace top gas as fuel gas.

[0017] Preferably, in the step S1, during the heating process, the heating temperature is 1050-1300°C.

[0018] Preferably, in step S1, CO and H in the high temperature reformed coal gas 2 Content ≥ 75wt%, CH 4 The content is ≤10wt%.

[0019] Preferably, in step S2, the temperature of the shaft furnace reducing gas formed by blending the high-temperature reformed coal gas with the high-pressure and low-temperature circulating furnace top gas is 900-1200°C.

[0020] A second aspect of the present invention provides a system for producing direct reduced iron using coke oven gas, comprising a vertical furnace, a furnace top gas treatment device, a gas mixing pipe and a gas heating device;

[0021] The top of the vertical furnace is provided with a top gas outlet, and the reducing gas section is provided with a reducing gas nozzle connected to the vertical furnace surrounding pipe, and the vertical furnace surrounding pipe is connected to the top gas processing device;

[0022] The top gas treatment device is connected to the top gas outlet of the vertical furnace and the vertical furnace enclosure pipe respectively; the top gas treatment device is used to remove dust and water from the top gas discharged from the vertical furnace to obtain circulating top gas, and then pressurize it and send it into the gas mixing pipe and the vertical furnace enclosure pipe;

[0023] The gas mixing pipe is connected to the furnace top gas processing device, the coke oven gas pipeline, and the gas heating device respectively, and is used to send the mixed gas formed by mixing the pressurized coke oven gas and the circulating furnace top gas into the gas heating device for heating;

[0024] The gas heating device comprises at least two regenerative gas heating furnaces; the bottom of the regenerative gas heating furnace is provided with a gas branch pipe connected to the gas mixing pipe, and the upper part is provided with a high-temperature reforming gas pipe connected to the vertical furnace surrounding pipe;

[0025] The system for producing direct reduced iron using coke oven gas is used to implement the process for producing direct reduced iron using coke oven gas as described in the first aspect of the present invention.

[0026] Preferably, the top gas treatment device comprises a scrubber connected to the top gas outlet of the vertical furnace top, a gas dehydration tower connected to the scrubber outlet, and a gas compressor connected to the gas dehydration tower;

[0027] The gas compressor is connected to the vertical furnace surrounding pipe and the gas mixing pipe respectively through a circulation pipeline.

[0028] Preferably, a fuel gas inlet and a smoke gas outlet are provided in the combustion chamber of the regenerative gas heating furnace;

[0029] The fuel gas inlet is connected to the outlet of the coal gas dehydration tower through a pipeline.

[0030] Preferably, a steam nozzle is provided on the gas branch pipe.

[0031] Compared with the prior art, the process and system for producing direct reduced iron using coke oven gas provided by the present invention has the following beneficial effects:

[0032] 1. The present invention can directly use coke oven gas, without deep purification of coke oven gas and without removing CO from furnace top gas. 2 It can be recycled without introducing oxygen to self-oxidize and release heat, and sacrificing the effective components of coke oven gas to heat the coke oven gas to a high temperature, so as to achieve the purpose of direct reduction of iron in a hydrogen-based vertical furnace;

[0033] 2. The process of the present invention is simple, and no purification equipment and decarbonization equipment are required. The coke oven gas is heated to a high temperature by a regenerative gas heating furnace, thereby achieving efficient and low-cost ironmaking using the coke oven gas completely. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a system for producing direct reduced iron using coke oven gas according to the present invention;

[0035] In the figure, 1, coke oven gas, 2, gas compressor, 3, chimney, 4, high-temperature reforming gas, 5, regenerative gas heating furnace, 6, vertical furnace reducing gas, 7, vertical furnace, 8, top gas, 9, scrubber, 10, gas dehydration tower, 11, fuel gas, 12, circulating top gas; 13, gas mixing pipe, 14, gas branch pipe; 15, vertical furnace surrounding pipe. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0037] Combination Figure 1 As shown, the present invention provides a process for producing direct reduced iron using coke oven gas, comprising the following steps:

[0038] S1, the pressurized coke oven gas 1 is mixed with the circulating furnace top gas 12 to form a mixed gas, which is then heated in a regenerative gas heating furnace 5. During the heating process, the mixed gas is reformed at high temperature to obtain a high-temperature reformed gas 4;

[0039] Specifically, the coke oven gas 1 does not need to be deeply purified, and only needs to meet the normal working requirements of the gas compressor 2 and the filter screen is not blocked; the top gas 8 from the top of the vertical furnace 7 is processed by dust removal and dehydration (here, physical water removal) to form a circulating top gas 12; the pressurized coke oven gas 1 is mixed with the circulating top gas 12 to form a mixed gas; the mixed gas is 4 :CO 2 +H 2 O molar ratio to determine whether water vapor needs to be added and the amount to be added. In principle, it is necessary to ensure that CH 4 :CO 2 +H 2 The molar ratio of O is 1 to 1.1:1.

[0040] The mixed coal gas enters the regenerative coal gas heating furnace 5 and is heated to 1050-1300°C. The specific heating temperature can be adjusted within the range of 1050-1300°C according to the actual situation. Under sufficiently high temperature conditions, CO in the mixed coal gas is 2 (mainly from the top gas 8 produced by the reduction of the vertical furnace 7), H 2 O(water vapor in the furnace top gas 8, if the mixed gas contains CO 2 and H 2 When O is insufficient, water vapor can be injected to react with CH 4 , tar, naphthalene, and olefins will quickly reform to form CO and H 2 After high temperature reforming, high temperature reformed coal gas 4 is obtained, including CO and H 2 Content ≥ 75wt%, CH 4 ≤10wt%, while tar, naphthalene and olefins are extremely small.

[0041] Among them, the regenerative coal gas heating furnace 5 can adopt the structure of top combustion, external combustion, etc., and the coal gas 8 on the top of the furnace after dust removal and dehydration is used as the fuel gas 11, which is sent to the combustion chamber of the regenerative coal gas heating furnace 5, mixed with the combustion air and burned in the combustion chamber to produce high-temperature flue gas, and the high-temperature flue gas passes through the regenerative body in the furnace from top to bottom, and the regenerative body in the furnace is heated to a high temperature (1050-1300°C), and after heat exchange, it becomes low-temperature flue gas and is discharged from the chimney 3 through the flue. When the regenerative body in the regenerative coal gas heating furnace 5 reaches a sufficient temperature, the combustion air and combustion gas in the combustion chamber are isolated, and then the mixed coal gas to be heated is introduced, and the mixed coal gas can be heated to a high temperature. Among them, at least two regenerative gas heating furnaces 5 are set up to complete the cycle of burning furnace → suffocating furnace → delivering gas → suffocating furnace → burning furnace. When one regenerative gas heating furnace 5 delivers high-temperature reforming gas 4 to the vertical furnace 7, the other regenerative gas heating furnaces 5 are disconnected from the vertical furnace 7 to carry out the stage of burning furnace or suffocating furnace waiting for gas delivery, similar to the blast furnace hot blast furnace, to achieve continuous heating and delivery of gas. Since the material of the heat storage body in the gas heating furnace is generally high-alumina brick, or mullite brick, or sillimanite brick or silica brick, etc., it will not react with carbon, so there is no risk of metal furnace tube strength failure; in addition, even if carbon deposits are generated in the stage of heating gas, they will be consumed by the residual oxygen in the flue gas in the stage of burning furnace, and will not block the channel.

[0042] S2, high-temperature reforming gas 4 is blended with high-pressure and low-temperature circulating furnace top gas 12 and then enters into the vertical furnace 7 as vertical furnace reduction gas 6, and the iron ore is reduced into DRI pellets and then discharged from the top of the vertical furnace 7 to obtain furnace top gas 8;

[0043] Specifically, the high-temperature reformed coal gas 4 obtained in step S1 is sent to the shaft furnace circumferential pipe 15, and in order to ensure the stability of the coal gas temperature entering the shaft furnace 7, it is blended with the high-pressure and low-temperature circulating furnace top gas 12 (i.e., the furnace top gas 8 after dust removal, dehydration, and pressurization) to reach a preset temperature of 900-1200°C before entering the shaft furnace 7. The high-temperature reformed coal gas 4 is blended with the high-pressure and low-temperature circulating furnace top gas 12 and enters the shaft furnace 7 as the shaft furnace reduction gas 6; the iron ore (such as pellets, etc.) is added from the upper part of the shaft furnace 7, moves from top to bottom in the shaft furnace 7, and completes heat transfer and reduction through convection with the shaft furnace reduction gas 6 from bottom to top, generating DRI pellets with high metallization rate and discharging from the bottom of the shaft furnace 7. After participating in the reduction of the iron ore, the high-temperature reformed coal gas 4 is discharged from the top of the shaft furnace 7 to obtain the furnace top gas 8.

[0044] S3, the top gas 8 is subjected to dust removal and dehydration treatment to obtain the circulating top gas 12.

[0045] Specifically, after the top gas 8 is discharged from the top of the vertical furnace 7, it is purified and dusted in a washing tower, and then dehydrated (i.e., physical water is removed) in a dehydration tower to obtain the circulating top gas 12;

[0046] The circulating top gas 12 is divided into two paths: one path is sent to the regenerative gas heating furnace 5 as fuel gas 11 to heat the coke oven gas 1 and provide heat energy for high-temperature reforming; the other path is pressurized by the gas compressor 2 and participates in the direct reduction process together with the coke oven gas 1. Specifically, a part of the pressurized circulating top gas 12 and the coke oven gas 1 enter the regenerative gas heating furnace 5 for high-temperature reforming (i.e., step S1) to obtain high-temperature reformed gas 4, and the other part is blended with the high-temperature reformed gas 4 before entering the vertical furnace 7 as vertical furnace reducing gas 6 to participate in the direct reduction process.

[0047] Combination Figure 1 The present invention also provides a system for producing direct reduced iron using coke oven gas, which is used to implement the above process and includes a vertical furnace 7, a top gas treatment device, a gas mixing pipe 13 and a gas heating device.

[0048] A top gas outlet is provided at the top of the vertical furnace 7, and a reducing gas nozzle connected to the vertical furnace surrounding pipe 15 is provided in the reducing gas section. The vertical furnace surrounding pipe 15 is connected to the top gas processing device; the vertical furnace 7 is used to reduce iron ore into DRI pellets, and discharge the top gas 8 generated in the reduction process from the top gas outlet of the vertical furnace 7.

[0049] The top gas treatment device is connected to the top gas outlet of the vertical furnace 7 and the vertical furnace enclosure pipe 15 respectively; the top gas treatment device is used to pressurize the circulating top gas 12 obtained after the top gas 8 discharged from the vertical furnace 7 is subjected to dust removal and dehydration treatment and send it to the gas mixing pipe 13 and the vertical furnace 7. In a specific embodiment, the top gas treatment device includes a scrubber 9 connected to the top gas outlet of the vertical furnace 7, a gas dehydration tower 10 connected to the outlet of the scrubber 9, and a gas compressor 2 connected to the gas dehydration tower 10; the gas compressor 2 is connected to the vertical furnace enclosure pipe 15 and the gas mixing pipe 13 respectively through a circulation pipeline.

[0050] The gas mixing pipe 13 is connected to the furnace top gas processing device, the coke oven gas 1 pipeline, and the gas heating device respectively. The gas mixing pipe 13 is used to send the mixed gas formed by mixing the pressurized coke oven gas 1 and the circulating furnace top gas 12 into the gas heating device for heating; wherein, the coke oven gas 1 pipeline is also provided with a gas compressor 2.

[0051] The gas heating device includes at least two regenerative gas heating furnaces 5, namely A and B; the bottom of the regenerative gas heating furnace 5 is provided with a gas branch pipe 14 connected to the gas mixing pipe 13, and the upper part is provided with a gas branch pipe 14 connected to the vertical furnace surrounding pipe 15. The gas heating device is used to heat the mixed gas of the coke oven gas 1 and the circulating furnace top gas 12 to 1050-1300°C, and in the heating process, the components of the coke oven gas 1 and the circulating furnace top gas 12 are subjected to high-temperature reforming to obtain the high-temperature reformed gas 4. In a specific embodiment, a water vapor nozzle is provided on the gas branch pipe 14 to add water vapor to the mixed gas, so as to convert CH in the mixed gas into water vapor. 4 :CO 2 +H 2 The molar ratio of O is adjusted to 1-1.1:1.

[0052] The process and system for producing direct reduced iron using coke oven gas of the present invention will be further introduced below with reference to specific examples.

[0053] Example

[0054] use Figure 1 The system for producing direct reduced iron using coke oven gas shown in the figure produces direct reduced iron, and the specific process is as follows:

[0055] (1) All coke oven gas 1 is used as the gas source, and the coke oven gas 1 does not need to be deeply purified. It only needs to meet the normal working requirements of the gas compressor 2 and the filter screen is not blocked. The coke oven gas 1 that does not need to be deeply purified (the composition is shown in Table 2) is pressurized by the gas compressor 2, and then mixed with the circulating furnace top gas 12 (i.e., the furnace top gas 8 that has been washed, dusted, and dehydrated) that has been pressurized by the gas compressor 2 to form a mixed gas (the composition is shown in Table 2), which is then sent to the regenerative gas heating furnaces A and B.

[0056] (2) A steam nozzle is provided on the gas branch pipe 14 where the mixed coal gas enters the inlet of the regenerative coal gas heating furnace A and B. 4 :CO 2 +H 2 O ratio to determine whether to add water vapor and the amount to be added. The principle is to ensure that CH 4 :CO 2 +H 2 The molar ratio of CH in the coke oven gas is between 1 and 1.1:1. The mixed gas is heated to a temperature range of 1050 to 1300°C in the regenerative gas heating furnaces A and B. 4 , tar, naphthalene, olefins and CO in circulating top gas 12 2 +H 2 O completes high-temperature dry and wet reforming during the heating process. The high-temperature reformed coal gas 4 after high-temperature reforming (as shown in Table 2) is mainly composed of CO+H2 (CO+H 2 ≥75wt%), and a very small amount of unreformed CH 4 (CH 4 The content is ≤10wt%).

[0057] When one of the regenerative gas heating furnaces A or B is heating the mixed gas, the other should be disconnected from the vertical furnace 7 through a high-temperature water-cooled valve and be in the furnace burning or furnace stuffing stage.

[0058] (3) The high-temperature reformed coal gas 4 is sent to the vertical furnace 7. Before entering the vertical furnace 7, it is blended with the high-pressure and low-temperature circulating furnace top gas 12 (i.e., the high-pressure and low-temperature circulating furnace top gas 12 that has been dust-removed, purified, dehydrated, and pressurized) to form the vertical furnace reducing gas 6 to ensure that the temperature of the coal gas 6 entering the vertical furnace 7 is stable. The process temperature of the coal gas is controlled in the range of 900 to 1200° C., and then enters the vertical furnace 7 to reduce the iron ore.

[0059] (4) The shaft furnace reducing gas 6 entering the shaft furnace 7 reduces the iron ore and is then discharged from the furnace top to become the furnace top gas 8. After being washed and dusted by the scrubber, the physical water is removed by the gas dehydration tower 10 to become the clean circulating furnace top gas 12 without physical water. The circulating furnace top gas 12 is then divided into two paths. One path is sent to the combustion chamber of the regenerative coal gas heating furnace A and B as the fuel gas 11, and is burned with the combustion-supporting air in the combustion chamber to generate high-temperature flue gas. The high-temperature flue gas transfers heat from top to bottom to the heat storage body in the regenerative coal gas heating furnace 5, and is then discharged from the lower flue of the regenerative coal gas heating furnace 5 until it reaches the chimney 3 and is discharged to the atmosphere. The other path is pressurized by the gas compressor 2 and then participates in the direct reduction process together with the coke oven gas 1, that is, a part of the pressurized circulating top gas 12 and the coke oven gas 1 enter the regenerative gas heating furnace 5 for high-temperature reforming to obtain high-temperature reformed gas 4, and the other part is blended with the high-temperature reformed gas 4 before entering the vertical furnace 7 as the vertical furnace reducing gas 6 to participate in the direct reduction process.

[0060] Table 2 Composition of coke oven gas, top gas, mixed gas and high temperature reforming gas

[0061] <![CDATA[H 2 ]]> CO <![CDATA[CO 2 ]]> <![CDATA[CH 4 ]]> <![CDATA[N 2 ]]> <![CDATA[H 2 The]]> Coke oven gas (%) 50～62 4～8 2～4 20～26 2～6 1～2.5 Top gas (%) 40～46 17～14 10～12 2～5 8～12 13～17 Mixed gas (%) 50～54 8～10 8～11 14～17 7～9 2～4 High temperature reformed gas (%) 56～62 23～27 1～3 5～10 7～9 0.50

[0062] In summary, the present invention can use coke oven gas as the gas source, the process gas of the self-circulating top gas is the main gas for the reduction reaction, and the CO generated in the whole system is 2 Part of it is used directly as raw gas for reforming, and the other part is discharged from the chimney as heating furnace fuel gas. The carbon emissions of this process are extremely low.

[0063] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A process for producing direct reduced iron using coke oven gas, characterized in that: The following steps are involved: S1, mixing the pressurized coke oven gas with the circulating furnace top gas to form a mixed gas, which is then heated in a regenerative gas heating furnace. During the heating process, the mixed gas undergoes high-temperature reforming to obtain a high-temperature reformed gas; S2, high-temperature reforming gas is blended with high-pressure and low-temperature circulating furnace top gas and then enters the vertical furnace as vertical furnace reduction gas, reducing the iron ore into DRI pellets and then discharged from the top of the vertical furnace to obtain furnace top gas; S3, the top gas is treated with dust removal and dehydration to obtain circulating top gas.

2. The process for producing direct reduced iron using coke oven gas according to claim 1, characterized in that: In the step S1, water vapor is added according to the molar ratio of CH4:CO2+H2O in the mixed coal gas to ensure that the molar ratio of CH4:CO2+H2O in the mixed coal gas is 1 to 1.1:

1.

3. The process for producing direct reduced iron using coke oven gas according to claim 1, characterized in that: In step S1, at least two regenerative gas heating furnaces are provided, and when one regenerative gas heating furnace delivers high-temperature reformed gas to the vertical furnace, the other regenerative gas heating furnaces are in the stage of burning or stewing and waiting for gas delivery; The regenerative gas heating furnace adopts circulating furnace top gas as fuel gas.

4. The process for producing direct reduced iron using coke oven gas according to claim 1, characterized in that: In the step S1, during the heating process, the heating temperature is 1050-1300°C.

5. The process for producing direct reduced iron using coke oven gas according to claim 1, characterized in that: In the step S1, the content of CO and H2 in the high-temperature reformed coal gas is ≥75wt%, and the content of CH4 is ≤10wt%.

6. The process for producing direct reduced iron using coke oven gas according to claim 1, characterized in that: In the step S2, the temperature of the shaft furnace reducing gas formed by blending the high-temperature reformed coal gas with the high-pressure and low-temperature circulating furnace top gas is 900-1200°C.

7. A system for producing direct reduced iron using coke oven gas, characterized in that: It includes a vertical furnace, a furnace top gas treatment device, a gas mixing pipe and a gas heating device; The top of the vertical furnace is provided with a top gas outlet, and the reducing gas section is provided with a reducing gas nozzle connected to the vertical furnace surrounding pipe, and the vertical furnace surrounding pipe is connected to the top gas processing device; The top gas treatment device is connected to the top gas outlet of the vertical furnace and the vertical furnace enclosure pipe respectively; the top gas treatment device is used to remove dust and water from the top gas discharged from the vertical furnace to obtain circulating top gas, and then pressurize it and send it into the gas mixing pipe and the vertical furnace enclosure pipe; The gas mixing pipe is connected to the furnace top gas processing device, the coke oven gas pipeline, and the gas heating device respectively, and is used to send the mixed gas formed by mixing the pressurized coke oven gas and the circulating furnace top gas into the gas heating device for heating; The gas heating device comprises at least two regenerative gas heating furnaces; the bottom of the regenerative gas heating furnace is provided with a gas branch pipe connected to the gas mixing pipe, and the upper part is provided with a high-temperature reforming gas pipe connected to the vertical furnace surrounding pipe; The system for producing direct reduced iron using coke oven gas is used to execute the process for producing direct reduced iron using coke oven gas as claimed in any one of claims 1 to 6.

8. The system for producing direct reduced iron using coke oven gas according to claim 7, characterized in that: The top gas treatment device comprises a scrubber connected to the top gas outlet of the vertical furnace top, a gas dehydration tower connected to the scrubber outlet, and a gas compressor connected to the gas dehydration tower; The gas compressor is connected to the vertical furnace surrounding pipe and the gas mixing pipe respectively through a circulation pipeline.

9. The system for producing direct reduced iron using coke oven gas according to claim 8, characterized in that: The combustion chamber of the regenerative gas heating furnace is provided with a fuel gas inlet and a smoke gas outlet; The fuel gas inlet is connected to the outlet of the coal gas dehydration tower through a pipeline.

10. The system for producing direct reduced iron using coke oven gas according to claim 7, characterized in that: The gas branch pipe is provided with a water vapor nozzle.

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