WO2023138057A1 - Cyclone- and molten iron wall-based smelting apparatus and method - Google Patents

Abstract

The present invention relates to the technical field of metal smelting. Disclosed are a cyclone- and molten iron wall-based smelting apparatus and method. The smelting apparatus comprises an outer cylinder and an inner cylinder; a gasification reduction reaction area and a gas reforming area are sequentially provided in the outer cylinder; the inner cylinder is located in the reduction reaction area; a plurality of heat exchange tubes are arranged in sequence in a circumferential direction to form the inner cylinder; the inner cavity of the inner cylinder is communicated with a main gas outlet; the end of the inner side of the heat exchange tubes distant from the main gas outlet is provided with a cold medium outlet. Or, the smelting apparatus comprises a main reaction furnace, a preheating pre-reduction furnace, and a high-temperature gas-solid separation apparatus which are sequentially communicated; the end in the main reaction furnace facing the preheating pre-reduction furnace is sequentially provided with a heating area, a combustion area, a gasification area and a reduction area; a solid-phase output end of the high-temperature gas-solid separation apparatus is communicated with a second powder nozzle of the gasification area. According to the present invention, a plurality of reactions are integrated into one reaction furnace, and thus, the metal smelting process is simplified.

Description

A swirl iron wall melting and smelting device and method

The present invention claims the priority of the Chinese patent application submitted to the China Patent Office on January 24, 2022, with the application number 202210081490.7 and the title of the invention "A device and method for swirling iron wall melting and smelting", the entire contents of which are incorporated in the present invention by reference.

technical field

The invention relates to the technical field of metal smelting, in particular to a swirl iron wall melting and smelting device and method.

Background technique

Non-blast furnace ironmaking technology is a clean and energy-saving new technology and new process, and its attention is gradually increasing. The prior art discloses a short-process smelting reduction ironmaking system and method. By optimizing the coal coking process, high-temperature powdered coke can be circulated in the furnace, and hydrogen-rich gas with high calorific value can be produced at the same time. The gas can be used to directly reduce iron ore powder. The prior art also discloses a fully preheated and gas-phase pre-reduced coal gasification combined with molten iron reduction process. Through the multi-stage preheated pre-reduction utilization of the coal gas produced in the coking process, the sensible heat and calorific value of the coal gas are fully utilized, and the system construction and energy utilization are further optimized.

Although the above scheme shortens the ironmaking process and realizes centralized control of pollutant emissions, the process is still very long, requiring many high-temperature devices and high-temperature pipelines, high investment costs and operating costs, and difficult to operate. Moreover, the high-temperature zone in the high-temperature melting furnace of the above scheme is far away from the furnace hearth, which is not conducive to the flow of molten iron and smelting reduction.

Contents of the invention

Aiming at the deficiencies in the prior art, the object of the present invention is to provide a swirl iron wall melting and smelting device and method, which integrates multiple reactions into one reaction furnace and reduces the metal smelting process.

In order to achieve the above object, the present invention is achieved through the following technical solutions:

In the first aspect, the embodiment of the present invention provides a swirl iron wall melting and smelting device, which includes an outer cylinder and an inner cylinder, the gasification reduction reaction zone and the gas reforming zone are sequentially arranged in the outer cylinder, and the inner cylinder is located in the reduction reaction zone;

A plurality of heat exchange tubes are arranged in sequence along the ring direction to form an inner cylinder. The inner cavity of the inner cylinder is connected to the main gas outlet, and the end of the heat exchange tube away from the main gas outlet is provided with a cold medium outlet, so that the cold medium passing into the heat exchange tube can mix with the gas in the gas reforming zone.

As a further implementation, the outer wall of the gasification reduction reaction zone is sequentially connected with the first powder nozzle, the first gas nozzle and the second powder nozzle from top to bottom, the first powder nozzle is used to feed coal powder or coke powder, the first gas nozzle is used to feed air or enriched oxygen, and the second powder nozzle is used to feed iron ore powder.

As a further implementation, the first powder nozzles, the first gas nozzles and the second powder nozzles are arranged in multiples at intervals along the circumference of the outer cylinder, and are tangent to the outer wall of the outer cylinder.

As a further implementation manner, the gas reforming zone is provided with a third powder nozzle and a second gas nozzle in sequence, the third powder nozzle is used for feeding carbon powder, and the second gas nozzle is used for feeding oxygen.

As a further implementation, the protruding ends of the heat exchange tubes communicate with the circulating gas ring pipe, and one side of the circulating gas ring pipe is connected with the circulating gas main pipe.

In the second aspect, the embodiment of the present invention also provides a swirl iron wall melting and smelting device, which includes a main reaction furnace, a preheating pre-reduction furnace and a high-temperature gas-solid separation device connected in sequence. In the main reaction furnace, a heating zone, a combustion zone, a gasification zone and a reduction zone are arranged in sequence towards the end of the preheating pre-reduction furnace; the solid phase output end of the high-temperature gas-solid separation device is connected with the second powder nozzle of the gasification zone, so that the molten solid material and the reducing gas from bottom to top form a counterflow.

As a further implementation, multiple sets of first gas nozzles and first powder nozzles tangential to the circumference of the main reaction furnace are arranged axially staggered outside the combustion zone. The first gas nozzles are used to feed air or oxygen-enriched gas, and the first powder nozzles are used to feed coal powder or coke powder.

As a further implementation, the connecting section between the preheating pre-reduction furnace and the main reaction furnace is provided with a third gas nozzle and a fourth powder nozzle in sequence, the third gas nozzle is used to feed circulating gas, the fourth powder nozzle is used to feed cold ore powder; the second powder nozzle is used to feed iron ore powder.

In the third aspect, the embodiment of the present invention also provides a working method of a swirl iron wall melting and smelting device, including:

Coal powder/coke powder is injected from the first powder nozzle, air/oxygen-enriched gas is injected from the first gas nozzle, and coal powder/coke powder reacts with air/oxygen-enriched gas in a high-temperature environment to generate coal gas;

Iron ore powder is injected from the second powder nozzle, melted under high temperature conditions and flows downward along the inner wall of the outer cylinder and the outer wall of the inner cylinder, and is generated by coal gas during the flow process to form molten iron;

After the reduction reaction, carbon powder is injected to reform the components in the gas;

The reformed gas enters the inner tube, mixes with the cold medium flowing out of the heat exchange tube, and flows out from the main gas outlet along the inner tube from bottom to top.

In the fourth aspect, the embodiment of the present invention also provides a working method of a swirl iron wall melting and smelting device, including:

Coal powder/coke powder is injected from the first powder nozzle, and air/oxygen-enriched gas is injected from the first gas nozzle to generate high-temperature and high-reducing potential gas;

The iron ore powder is injected from the second powder nozzle above the gasification zone, melted and adhered to the wall in a high-temperature environment, and then flows from top to bottom along the inner wall of the main reactor, while the high reducing potential airflow generated in the gasification zone flows from bottom to top, forming a countercurrent;

The coal gas after smelting reduction enters the preheating pre-reduction furnace, and the third gas nozzle is sprayed into the circulating gas to cool down; the fourth powder nozzle is sprayed into normal-temperature ore powder to preheat and pre-reduce the cold ore powder;

The ore powder enters the high-temperature gas-solid separation device along with the gas, and the preheated and pre-reduced ore powder is sent to the main reaction furnace for further melting and smelting.

The beneficial effects of the present invention are as follows:

(1) The present invention integrates pulverized coal coking, gasification and molten iron reduction into one reaction furnace, which reduces the metal smelting process; by injecting carbon powder into the reduced gas, the components in the gas are reformed, which can effectively increase the proportion of effective gas in the reduced gas and improve its utilization rate.

(2) The inner pipe of the present invention is composed of a plurality _of heat exchange tubes arranged in the circumferential direction. The cold medium is passed into the heat exchange tubes. The cold medium flows from top to bottom in the heat exchange tubes, flows out from the lower side of the heat exchange tubes, and _flows out from bottom to top after mixing with the reformed gas. Mix and heat up, and continue the reforming reaction with unreacted carbon.

(3) The present invention integrates combustion, gasification and reduction into one main reaction furnace, which reduces the metal smelting process; through the top-down flow of molten iron slag attached to the wall and the bottom-up flow of the main gas to form a countercurrent, the reduction effect is enhanced.

(4) The coal gas after smelting reduction in the present invention enters the preheating pre-reduction furnace at the upper part, and is sprayed into the circulating return coal gas to cool down through the circulating gas nozzle, so that its temperature drops to the range of 900-1200°C, where the normal temperature mineral powder is sprayed from the cold mineral powder nozzle, and the mineral powder is fully mixed with the cooled gas and goes upward after a certain period of time to complete the preheating and pre-reduction of the cold mineral powder.

(5) The furnace hearth of the present invention is arranged at the bottom of the reaction furnace, which solves the problem that the high temperature area is far away from the furnace hearth, which is unfavorable to molten iron flow and smelting reduction.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention.

Fig. 1 is a schematic structural view of Embodiment 1 of the present invention;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is the B-B sectional view of Fig. 1;

Fig. 4 is a schematic structural diagram of Embodiment 2 of the present invention;

Fig. 5 is a C-C sectional view of Fig. 4 .

Among them, I, gasification and reduction reaction zone, II, coal gas reforming zone, III, iron slag storage zone, IV, coal gas heating and reforming zone, V, temperature increasing zone, VI, combustion zone, VII, gasification zone, VIII, reduction zone, IX, preheating and pre-reduction zone;

1. First powder nozzle, 2. First gas nozzle, 3. Second powder nozzle, 4. Heat exchange tube, 5. Temperature-resistant coating, 6. Cooling medium outlet, 7. Third powder nozzle, 8. Second gas nozzle, 9. Hearth, 10. Slag outlet, 11. Liquid outlet, 12. Circulating gas main pipe, 13. Circulating gas ring pipe, 14. Main gas outlet, 15. Third gas nozzle, 16. Fourth powder nozzle, 17. Gas phase outlet, 18. High-temperature gas-solid separation device, 19. Iron ore powder.

Detailed ways

Embodiment one:

This embodiment provides a swirling iron wall melting and smelting device, as shown in Figure 1, comprising an outer cylinder and an inner cylinder coaxially arranged, the outer cylinder is a cyclone structure, that is, the outer cylinder includes a cylindrical section and a conical section connected as one, and the inner cylinder extends into the interior of the outer cylinder and has a certain distance from the junction of the cylindrical section and the conical section.

The gasification reduction reaction zone I is formed between the inner wall of the outer cylinder and the outer wall of the inner cylinder, the conical section of the outer cylinder is the gas reforming zone II, the outlet end of the conical section is connected to the hearth 9, and the iron slag storage zone III is formed in the hearth 9; the gas heating reforming zone IV is formed in the inner cylinder.

Specifically, the top of the inner cylinder (with reference to the direction shown in FIG. 1 ) protrudes a certain length from the top surface of the outer cylinder, the top of the inner cavity of the inner cylinder communicates with the main gas outlet 14, and the bottom is a through opening that communicates with the outer cylinder. The main gas outlet 14 is used to connect heat exchange equipment, such as high temperature air-gas heat exchanger, waste heat boiler, etc.

In this embodiment, the inner cylinder includes a plurality of heat exchange tubes 4 parallel to each other, and the plurality of heat exchange tubes 4 are welded and fixed along the circumferential direction to form a cylinder structure, and the cylinder structure is covered with a heat-resistant coating 5; the heat-resistant coating 5 is constructed of high-temperature refractory materials, which can withstand temperatures of 1600°C.

The bottom end of each heat exchange tube 4 is blocked, and the top end communicates with the circulating gas ring pipe 13; the circulating gas ring pipe 13 is fixed outside the main gas outlet 14. As shown in FIG. 2 , one side of the circulating gas ring pipe 13 communicates with the circulating gas main pipe 12 , and cold medium is input to each heat exchange tube 4 through the circulating gas main pipe 12 .

A cold medium outlet 6 is provided on the inner wall of the inner cylinder near the through opening at the bottom. The flow direction of the cold medium is from top to bottom along the heat exchange tube 4. At the cold medium outlet 6, it is sprayed into the inner cavity of the inner cylinder along the radial direction. After mixing with high-temperature gas, it flows from the bottom to the top of the inner cylinder, and at the same time completes the heat exchange with the cold medium in the tube. The cold medium airflow is fed radially from the side hole, and the outlet air velocity is 5-20m/s.

In the heat exchange tube 4 of this embodiment, the low-temperature, low-reducing potential gas is fed back from top to bottom, and is mixed with the reformed gas at the outlet and discharged upward, which not only has the effect of reducing the temperature of the high-temperature gas, but also increases its own temperature, and at the same time realizes the effect of self-reforming by using residual carbon.

In this embodiment, the cold medium is cold coal gas or reduced exhaust gas.

The inner wall of the outer cylinder is also provided with a heat-resistant coating 5, and the outer cylinder is provided with a first powder nozzle 1, a first gas nozzle 2, and a second powder nozzle 3 in sequence along the axial direction near the top end, and each nozzle is arranged at intervals along the outer cylinder. The arrangement is the same.

Taking the first powder nozzle 1 as an example, as shown in Figure 2, the first powder nozzle 1 is tangent to the outer cylinder, and the rotation direction of each first powder nozzle 1 is consistent. The number of first powder nozzles 1 can be 3-8, preferably, 4 first powder nozzles 1 are provided.

The first powder nozzle 1 is a pulverized coal/coke powder nozzle, and the conveying medium is nitrogen or coal gas, and the gas velocity is 50-100m/s. The first gas nozzle 2 is an air/oxygen-enriched nozzle with a gas velocity of 50-200m/s. The second powder nozzle 3 is an iron ore powder nozzle, which transports iron ore powder and the matching flux (dolomite powder, limestone powder, etc.), and the conveying medium is nitrogen or coal gas, and the gas velocity is 50-100m/s.

Coal powder/coke powder is injected from the first powder nozzle 1, and air/oxygen-enriched gas is injected from the first gas nozzle 2, both entering tangentially. Under high temperature environment, coal powder/coke powder reacts with air/oxygen-enriched gas to generate coal gas.

The iron ore powder is sprayed from the second powder nozzle 3, and also enters in a tangential direction. Under the action of centrifugal force, the iron ore powder and flux are thrown to the inner wall of the outer cylinder and the outer wall of the inner cylinder to form a molten iron (slag) wall, which plays the role of protecting the wall with slag. The molten iron (slag) wall flows downward along the wall surface, and a reduction reaction occurs with the reducing atmosphere along the way. At the same time, the molten iron (slag) wall contains carbon, and the iron reduction reaction can directly occur during the flow process.

A third powder nozzle 7 and a second gas nozzle 8 are arranged at the junction of the cylindrical section and the tapered section of the outer cylinder, and a plurality of the third powder nozzle 7 and the second gas nozzle 8 are also arranged at intervals along the circumference of the outer cylinder, and the third powder nozzle 7 and the second gas nozzle 8 are tangent to the outer cylinder.

The second gas nozzle 8 is an oxygen nozzle, which is used to raise the temperature, and the temperature is controlled at 1500-1600°C to ensure smooth flow of iron slag; the air velocity is 30-100m/s. The third powder nozzle 7 is a carbon powder nozzle, the conveying medium is nitrogen or coal gas, and the air velocity is 30-100m/s. After the reduction reaction, the reduction potential of the gas decreases, the concentration of _CO2 increases, and the airflow reaches the end of the inner cylinder and turns upwards to enter the inner cylinder. The carbon powder nozzle is set in the airflow turning area. In a high temperature environment, _CO2 reacts with C to generate CO, which increases its reduction potential again, so as to realize the reformation of the reduced gas.

A slag port 10 is provided on one side of the hearth 9, and a liquid outlet 11 is provided on the other side. After gas-liquid separation, the mixture of molten iron and slag flows into the hearth 9 at the bottom through the conical section, thereby completing the melting and smelting of iron ore powder.

Embodiment two:

This embodiment provides a working method of a swirl iron wall melting and smelting device, wherein the smelting device adopts the structure described in Embodiment 1, including the following steps:

Gasification reaction: Coal powder/coke powder is injected from the first powder nozzle 1, and air/oxygen-rich gas is injected from the first gas nozzle 2. Under high temperature environment, coal powder/coke powder reacts with air/oxygen-rich gas to generate coal gas.

Reduction reaction: Iron ore powder is sprayed from the second powder _nozzle 3. Under the action of centrifugal force, iron ore powder and flux are thrown towards the inner wall of the outer cylinder and the outer wall of the inner cylinder, and melted at high temperature to form a molten iron (slag) wall.

Reforming reaction: After the reduction reaction, CO ₂ and H ₂ O(g) in the gas increase, while CO and H ₂ decrease, resulting in a reduction in the reduction potential. The temperature of the gas after reduction is still very high, up to 1500-1600°C. At this time, injecting carbon powder can easily reform the CO ₂ and H ₂ O(g) components in the gas to convert them into CO and H ₂ , but at the same time, the temperature will drop to about 1300°C.

Reformed gas temperature adjustment/circulating gas heating and reforming: Reformed gas enters the inner pipe, which is surrounded by temperature-resistant heat exchange tubes 4, and cold medium (cold gas or reduced exhaust gas) is passed into the heat exchange tubes 4. The cold medium flows from top to bottom in the heat exchange tubes 4, flows out from the lower side of the heat exchange tubes 4, mixes with the reformed gas, and then flows out from bottom to top. First, the cold medium plays the role of adjusting the temperature of the reformed gas to avoid excessively high outlet temperature, which affects the normal operation of subsequent equipment; second, the CO ₂ and H ₂ O(g) components in the cold medium are directly mixed with the 1300°C reformed gas to raise the temperature, and continue the reforming reaction with unreacted carbon.

The reformed gas flows out from the main gas outlet 14, and the outlet temperature is 900-1200°C, followed by conventional heat exchange equipment (gas heat exchanger, waste heat boiler, etc.) for preheating and recovery. The reformed gas can be directly used as industrial gas or as synthesis gas.

After reduction, the iron slag mixture flows into the iron slag storage area III in a liquid state at 1500-1600°C.

Embodiment three:

This embodiment provides a swirl iron wall melting and smelting device. As shown in FIG. 4 , it is generally vertically arranged, and includes a main reaction furnace, a preheating and pre-reduction furnace, and a high-temperature gas-solid separation device connected in sequence. A hearth is arranged at the bottom of the main reaction furnace, and an iron slag storage area III is formed in the hearth. One side of the iron slag storage area III is connected to the slag port 10, and the other side is connected to the liquid outlet 11.

The connecting section between the main reaction furnace and the hearth adopts a cone structure so that the wall-attached molten iron and liquid slag flow into the hearth; the hearth is a commonly used structure in the current blast furnace smelting technology, and the temperature in the hearth is maintained at 1500-1600 °C. In this embodiment, the taper of the pyramid structure is 25-75°. The main reaction furnace is an upward airflow bed structure, and the inner surface of the furnace is coated with a heat-resistant coating, with a maximum temperature resistance of 1700 °C.

From bottom to top in the main reaction furnace, there are warming zone V, combustion zone VI, gasification zone VII and reduction zone VIII, and preheating and pre-reduction zone IX is formed in the preheating and pre-reduction furnace. The main reaction furnace is based on high-temperature gasification of pulverized coal/coke, and injects preheated/pre-reduced iron ore powder at the same time of gasification, relying on the generated reducing atmosphere and solid carbon to achieve rapid melting and smelting of iron ore powder in a high-temperature environment.

The main reaction furnace mainly produces raw material gasification and smelting reduction of mineral powder. The main reaction furnace corresponds to the combustion zone VI and the gasification zone VII, and sets multiple groups of first gas nozzles 2 and first powder nozzles 1 in an axial direction. s.

The first powder nozzle 1 is a pulverized coal/coke powder nozzle, and the medium used to transport pulverized coal/coke powder is nitrogen or gas, the temperature is ≤100°C, and the gas velocity is 50-100m/s.

As shown in Fig. 5, a plurality of first gas nozzles 2 and first powder nozzles 1 are arranged at intervals along the circumference of the main reaction furnace, and are tangent to the outer wall of the main reaction furnace, and the rotation direction of each nozzle is consistent. The number of nozzles in each group is 3-8, preferably 4.

In this embodiment, a group of air/oxygen-enriched nozzles is set at the junction of the combustion zone VI and the temperature increasing zone V to maintain the temperature and ensure the temperature of the molten iron and liquid slag. Combustion zone VI and gasification zone VII are equipped with pulverized coal/coke nozzles and air/oxygen-enriched nozzles, where raw material combustion and gasification reactions mainly occur, generating a reducing atmosphere and maintaining a high temperature (about 1600°C).

Multiple groups of second powder nozzles 3 are set in the reduction zone VIII. The second powder nozzles 3 are iron ore powder nozzles. The mineral powder nozzles are connected to the solid phase outlet of the high-temperature gas-solid separation device 18 and are mainly used to transport preheated and pre-reduced mineral powders. The melting and smelting of mineral powders mainly occurs in the reduction zone. In this embodiment, two groups of second powder nozzles 3 are arranged at intervals along the axial direction of the main reactor, and each group has multiple groups. The arrangement of the second powder nozzles 3 is the same as that of the first powder nozzles 1 .

The preheating and pre-reduction zone IX is arranged on the upper part of the main reaction furnace and has an upward airflow bed structure. In this embodiment, the preheating and pre-reduction furnace includes a first passage communicating with the main reaction furnace and a second passage communicating with the high-temperature gas-solid separation device, and the second passage is perpendicular to the first passage.

The inner diameter of the preheating and pre-reduction zone IX is smaller than the inner diameter of the main reaction furnace to increase the airflow velocity to ensure that the cold ore powder is smoothly carried by the airflow to complete the preheating and pre-reduction. In this embodiment, the flow rate of the airflow in the preheating pre-reduction zone IX is 5-7m/s, and the residence time of the ore powder in the reaction zone is 3-7s.

The connecting end of the first channel and the main reaction furnace is provided with a third gas nozzle 15 and a fourth powder nozzle 16 from bottom to top in sequence, and a plurality of third gas nozzles 15 and fourth powder nozzles 16 are arranged along the circumference of the preheating pre-reduction furnace; and the third gas nozzle 15 and the fourth powder nozzle 16 are tangent to the outer wall of the preheating pre-reduction furnace.

The third gas nozzle 15 is a circulating gas nozzle, which is used to regulate the temperature of the airflow entering the preheating pre-reduction zone IX, and the temperature is controlled at 900-1200°C. The fourth powder nozzle 16 is a cold ore powder nozzle, which is connected to the solid phase outlet of the high-temperature gas-solid separation device 18. The cold ore powder is preheated and pre-reduced by making full use of the sensible heat and reduction potential of the coal gas after melting and smelting.

It is used to transport cold ore powder into the preheating pre-reduction furnace, the transport medium used is nitrogen or coal gas, the temperature is ≤100°C, and the gas velocity is 30-100m/s.

The high-temperature gas-solid separation device 18 is equipped with a gas phase outlet 17 at the top and a solid phase outlet at the bottom. The solid phase outlet is preheated and pre-reduced iron ore powder 19, which is directly sent to the main reaction furnace for melting and smelting. The gas phase outlet is connected to a conventional waste heat utilization device and a gas environmental protection device. The processed gas can be used as fuel or raw material according to demand.

The high-temperature gas-solid separation device 18 adopts a cyclone separator structure, and its temperature resistance range is 800-1200°C.

Embodiment four:

This embodiment provides a working method of a swirl iron wall melting and smelting device, wherein the smelting device adopts the structure described in Embodiment 3, including the following steps:

First, combustion gasification of pulverized coal/coke:

The reaction mainly takes place in the combustion zone VI and gasification zone VII of the main reaction furnace. Coal powder/coke powder is injected from the first powder nozzle 1, and air/oxygen-enriched gas is injected from the first gas nozzle 2. By distributing the air and material ratios of different nozzle groups, a combustion zone VI is formed in the main reactor furnace to generate high-temperature flue gas to provide heat for the system. A gasification zone VII is formed above the combustion zone VI of the main reactor furnace to generate high-temperature and high-reducing potential gas.

Secondly, melting and smelting of preheated pre-reduced ore powder:

The preheated and pre-reduced iron ore powder 19 is fed from the second powder nozzle 3, and the feeding position is in the middle and upper part of the gasification zone VII. The high-speed tangential feeding method throws the preheated and pre-reduced iron ore powder 19 to the wall of the furnace body, melts and adheres to the wall in a high temperature environment, and then flows from top to bottom along the wall. The high reducing potential airflow generated by the gasification zone VII flows from bottom to top, and the reverse flow of gas-solid (liquid) phase is more conducive to the reduction reaction, thereby enhancing its reduction efficiency. In addition, part of the unreacted carbon is also contained in the molten phase attached to the wall. Under high temperature environment, the direct reduction of iron by carbon will also occur in the molten phase attached to the wall, further enhancing its reduction efficiency.

Subsequently, the cooling of the gas after smelting reduction and the preheating and pre-reduction of cold ore powder:

Although the reduction potential of the coal gas decreases after smelting reduction, its temperature is still high, 1400-1500°C. The coal gas directly enters the upper preheating pre-reduction furnace from the outlet on the top of the main reaction furnace. At the connection between the preheating pre-reduction furnace and the main reaction furnace, the third gas nozzle 15 is injected into the circulating return gas (temperature 50-150°C) to cool down, so that the temperature drops to 900-1200°C. Afterwards, fully mix with the cooled gas and go up, and complete the preheating and pre-reduction of cold ore powder within 3-7s.

Finally, the ore powder enters the high-temperature gas-solid separation device 9 along with the gas. After separation, the preheated and pre-reduced ore powder is sent to the main reaction furnace for further melting and smelting. The outlet gas is recovered and purified by conventional waste heat and used as fuel for self-use or external use by users.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, there may be various modifications and changes in the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (10)

1. A swirl iron wall melting and smelting device, characterized in that it includes an outer cylinder and an inner cylinder, a gasification reduction reaction zone and a gas reforming zone are arranged in the outer cylinder in sequence, and the inner cylinder is located in the reduction reaction zone;

   A plurality of heat exchange tubes are arranged in sequence along the ring direction to form an inner cylinder. The inner cavity of the inner cylinder is connected to the main gas outlet, and the end of the heat exchange tube away from the main gas outlet is provided with a cold medium outlet, so that the cold medium passing into the heat exchange tube can mix with the gas in the gas reforming zone.
2. A swirl iron wall melting and smelting device according to claim 1, wherein the outer wall of the gasification reduction reaction zone is connected to the first powder nozzle, the first gas nozzle and the second powder nozzle in sequence from top to bottom, the first powder nozzle is used to feed coal powder or coke powder, the first gas nozzle is used to feed air or oxygen-enriched, and the second powder nozzle is used to feed iron ore powder.
3. A swirl iron wall melting and smelting device according to claim 2, characterized in that, the first powder nozzle, the first gas nozzle and the second powder nozzle are arranged in multiples at intervals along the circumference of the outer cylinder, and are tangent to the outer wall of the outer cylinder.
4. The swirl iron wall melting and smelting device according to claim 1, wherein the gas reforming zone is provided with a third powder nozzle and a second gas nozzle in sequence, the third powder nozzle is used for feeding carbon powder, and the second gas nozzle is used for feeding oxygen.
5. The swirl iron wall melting and smelting device according to claim 1, wherein the protruding end of the heat exchange tube is connected to the circulating gas ring pipe, and one side of the circulating gas ring pipe is connected to the circulating gas main pipe.
6. A swirl iron wall melting and smelting device is characterized in that it comprises a main reaction furnace, a preheating pre-reduction furnace and a high-temperature gas-solid separation device connected in sequence, and a temperature-increasing zone, a combustion zone, a gasification zone and a reduction zone are sequentially arranged in the main reaction furnace towards the end of the preheating pre-reduction furnace; the solid-phase output end of the high-temperature gas-solid separation device communicates with the second powder nozzle of the gasification zone, so that the molten solid material and the reducing gas from bottom to top form countercurrent flow.
7. A swirl iron wall melting and smelting device according to claim 6, characterized in that a plurality of groups of first gas nozzles and first powder nozzles tangential to the circumferential direction of the main reaction furnace are arranged axially on the outer side of the combustion zone, the first gas nozzles are used to feed air or enriched oxygen, and the first powder nozzles are used to feed coal powder or coke powder.
8. A swirl iron wall melting and smelting device according to claim 6, characterized in that, the connecting section between the preheating pre-reduction furnace and the main reaction furnace is provided with a third gas nozzle and a fourth powder nozzle in sequence, the third gas nozzle is used to feed circulating gas, the fourth powder nozzle is used to feed cold ore powder, and the second powder nozzle is used to feed iron ore powder.
9. The working method of a swirl iron wall melting and smelting device according to any one of claims 1-5, characterized in that it comprises:

   Coal powder/coke powder is injected from the first powder nozzle, air/oxygen-enriched gas is injected from the first gas nozzle, and coal powder/coke powder reacts with air/oxygen-enriched gas in a high-temperature environment to generate coal gas;

   Iron ore powder is injected from the second powder nozzle, melted under high temperature conditions and flows downward along the inner wall of the outer cylinder and the outer wall of the inner cylinder, and is generated by coal gas during the flow process to form molten iron;

   After the reduction reaction, carbon powder is injected to reform the components in the gas;

   The reformed gas enters the inner tube, mixes with the cold medium flowing out of the heat exchange tube, and flows out from the main gas outlet along the inner tube from bottom to top.
10. The working method of a swirl iron wall melting and smelting device according to any one of claims 6-8, characterized in that it comprises:

    Coal powder/coke powder is injected from the first powder nozzle, and air/oxygen-enriched gas is injected from the first gas nozzle to generate high-temperature and high-reducing potential gas;

    The iron ore powder is injected from the second powder nozzle above the gasification zone, melted and adhered to the wall in a high-temperature environment, and then flows from top to bottom along the inner wall of the main reactor, while the high reducing potential airflow generated in the gasification zone flows from bottom to top, forming a countercurrent;

    The coal gas after smelting reduction enters the preheating pre-reduction furnace, and the third gas nozzle is sprayed into the circulating gas to cool down; the fourth powder nozzle is sprayed into normal temperature mineral powder for preheating and pre-reduction of cold mineral powder;

    The ore powder enters the high-temperature gas-solid separation device along with the gas, and the preheated and pre-reduced ore powder is sent to the main reaction furnace for further melting and smelting.

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