Intermediate-temperature preheating smelting reduction ironmaking system

Abstract

The invention discloses a medium-temperature preheating smelting reduction ironmaking system, which comprises a smelting reduction furnace, a smelting reduction furnace, a preheating furnace and a preheating furnace, the waste heat recovery part is connected to the coal gas outlet so as to change the high-temperature coal gas into medium-temperature coal gas; the heat exchange device is connected to the waste heat recovery part and the carrier gas source, and the heat exchange device is used for carrying out heat exchange on the normal-temperature injection carrier gas and the medium-temperature coal gas conveyed by the waste heat recovery part so as to obtain medium-temperature injection carrier gas; the hot ore supply part is connected to the heat exchange device and the smelting reduction furnace, and the hot ore supply part is used for providing preheated hot iron ore powder and conveying the hot iron ore powder to the smelting reduction furnace through medium-temperature injection carrier gas; and the pulverized coal supply part is connected to the heat exchange device and the smelting reduction furnace and conveys pulverized coal to the smelting reduction furnace through medium-temperature injection carrier gas. Hot iron ore powder and pulverized coal are conveyed through medium-temperature injection carrier gas, heat preservation is conducted on the hot iron ore powder and the pulverized coal, heat loss is reduced, reduction reaction is facilitated, the coal ratio is reduced, the ironmaking yield is increased, and energy conservation and environment protection are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of non-blast furnace ironmaking, and particularly to a medium-temperature preheating smelting reduction ironmaking system. Background Art

[0002] At present, the non-blast furnace smelting reduction ironmaking process has gradually been recognized and promoted in the industry, but there are still problems such as high unit process energy consumption, high carbon emissions, waste of waste heat of smelting reduction gas, and insufficient reduction reaction with low output in smelting reduction ironmaking. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0004] To this end, the present invention provides a medium-temperature preheating smelting reduction ironmaking system.

[0005] In view of this, according to an embodiment of the present application, a medium-temperature preheating smelting reduction ironmaking system is proposed, including:

[0006] A smelting reduction furnace, which is provided with a gas discharge port;

[0007] A waste heat recovery unit, connected to the gas discharge port, for recovering and utilizing the heat energy of the high-temperature gas discharged through the gas discharge port to turn the high-temperature gas into medium-temperature gas;

[0008] A heat exchange device, connected to the waste heat recovery unit and a carrier gas source, for exchanging heat between the normal-temperature blowing carrier gas transported by the carrier gas source and the medium-temperature gas transported by the waste heat recovery unit to obtain medium-temperature blowing carrier gas;

[0009] A hot ore supply unit, respectively connected to the heat exchange device and the smelting reduction furnace, for providing preheated hot iron ore powder and transporting the hot iron ore powder to the smelting reduction furnace through the medium-temperature blowing carrier gas;

[0010] A pulverized coal supply unit, respectively connected to the heat exchange device and the smelting reduction furnace, for providing pulverized coal and transporting the pulverized coal to the smelting reduction furnace through the medium-temperature blowing carrier gas.

[0011] In a feasible embodiment, the temperature of the medium-temperature blowing carrier gas is 120°C to 240°C.

[0012] In a feasible embodiment, the waste heat recovery unit includes:

[0013] A waste heat recovery device, connected to the gas discharge port, for initially recovering and utilizing the heat energy of the high-temperature gas;

[0014] The waste heat boiler is connected to the above-mentioned waste heat recovery device and the above-mentioned gas input end. The waste heat boiler is used to recover and reuse the heat energy of the above-mentioned high-temperature gas, so as to convert the above-mentioned high-temperature gas into the above-mentioned medium-temperature gas and transport the above-mentioned medium-temperature gas to the above-mentioned heat exchange device.

[0015] In a feasible implementation manner, the above-mentioned medium-temperature preheating smelting reduction ironmaking system further includes:

[0016] A cyclone dust removal device is arranged between the above-mentioned waste heat recovery device and the above-mentioned waste heat boiler.

[0017] In a feasible implementation manner, the above-mentioned medium-temperature preheating smelting reduction ironmaking system further includes:

[0018] A gas dust removal device is respectively connected to the above-mentioned heat exchange device and the above-mentioned waste heat boiler, and is used for dust removal of the gas after heat exchange by the above-mentioned heat exchange device and a part of the above-mentioned medium-temperature gas discharged from the above-mentioned waste heat boiler.

[0019] In a feasible implementation manner, the dust content of the gas treated by the above-mentioned cyclone dust removal device is 5 g / Nm 3 ~20 g / Nm 3 ;

[0020] The dust content of the gas treated by the above-mentioned gas dust removal device is less than or equal to 5 mg / Nm 3 .

[0021] In a feasible implementation manner, the above-mentioned hot ore supply section includes:

[0022] A hot ore screw feeder is connected to the above-mentioned heat exchange device;

[0023] A hot ore injection device is used to inject the above-mentioned hot iron ore powder into the above-mentioned hot ore screw feeder;

[0024] A first spray gun is respectively connected to the above-mentioned hot ore screw feeder and the smelting reduction furnace, and is used to transport the above-mentioned hot iron ore powder to the above-mentioned smelting reduction furnace.

[0025] In a feasible implementation manner, the above-mentioned pulverized coal supply section includes:

[0026] A rotary coal feeder is connected to the above-mentioned heat exchange device, and the above-mentioned medium-temperature injection carrier gas is provided to the rotary coal feeder through the above-mentioned heat exchange device;

[0027] A pulverized coal injection device is used to inject the above-mentioned pulverized coal into the above-mentioned rotary coal feeder;

[0028] A second spray gun is respectively connected to the above-mentioned rotary coal feeder and the smelting reduction furnace, and is used to transport the above-mentioned pulverized coal heated and raised in temperature by heat exchange with the above-mentioned medium-temperature injection carrier gas to the above-mentioned smelting reduction furnace.

[0029] In a feasible implementation manner, the temperature of the above-mentioned hot iron ore powder is 600°C to 700°C, and the particle size is less than 10 mm;

[0030] The temperature of the pulverized coal blown into the above-mentioned rotary coal feeder by the above-mentioned pulverized coal injection device is 80°C to 200°C, and the particle size is less than 3 mm;

[0031] The temperature of the pulverized coal transported to the above-mentioned smelting reduction furnace by the above-mentioned second spray gun is greater than or equal to 80°C, and the particle size is less than 3 mm.

[0032] In a feasible implementation manner, the injection carrier gas stored in the above-mentioned carrier gas source is nitrogen or carbon dioxide.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects: The medium-temperature preheating smelting reduction ironmaking system provided by the embodiments of the present application is provided with a smelting reduction furnace, a waste heat recovery unit, a heat exchange device, a hot ore supply unit, and a pulverized coal supply unit. Among them, the smelting reduction furnace is provided with a gas discharge port, and the waste heat recovery unit is connected to the gas discharge port to recover and utilize the heat energy of the high-temperature gas discharged through the gas discharge port during the reduction reaction of the smelting reduction furnace. After the waste heat recovery unit absorbs the heat of the high-temperature gas, the high-temperature gas becomes medium-temperature gas. The heat exchange device is connected to the waste heat recovery unit and the carrier gas source. The carrier gas source can transport the normal-temperature injection carrier gas to the heat exchange device, and at the same time, the waste heat recovery unit transports the medium-temperature gas to the heat exchange device, so as to exchange heat between the normal-temperature injection carrier gas and the medium-temperature gas through the heat exchange device to obtain medium-temperature injection carrier gas. The hot ore supply unit is respectively connected to the heat exchange device and the smelting reduction furnace. The hot ore supply unit can provide preheated hot iron ore powder and transport the hot iron ore powder to the smelting reduction furnace through the medium-temperature injection carrier gas. The pulverized coal supply unit is respectively connected to the heat exchange device and the smelting reduction furnace. Pulverized coal is provided through the pulverized coal supply unit, and the pulverized coal is transported to the smelting reduction furnace through the medium-temperature injection carrier gas. With such a setting, the heat of the gas can be recovered and utilized by the waste heat recovery unit, and while preparing the medium-temperature injection carrier gas, energy waste can be reduced. The pulverized coal is used as a reducing agent, which is beneficial to the reduction reaction. During the process of transporting the pulverized coal through the medium-temperature injection carrier gas, the medium-temperature injection carrier gas can heat the pulverized coal to increase the temperature of the pulverized coal and further improve the reduction effect. During the process of transporting the hot iron ore powder through the medium-temperature injection carrier gas, the medium-temperature injection carrier gas can keep the hot iron ore powder warm to reduce the heat loss of the hot iron ore powder, which is beneficial to the reduction reaction of the hot iron ore powder, reduce the amount of pulverized coal used to reduce the coal ratio, reduce the carbon emissions during the smelting reduction ironmaking process, and increase the ironmaking output. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] By reading the detailed description of the exemplary embodiments below, various other advantages and benefits will become apparent to those of ordinary skill in the art. The drawings are only for the purpose of showing the exemplary embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0035] Figure 1 Schematic structural diagram of a medium-temperature preheating smelting reduction ironmaking system according to an embodiment provided by the present application.

[0036] Among them, Figure 1 The corresponding relationship between the reference numerals and the component names in the drawings is as follows:

[0037] 10 Smelting reduction furnace, 11 Heat exchange device, 12 Hot ore screw feeder, 13 Rotary coal feeder, 14 Waste heat recovery device, 15 Cyclone dust removal device, 16 Waste heat boiler, 17 Gas dust removal device, 18 Hot ore injection device, 19 First spray gun, 20 Pulverized coal injection device, 21 Second spray gun. Detailed implementation manners

[0038] The exemplary embodiments of the present application will be described in more detail below with reference to the drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0039] As Figure 1 shown, according to an embodiment of the present application, a medium-temperature preheating smelting reduction ironmaking system is proposed, including: a smelting reduction furnace 10, the smelting reduction furnace 10 is provided with a gas discharge port; a waste heat recovery section, connected to the gas discharge port, for recovering and utilizing the heat energy of the high-temperature gas discharged through the gas discharge port to turn the high-temperature gas into medium-temperature gas; a heat exchange device 11, connected to the waste heat recovery section and the carrier gas source, the heat exchange device 11 is used for heat exchange between the normal-temperature injection carrier gas transported by the carrier gas source and the medium-temperature gas transported by the waste heat recovery section to obtain medium-temperature injection carrier gas; a hot ore supply section, respectively connected to the heat exchange device 11 and the smelting reduction furnace 10, the hot ore supply section is used for providing preheated hot iron ore powder, and transporting the hot iron ore powder to the smelting reduction furnace 10 through the medium-temperature injection carrier gas; a pulverized coal supply section, respectively connected to the heat exchange device 11 and the smelting reduction furnace 10, the pulverized coal supply section is used for providing pulverized coal, and transporting the pulverized coal to the smelting reduction furnace 10 through the medium-temperature injection carrier gas.

[0040] It can be understood that the medium-temperature preheating smelting reduction ironmaking system provided by the embodiments of the present application is provided with a smelting reduction furnace 10, a waste heat recovery unit, a heat exchange device 11, a hot ore supply unit, and a pulverized coal supply unit. Among them, the smelting reduction furnace 10 is provided with a gas discharge port, and the waste heat recovery unit is connected to the gas discharge port to recover and utilize the heat energy of the high-temperature gas discharged from the gas discharge port during the reduction reaction of the smelting reduction furnace 10. After the waste heat recovery unit absorbs the heat of the high-temperature gas, the high-temperature gas becomes medium-temperature gas. The heat exchange device 11 is connected to the waste heat recovery unit and the carrier gas source. The carrier gas source can transport the normal-temperature injection carrier gas to the heat exchange device 11, and at the same time, the waste heat recovery unit transports the medium-temperature gas to the heat exchange device 11, so as to exchange heat between the normal-temperature injection carrier gas and the medium-temperature gas through the heat exchange device 11 to obtain the medium-temperature injection carrier gas. The hot ore supply unit is respectively connected to the heat exchange device 11 and the smelting reduction furnace 10. The hot ore supply unit can provide preheated hot iron ore powder and transport the hot iron ore powder to the smelting reduction furnace 10 through the medium-temperature injection carrier gas. The pulverized coal supply unit is respectively connected to the heat exchange device 11 and the smelting reduction furnace 10. Pulverized coal is provided through the pulverized coal supply unit, and the pulverized coal is transported to the smelting reduction furnace 10 through the medium-temperature injection carrier gas. With such a setting, the heat energy of the gas can be recovered and utilized by the waste heat recovery unit. While preparing the medium-temperature injection carrier gas, energy waste can be reduced. The pulverized coal is beneficial to the reduction reaction as a reducing agent, and during the process of transporting the pulverized coal through the medium-temperature injection carrier gas, the medium-temperature injection carrier gas can heat the pulverized coal to increase the temperature of the pulverized coal and further improve the reduction effect. During the process of transporting the hot iron ore powder through the medium-temperature injection carrier gas, the medium-temperature injection carrier gas can keep the hot iron ore powder warm to reduce the heat loss of the hot iron ore powder, which is beneficial to the reduction reaction of the hot iron ore powder, reduce the amount of pulverized coal used to reduce the coal ratio, reduce the carbon emission during the smelting reduction ironmaking process, and increase the ironmaking output.

[0041] It should be noted that the injection carrier gas can be selected from inert gases and gases that do not affect the reduction reaction.

[0042] In some examples, the temperature of the above-mentioned medium-temperature injection carrier gas is 120°C to 240°C.

[0043] It can be understood that the temperature of the medium-temperature injection carrier gas is 120°C to 240°C to keep the hot iron ore powder warm and reduce the heat loss of the hot iron ore powder.

[0044] In some examples, as Figure 1 shown, the above-mentioned waste heat recovery unit includes: a waste heat recovery device 14, connected to the above-mentioned gas discharge port, for initially recovering and utilizing the heat energy of the above-mentioned high-temperature gas; a waste heat boiler 16, connected to the above-mentioned waste heat recovery device 14 and the above-mentioned gas input end, and the waste heat boiler 16 is used to recover and utilize the heat energy of the above-mentioned high-temperature gas again to change the above-mentioned high-temperature gas into the above-mentioned medium-temperature gas and transport the above-mentioned medium-temperature gas to the transport heat exchange device 11.

[0045] It can be understood that the waste heat recovery section is provided with a waste heat recovery device 14 and a waste heat boiler 16. Among them, the waste heat recovery device 14 is connected to the gas discharge port and is used to receive the high-temperature gas generated after the reduction reaction in the smelting reduction furnace 10. The temperature of the high-temperature gas is 1400°C to 1600°C, and the pressure of the high-temperature gas is 0.08 MPa to 0.25 MPa. The waste heat recovery device 14 recovers and utilizes the heat of the high-temperature gas to improve the thermal energy utilization rate and reduce thermal energy waste. Under the action of the waste heat recovery device 14, the temperature of the high-temperature gas drops to 750°C to 850°C, and the pressure is 0.08 MPa to 0.25 MPa. The waste heat boiler 16 is connected to the waste heat recovery device 14 and the gas input end. After the waste heat recovery device 14 transports the gas that has absorbed heat energy to the waste heat boiler 16, the waste heat boiler 16 recovers and utilizes the heat of the gas again to improve the thermal energy utilization rate and reduce thermal energy waste. After the action of the waste heat boiler 16, the temperature of the gas becomes 150°C to 250°C, and the pressure is 0.08 MPa to 0.25 MPa. Thus, under the action of the waste heat recovery device 14 and the waste heat boiler 16, the high-temperature gas is changed into medium-temperature gas to facilitate heat exchange with normal-temperature injection carrier gas.

[0046] In some examples, such as Figure 1 shown, the above medium-temperature preheating smelting reduction ironmaking system further includes: a cyclone dust removal device 15, which is arranged between the above waste heat recovery device 14 and the above waste heat boiler 16.

[0047] It can be understood that the medium-temperature preheating smelting reduction ironmaking system can also be provided with a cyclone dust removal device 15. Specifically, the cyclone dust removal device 15 is arranged between the waste heat recovery device 14 and the waste heat boiler 16. The cyclone dust removal device 15 removes some dust in the gas transported from the waste heat recovery device 14 to the waste heat boiler 16 to improve the purity of the gas. Specifically, the dust content of the high-temperature gas generated after the reduction reaction in the smelting reduction furnace 10 is 20 g / Nm 3 to 50 g / Nm 3 , and after the waste heat recovery device 14 absorbs heat, the dust content of the gas remains unchanged. After the gas is transported to the cyclone dust removal device 15 for action, the dust content of the gas can be reduced to 5 g / Nm 3 to 20 g / Nm 3 to improve the purity of the gas. And the temperature of the gas at the inlet of the cyclone dust removal device 15 is 750°C to 850°C. After the dust removal operation of the cyclone dust removal device 15, part of the heat is lost, and the heat of the gas becomes 700°C to 840°C.

[0048] In some examples, such as Figure 1As shown, the above-mentioned medium-temperature preheating molten reduction ironmaking system also includes: a coal gas dust removal device 17, which is respectively connected to the above-mentioned heat exchange device 11 and the above-mentioned waste heat boiler 16, and is used to remove dust from the coal gas after heat exchange in the above-mentioned heat exchange device 11 and part of the above-mentioned medium-temperature coal gas discharged from the above-mentioned waste heat boiler 16.

[0049] It is understandable that the medium-temperature preheating molten reduction ironmaking system may also be provided with a gas dust removal device 17. Specifically, the gas dust removal device 17 is connected to the heat exchange device 11 and the waste heat boiler 16, respectively. Among them, the gas dust removal device 17 is connected to the heat exchange device 11, and part of the medium-temperature coal gas treated by the waste heat boiler 16 enters the heat exchange device 11, so that the medium-temperature coal gas and the normal temperature injection carrier gas are heat exchanged through the heat exchange device 11, which is conducive to improving the heat exchange efficiency of the heat exchange device 11, increasing the temperature of the injection carrier gas, and reducing the dust accumulation phenomenon of the heat exchange device 11. The medium-temperature coal gas after heat exchange in the heat exchange device 11 becomes medium-low temperature coal gas, and the medium-low temperature coal gas is transported to the coal gas dust removal device 17 to remove dust through the coal gas dust removal device 17 to further improve the purity of the coal gas. Another part of the medium-temperature coal gas and the medium-low temperature coal gas treated by the waste heat boiler 16 are combined and transported to the coal gas dust removal device 17 for purification, so as to output medium-low temperature pure coal gas for easy use. The dust content of the low-temperature pure coal gas after being purified by the coal gas dust removal device 17 is less than or equal to 5 mg / Nm 3 , and the pressure value is 0.08MPa to 0.25MPa.

[0050] It is understandable that the coal gas dust removal device 17 can use a dry dust removal device to further reduce the energy consumption of the dust removal operation, which is beneficial to improve the cleanliness of the coal gas while further improving the energy saving of smelting reduction smelting.

[0051] In some examples, the dust content of the coal gas after being treated by the cyclone dust removal device 15 is 5g / Nm 3 ~20g / Nm 3 The dust content of the gas after being treated by the above-mentioned gas dust removal device 17 is less than or equal to 5mg / Nm 3 .

[0052] It is understood that the gas temperature delivered to the heat exchange device 11 by the waste heat boiler 16 is 150°C to 250°C, the pressure is 0.08MPa to 0.25MPa, and the dust content is 5g / Nm 3 Up to 20g / Nm 3 The temperature of the normal temperature spray carrier gas delivered to the heat exchange device 11 is 0°C to 40°C, the pressure is 0.8MPa to 1.0MPa, and the dust content is less than or equal to 5mg / Nm 3; The medium-temperature injection carrier gas and the medium-low temperature coal gas are obtained after the normal-temperature injection carrier gas and the medium-temperature coal gas are heat-exchanged. Among them, the temperature of the medium-temperature injection carrier gas is 120°C to 240°C, the pressure is 0.8 MPa to 1.0 MPa, and the dust content is less than or equal to 5 mg / Nm 3 ; The temperature of the medium-low temperature coal gas is 120°C to 250°C, the pressure is 0.08 MPa to 0.25 MPa, and the dust content is 5 g / Nm 3 to 20 g / Nm 3 .

[0053] In some examples, as Figure 1 shown, the above-mentioned hot ore supply unit includes: a hot ore screw feeder 12, connected to the above-mentioned heat exchange device 11; a hot ore injection device 18, used to inject the above-mentioned hot iron ore powder into the above-mentioned hot ore screw feeder 12; a first spray gun 19, respectively connected to the above-mentioned hot ore screw feeder 12 and the smelting reduction furnace 10, and used to transport the above-mentioned hot iron ore powder to the above-mentioned smelting reduction furnace 10.

[0054] It can be understood that the hot ore supply unit can be provided with a hot ore screw feeder 12, a hot ore injection device 18 and a first spray gun 19. Among them, the hot ore injection device 18 can inject the preheated hot iron ore powder into the hot ore screw feeder 12, and transport the hot iron ore powder into the smelting reduction furnace 10 through the first spray gun 19. Specifically, the hot ore screw feeder 12 is connected to the heat exchange device 11, and the heat exchange device 11 can transport the medium-temperature injection carrier gas to the hot ore screw feeder 12, so that while transporting the hot iron ore powder through the medium-temperature injection carrier gas, the hot iron ore powder is heat-insulated, reducing the temperature loss of the hot iron ore powder, which is beneficial to the reduction reaction, improves the output, reduces the coal ratio, and saves energy and protects the environment.

[0055] In some examples, as Figure 1 shown, the above-mentioned pulverized coal supply unit includes: a rotary coal feeder 13, connected to the above-mentioned heat exchange device 11, and the above-mentioned heat exchange device 11 provides the above-mentioned medium-temperature injection carrier gas for the above-mentioned rotary coal feeder 13; a pulverized coal injection device 20, used to inject the above-mentioned pulverized coal into the above-mentioned rotary coal feeder 13; a second spray gun 21, respectively connected to the above-mentioned rotary coal feeder 13 and the smelting reduction furnace 10, and used to transport the above-mentioned pulverized coal heated and raised in temperature by heat exchange with the above-mentioned medium-temperature injection carrier gas to the above-mentioned smelting reduction furnace 10.

[0056] It is understandable that the pulverized coal supply section may be provided with a rotary coal feeder 13, a pulverized coal injection device 20, and a second spray gun 21. Among them, the pulverized coal injection device 20 can inject the preheated pulverized coal into the rotary coal feeder 13, and convey the pulverized coal into the smelting reduction furnace 10 through the second spray gun 21. Specifically, the rotary coal feeder 13 is connected to the heat exchange device 11, and the heat exchange device 11 can convey medium-temperature injection carrier gas to the rotary coal feeder 13, so that while conveying the pulverized coal through the medium-temperature injection carrier gas, the pulverized coal is insulated, and the combustion of the pulverized coal during the conveying process due to excessive temperature is avoided, the reliability is improved, and the temperature of the pulverized coal is more suitable for the reduction reaction, which is beneficial to the progress of the reduction reaction, thereby achieving increased output, reduced coal ratio, energy conservation and environmental protection.

[0057] In some examples, the injection carrier gas stored in the above carrier gas source is nitrogen or carbon dioxide.

[0058] It is understandable that the injection carrier gas can be selected from nitrogen or carbon dioxide. The gas has a large stock, low price, mature transportation and storage technology, and will not affect the reduction reaction, with high reliability.

[0059] In some examples, the temperature of the above hot iron ore powder is 600°C to 700°C, and the particle size is less than 10 mm; the temperature of the pulverized coal injected into the above rotary coal feeder 13 by the above pulverized coal injection device 20 is 80°C to 200°C, and the particle size is less than 3 mm; the temperature of the pulverized coal conveyed to the above smelting reduction furnace 10 through the above second spray gun 21 is greater than or equal to 80°C, and the particle size is less than 3 mm.

[0060] It is understandable that the temperature of the preheated hot iron ore powder is 600°C to 700°C, and the particle size is less than 10 mm. After the preheated hot iron ore powder and the medium-temperature injection carrier gas are mixed, the temperature of the hot iron ore powder conveyed to the first spray gun 19 is greater than or equal to 600°C. The temperature of the preheated pulverized coal is 80°C to 200°C, and the particle size is less than 3 mm. After the preheated pulverized coal and the medium-temperature injection carrier gas are mixed, the temperature of the pulverized coal conveyed to the second spray gun 21 is greater than or equal to 80°C. So that the temperatures of the hot iron ore powder and the pulverized coal are more suitable for the reduction reaction, which is beneficial to the progress of the reduction reaction, thereby achieving increased output, reduced coal ratio, energy conservation and environmental protection.

[0061] In the present invention, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plural" means two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected to", "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. These terms are only used for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0063] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A medium-temperature preheating smelting reduction ironmaking system, characterized in that, Comprising: A smelting reduction furnace provided with a gas discharge outlet; A waste heat recovery section connected to the gas discharge outlet for recovering and utilizing the heat energy of the high-temperature gas discharged through the gas discharge outlet to convert the high-temperature gas into medium-temperature gas; A heat exchange device connected to the waste heat recovery section and a carrier gas source, the heat exchange device being used for heat exchange between the normal-temperature injection carrier gas transported by the carrier gas source and the medium-temperature gas transported by the waste heat recovery section to obtain medium-temperature injection carrier gas; A hot ore supply section respectively connected to the heat exchange device and the smelting reduction furnace, the hot ore supply section being used for providing preheated hot iron ore powder and transporting the hot iron ore powder to the smelting reduction furnace through the medium-temperature injection carrier gas; A pulverized coal supply section respectively connected to the heat exchange device and the smelting reduction furnace, the pulverized coal supply section being used for providing pulverized coal and transporting the pulverized coal to the smelting reduction furnace through the medium-temperature injection carrier gas.

2. The medium-temperature preheating smelting reduction ironmaking system according to claim 1, characterized in that The temperature of the medium-temperature injection carrier gas is 120°C to 240°C.

3. The medium-temperature preheating smelting reduction ironmaking system according to claim 1, wherein The waste heat recovery section includes: A waste heat recovery device connected to the gas discharge outlet for initially recovering and utilizing the heat energy of the high-temperature gas; A waste heat boiler connected to the waste heat recovery device and the gas input end, the waste heat boiler being used for re-recovering and utilizing the heat energy of the high-temperature gas to convert the high-temperature gas into the medium-temperature gas and transporting the medium-temperature gas to the heat exchange device.

4. The medium-temperature preheating smelting reduction ironmaking system according to claim 2, wherein, It further includes: A cyclone dust removal device provided between the waste heat recovery device and the waste heat boiler.

5. The medium-temperature preheating smelting reduction ironmaking system according to claim 4, wherein It further includes: A gas dust removal device respectively connected to the heat exchange device and the waste heat boiler for dust removal of the gas after heat exchange by the heat exchange device and a part of the medium-temperature gas discharged from the waste heat boiler.

6. The medium-temperature preheating smelting reduction ironmaking system according to claim 5, characterized in that The dust content of the gas after being treated by the cyclone dust removal device is 5g / Nm 3 ~20g / Nm 3 ; The dust content of the gas treated by the gas dust removal device is less than or equal to 5 mg / Nm 3 .

7. The medium-temperature preheating smelting reduction ironmaking system according to claim 1, wherein, The hot ore supply section includes: A hot ore screw feeder connected to the heat exchange device; A hot ore injection device for injecting the hot iron ore powder into the hot ore screw feeder; A first spray gun respectively connected to the hot ore screw feeder and the smelting reduction furnace for transporting the hot iron ore powder to the smelting reduction furnace.

8. The medium-temperature preheating smelting reduction ironmaking system according to claim 7, wherein The pulverized coal supply section includes: A rotary coal feeder connected to the heat exchange device, and the heat exchange device provides the medium-temperature injection carrier gas for the rotary coal feeder; A pulverized coal injection device for injecting the pulverized coal into the rotary coal feeder; A second spray gun respectively connected to the rotary coal feeder and the smelting reduction furnace for transporting the pulverized coal heated by heat exchange with the medium-temperature injection carrier gas to the smelting reduction furnace.

9. The medium-temperature preheating smelting reduction ironmaking system according to claim 8, characterized in that The temperature of the hot iron ore powder is 600°C to 700°C and the particle size is less than 10 mm; The temperature of the pulverized coal injected into the rotary coal feeder by the pulverized coal injection device is 80°C to 200°C and the particle size is less than 3 mm; The temperature of the pulverized coal transported to the smelting reduction furnace through the second spray gun is greater than or equal to 80°C and the particle size is less than 3 mm.

10. The medium-temperature preheating smelting reduction ironmaking system according to any one of claims 1 to 9, characterized in that the injection carrier gas stored in the carrier gas source is nitrogen or carbon dioxide.

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