CN115305305A - Self-heating gas-based shaft furnace direct reduction method and reduction device - Google Patents

Abstract

The invention discloses a direct reduction method and a reduction device of a self-heating gas-based shaft furnace, which belong to the field of direct reduction. The transition section of the shaft furnace body of the reduction device is composed of n parallel cavities, the two ends of each cavity are respectively connected with the reduction section and the cooling section, each cavity is wound with an induction coil, and the cooling section is arranged with uniform distribution around the furnace body of the cooling section. gas inlet. The induction coil in the transition section heats the direct reduced iron, the thermally reduced iron reformates and heats the flowing reducing gas, and the hot reducing gas enters the reducing section and reacts with the falling iron oxides to reduce the iron oxides; the newly reduced thermal reduction The iron enters the transition section, continues to heat and reform the new raw gas, and is reheated by electromagnetic induction at the same time. After the reduced iron in the transition section enters the cooling section, it is discharged out of the furnace. The invention can not only avoid the problem of carbon deposition, blockage or burning through the heating pipeline caused by heating the raw gas outside the shaft furnace, but also can make CO ₂ , NO _and exhaust gas zero or reduce the emission, and can also reduce the project investment.

Description

Self-heating gas-based shaft furnace direct reduction method and reduction device

technical field

The invention belongs to the field of direct reduction, and in particular relates to a direct reduction method and a reduction device of a self-heating gas-based shaft furnace.

Background technique

The gas-based shaft furnace direct reduction process is the world's largest direct reduction iron technology. As a high-quality raw material used in electric furnace, converter, blast furnace, powder metallurgy and other industries, direct reduced iron has been paid more and more attention by the state and metallurgical industry personnel in recent years. As a raw material for electric furnace steelmaking, direct reduced iron can improve the purity of molten steel and is a high-quality raw material for special steel smelting. Especially for electric furnace enterprises with unstable scrap quality, adding direct reduced iron can dilute harmful elements in steel and stabilize the quality of molten steel. Direct reduced iron does not use coke, and iron ore does not need to be sintered, which not only saves coking coal resources, but also reduces the two links of coking and sintering, which are the largest waste gas emissions in iron and steel enterprises, and is more environmentally friendly than the blast furnace process. However, the existing gas-based shaft furnace technology uses natural gas as raw material gas, and the current situation of fuel resources in China is less gas and more coal. The most usable gas sources are coke oven gas and coal-based gas, especially coke oven gas. . my country is a big country of coke production, and coke oven gas is abundant, but the technology using coke oven gas as raw material gas cannot be applied to the process of gas-based shaft furnace using natural gas as gas source, coke oven gas is more likely to deposit carbon during the heating process outside the shaft furnace , affect the normal operation of production, and seriously cause production accidents, which has become one of the main reasons restricting the promotion of gas-based shaft furnaces in my country; another reason affecting the promotion of gas-based shaft furnaces in my country is the large investment. The reformation of reducing gas raw materials, the external heating equipment of the shaft furnace and its supporting deep purification equipment account for more than 50% of the total equipment investment, which makes the overall investment too large; in addition, the existing gas-based shaft furnace process requires at least Burning 1/3 of the top gas of the shaft furnace is used to heat the gas required for the reduction reaction, which not only wastes precious reducing gas resources, but also emits a large amount of CO ₂ and NO _x .

Contents of the invention

In order to solve the above technical problems, the present invention provides a self-heating gas-based shaft furnace direct reduction method. Using this method can not only avoid carbon deposition and blockage of heating pipes when heating the raw material gas outside the shaft furnace, but also ensure the normal operation of production; it can also make zero emission of CO ₂ and NO _x exhaust gas or reduce the emission of CO ₂ and NO _x Quantity; can also reduce equipment investment. Other objects of the present invention will be pointed out later, or will be obvious to those skilled in the art.

The raw material gas in the present invention refers to one or more mixed gases of coke oven gas, natural gas, hydrogen, coal gas after decarbonation and nitrogen removal, converter gas, blast furnace gas, and coalbed methane.

To achieve the above object, the inventive method adopts the following technical solutions:

A self-heating gas-based shaft furnace direct reduction method, including adding iron oxides with a certain particle size into the gas-based shaft furnace from the top of the furnace, reducing gas entering the furnace from the outside of the shaft furnace, and in the shaft furnace, iron oxides and reducing gas A reduction reaction occurs to generate direct reduced iron, and the direct reduced iron is discharged out of the furnace after passing through the cooling section of the shaft furnace. area, the direct reduced iron is heated by electromagnetic induction through the induction coil, and the reducing gas enters the shaft furnace from the furnace gas inlet below the electromagnetic induction coil, flows through the electromagnetic induction heating area, is heated by the high-temperature direct reduced iron, and the heated reducing gas flows upwards , reacts with iron oxides to generate direct reduced iron.

Compared with the prior art, the inventive method has the following beneficial effects:

1) The present invention uses electromagnetic induction heating technology to realize the use of high-temperature direct reduced iron to heat the reducing gas in the shaft furnace, and the direct reduced iron can make various hydrocarbons in the reducing gas react with water and/or carbon dioxide to form Useful reducing gas, which not only completes the self-reforming of various hydrocarbons, but also avoids the problem of carbon deposition and blockage of heating pipes caused by heating raw material gas outside the shaft furnace;

2) When the reducing gas is all heated by the hot direct reduced iron, fuel combustion heating is no longer needed, and the exhaust gas of the whole process is zero-emission;

3) Since the reducing gas does not need the reforming process outside the furnace, the process scheme of the present invention removes the reforming process outside the furnace, and the investment is greatly reduced;

4) Since there is no high-cost catalyst consumption in the reforming process outside the furnace and the overall investment is low, the production cost is reduced.

The preferred version of the inventive method is:

The reducing gas is derived from any of the following gases:

(1) raw material gas;

(2) The shaft furnace self-produces the mixed gas of purified coal gas and raw material gas.

When the reducing gas comes from the raw material gas, the raw material gas enters the shaft furnace from the furnace body gas inlet below the electromagnetic induction coil, flows through the heating area of the furnace body induction coil, and is heated by the hot direct reduced iron. After the base shaft furnace is heated externally, it enters the shaft furnace from the furnace body gas inlet above the electromagnetic induction coil, and the heated reducing gas and the purified gas produced by the shaft furnace react with iron oxides during reverse operation, and the iron oxides are reduced to Direct reduced iron.

When the shaft furnace is opened, along the height direction of the furnace body, the charge in the furnace body at the same position as the induction coil is a ferromagnetic metal material with a certain particle size. The upper end of the ferromagnetic metal material is higher than or equal to the upper end of the induction coil. On the material is iron oxide with a certain particle size, and the electromagnetic induction heating of the ferromagnetic metal material through the induction coil wound around the furnace body provides the initial heat for the reduction reaction in the shaft furnace.

A temperature monitoring device is installed inside the shaft furnace body where the induction coil is wound. The temperature monitoring device is interlocked with the switch controlling the power supply of the induction coil. By setting the upper and lower limits of the temperature range of the monitoring device, the switch of the power supply of the induction coil is controlled.

The furnace body gas inlet above the electromagnetic induction coil is located at the lower part of the reduction section of the gas-based shaft furnace, and the furnace body gas inlet below the electromagnetic induction coil is located at the cooling section of the gas-based shaft furnace.

Compared with the prior art, the preferred solution of the present invention also has the following beneficial effects:

Since the self-produced purified gas of the shaft furnace has removed the components that are prone to carbon deposition, according to the resource conditions of different regions, the self-produced purified gas of the shaft furnace can flexibly use electric energy and other energy sources to increase the adaptability of technology and equipment;

In order to achieve the above object, the reduction device of the present invention adopts the following technical solutions:

A self-heating gas-based shaft furnace direct reduction device includes a charging device, a shaft furnace body, and a discharge device. The shaft furnace body includes a preheating section, a reduction section, a transition section, and a cooling section. The passing band is n parallel cavities, one end of each cavity is connected with the reduction section, and the other end is connected with the cooling section, the cavity is wound with an electromagnetic induction coil, the induction coil is connected with the power supply, and the cooling section is arranged with uniform Distributed gas inlets.

Compared with the prior art, the device of the present invention has the following beneficial effects:

(1) The reforming equipment for the reducing gas raw material in the prior art, the external heating equipment for the shaft furnace and the supporting deep purification equipment are omitted. Not only the investment in reforming equipment and external heating equipment for shaft furnace is large, but also the investment in deep purification equipment is also large because the reforming catalyst has strict requirements on the raw material composition of reducing gas. By adopting the integrated technology of the electromagnetic induction heating device and the shaft furnace reactor device of the present invention, the raw material gas does not need to be reformed outside the furnace, which greatly reduces equipment investment;

(2) Adopting the integrated technology of the electromagnetic induction heating device and the shaft furnace reactor device of the present invention, the shaft furnace self-replenishment heat is realized, so that the direct reduced iron has sufficient heat source to heat the gas in the furnace, and the raw material is heated for the direct reduced iron Gas, which catalyzes the reaction of various hydrocarbons in the raw material gas with water and/or carbon dioxide to generate useful reducing gases, avoiding carbon deposition caused by external heating of the shaft furnace, and creating conditions.

The preferred version of the device of the present invention is:

The cavity arrangement of the transition section adopts one of the following two methods:

(1) A central cavity is arranged at the center of the transition section, and the other cavities have the same size and structure and are evenly distributed around the central cavity in a ring;

(2) There is only one cavity in the transition section.

The cavity is cylindrical.

The connection between the cylindrical cavity and the reduction section is in the shape of a bell mouth.

The invention makes full use of the magnetic and electrical properties of direct reduced iron in the physical field, the catalyst performance in the chemical industry, and the heat transfer performance in the thermal engineering field, combining electromagnetic induction heating technology, high-temperature catalytic reforming technology of hydrocarbons, spherical The type hot blast stove technology not only solves the problem of carbon deposition in the heating of reducing gas raw materials, but also solves the problem of exhaust gas emission, and greatly reduces equipment investment.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the self-heating gas-based shaft furnace body of the present invention, and a plurality of cylindrical cavities are arranged in the transition section;

Fig. 2 is the schematic sectional view of line A-A in Fig. 1 of the present invention;

Fig. 3 is a schematic flow chart of the direct reduction method of the self-heating gas-based shaft furnace of the present invention, two rows of gas inlets in the cooling section, and a plurality of cylindrical cavities arranged in the transition section;

Fig. 4 is another schematic flow chart of the self-heating gas-based shaft furnace direct reduction method of the present invention, a row of gas inlets in the reduction section, a row of gas inlets in the cooling section, and a plurality of cylindrical cavities arranged in the transition section;

Fig. 5 is another schematic flow chart of the direct reduction method of the self-heating gas-based shaft furnace of the present invention, a row of gas inlets in the reduction section, a row of gas inlets in the cooling section, and a cylindrical cavity arranged in the transition section;

Fig. 6 is another schematic flow chart of the direct reduction method of the self-heating gas-based shaft furnace of the present invention, a row of gas inlets of the shaft furnace, and a cylindrical cavity arranged in the transition section;

Fig. 7 is a schematic structural view of the self-heating gas-based shaft furnace direct reduction device of the present invention, a plurality of cylindrical cavities are arranged in the transition section, and two rows of gas inlets are arranged in the cooling section of the shaft furnace;

Fig. 8 is another structural schematic diagram of the self-heating gas-based shaft furnace direct reduction device of the present invention, a cylindrical cavity is arranged in the transition section, a row of gas inlets in the reduction section, and a row of gas inlets in the cooling section;

Fig. 9 is another structural schematic diagram of the self-heating gas-based shaft furnace direct reduction device of the present invention, a plurality of cylindrical cavities are arranged in the transition section, a row of gas inlets in the reduction section, and a row of gas inlets in the cooling section;

Fig. 10 is another structural schematic diagram of the self-heating gas-based shaft furnace direct reduction device of the present invention, a cylindrical cavity is arranged in the transition section, and a row of gas inlets of the shaft furnace;

The marks in the figure are: 1-shaft furnace, 11-shaft furnace preheating section, 12-shaft furnace reduction section, 13-shaft furnace cooling section, 14-shaft furnace transition section, 131-cooling section loosener, 141-round Cylindrical central cavity, 142-cylindrical surrounding cavity, 143-refractory material, 144-outer furnace body, 145-temperature monitoring device, 146-electromagnetic induction coil, 147-cut valve, 151-shaft furnace gas inlet 1, 152-shaft furnace gas inlet 2, 153-shaft furnace gas inlet 3, 16-shaft furnace top loading device, 2-raw material gas, 3-shaft furnace self-produced purified gas after dedusting and carbon dioxide removal, 31- Shaft furnace gas after dedusting, 4-decarbonation device, 5-reduced iron, 6-humidifier, 7-shaft furnace discharge device, 8-gas heating device outside the shaft furnace, 9-dust removal device.

Detailed ways

In order to fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments, but the present invention is not limited thereto.

Taking seven cylindrical cavities arranged in the transition section of the shaft furnace body as an example, the structure of the shaft furnace body with n parallel cavities in the transition section is described below: Please refer to Figure 1 and Figure 2, the shaft furnace body 1 includes a preheating section 11. Reduction section 12, transition section 14 and cooling section 13. The cooling section is provided with a loose feeder 131, which is connected to the furnace body of the cooling section 13, and the transition section includes a cylindrical central cavity 141 and 6 cylinders evenly distributed in a ring around the cylindrical central cavity 141 Cavity 142 around the shape, 6 cylindrical surrounding cavities 142 have the same structure and size, and the structure and size of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 can be the same or different. In this example, 7 The two cylindrical cavities have the same structure and size. One end of each cylindrical central cavity 141 and cylindrical peripheral cavity 142 communicates with the reduction section 12 , and the other end communicates with the cooling section 13 , and the connection with the reduction section 12 is in the shape of a trumpet. The furnace body of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 is sequentially composed of refractory material 143, electromagnetic induction coil 146 and outer furnace body 144 from the inside to the outside. The outer wall of the refractory material 143 is wound with the electromagnetic induction coil 146, and the induction coil 146 is connected with the intermediate frequency or power frequency power supply, the induction coil 146 is a hollow copper tube, the copper tube is cooled by water, the inner wall of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 is provided with a temperature monitoring device 145, the temperature monitoring device 145 controls the power switch. When the temperature reaches the upper limit of the control range, the switch is closed and the electromagnetic induction stops working. When the temperature reaches the lower limit of the control range, the switch is activated and the electromagnetic induction starts to work. A cut-off valve is set at both ends of each cylindrical cavity 147, used for maintenance of related facilities of cylindrical cavity. The upper and lower parts of the cooling section 13 are arranged with shaft furnace gas inlet 2 152 and gas inlet 3 153 evenly distributed around the shaft of the cooling section 13 .

Below is the embodiment of a kind of self-heating gas-based shaft furnace direct reduction method provided for the present invention:

Embodiment one

Please refer to Fig. 1, 2 and Fig. 3, the shaft furnace self-produced purified coal gas 3 and a part of raw material gas 2 enter the shaft furnace 1 from the gas inlet 2 152 in the upper part of the cooling section 13 in this embodiment, and another part of the raw material gas 2 enters in the shaft furnace 1 from the lower part of the cooling section 13 The gas inlet 3 153 enters the shaft furnace 1, and the raw material gas 2 adopts coke oven gas, the coke oven gas volume is about 400M ³ , and the coke oven gas generally has the following main components: about 60% H ₂ , about 8% CO, about 23% CH ₄ , about 2% H ₂ O, about 2% CO ₂ , about 3% unsaturated hydrocarbons above C ₂ . Methods as below:

Fe oxides with a particle size of 8-16 mm are fed into the gas-based shaft furnace 1 from the furnace top charging device 16, and all the crude gas produced by the shaft furnace is purified by the dust removal device 9 and the carbon dioxide removal device 4 to become the shaft furnace self-produced gas Purified gas 3, the shaft furnace self-produced purified gas 3 is about 1100M ³ , H ₂ /CO is about 1.7-1.8, and generally has the following main composition: about 56% H ₂ , about 31% CO, about 2% CH ₄ , about 6% H ₂ O, about 2% CO ₂ . The released carbon dioxide is made into dry ice and other products for sale or personal use. Mix a part of the coke oven gas with the purified gas 3 produced by the shaft furnace, and the mixed gas passes through the humidifier 6 to increase the moisture content to meet the requirements for the reforming of hydrocarbons in the mixed gas, and then the mixed gas is sent from the vertical Gas inlet 2 152 in the upper furnace body of the cooling section 13 below the position of the electromagnetic induction coil 146 of the furnace is sprayed into the shaft furnace, and another part of coke oven gas is sprayed into the shaft furnace from the gas inlet 3 153 in the lower part of the cooling section 13. The coke oven gas injected in 153 exchanges heat with the falling direct reduced iron 5, and carburizing reaction occurs at the same time, the heated coke oven gas continues to rise, and flows through the transition section 14 of the shaft furnace together with the mixed gas injected in the gas inlet 2 152 The electromagnetic induction heating zone of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 is continuously heated by the heated direct reduced iron 5. When the temperature monitoring device 145 detects that the temperature of the electromagnetic induction heating zone reaches 1000 degrees, the electric The magnetic induction power supply is turned off until the temperature monitoring device 145 detects that the temperature of the electromagnetic induction heating zone reaches 900 degrees again, and the electromagnetic induction power supply is started again to supplement heat for the direct reduction iron 5 through electromagnetic induction; Under the catalysis of iron 5, the hydrocarbons in the mixed gas are reformed into reducing gases of _H2 and CO; the reformed hot mixed gas flows out of the shaft furnace transition section 14, enters the shaft furnace reduction section 12, and is connected with the shaft furnace The iron oxide falling from the upper part through the preheating section 11 reacts during the reverse operation, and the iron oxide is reduced to direct reduced iron 5; the newly reduced thermal direct reduced iron 5 enters the electromagnetic induction heating zone of the transition section 14 of the shaft furnace, and It continues to be responsible for heating and reforming the newly entered mixed gas, and at the same time accepts reheating by electromagnetic induction. The direct reduced iron 5 previously in the transition section 14 of the shaft furnace enters the cooling section 13 of the shaft furnace. 5 bonding, loosen the direct reduced iron 5 with the loosener 131, when the temperature of the direct reduced iron 5 in the cooling section drops below about 50 degrees, it is discharged through the discharge device 7 and transported to the product yard. On the other hand, after the hot mixed gas reacts with the iron oxide in the reduction section 12 of the shaft furnace, it enters the preheating section 11 at the upper part of the shaft furnace. Compared with time, the temperature decreases, the content of H ₂ and CO decreases, and the content of H ₂ O and CO ₂ increases, forming the shaft furnace self-produced crude gas, which enters the shaft furnace gas dust removal device 9 through the furnace top gas pipeline.

When the shaft furnace is started, iron oxide pellets with a particle size of 8-16 mm are first added to the shaft furnace 1 until the position of the furnace gas inlet 2 152, and then low-carbon steel balls with a particle size of 8-16 mm are added. The height of the stacked carbon steel balls is at least flush with the upper end of the induction coil 146, and preferably reaches the upper edge of the reduction section 12, and iron oxide pellets with a particle size of 8-16 mm are added on the carbon steel balls. After feeding, start the induction coil 146 wound around the furnace body to heat the carbon steel by electromagnetic induction. When the temperature monitoring device 145 detects that the temperature of the electromagnetic induction heating zone reaches 900 degrees, the humidified coke oven gas is blown in from the gas inlet 152 of the furnace body , the coke oven gas flows through the electromagnetic induction heating zone of the transition section 14 of the shaft furnace, and is heated by the hot carbon steel. Under the catalytic action of the carbon steel, the hydrocarbons in the raw gas in the transition section 14 of the shaft furnace are reformed into H ₂ and CO reducing gas; the reformed hot raw material gas flows out of the shaft furnace transition section 14 and enters the shaft furnace reduction section 12. According to this method, the initial heat is provided for the reduction reaction in the shaft furnace.

The self-heating gas-based shaft furnace direct reduction device in this embodiment saves the reforming system and heating furnace system of the traditional shaft furnace, and the investment is greatly reduced; since the self-produced gas of the shaft furnace is purified and fully circulated, there is no fuel heating process, so there is no carbon emission. The coke oven gas is not heated outside the furnace, and there is no carbon deposition.

Embodiment two

Please refer to Fig. 2 and Fig. 4, in this embodiment, after the shaft furnace self-produced purified coal gas 3 is heated by the shaft furnace external heating furnace 8, it enters the shaft furnace 1 from the gas inlet one 151 at the lower part of the reduction section 12, and the raw material gas 2 is cooled from the The gas inlet 2 152 on the upper part of section 13 enters the shaft furnace 1, and the raw material gas 2 is heated by the hot direct reduced iron 5 in the shaft furnace 1, and the raw material gas 2 adopts coke oven gas, the coke oven gas volume is about 600M ³ , and the composition is as mentioned above . Methods as below:

Fe oxides with a particle size of 8-16mm are added to the gas-based shaft furnace 1 from the furnace top charging device 16, and the crude gas produced by the shaft furnace is first dedusted by the dust removal device 9, and about 30% of the shaft furnace gas 31 after dust removal is used as heating The fuel for furnace 8, the remaining 70% of the gas is processed by the decarbonation device 4 and becomes the purified gas 3 produced by the shaft furnace. At this time, the gas volume of the purified gas 3 produced by the shaft furnace is about 750M ³ , H ₂ /CO About 1.8, the ingredients are as mentioned before. The released carbon dioxide is made into dry ice and other products for sale or personal use. The self-produced purified gas 3 of the shaft furnace after the high temperature reaction in the shaft furnace has removed components that are prone to carbon deposition, and will not deposit carbon when heated outside the shaft furnace. The self-produced purified gas 3 of the shaft furnace can be hydrogenated before entering the heating furnace 8 Increase the _H2 /CO value without adding hydrogen. In this example, after directly heating to 900-980 degrees without adding hydrogen, the gas enters the shaft furnace through the gas inlet-151 above the position of the electromagnetic induction coil 146 of the shaft furnace body. Gas inlet one 151 is located at the lower part of the reduction section. The coke oven gas passes through the humidifier 6 to increase the water vapor content of the coke oven gas to meet the requirements for the reforming of hydrocarbons in the coke oven gas, and then the coke oven gas passes through the gas inlet 2 152 below the electromagnetic induction coil 146 of the furnace body Entering the shaft furnace, the furnace body gas inlet 2 152 is located at the upper part of the cooling section 13; the coke oven gas flows through the electromagnetic induction heating zone of the cylindrical central cavity 141 of the shaft furnace transition section 14 and the cylindrical surrounding cavity 142, and is heated When the temperature monitoring device 145 detects that the temperature of the electromagnetic induction heating zone reaches 1050 degrees, the electromagnetic induction power supply is turned off, and when the temperature monitoring device 145 detects that the temperature of the electromagnetic induction heating zone reaches 900 degrees, the electromagnetic induction power supply starts , supplementing heat for direct reduced iron 5 through electromagnetic induction; under the catalysis of direct reduced iron 5, the hydrocarbons in the raw gas in the transition section 14 of the shaft furnace are reformed into reducing gases of H2 and CO; reformed The hot raw material gas flows out of the shaft furnace transition section 14 and enters the shaft furnace reduction section 12, where it merges with the shaft furnace self-produced purified gas 3 that enters from the shaft gas inlet 151. The iron oxides falling from the preheating section 11 react during the reverse operation, and the iron oxides are reduced to direct reduced iron 5; the newly reduced thermal direct reduced iron 5 enters the electromagnetic induction heating zone of the transition section 14 of the shaft furnace, where Continue to be responsible for heating and reforming the newly incoming raw material gas, and at the same time receive reheating by electromagnetic induction. The direct reduced iron 5 previously in the transition section 14 of the shaft furnace enters the cooling section 13 of the shaft furnace. In order to prevent the direct reduced iron 5 from sticking during the cooling process Knot, loosen the direct reduced iron 5 with a looser 131, when the direct reduced iron 5 in the cooling section cools down to about 720-750 degrees, then enter the hot briquetting device through the discharge device 7, and hot press it into a briquette iron of 100x50x30mm. transported to the product yard; on the other hand, the hot mixed gas enters the upper preheating section 11 of the shaft furnace after reacting with iron oxides in the reduction section 12 of the shaft furnace, and flows out of the preheating section 11 after preheating the iron oxides here. Compared with the reduction stage 12, the temperature of the mixed gas decreases, the content of H ₂ and CO decreases, and the content of H ₂ O and CO ₂ increases, forming the self-produced crude gas of the shaft furnace, and the self-produced crude gas enters the shaft through the furnace top gas pipeline. Furnace gas dust removal device 9.

The self-heating gas-based shaft furnace direct reduction device in this embodiment saves the reforming system of the traditional shaft furnace and reduces the overall investment; since the raw material gas is heated by electromagnetic, it reduces carbon emissions. This embodiment is applicable to areas where the problem of carbon deposition in the raw material gas is to be solved and gas resources are cheap.

Embodiment Three

Please refer to Fig. 5. Fig. 5 is another schematic flow diagram of the direct reduction method of the self-heating gas-based shaft furnace of the present invention. A cylindrical cavity is arranged in the transition section, and the other is the same as in the second embodiment.

Embodiment Four

Please refer to Fig. 6. Fig. 6 is another schematic flow chart of the direct reduction method of the self-heating gas-based shaft furnace of the present invention. In this embodiment, the raw material gas and the purified gas produced by the shaft furnace enter from a shaft furnace gas inlet, and a circle is arranged in the transition section. The cylindrical cavity is the same as the first embodiment.

Below is the embodiment of a kind of self-heating gas-based shaft furnace direct reduction device provided for the present invention:

Embodiment one

Referring to Fig. 1, Fig. 2 and Fig. 7, the self-heating gas-based shaft furnace direct reduction device in this embodiment includes a charging device 16, a shaft furnace body 1, and a discharge device 7, and the shaft furnace body 1 includes a preheating section 11 , Reduction section 12, transition section 14 and cooling section 13. The charging device 16 communicates with the upper opening of the shaft furnace body 1 , and the discharging device 7 is located at the lower opening of the shaft furnace body 1 . The transition section includes a cylindrical central cavity 141 and around the cylindrical central cavity 141, 6 cylindrical surrounding cavities 142 uniformly distributed in a ring shape, the 6 cylindrical surrounding cavities 142 have the same structure and size, The structure and size of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 may be the same or different. In this example, the structures and sizes of the seven cylindrical cavities are all the same. One end of each cylindrical central cavity 141 and cylindrical peripheral cavity 142 communicates with the reduction section 12 , and the other end communicates with the cooling section 13 , and the connection with the reduction section is in the shape of a trumpet. The furnace body of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 is sequentially composed of refractory material 143, electromagnetic induction coil 146 and outer furnace body 144 from the inside to the outside. The outer wall of the refractory material 143 is wound with the electromagnetic induction coil 146, and the induction coil 146 is connected with the intermediate frequency or power frequency power supply, the induction coil 146 is a hollow copper tube, the copper tube is cooled by water, the inner wall of the cylindrical central cavity 141 and the cylindrical surrounding cavity 142 is provided with a temperature monitoring device 145, the temperature monitoring device 145 controls the power switch. When the temperature reaches the upper limit of the control range, the switch is closed and the electromagnetic induction stops working. When the temperature reaches the lower limit of the control range, the switch is activated and the electromagnetic induction starts to work. A cut-off valve is set at both ends of each cylindrical cavity 147, used for maintenance of related facilities of cylindrical cavity. The cooling section 13 is provided with a loose feeder 131, and the loose feeder 131 is connected with the furnace body of the cooling section 13, and the upper part of the cooling section 13 is arranged with shaft furnace gas inlets 2 152 evenly distributed around the furnace body of the cooling section 13; the lower part of the cooling section 13 , there are shaft furnace gas inlets 3 153 evenly distributed around the shaft of the cooling section 13 . The shaft furnace gas inlet 2 152 is connected with the gas mixture pipeline of the shaft furnace itself and a part of the raw material gas 2 , and the shaft furnace gas inlet 3 153 is connected with the pipeline of another part of the raw material gas 2 .

The transition section of the shaft furnace body in this embodiment adopts the structure of one cylindrical central cavity and six cylindrical surrounding cavities to make the gas flow rate and temperature in the shaft furnace evenly distributed. In this embodiment, both the raw material gas and the self-produced coal gas produced by the shaft furnace are heated and reformed in the shaft furnace, and there is no heating and reforming system outside the shaft furnace.

Embodiment two

Please refer to Fig. 8, the self-heating gas-based shaft furnace direct reduction device of this embodiment includes a charging device 16, a shaft furnace body 1, and a discharge device 7, and the shaft furnace body 1 includes a preheating section 11, a reduction section 12, a transition Section 14 and cooling section 13. The charging device 16 communicates with the upper opening of the shaft furnace body 1 , and the discharging device 7 is located at the lower opening of the shaft furnace body 1 . The lower part of the reduction section 12 is arranged with shaft furnace gas inlets 1 151 uniformly distributed around the shaft of the reduction section 12 . The gas inlet 151 of the shaft furnace is communicated with one end of the heater 8, and the other end of the heater 8 is communicated with one end of the pipeline for purifying the gas 3 of the shaft furnace itself. The cooling section 13 is provided with a feeder 131, which is connected to the furnace body of the cooling section 13, and the upper part of the cooling section 13 is arranged with shaft furnace gas inlets 2 152 evenly distributed around the furnace body of the cooling section 13. The shaft furnace gas inlet 2 152 is in communication with the feed gas 2 pipeline. The transition section of this embodiment has only one cylindrical central cavity 141, one end of the cylindrical central cavity 141 communicates with the reduction section 12, the other end communicates with the cooling section 13, and the connection with the reduction section is in the shape of a trumpet. The internal structure of the cylindrical central cavity 141 is the same as that of the cylindrical central cavity of FIG. , the switch is turned off, and the electromagnetic induction stops working. When the temperature reaches the lower limit of the control range, the switch is activated, and the electromagnetic induction starts to work. A cut-off valve 147 is set at both ends of each cylindrical cavity for maintenance of the cylindrical cavity. related facilities. In this embodiment, there is no reforming system outside the shaft furnace.

Embodiment Three

Please refer to Fig. 9, this embodiment is another structural schematic diagram of the self-heating gas-based shaft furnace direct reduction device of the present invention, a plurality of cylindrical cavities are arranged in the transition section, and the other structures are the same as in the second embodiment;

Embodiment Four

Please refer to Fig. 10, this embodiment is another structural schematic diagram of the self-heating gas-based shaft furnace direct reduction device of the present invention, a cylindrical cavity is arranged in the transition section, a gas inlet of the shaft furnace is arranged, the shaft furnace gas inlet 2 152 is connected with the shaft furnace Furnace self-cleaning coal gas 3 and the mixed gas pipeline of raw material gas 2 are communicated, and other structures are identical with embodiment one;

The above embodiments are applicable to one or more mixed gases of coke oven gas, natural gas, hydrogen, and coal gas after decarbonation and nitrogen removal, converter gas, blast furnace gas, and coalbed methane.

What enumerated above is only the preferred embodiment of the present invention, certainly those skilled in the art can carry out modification and modification to the present invention, if these modification and modification belong to the scope of the claims of the present invention and its equivalent technology, all should be considered as the present invention. The scope of protection of the invention,.

Claims (10)

1. A self-heating gas-based shaft furnace direct reduction method comprises the steps of adding iron oxide with certain granularity into a gas-based shaft furnace from the top of the shaft furnace, feeding reducing gas into the furnace from the outside of the shaft furnace, carrying out reduction reaction on the iron oxide and the reducing gas in the shaft furnace to generate direct reduced iron, and discharging the direct reduced iron out of the furnace after passing through a cooling section of the shaft furnace.

2. A self-heating gas-based shaft furnace direct reduction process according to claim 1, characterized in that the reducing gas is derived from any one of the following gases:

(1) Raw material gas;

(2) The shaft furnace produces the mixed gas of purified gas and raw material gas.

3. The method according to claim 2, wherein when the reducing gas is derived from the raw material gas, the raw material gas enters the shaft furnace from a furnace body gas inlet below the electromagnetic induction coil, flows through the heating zone of the furnace body induction coil, and is heated by the hot direct reduced iron, the self-produced purified gas of the shaft furnace enters the shaft furnace from the furnace body gas inlet above the electromagnetic induction coil after being heated outside the gas-based shaft furnace, the heated reducing gas and the self-produced purified gas of the shaft furnace react with the iron oxide during the reverse running process, and the iron oxide is reduced to the direct reduced iron.

4. The direct reduction method of claim 1, wherein the charge material in the shaft located at the same position as the induction coil along the height direction of the shaft is a ferromagnetic metal material with a certain size, the upper end of the ferromagnetic metal material is higher than or equal to the upper end of the induction coil, and iron oxide with a certain size is provided on the ferromagnetic metal material, and the iron oxide is heated by the induction coil wound around the shaft to provide the initial heat for the reduction reaction in the shaft.

5. A direct reduction method for a self-heating gas-based shaft furnace as claimed in claim 1, 3 or 4, characterized in that a temperature monitoring device is provided inside the shaft of the shaft furnace around which the induction coil is wound, the temperature monitoring device is interlocked with a switch for controlling the power supply of the induction coil, and the switch for controlling the power supply of the induction coil is controlled by setting the upper and lower limit values of the temperature range of the monitoring device.

6. A self-heating gas-based shaft furnace direct reduction method according to claim 1 or 3, wherein the shaft gas inlet above the electromagnetic induction coil is located at the lower part of the reduction section of the gas-based shaft furnace, and the shaft gas inlet below the electromagnetic induction coil is located at the cooling section of the gas-based shaft furnace.

7. The utility model provides a self-heating gas-based shaft furnace direct reduction device, includes charging devices, shaft furnace body, discharging device, and the shaft furnace body includes preheating section, reduction section, changeover portion and cooling zone, and its characterized in that changeover portion is a n cavity that connects in parallel, and every cavity one end and reduction section lower part intercommunication, the other end and cooling zone intercommunication, cavity winding electromagnetic induction coil, induction coil and power link to each other, and the cooling zone is arranged around the gas inlet of cooling zone shaft of a furnace evenly distributed.

8. A self-heating gas-based shaft furnace direct reduction apparatus according to claim 7, wherein the cavity arrangement of the transition section is either of the following two ways:

(1) A central cavity is arranged at the central position of the transition section, and other cavities have the same size and structure and are uniformly distributed around the central cavity in an annular manner;

(2) The transition section is provided with only one cavity.

9. A self-heating gas-based shaft furnace direct reduction apparatus according to claim 7 or 8, wherein the chamber is cylindrical.

10. A self-heating gas-based shaft furnace direct reduction apparatus according to claim 9, wherein each cylindrical chamber is flared at the connection with the reduction zone.

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