Flash furnace flue molten salt waste heat recovery system

Abstract

The utility model discloses flash furnace flue molten salt waste heat recovery system, include: flash furnace, and flash furnace includes reaction tower and molten pool, and is equipped with the heat exchanger for absorbing flue gas heat in the flue, the heat storage part includes hot molten salt jar and cold molten salt jar, and hot molten salt jar and cold molten salt jar are used to store molten salt, and the outlet of cold molten salt jar is connected with the molten salt import of heat exchanger through first pipe line, and the molten salt export of heat exchanger is connected with the import of hot molten salt jar through second pipe line, the preheater, and the molten salt import of preheater is connected with the outlet of hot molten salt jar through third pipe line, and the molten salt export of preheater is connected with the import of cold molten salt jar through fourth pipe line, and the cold source export of preheater is connected with the import of reaction tower, and the cold source import of preheater can be at least one of air and mineral powder. Therefore, according to the flash furnace flue molten salt waste heat recovery system of the utility model can realize the efficient nearby reuse system of waste heat and high safety.

Description

Technical Field

[0001] This utility model relates to the field of metallurgical technology, specifically to a flash furnace flue molten salt waste heat recovery system. Background Technology

[0002] In the metallurgical industry, flash furnaces are key equipment in the smelting of copper-nickel sulfide ores. The high-temperature flue gas (approximately 1200-1400℃) generated during the smelting process passes sequentially through an ascending flue (reduced to 1000℃) and a horizontal flue (reduced to 800-1000℃) before finally entering the waste heat boiler system. In related technologies, water-cooled walls are commonly used for flue gas duct protection, requiring the flue gas sidewall temperature to be <600℃ to prevent slagging; this temperature allows for a significant margin. Circulating water or boiler makeup water is circulated through the internal pipes of the water-cooled walls for cooling, and high pressure is maintained within the pipes to suppress cooling water vaporization. This flue gas cooling and protection method results in significant heat loss and prominent safety hazards. If the water-cooled wall pipes rupture, the leaking cooling water coming into contact with the high-temperature molten pool (such as slag) can trigger a steam explosion, threatening equipment and personnel safety. Furthermore, there are issues with fuel dependence and ash accumulation: to maintain the furnace temperature, a certain amount of fuel (such as pulverized coal and heavy oil) needs to be injected, which not only increases production costs but also generates additional emissions due to fuel combustion. At the same time, pulverized coal ash tends to accumulate in the furnace, reducing heat transfer efficiency and exacerbating the erosion of refractory materials. Utility Model Content

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a flash furnace flue molten salt waste heat recovery system.

[0004] The flash furnace flue molten salt waste heat recovery system of this utility model embodiment includes: A flash furnace, comprising a reaction tower and a molten pool, wherein the outlet of the reaction tower is connected to the inlet of the molten pool, the flue gas outlet of the molten pool is connected to the inlet of a flue, and a heat exchanger for absorbing heat from the flue gas is provided in the flue. The heat storage unit includes a hot molten salt tank and a cold molten salt tank, which are used to store molten salt. The outlet of the cold molten salt tank is connected to the molten salt inlet of the heat exchanger through a first pipeline, and the molten salt outlet of the heat exchanger is connected to the inlet of the hot molten salt tank through a second pipeline. The preheater has a molten salt inlet connected to the outlet of the hot molten salt tank via a third pipe, a molten salt outlet connected to the inlet of the cold molten salt tank via a fourth pipe, and a cold source outlet connected to the inlet of the reaction tower. The cold source inlet of the preheater can be supplied with at least one of mineral powder and air so that the preheater can heat at least one of the mineral powder and air supplied to the reaction tower.

[0005] Therefore, the flash furnace flue molten salt waste heat recovery system according to the present invention can achieve efficient local reuse of waste heat and has high system self-sufficiency and safety.

[0006] In some embodiments, the preheater includes a mineral powder preheater, wherein the cold source inlet of the mineral powder preheater is used to introduce mineral powder; Alternatively, the preheater may include an air preheater, wherein the cold source inlet of the air preheater is used to introduce air; Alternatively, the preheater may include a mineral powder preheater and an air preheater.

[0007] In some embodiments, the preheater includes the mineral powder preheater, wherein the temperature of the mineral powder discharged from the mineral powder preheater is greater than or equal to 300°C and less than or equal to 350°C.

[0008] The waste heat recovery system for molten salt in the flue gas of this utility model embodiment also includes a dryer and a feed hopper for drying mineral powder. The mineral powder enters the dryer, the mineral powder preheater and the feed hopper in sequence and then enters the reaction tower. The temperature of the mineral powder discharged from the dryer is greater than or equal to 100°C and less than or equal to 150°C.

[0009] In some embodiments, the preheater includes the air preheater, wherein the temperature of the air discharged from the air preheater is greater than or equal to 350°C and less than or equal to 450°C.

[0010] In some embodiments, the heat exchanger includes a plurality of heat exchange sections, which are spaced apart along the extension direction of the flue. The outlet of the cold molten salt tank is connected to the molten salt inlet of the plurality of heat exchange sections, and the molten salt outlet of the plurality of heat exchange sections is connected to the inlet of the hot molten salt tank.

[0011] In some embodiments, the flue includes a first flue and a second flue, the flue gas outlet of the molten pool, the first flue and the second flue are connected in sequence, the first flue is an ascending flue extending in the vertical direction, and the second flue is a horizontal flue extending in the horizontal direction. At least a portion of the plurality of heat exchange units is located within the first flue, and at least a portion of the plurality of heat exchange units is located within the second flue.

[0012] In some embodiments, the flue is provided with a molten salt tank for collecting leaked molten salt, the molten salt tank being located below the heat exchanger and the opening of the molten salt tank facing upwards.

[0013] In some embodiments, The leaked molten salt collected in the molten salt tank in the first flue can be discharged into the molten pool; The molten salt tank inside the second flue is equipped with a guide pipe, and the outlet of the guide pipe extends into a waste salt collection container located outside the flue. The surfaces of the molten salt tank and the guide pipe are provided with anti-corrosion coatings; The slope of the molten salt tank in the second flue is greater than or equal to 1° and less than or equal to 10°.

[0014] In some embodiments, the flash furnace flue molten salt waste heat recovery system further includes an infrared monitoring device for monitoring whether the heat exchanger is leaking; and / or The temperature of the molten salt in the hot molten salt tank is greater than or equal to 500°C and less than or equal to 700°C; The temperature of the molten salt in the cold molten salt tank is greater than or equal to 200°C and less than or equal to 500°C. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a flash furnace flue molten salt waste heat recovery system according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of a flash furnace flue molten salt waste heat recovery system according to another embodiment of the present invention.

[0017] Figure 3 yes Figure 1 A schematic diagram of the molten salt temperature during operation of the flash furnace flue molten salt waste heat recovery system.

[0018] Figure 4 yes Figure 2 A schematic diagram of the molten salt temperature during operation of the flash furnace flue molten salt waste heat recovery system.

[0019] Figure label: 1. Flash furnace; 11. Reaction tower; 12. Molten pool; 13. Dryer; 14. Feed hopper; 2. Flue; 21. First flue; 22. Second flue; 23. Heat exchanger; 231. Heat exchange section; 3. Hot melt salt tank; 4. Cold melt salt tank; 5. Preheater; 61. First pipeline, 62. Second pipeline, 63. Third pipeline, 64. Fourth pipeline. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] The following description, with reference to the accompanying drawings, describes an embodiment of the flash furnace flue molten salt waste heat recovery system of this utility model. For example... Figures 1 to 4 As shown, the flash furnace flue molten salt waste heat recovery system according to an embodiment of the present invention includes a flash furnace 1, a heat storage section and a preheater 5.

[0022] The flash furnace 1 includes a reaction tower 11 and a molten pool 12. The outlet of the reaction tower 11 is connected to the inlet of the molten pool 12, and the flue gas outlet of the molten pool 12 is connected to the inlet of a flue duct 2. A heat exchanger 23 for absorbing heat from the flue gas is installed in the flue duct 2. Specifically, the reaction tower 11 has an opening at the top and an outlet at the bottom. After the ore powder and air enter the reaction tower 11 and react, they enter the molten pool 12 to continue the reaction. The resulting flue gas can enter the flue duct 2. The slag in the upper part of the molten pool 12 exits from the slag outlet, and the molten metal exits from the matte outlet. For example, the high-temperature alloy tubes of the heat exchanger 23 form a molten salt channel to facilitate the flow of liquid molten salt. Cold molten salt enters the inlet of the molten salt channel, exchanges heat with the high-temperature flue gas through a wall-to-wall process, and becomes hot molten salt, which flows out from the outlet of the molten salt channel. The outlet of the flue duct 2 is connected to a waste heat boiler.

[0023] The heat storage unit includes a hot molten salt tank 3 and a cold molten salt tank 4. Both tanks store molten salt, with the molten salt in the hot molten salt tank 3 at a higher temperature than that in the cold molten salt tank 4. The outlet of the cold molten salt tank 4 is connected to the molten salt inlet of the heat exchanger 23 via a first pipe 61, and the molten salt outlet of the heat exchanger 23 is connected to the inlet of the hot molten salt tank 3 via a second pipe 62. This allows the low-temperature molten salt in the cold molten salt tank 4 to enter the heat exchanger 23 through the first pipe 61 to absorb heat, and the high-temperature molten salt in the heat exchanger 23, after absorbing heat, to enter the hot molten salt tank 3 for storage via the second pipe 62.

[0024] In some embodiments, the first pipeline 61 and the second pipeline 62 are equipped with a molten salt pump and a molten salt flow regulating valve to transport molten salt and regulate the molten salt flow rate in the first pipeline 61 and the second pipeline 62. Specifically, the hot molten salt tank 3 and the cold molten salt tank 4 serve as buffer tanks. The volumes of the hot molten salt tank 3 and the cold molten salt tank 4 are reserved with a margin of 15%-25% according to the maximum molten salt flow rate requirement. The molten salt pump is reserved with a margin of 10%-20% according to the maximum molten salt flow rate requirement to absorb the molten salt temperature change caused by flue gas flow fluctuations, and the frequency conversion output of the molten salt pump is controlled by a PID algorithm.

[0025] In some embodiments, the molten salt in the hot molten salt tank 3 and the cold molten salt tank 4 is nitrate molten salt, carbonate molten salt, or chloride molten salt. The temperature of the molten salt in the hot molten salt tank 3 is greater than or equal to 500°C and less than or equal to 700°C. The temperature of the molten salt in the cold molten salt tank 4 is greater than or equal to 200°C and less than or equal to 500°C.

[0026] In some embodiments, the molten salt working medium in the hot molten salt tank 3 and the cold molten salt tank 4 is selected according to the site conditions and heating temperature requirements. The molten salt working medium can be NaNO3-KNO3 nitrate (working temperature range 290℃-560℃), NaNO3-KNO3-Ca(NO3)2-NaNO2 nitrate (working temperature range 230℃-650℃), MgCl2-KCl-NaCl chloride (working temperature range 420℃-800℃) or ZnCl2-KCl-NaCl chloride (working temperature range 250℃-850℃), etc.

[0027] like Figure 1 and Figure 2 As shown, the molten salt inlet of preheater 5 is connected to the outlet of hot molten salt tank 3 via a third pipe 63, and the molten salt outlet of preheater 5 is connected to the inlet of cold molten salt tank 4 via a fourth pipe 64. The cold source outlet of preheater 5 is connected to the inlet of reaction tower 11, and the cold source inlet of preheater 5 can be supplied with at least one of mineral powder and air so that preheater 5 can heat at least one of the mineral powder and air supplied to reaction tower 11. Specifically, the high-temperature molten salt in hot molten salt tank 3 serves as the heat source for preheater 5 and can be supplied to preheater 5 via the third pipe 63. The molten salt that has released heat in preheater 5 can be returned to cold molten salt tank 4 for storage via the fourth pipe 64. Preheater 5 is used to heat at least one of the mineral powder and air supplied to reaction tower 11 so that at least one of the mineral powder and air supplied to reaction tower 11 can absorb the heat from the molten salt, thereby reducing the heat consumption of mineral powder and air in reaction tower 11.

[0028] like Figure 1 As shown, in some embodiments, the preheater 5 includes a mineral powder preheater, the cold source inlet of which is used to introduce mineral powder. Specifically, the temperature of the mineral powder discharged from the mineral powder preheater is greater than or equal to 300°C and less than or equal to 350°C, that is, the mineral powder preheater can heat the temperature of the mineral powder to between 300°C and 350°C. For example, the mineral powder preheater is a fluidized bed or moving bed heat exchanger.

[0029] like Figure 1 As shown, in some embodiments, the flash furnace flue molten salt waste heat recovery system according to this utility model further includes a dryer 13 and a feed hopper 14 for drying mineral powder. The feed hopper 14 is used to contain mineral powder, which sequentially enters the dryer 13, the mineral powder preheater, and the feed hopper 14 before being fed into the reaction tower 11. The temperature of the mineral powder discharged from the dryer 13 is greater than or equal to 100°C and less than or equal to 150°C. Mineral powder at 100°C to 150°C can be heated to between 300°C and 350°C in the mineral powder preheater.

[0030] like Figure 2As shown, in some embodiments, the preheater 5 includes an air preheater, the cold source inlet of which is used to introduce air. Specifically, the temperature of the air discharged from the air preheater is greater than or equal to 350°C and less than or equal to 450°C. For example, the air preheater is a U-tube, coaxial, or spiral plate heat exchanger.

[0031] In some embodiments, the preheater 5 may include multiple types of preheaters, including a mineral powder preheater and an air preheater. Both the mineral powder preheater and the air preheater can use the high-temperature molten salt in the hot molten salt tank 3 as a heat source, so as to heat the mineral powder entering the reaction tower 11 using the mineral powder preheater and heat the air entering the reaction tower 11 using the air preheater.

[0032] like Figure 1 and Figure 2 As shown, in some embodiments, the heat exchanger 23 includes a plurality of heat exchange sections 231, which are spaced apart along the extension direction of the flue 2. The outlet of the cold molten salt tank 4 is connected to the molten salt inlets of the plurality of heat exchange sections 231, and the molten salt outlets of the plurality of heat exchange sections 231 are connected to the inlets of the hot molten salt tank 3. Specifically, the outlet of the cold molten salt tank 4 is connected to the molten salt inlets of the plurality of heat exchange sections 231 through a plurality of branches of the first pipeline 61, and the molten salt outlets of the plurality of heat exchange sections 231 are connected to the inlets of the hot molten salt tank 3 through a plurality of branches of the second pipeline 62.

[0033] In some embodiments, the flue 2 includes a first flue 21 and a second flue 22, with the flue gas outlet of the molten pool 12, the first flue 21, and the second flue 22 sequentially connected. The first flue 21 is an ascending flue 2 extending vertically, and the second flue 22 is a horizontal flue 2 extending horizontally. At least a portion of a plurality of heat exchange sections 231 is located within the first flue 21, and at least a portion of the plurality of heat exchange sections 231 is located within the second flue 22. For example, the first heat exchange section of the plurality of heat exchange sections 231 is located within the first flue 21, and the second heat exchange section of the plurality of heat exchange sections 231 is located within the second flue 22.

[0034] In some embodiments, the flue 2 is provided with a molten salt tank for collecting leaked molten salt. The molten salt tank is located below the heat exchanger 23, with its opening facing upwards. A guide pipe is provided on the molten salt tank and communicates with it. Specifically, the leaked molten salt is collected in the molten salt tank and then discharged along the guide pipe to prevent blockage of the flue and disruption of the normal operation of the waste heat boiler.

[0035] The leaked molten salt collected in the molten salt tank within the first flue 21 can be discharged into the molten pool 12. Specifically, the outlet of the molten salt tank within the first flue 21 faces the molten pool 12 and is located above the liquid surface of the molten pool 12. The leaked molten salt at the first flue 21 (rising flue) is directly discharged into the molten pool 12, floating on the surface of the slag layer in the molten pool 12, and is removed simultaneously during the slag removal operation. That is, the molten salt leaking from the first flue 21 is discharged into the molten pool 12.

[0036] A guide pipe is installed on the molten salt tank inside the second flue 22, and the outlet of the guide pipe extends into the waste salt collection container located outside the flue 2. Specifically, the leaked molten salt at the second flue 22 (horizontal flue) is directly discharged into the waste salt collection container outside the flue 2. That is, the molten salt leaking from the second flue 22 is discharged from the flue 2.

[0037] In some embodiments, the slope of the molten salt tank within the second flue 22 is greater than or equal to 1° and less than or equal to 10°. For example, the first end of the molten salt tank within the second flue 22 is located above the second end of the molten salt tank, and the inlet of the guide pipe on the molten salt tank within the second flue 22 is connected to the bottom of the tank at the second end, thereby facilitating the flow of molten salt within the molten salt tank to the guide pipe. For example, the slope of the molten salt tank is 6° or 8°.

[0038] The leaked molten salt at flue 2 (horizontal flue) is collected in a waste salt collection container through a molten salt tank and a guide pipe. For example, the waste salt collection container is located in the second flue 22 (horizontal flue) and is used to collect the leaked molten salt in the heat exchange section 231 of the second flue 22.

[0039] In some embodiments, the surfaces of the molten salt tank and the guide pipe are provided with an anti-corrosion coating, thereby improving the service life of the molten salt tank and the guide pipe. For example, the anti-corrosion coating is a silicon nitride ceramic layer, alumina, or a double-layer nickel coating, which slows down molten salt corrosion.

[0040] The flash furnace flue molten salt waste heat recovery system according to an embodiment of this utility model also includes an infrared monitoring device for monitoring whether the heat exchanger 23 is leaking. The infrared monitoring device scans the temperature of the outer wall of the heat exchanger 23 in the flue 2 in real time using an infrared thermal imager. When the local temperature drop exceeds a set threshold, an alarm is triggered and an emergency molten salt reflux procedure is initiated.

[0041] like Figure 1 and Figure 3 As shown, in one specific embodiment, cold molten salt at 290°C is drawn from the cold molten salt tank 4 as needed and supplied to the heat exchanger 23 to absorb the waste heat from the flue gas at 950°C and 1200°C, and to control the temperature of the flue duct 2 within a reasonable range (more than 50°C lower than the ash melting point). Simultaneously, the molten salt is heated to 560°C and stored in the hot molten salt tank 4. Hot molten salt is drawn from the hot molten salt tank 4 as needed and supplied to the preheater 5 to heat the 110°C concentrate powder to 300°C before sending it into the flash furnace 1. Simultaneously, the molten salt is cooled to 290°C and stored in the cold molten salt tank 4, forming a closed-loop cycle.

[0042] like Figure 2 and Figure 4As shown, in another specific embodiment, molten salt at 230°C is drawn from the molten salt tank 4 as needed and supplied to the heat exchanger 23 to absorb the waste heat from the flue gas at 950°C and 1200°C, and to control the temperature of the flue duct 2 within a reasonable range (more than 50°C lower than the ash melting point). Simultaneously, the molten salt is heated to 580°C and stored in the hot molten salt tank 4. Hot molten salt is drawn from the hot molten salt tank 4 as needed and supplied to the preheater 5 to heat ambient air to 400°C before sending it into the flash furnace 1. Simultaneously, the molten salt is cooled to 230°C and stored in the molten salt tank 4, forming a closed-loop cycle.

[0043] The flash furnace flue molten salt waste heat recovery system according to an embodiment of this utility model includes a control system. The control system includes temperature sensors, pressure sensors, a molten salt flow controller, and a molten salt storage tank level gauge, etc., to adjust the molten salt pump speed and the opening of the flow regulating valve in real time, thereby reducing the fluctuation of flue gas heat input to the waste heat boiler. For example, temperature sensors and pressure sensors are installed in the flue 2, the first pipeline 61 to the fourth pipeline 64, the hot molten salt tank 3, and the cold molten salt tank 4; a molten salt flow controller is installed in the first pipeline 61 to the fourth pipeline 64, and a molten salt storage tank level gauge is installed in the hot molten salt tank 3 and the cold molten salt tank 4.

[0044] According to this embodiment of the flash furnace flue molten salt waste heat recovery system, the cold molten salt is extracted from the cold molten salt tank 4 as needed and supplied to the heat exchanger 23 of the flue 2 to absorb the waste heat of the high-temperature flue gas and control the temperature of the flue 2 within a reasonable range. Simultaneously, the molten salt is heated to a specified temperature and stored in the hot molten salt tank 3. The hot molten salt is extracted from the hot molten salt tank 3 as needed and supplied to the preheater 5 to heat the concentrate powder or air to a specified temperature before sending it into the flash furnace 1. Simultaneously, the molten salt is cooled to a specified temperature and stored in the cold molten salt tank 4, forming a closed loop. This flash furnace flue molten salt waste heat recovery system uses high-temperature molten salt as a cooling medium to directly recover waste heat from the high-temperature section of the flue gas, effectively reducing the heat grade loss of waste heat and improving waste heat utilization. The density of the molten salt is lower than that of matte and slag; even if it leaks, it will not sink into the molten pool but will float on the surface of the slag layer and can be discharged with the slag, eliminating the explosion hazard caused by water-cooled wall leaks and not affecting the quality of the matte. The waste heat recovered from molten salt can be used nearby to preheat the concentrate or air entering the furnace, improving waste heat utilization and smelting reaction rate, reducing fuel consumption, carbon emissions, and fly ash deposition. Molten salt heat exchange is easy to regulate, smoothing fluctuations in flue gas flow and temperature, ensuring stable operation of subsequent waste heat boilers and turbines. This reduces energy consumption, emissions, production costs, and safety risks in the furnace system, and also improves the flexibility of waste heat boilers.

[0045] Therefore, the flash furnace flue molten salt waste heat recovery system according to the present invention can achieve efficient local reuse of waste heat and has high system self-sufficiency and safety.

[0046] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0048] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0049] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flash furnace flue molten salt waste heat recovery system, characterized in that, include: A flash furnace, comprising a reaction tower and a molten pool, wherein the outlet of the reaction tower is connected to the inlet of the molten pool, the flue gas outlet of the molten pool is connected to the inlet of a flue, and a heat exchanger for absorbing heat from the flue gas is provided in the flue. The heat storage unit includes a hot molten salt tank and a cold molten salt tank, which are used to store molten salt. The outlet of the cold molten salt tank is connected to the molten salt inlet of the heat exchanger through a first pipeline, and the molten salt outlet of the heat exchanger is connected to the inlet of the hot molten salt tank through a second pipeline. The preheater has a molten salt inlet connected to the outlet of the hot molten salt tank via a third pipe, a molten salt outlet connected to the inlet of the cold molten salt tank via a fourth pipe, and a cold source outlet connected to the inlet of the reaction tower. The cold source inlet of the preheater can be supplied with at least one of mineral powder and air so that the preheater can heat at least one of the mineral powder and air supplied to the reaction tower.

2. The flash furnace flue molten salt waste heat recovery system according to claim 1, characterized in that, The preheater includes a mineral powder preheater, and the cold source inlet of the mineral powder preheater is used to introduce mineral powder. Alternatively, the preheater may include an air preheater, wherein the cold source inlet of the air preheater is used to introduce air; Alternatively, the preheater may include a mineral powder preheater and an air preheater.

3. The flash furnace flue molten salt waste heat recovery system according to claim 2, characterized in that, The preheater includes the mineral powder preheater, wherein the temperature of the mineral powder discharged from the mineral powder preheater is greater than or equal to 300°C and less than or equal to 350°C.

4. The flash furnace flue molten salt waste heat recovery system according to claim 3, characterized in that, It also includes a dryer and a feed hopper for drying mineral powder. The mineral powder enters the dryer, the mineral powder preheater and the feed hopper in sequence and then enters the reaction tower. The temperature of the mineral powder discharged from the dryer is greater than or equal to 100°C and less than or equal to 150°C.

5. The flash furnace flue molten salt waste heat recovery system according to claim 2, characterized in that, The preheater includes the air preheater, wherein the temperature of the air discharged from the air preheater is greater than or equal to 350°C and less than or equal to 450°C.

6. The flash furnace flue molten salt waste heat recovery system according to claim 1, characterized in that, The heat exchanger includes multiple heat exchange sections, which are spaced apart along the extension direction of the flue. The outlet of the cold molten salt tank is connected to the molten salt inlet of each of the multiple heat exchange sections, and the molten salt outlet of each of the multiple heat exchange sections is connected to the inlet of the hot molten salt tank.

7. The flash furnace flue molten salt waste heat recovery system according to claim 6, characterized in that, The flue includes a first flue and a second flue. The flue gas outlet of the molten pool, the first flue and the second flue are connected in sequence. The first flue is an ascending flue extending in the vertical direction, and the second flue is a horizontal flue extending in the horizontal direction. At least a portion of the plurality of heat exchange units is located within the first flue, and at least a portion of the plurality of heat exchange units is located within the second flue.

8. The flash furnace flue molten salt waste heat recovery system according to claim 7, characterized in that, The flue is equipped with a molten salt tank for collecting leaked molten salt. The molten salt tank is located below the heat exchanger, and the opening of the molten salt tank faces upward.

9. The flash furnace flue molten salt waste heat recovery system according to claim 8, characterized in that, The leaked molten salt collected in the molten salt tank in the first flue can be discharged into the molten pool; The molten salt tank inside the second flue is equipped with a guide pipe, and the outlet of the guide pipe extends into a waste salt collection container located outside the flue. The surfaces of the molten salt tank and the guide pipe are provided with anti-corrosion coatings; The slope of the molten salt tank in the second flue is greater than or equal to 1° and less than or equal to 10°.

10. The flash furnace flue molten salt waste heat recovery system according to claim 1, characterized in that, The flash furnace flue molten salt waste heat recovery system also includes an infrared monitoring device for monitoring whether the heat exchanger is leaking; and / or The temperature of the molten salt in the hot molten salt tank is greater than or equal to 500°C and less than or equal to 700°C; The temperature of the molten salt in the cold molten salt tank is greater than or equal to 200°C and less than or equal to 500°C.

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