Radiation heating type reduction furnace and reduction method thereof

Abstract

The invention discloses a radiation heating type reduction furnace which comprises a furnace chamber and a spray gun, the furnace chamber is provided with a feeding channel, the top of the furnace chamber is provided with a gas discharge port, the bottom of the furnace chamber is provided with a slag outlet, the spray gun comprises a mixing chamber, a raw material inlet and a reducing gas inlet, and the reducing gas inlet and the raw material inlet are both communicated with the mixing chamber. The reduction furnace has the gasification characteristics of an entrained-flow bed and a fluidized bed through the synergistic effect of the spray guns and the gas filling channel, the problems that a traditional reduction furnace is low in heat efficiency and uneven in mixing are solved, and deep fusion and rapid reaction of reduced materials and reducing gas in a furnace cavity are achieved. The invention further discloses another reduction method of the radiation heating type reduction furnace. The reduction method comprises a preheating step, a gas preparation step, a material preparation step, a mixed injection step, a reaction control step and a product discharge step. The reduction reaction method is simple in step and convenient to implement, and deep fusion and rapid reaction of the reduced material and the reducing gas in the furnace chamber are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of reduction furnaces, and in particular to a radiation heating type reduction furnace and a reduction method thereof. Background Art

[0002] Reduction furnaces are widely used in coal-to-gasification, metallurgy, chemical engineering, and materials preparation. Their core function is to reduce metal elements in metal oxides or other compounds to elemental or low-oxidation states under high-temperature conditions. However, traditional reduction furnaces are heated using indirect or convection heating. Indirect heating suffers from low heat conduction efficiency and uneven temperature distribution within the furnace, which can easily lead to localized overheating, affecting the uniformity of the reduction reaction and product quality. Convection heating requires large amounts of circulating gas, increasing equipment complexity and operating costs. Furthermore, the gas flow may carry away some heat, resulting in energy waste.

[0003] Traditional reduction furnaces also have shortcomings in charging and mixing. Entrained-bed furnaces achieve efficient mixing of the reduced material and reducing gas through co-current flow, increasing reaction rates. However, this results in a concentrated reaction zone and prolonged processing. Fluidized beds use secondary air intake to create an upward flow, enhancing the contact area between the reduced material and the gas and improving mixing efficiency. However, maintaining a boiling state requires strict airflow control and temperature distribution, increasing operational complexity and energy consumption. Summary of the Invention

[0004] The purpose of the present invention is to provide a radiation-heating reduction furnace, which, through the coordinated action of a spray gun and a gas-feeding channel, enables the reduction furnace to have the gasification characteristics of an entrained flow bed and a fluidized bed, thereby solving the problems of low thermal efficiency and uneven mixing in traditional reduction furnaces, and realizing deep fusion and rapid reaction of the reduced material and reducing gas in the furnace chamber.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A radiation heating reduction furnace comprises a cylindrical furnace chamber, a feeding channel is provided on the furnace chamber, a gas exhaust port is provided at the top of the furnace chamber, a slag outlet is provided at the bottom of the furnace chamber, and a plurality of spray guns are provided, wherein the spray guns comprise a mixing chamber, a raw material inlet and a reducing gas inlet, and the reducing gas inlet and the raw material inlet are both connected to the mixing chamber. The number of the feeding channels corresponds to the number of the spray guns, and the spray guns are connected to the furnace chamber through the feeding channels. The plurality of spray guns are arranged along the circumferential direction of the bottom of the furnace shell, and each feeding channel forms an acute angle with the longitudinal center line of the furnace chamber; and the extension lines of the plurality of feeding channels intersect in the internal space of the furnace chamber and converge at a point or a small area, and the convergence point or area is located on the longitudinal center line of the furnace chamber.

[0007] Preferably, a gas supply channel is further provided at the bottom of the furnace cavity, the gas supply channel is parallel to the feeding channel, and the gas supply channel is arranged below the feeding channel.

[0008] Preferably, the furnace cavity side wall is covered with a furnace shell, and a partition is provided between the furnace shell and the furnace cavity, and the partition is used to hold the heating unit; the furnace cavity side wall is a radiation wall, which is used to provide the heat source required for the reduction reaction by radiation heating.

[0009] Preferably, the heating unit is a gas burner.

[0010] Preferably, a flue is further provided on the furnace shell, and the flue is used to connect the compartment with the outside.

[0011] Preferably, a first conical portion is provided on the top of the furnace cavity, the large end of the first conical portion is connected to the furnace cavity, and the small end of the first conical portion is connected to the gas discharge port for collecting the gas.

[0012] Preferably, a second conical portion is provided at the bottom of the furnace chamber, the large end of the second conical portion is connected to the furnace chamber, and the small end of the second conical portion is connected to the slag outlet for gathering materials.

[0013] Preferably, the slag outlet includes a straight cylindrical portion connected to the small end of the second tapered portion, and at least two branch pipes are provided at the bottom of the straight cylindrical portion.

[0014] In this technical solution, a spacer is provided between the furnace shell and the furnace chamber to house the heating unit. Furthermore, the sidewalls of the furnace chamber are radiant walls. This utilizes radiant heating to provide the heat source required for the reduction reaction, enabling the heating unit to uniformly heat the furnace chamber. Furthermore, radiant heating eliminates oxidation during the gasification process, simplifying reaction conditions. The operator can control the temperature simply by adjusting the gas supply to the heating unit.

[0015] By evenly arranging multiple spray guns in a circumferential direction at the bottom of the furnace shell, the multiple spray guns work together to increase the amount of material added per unit time, improve overall production efficiency, and meet the needs of large-scale industrial production. A mixing chamber, a raw material inlet, and a reducing gas inlet are provided inside the spray gun. The reducing gas inlet and the raw material inlet are both connected to the mixing chamber, so that the reduced material and the reducing gas are mixed in the mixing chamber and then sprayed into the furnace cavity in parallel, giving it the gasification characteristics of an entrained flow bed. A gas supply channel is also provided at the bottom of the furnace cavity to replenish reducing gas into the furnace cavity to enhance the convection and mixing effects of the gas in the furnace cavity and improve the reaction efficiency. The air inlet direction of the gas supply channel is parallel to the feeding channel and is arranged below the feeding channel to form an upward airflow. When the reduced material and the reducing gas enter the furnace chamber in parallel, under the guidance of the feeding channel and the spraying action of the spray gun, the mixture formed by the reduced material and the reducing gas collides violently at the intersection in the furnace chamber. At the same time, the rising airflow provides an additional upward force for the mixture formed by the reduced material and the reducing gas, so that the reduced material is not only driven by the spraying force of the spray gun in the furnace, but also supported and dispersed by the rising airflow. The dual force makes it easier for the reduced material to disperse in the furnace chamber and form a more uniform distribution, so that the reduced material forms a more intense boiling state in the furnace chamber, thereby increasing the reaction rate, which is similar to the gasification characteristics of a fluidized bed.

[0016] Another object of the present invention is to provide a reduction reaction method for a radiation heating type reduction furnace, which has simple steps and is easy to implement, while achieving deep fusion and rapid reaction of the reduced material and reducing gas in the furnace chamber.

[0017] In order to achieve the above object, the present invention adopts the following technical solutions:

[0018] A reduction reaction method in a radiation heating type reduction furnace comprises the following steps:

[0019] Preheating step: Use a gas burner to heat the inner wall of the reduction furnace to above 600 degrees to form a radiation heating environment;

[0020] Gas preparation step: preparing reducing gas, wherein the reducing gas is at least one of steam, hydrogen, and carbon monoxide, and pressurizing the reducing gas;

[0021] Material preparation steps: Grind the reduced material into a powder with a diameter of less than 3 mm;

[0022] Auxiliary air flow introduction: the reducing gas is introduced into the furnace chamber from the gas supply channel;

[0023] Mixing and spraying step: the pressurized reducing gas is introduced into the mixing chamber of the spray gun through the reducing gas inlet and the prepared materials are introduced into the raw material inlet in a certain proportion, and then the mixed materials are sprayed into the furnace cavity.

[0024] Reaction control step: Use the gas burner to continue heating the inner wall of the furnace chamber until the temperature reaches the reduction requirement. Use the computer-aided system to monitor and adjust the gas flow and material supply in the furnace chamber to meet the needs of the reduction reaction;

[0025] Product discharge step: After the reaction reaches equilibrium, the reduced material or ash is discharged through the slag outlet at the bottom of the furnace chamber, and the reacted gas is discharged through the gas discharge port at the top of the furnace chamber, and the discharged gas is purified.

[0026] In the above technical solution, the following technical effects are achieved through step-by-step control:

[0027] 1. Improve thermal efficiency: During the preheating step, a gas burner is used to heat the inner wall of the reduction furnace to over 600 degrees Celsius, creating a radiant heating environment. This avoids energy loss in traditional heat conduction paths and achieves efficient heat transfer and rapid temperature rise.

[0028] 2. Enhanced mixing uniformity: By mixing powdered materials (particle size less than 3mm) with pressurized reducing gas in the spray gun mixing chamber and then spraying them into the furnace cavity in parallel, the rapid mixing of materials and reducing gas is promoted, thereby improving the reaction efficiency;

[0029] 3. Intelligent dynamic control: Based on the computer-aided system, the reducing gas flow rate and material ratio data in the furnace chamber are fed back in real time to eliminate manual operation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the top structure of the present invention.

[0032] In the figure, 1 is a furnace chamber; 11 is a feeding channel; 12 is a radiation wall; 13 is a gas exhaust port; 14 is a slag outlet; 141 is a straight cylindrical portion; 142 is a branch pipe; 15 is a first tapered portion; 16 is a second tapered portion; 2 is a furnace shell; 3 is a partition; 31 is a flue; 4 is a spray gun; 41 is a mixing chamber; 42 is a raw material inlet; 43 is a reducing gas inlet; 5 is a gas feeding channel. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings:

[0034] like Figure 1 and Figure 2As shown, a high-efficiency radiation-heating reduction furnace includes a cylindrical furnace chamber 1. The furnace chamber 1 serves as the core area for the reduction reaction. A gas exhaust port 13 is provided at the top for discharging the reacted gas, and a slag outlet 14 is provided at the bottom of the furnace chamber 1 for discharging the slag. A furnace shell 2 is sheathed on the side wall of the furnace chamber 1. A partition 3 is provided between the furnace shell 2 and the furnace chamber 1 to accommodate the heating unit. At the same time, the side wall of the furnace chamber 1 is a radiation wall 12 made of silicon carbide. The radiation heating method provides the heat source required for the reduction reaction, allowing the heating unit to uniformly heat the furnace chamber 1. In addition, the use of radiation heating eliminates oxidation reactions during the gasification process, thereby simplifying the reaction conditions. The operator only needs to adjust the gas supply to the heating unit to control the temperature, reducing the difficulty of operation.

[0035] The heating unit can adopt a gas burner, and the output of radiant heat energy can be adjusted according to the specific process requirements, so as to realize the control of the reaction temperature in the furnace chamber 1. A plurality of spray guns 4 are evenly arranged along the circumference of the bottom of the furnace shell 2, preferably six, and the plurality of spray guns 4 work together to increase the feeding amount per unit time, improve the overall production efficiency, and meet the needs of large-scale industrial production. The number of feeding channels 11 corresponds to the number of spray guns 4, and the spray guns 4 are connected to the furnace chamber 1 through the feeding channels 11. An acute angle is formed between each feeding channel 11 and the longitudinal center line of the furnace chamber 1. The extension lines of the plurality of feeding channels 11 intersect in the internal space of the furnace chamber 1 and converge at a point or a small area. The convergence point or area is located on the longitudinal center line of the furnace chamber 1. The spray gun 4 is provided with a mixing chamber 41, a raw material inlet 42, and a reducing gas inlet 43. The reducing gas inlet 43 and the raw material inlet 42 are both connected to the mixing chamber 41. The reduced material is added to the mixing chamber 41 through the raw material inlet 42, and the reducing gas is added to the mixing chamber 41 through the reducing gas inlet 43. The reduced material and the reducing gas are mixed in the mixing chamber 41 and then sprayed into the furnace chamber 1 in parallel, which promotes the rapid mixing of the reduced material and the reducing gas, improves the reaction efficiency, and makes it have the gasification characteristics of an entrained flow bed. An air supply channel 5 is also provided at the bottom of the furnace chamber 1 for replenishing reducing gas into the furnace chamber 1 to enhance the convection and mixing effect of the reducing gas and the reduced material in the furnace chamber 1 and improve the reaction efficiency. The air supply channel 5 is parallel to the feeding channel 11 and is arranged below the feeding channel 11 to form an upward airflow. When the reduced material and reducing gas enter the furnace chamber 1 in parallel flow, the mixture of the reduced material and reducing gas violently collides at the intersection within the furnace chamber 1, guided by the feeding channel 11 and sprayed by the lance 4. Simultaneously, the rising airflow provides additional upward force to the reduced material within the furnace chamber 1, so that the reduced material is not only propelled by the lance spray, but also lifted and dispersed by the rising airflow. This dual force makes it easier to disperse the reduced material within the furnace chamber 1, forming a more uniform distribution. This leads to a more intense boiling state within the furnace chamber 1, allowing the reducing gas and the reduced material to fully contact each other, thereby improving the reaction rate and efficiency, similar to the gasification characteristics of a fluidized bed. The furnace shell 2 is also provided with a flue 31, which connects the compartment 3 to the outside world and discharges the flue gas after the fuel burner combustion.

[0036] The top of the furnace chamber 1 is provided with a first tapered portion 15. The large end of the first tapered portion 15 is connected to the furnace chamber 1, and the small end is connected to the gas discharge port 13, which is used to collect the reacted gases for easy discharge. The bottom of the furnace chamber 1 is provided with a second tapered portion 16. The large end of the second tapered portion 16 is connected to the furnace chamber 1, and the small end is connected to the slag outlet 14, which is used to collect materials for easy discharge. The slag outlet 14 includes a straight cylindrical portion 141 connected to the small end of the second tapered portion 16. At the bottom of the straight cylindrical portion 141, there are at least two branch pipes 142. The two branch pipes 142 can serve as backup for subsequent processing or collection.

[0037] Operational process: When using the radiation-heating reduction furnace of the present invention, the temperature inside the furnace must first be heated to above 600 degrees Celsius using gas or electricity, and the valve of the gas supply channel 5 is opened to blow reducing gas into the furnace. Then, reducing gas is added to the spray gun 4 through the reducing gas inlet 43. Powdered reduced material is added to the spray gun 4 through the raw material inlet 42. After mixing in the mixing chamber 41, the powdered reduced material is sprayed into the furnace chamber 1 in parallel. The gas supply is then adjusted from small to large until the temperature of the furnace chamber 1 reaches the required reduction temperature and the reaction reaches equilibrium.

[0038] During the reaction process, the reducing gas flow rate and the supply of the reduced material in the furnace chamber 1 are monitored and adjusted by a computer-aided system to meet the needs of the reduction reaction. The gas after the reaction is discharged from the gas exhaust port 13; the reduced material or ash is discharged from the slag outlet 14; and the flue gas after combustion is discharged from the flue 31.

[0039] The present invention relates to a reduction reaction method of a radiation heating type reduction furnace, comprising the following steps:

[0040] 1. Preheating step: Use a gas burner to heat the temperature in the reduction furnace chamber 1 to above 600 degrees to form a radiant heating environment;

[0041] 2. Gas preparation step: preparing reducing gas, which is at least one of steam, hydrogen, and carbon monoxide, and pressurizing it;

[0042] 3. Material preparation step: Grind the reduced material into a powder with a diameter of less than 3 mm;

[0043] 4. Auxiliary air flow introduction: the reducing gas is introduced into the furnace chamber 1 from the gas supply channel 5;

[0044] 5. Mixing and spraying step: the pressurized reducing gas is introduced into the mixing chamber 41 of the spray gun 4 through the reducing gas inlet 43 and the prepared materials are introduced into the mixing chamber 41 of the spray gun 4 through the raw material inlet 42 in a certain proportion. After being mixed in the mixing chamber 41, they are sprayed into the furnace chamber 1 in parallel;

[0045] 6. Reaction control step: Use the gas burner to continue heating the furnace chamber 1 until the temperature reaches the reduction requirement, and monitor and adjust the reducing gas flow and material supply in the furnace chamber 1 through the computer-aided system to meet the needs of the reduction reaction;

[0046] 7. Product discharge step: After the reaction reaches equilibrium, the reduced product or ash is discharged through the slag outlet 14 at the bottom of the furnace chamber 1, and the reacted gas is discharged through the gas discharge port 13 at the top of the furnace chamber 1, and the discharged gas is purified.

[0047] Example 1: Coal-to-gas

[0048] The present invention is applied to the field of coal gasification, using a radiation heating type reduction furnace to carry out coal gasification reaction. Due to the use of radiation heating, the gasification agent can be pure steam, and the reduction products are mainly H2, CH4 and CO. The calorific value of the coal gas reaches (2500-3000Kcal / Nm 3 This high-value gas can be directly used in heating, synthetic ammonia, LNG, hydrogen smelting, power generation and other fields.

[0049] During operation, the gas burner first heats the furnace chamber 1 to 600 degrees Celsius. Coal is then ground into a powder with a diameter less than 3 mm and fed into the lance 4 through the raw material inlet 42. Pressurized steam is then fed into the lance through the reducing gas inlet 43. Steam is then sprayed into the furnace chamber 1 through the gas supply channel 5. The material and pressurized steam are then injected into the furnace chamber 1 in parallel through the lance 4. The combustion rate of the gas is then controlled to bring the temperature in the furnace chamber 1 to the coal gasification reaction temperature. During the reaction, a computer-aided system monitors and adjusts the steam flow rate and material supply within the furnace chamber 1 to ensure efficient reaction. The reacted gas is discharged through the gas exhaust port 13, and the ash is discharged through the slag outlet 14.

[0050] Example 2: Flash Ironmaking

[0051] The present invention is applied to the field of flash ironmaking, and uses a radiation-heated reduction furnace to carry out the reduction reaction of iron. Due to the use of radiation heating, hydrogen or gray hydrogen can be used as the reducing agent, achieving the purpose of energy saving and environmental protection.

[0052] During the specific operation, the gas burner first heats the temperature in the furnace chamber 1 to 600 degrees; then the iron ore is ground into a powder material with a diameter of less than 3 mm and added to the spray gun 4 through the raw material inlet 42. The pressurized hydrogen is added to the spray gun through the reducing gas inlet 43; then the hydrogen is sprayed into the furnace chamber 1 through the gas supply channel 5; then the material and the pressurized hydrogen are sprayed into the furnace chamber 1 in parallel through the spray gun 4. At this time, the combustion amount of the gas is controlled to make the temperature in the furnace chamber 1 reach the reduction reaction temperature of iron. During the reaction process, the computer-aided system monitors and adjusts the hydrogen flow rate and material supply in the furnace chamber 1 to ensure the efficient progress of the reaction. The molten iron or solid iron after the reaction (the temperature in the furnace chamber 1 is adjusted as needed so that the iron after the reaction is in the form of molten iron or solid iron) is discharged through the slag outlet 14, and the gas after the reaction is discharged through the gas exhaust port 13.

[0053] This embodiment is only an illustration of the concept and implementation of the present invention, and does not limit it. Under the concept of the present invention, technical solutions that have not been substantially changed are still within the scope of protection.

Claims

1. A radiation heating type reduction furnace, comprising a cylindrical furnace chamber, a charging channel provided on the furnace chamber, a gas discharge port provided at the top of the furnace chamber, and a slag outlet provided at the bottom of the furnace chamber, characterized in that: It also includes multiple spray guns, which include a mixing chamber, a raw material inlet and a reducing gas inlet. The reducing gas inlet and the raw material inlet are both connected to the mixing chamber. The number of the feeding channels corresponds to the number of the spray guns. The spray guns are connected to the furnace chamber through the feeding channels. The multiple spray guns are arranged along the circumferential direction of the bottom of the furnace shell, and each feeding channel forms an acute angle with the longitudinal center line of the furnace chamber; and the extension lines of the multiple feeding channels intersect in the internal space of the furnace chamber and converge at a point or a small area. The convergence point or area is located on the longitudinal center line of the furnace chamber.

2. The radiation heating type reduction furnace according to claim 1, characterized in that: A gas supply channel is also provided at the bottom of the furnace cavity. The gas supply channel is parallel to the feeding channel and is arranged below the feeding channel.

3. The radiation heating type reduction furnace according to claim 2, characterized in that: The furnace cavity side wall is sheathed with a furnace shell, and a partition is provided between the furnace shell and the furnace cavity, and the partition is used to hold the heating unit; the furnace cavity side wall is a radiation wall, which is used to provide the heat source required for the reduction reaction by radiation heating.

4. The radiation heating type reduction furnace according to claim 3, characterized in that: The heating unit is a gas burner.

5. The radiation heating type reduction furnace according to claim 4, characterized in that: A flue is also provided on the furnace shell, and the flue is used to connect the compartment with the outside.

6. The radiation heating type reduction furnace according to any one of claims 1 to 5, characterized in that: A first conical portion is provided on the top of the furnace cavity, wherein a large end of the first conical portion is connected to the furnace cavity, and a small end of the first conical portion is connected to a gas discharge port for collecting gas.

7. The radiation heating type reduction furnace according to claim 6, characterized in that: A second conical portion is provided at the bottom of the furnace cavity, a large end of the second conical portion is connected to the furnace cavity, and a small end of the second conical portion is connected to the slag outlet for gathering materials.

8. The radiation heating type reduction furnace according to claim 7, characterized in that: The slag outlet includes a straight cylindrical portion connected to the small end of the second tapered portion, and at least two branch pipes are provided at the bottom of the straight cylindrical portion.

9. A reduction reaction method using a radiation heating type reduction furnace, wherein the reduction furnace used in the reduction method is the reduction furnace according to any one of claims 1 to 5, characterized in that: The following steps are involved: Preheating step: Use gas to heat the inner wall of the reduction furnace to above 600 degrees to form a radiation heating environment; Gas preparation step: preparing reducing gas, wherein the reducing gas is at least one of steam, hydrogen, and carbon monoxide, and pressurizing the reducing gas; Material preparation steps: Grind the reduced material into a powder with a diameter of less than 3 mm; Mixing and spraying step: the pressurized reducing gas is introduced into the mixing chamber of the spray gun through the reducing gas inlet and the prepared materials are introduced into the raw material inlet in a certain proportion, and then the mixed materials are sprayed into the furnace cavity. Reaction control step: Use gas to continue heating the inner wall of the furnace chamber until the temperature reaches the reduction requirement. Use a computer-aided system to monitor and adjust the gas flow and material supply in the furnace chamber to meet the needs of the reduction reaction; Product discharge step: After the reaction reaches equilibrium, the reduced material or ash is discharged through the slag outlet at the bottom of the furnace chamber, and the reacted gas is discharged through the gas discharge port at the top of the furnace chamber, and the exhaust gas is purified.

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