A flash preheating apparatus

Abstract

The application discloses a flash preheating device, which comprises a plurality of flash tanks and a preheating tank. The plurality of flash tanks are sequentially connected to form multi-stage flash evaporation, and respectively produce steam with gradually reduced temperature. The preheating tank comprises an inner cylinder and an outer sleeve. The inner cylinder is provided with a pipeline for passing ore pulp. The outer sleeve is coaxially arranged outside the inner cylinder. A sandwich region is formed between the outer sleeve and the inner cylinder. The sandwich region is divided into steam regions corresponding to the flash tanks along the axial direction. The adjacent steam regions are communicated with each other. The steam regions are respectively connected to steam with gradually increased temperature along the ore pulp flow direction. When the ore pulp passes through the inner cylinder, the steam with high temperature is introduced into the sandwich region to exchange heat with the ore pulp, and then enters the adjacent sandwich region to mix with the steam with low temperature and continue to exchange heat with the ore pulp. In this way, the steam with high temperature is repeatedly exchanged to fully utilize the heat.

Description

Technical Field

[0001] This application relates to the field of mineral preheating technology, specifically to a flash preheating device. Background Technology

[0002] Lateritic nickel ore is a loose, clayey, multi-mineral aggregate formed from nickel-bearing olivine bedrock in tropical or subtropical regions through long-term weathering, leaching, dissemination, and alteration. It contains metallic components such as nickel, cobalt, chromium, magnesium, and aluminum. Currently, the hydrometallurgical route using sulfuric acid leaching under high temperature and pressure is one of the mainstream smelting processes for lateritic nickel ore. Before entering the next solid-liquid separation process, the leached slurry must undergo cooling and depressurization treatment. Flash evaporators are the main equipment for this process. Flash evaporation generates a large amount of high-temperature steam. Currently, the hydrometallurgical route for lateritic nickel ore generally uses three-stage flash evaporation, which produces steam at three different temperatures.

[0003] Patent CN117120150A provides a combined heat exchange system for flash tanks and preheaters in the leaching of laterite nickel ore, including a high-pressure reactor, a preheating tower, and a flash tank. The preheating tower is connected to the inlet of the high-pressure reactor. The flash tank is connected to the outlet of the high-pressure reactor and is also connected to the preheating tower via a steam pipe. Each stage of the flash tank is equipped with a corresponding stage of the preheating tower to preheat the ore step by step.

[0004] However, the existing technology has the following problems: the steam generated by the first-stage flash evaporation and the second-stage flash evaporation has a high temperature and still has a lot of heat after passing through the preheating tower. Directly discharging it will result in energy waste. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a flash preheating device to solve the technical problem of low heat utilization rate in existing slurry preheating technology.

[0006] To achieve the above-mentioned technical objectives, this application adopts the following technical solution: This application provides a flash preheating device, comprising: Multiple flash tanks, connected sequentially to form a multi-stage flash evaporation system, each producing steam at a gradually decreasing temperature; and, The preheating tank includes an inner cylinder and an outer cylinder. A pipe for the flow of slurry is formed inside the inner cylinder. The outer cylinder is coaxially sleeved outside the inner cylinder. An interlayer region is formed between the outer cylinder and the inner cylinder. The interlayer region is divided axially into steam regions that correspond one-to-one with and are connected to the flash tank. Adjacent steam regions are connected to each other. Steam with progressively increasing temperature is introduced into each steam region along the slurry flow direction.

[0007] In some embodiments, the inner cylinder is inclined, with an inlet at the lower end and an outlet at the higher end.

[0008] In some embodiments, a plurality of annular baffles are provided between the outer sleeve and the inner sleeve, the annular baffles dividing the interlayer region into a plurality of vapor regions along the axial direction, and the annular baffles are provided with through holes to allow adjacent vapor regions to communicate.

[0009] In some embodiments, the flash tank has a liquid inlet, a liquid outlet, and an exhaust port. The liquid inlet is used to introduce the liquid to be flashed, the liquid outlet is used to discharge the liquid after flashing, and the exhaust port is used to discharge the vapor formed during flashing.

[0010] In some embodiments, the number of flash tanks is three, namely a first flash tank, a second flash tank, and a third flash tank, which are connected in sequence.

[0011] In some embodiments, two annular baffles are included to divide the interlayer region into a first steam region, a second steam region, and a third steam region, wherein the third steam region, the second steam region, and the first steam region are arranged along the slurry transport direction; the first steam region is connected to the exhaust port of the first flash tank, the second steam region is connected to the exhaust port of the second flash tank, and the third steam region is connected to the exhaust port of the third flash tank.

[0012] In some embodiments, a one-way valve is provided at the through hole of the annular baffle, the one-way valve allowing steam to flow only in the opposite direction to the transport of the ore.

[0013] In some embodiments, the inner cylinder is provided with a first pipe, a second pipe, and a third pipe. The two ends of the first pipe are connected to the first steam region, the two ends of the second pipe are connected to the second steam region, and the two ends of the third pipe are connected to the third steam region.

[0014] In some embodiments, the inner cylinder is made of a thermally conductive material.

[0015] In some embodiments, the outer surface of the outer sleeve is covered with heat-insulating cotton.

[0016] Compared with existing technologies, the flash preheating equipment provided in this application includes multiple flash tanks and a preheating tank. The multiple flash tanks are connected sequentially to form a multi-stage flash process, each producing steam with a gradually decreasing temperature. The preheating tank includes an inner cylinder and an outer cylinder. A pipe for slurry flow is formed within the inner cylinder. The outer cylinder is coaxially fitted around the outside of the inner cylinder, forming a sandwich region between the outer cylinder and the inner cylinder. This sandwich region is axially divided into steam regions corresponding to and connected to each flash tank. Adjacent steam regions are interconnected. Steam with progressively increasing temperatures is introduced into each steam region along the slurry flow direction. When the slurry enters the inner cylinder, the higher-temperature steam enters the sandwich region and exchanges heat with the slurry. Then, it enters an adjacent sandwich region, mixes with the lower-temperature steam, and continues to exchange heat with the slurry. This process is repeated, allowing the higher-temperature steam to undergo multiple heat exchanges, thus fully utilizing its heat.

[0017] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it according to the contents of the specification, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings. The specific implementation methods of this application are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the flash preheating equipment provided in this application; Figure 2 This is a schematic diagram of the preheating tank in another embodiment.

[0019] Explanation of reference numerals in the attached figures: 1-Flash tank, 1a-Inlet, 1b-Outlet, 1c-Exhaust port, 11-First flash tank, 12-Second flash tank, 13-Third flash tank, 2-Preheating tank, 21-Inner cylinder, 211-First pipe, 212-Second pipe, 213-Third pipe, 22-Outer sleeve, 23-Jack jacket area, 23a-First steam area, 23b-Second steam area, 23c-Third steam area, 24-Annular baffle. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a flash preheating device in one embodiment of this application.

[0022] This application provides a flash preheating device, including: multiple flash tanks 1 and preheating tanks 2, wherein the multiple flash tanks 1 are connected sequentially to form a multi-stage flash evaporation, each producing steam with a gradually decreasing temperature; the preheating tank 2 includes an inner cylinder 21 and an outer cylinder 22, wherein a pipe for slurry flow is formed inside the inner cylinder 21, and the outer cylinder 22 is coaxially sleeved outside the inner cylinder 21, wherein an interlayer region 23 is formed between the outer cylinder 22 and the inner cylinder 21, and the interlayer region 23 is axially divided into steam regions corresponding to and connected to the flash tanks 1, and adjacent steam regions are connected to each other, wherein steam with a gradually increasing temperature is introduced into the steam regions along the slurry flow direction.

[0023] In this application, slurry is introduced into the inner cylinder 21, and higher temperature steam is introduced into the interlayer region 23 to exchange heat with the slurry. Then, it enters the adjacent interlayer region 23 to mix with lower temperature steam and continue to exchange heat with the slurry. This process is repeated to allow the higher temperature steam to exchange heat multiple times, thus making full use of its heat.

[0024] The flash tank 1 has a liquid inlet 1a, a liquid outlet 1b, and an exhaust port 1c. The liquid inlet 1a is used to introduce the liquid to be flashed, the liquid outlet 1b is used to discharge the liquid after flashing, and the exhaust port 1c is used to discharge the steam generated during flashing.

[0025] In this embodiment, there are three flash tanks 1: a first flash tank 11, a second flash tank 12, and a third flash tank 13. These three flash tanks are connected sequentially. The inlet of the first flash tank 11 is connected to a high-pressure reactor. The slurry leached from the high-pressure reactor passes through the first flash tank 11, the second flash tank 12, and the third flash tank 13 sequentially. After exiting from the third flash tank 13, it enters the next processing step. The first flash tank 11, the second flash tank 12, and the third flash tank 13 can progressively depressurize the slurry leached from the high-pressure reactor, preventing excessive pressure on the flash tanks and thus protecting each flash tank 1.

[0026] It is understood that in other embodiments, the number of flash tanks 1 is not limited. For example, there may be two, four or more. The number of flash tanks can be determined according to the actual pressure relief requirements, and no further limitation is made here.

[0027] In this embodiment, the inner cylinder 21 is made of a heat-conducting material, which can quickly conduct the heat of the steam to the slurry inside the inner cylinder 21.

[0028] To extend the heat exchange time and improve the heat exchange efficiency of the slurry, the inner cylinder 21 is inclined, with an inlet at the lower end and an outlet at the higher end. The ore enters the inner cylinder 21 from the lower end, gradually accumulates, and finally overflows from the higher end, effectively extending the time the ore spends within the inner cylinder 21 and ensuring sufficient heat exchange.

[0029] The outer sleeve 22 is covered with heat insulation cotton to prevent the heat of the steam from being lost.

[0030] A plurality of annular baffles 24 are provided between the outer sleeve 22 and the inner cylinder 21. The annular baffles 24 divide the interlayer region 23 into the vapor region along the axial direction. The annular baffles 24 are provided with through holes to allow the adjacent vapor regions to communicate.

[0031] In this embodiment, two annular baffles 24 are included to divide the interlayer region 23 into a first steam region 23a, a second steam region 23b, and a third steam region 23c. The third steam region 23c, the second steam region 23b, and the first steam region 23a are arranged along the slurry transport direction. The first steam region 23a is connected to the exhaust port of the first flash tank 11, the second steam region 23b is connected to the exhaust port of the second flash tank 12, and the third steam region 23c is connected to the exhaust port of the third flash tank 13.

[0032] In actual production, the temperature of the first steam discharged from the first flash tank 11 is around 200°C, the temperature of the second steam discharged from the second flash tank 12 is around 150°C, and the temperature of the third steam discharged from the third flash tank 13 is around 110°C. The third steam discharged from the third flash tank 13 is introduced into the third steam region 23c and exchanges heat with the slurry. After heat exchange, the third steam is discharged, and the slurry flows to the region corresponding to the second steam region 23b. The second steam discharged from the second flash tank 12 is introduced into the second steam region 23b and exchanges heat with the slurry. After heat exchange, the second steam enters the third steam region 23c for further heat exchange. The slurry, after heat exchange, is further heated and flows to the region corresponding to the first steam region 23a. The first steam discharged from the first flash tank 11 is introduced into the first steam region 23a and exchanges heat with the slurry. The second steam, after heat exchange, enters the second steam region 23b for further heat exchange. The slurry undergoes three heat exchanges, with its temperature gradually increasing, and is then sent to the high-pressure reactor. The first steam with the highest temperature exchanged heat with the slurry three times, and the second steam with the second highest temperature exchanged heat with the slurry twice, making full use of the heat of the steam and improving the heat utilization rate.

[0033] In this embodiment, a one-way valve is provided at the through hole of the annular baffle 24. The one-way valve only allows steam to flow in the opposite direction to the transport of the ore. The function of the one-way valve is to restrict the flow direction of steam and avoid chaotic steam flow within the interlayer region 23.

[0034] Please see Figure 2 In some other feasible embodiments, the inner cylinder 21 is provided with a first pipe 211, a second pipe 212, and a third pipe 213. The two ends of the first pipe 211 are connected to the first steam region 23a, the two ends of the second pipe 212 are connected to the second steam region 23b, and the two ends of the third pipe 213 are connected to the third steam region 23c. Since the ore is in the form of slurry, when it is inside the inner cylinder 21, the ore located in the center of the inner cylinder 21 receives less heat, and a temperature difference may occur between it and the ore near the inner wall of the inner cylinder 21. The first pipe 211, the second pipe 212, and the third pipe 213 can improve the temperature uniformity of the ore and avoid a large temperature difference between the inner and outer layers of the ore.

[0035] To better understand this application, the technical solution of this application will be described in detail below with reference to the accompanying drawings: The slurry leached from the high-pressure reactor sequentially passes through the first flash tank 11, the second flash tank 12, and the third flash tank 13. The temperature of the first steam discharged from the first flash tank 11 is approximately 200°C, the temperature of the second steam discharged from the second flash tank 12 is approximately 150°C, and the temperature of the third steam discharged from the third flash tank 13 is approximately 110°C. The third steam discharged from the third flash tank 13 is introduced into the third steam region 23c and exchanges heat with the slurry. After heat exchange, the third steam is discharged, and the slurry flows to the region corresponding to the second steam region 23b. The second steam discharged from the second flash tank 12 is introduced into the second steam region 23b and exchanges heat with the slurry. After heat exchange, the second steam enters the third flash tank 13. The gas region 23c continues to exchange heat; while the slurry that has completed heat exchange is further heated and flows to the region corresponding to the first steam region 23a. The first steam discharged from the first flash tank 11 is introduced into the first steam region 23a and exchanges heat with the slurry. The second steam that has completed heat exchange enters the second steam region 23b to continue heat exchange, while the slurry completes three heat exchanges, with the temperature gradually increasing and being sent to the high-pressure reactor. The steam in the first steam region 23a, the steam in the second steam region 23b, and the steam in the third steam region 23c also flow through the first pipe 211, the second pipe 212, and the third pipe 213, respectively, which can improve the uniformity of the ore temperature and avoid a large temperature difference between the inner and outer layers of the ore.

[0036] The beneficial effects of this application are as follows: It includes multiple flash tanks and a preheating tank, with the multiple flash tanks connected sequentially to form a multi-stage flash evaporation process, each producing steam with a gradually decreasing temperature. The preheating tank includes an inner cylinder and an outer cylinder. A pipe for slurry flow is formed within the inner cylinder, and the outer cylinder is coaxially fitted around the outside of the inner cylinder. An interlayer region is formed between the outer cylinder and the inner cylinder, and this interlayer region is axially divided into steam regions corresponding to and connected to each of the flash tanks. Adjacent steam regions are interconnected, and steam with progressively increasing temperatures is introduced into each steam region along the slurry flow direction. When the slurry enters the inner cylinder, the higher-temperature steam enters the interlayer region and exchanges heat with the slurry. Then, it enters an adjacent interlayer region, mixes with the lower-temperature steam, and continues to exchange heat with the slurry. This process is repeated, allowing the higher-temperature steam to undergo multiple heat exchanges, thus fully utilizing its heat.

[0037] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of the claims of this application.

Claims

1. A flash preheating device, characterized in that, include: Multiple flash tanks are connected in sequence to form a multi-stage flash evaporation system, each producing steam with a gradually decreasing temperature. as well as, The preheating tank includes an inner cylinder and an outer cylinder. A pipe for the flow of slurry is formed inside the inner cylinder. The outer cylinder is coaxially sleeved outside the inner cylinder. An interlayer region is formed between the outer cylinder and the inner cylinder. The interlayer region is divided axially into steam regions that correspond one-to-one with and are connected to the flash tank. Adjacent steam regions are connected to each other. Steam with progressively increasing temperature is introduced into each steam region along the slurry flow direction.

2. The flash preheating equipment according to claim 1, characterized in that, The inner cylinder is inclined, with an inlet at the lower end and an outlet at the higher end.

3. The flash preheating equipment according to claim 2, characterized in that, A plurality of annular baffles are provided between the outer sleeve and the inner cylinder. The annular baffles divide the interlayer region into a plurality of vapor regions along the axial direction. Through holes are provided on the annular baffles to allow adjacent vapor regions to communicate.

4. The flash preheating equipment according to claim 3, characterized in that, The flash tank has a liquid inlet, a liquid outlet, and an exhaust port. The liquid inlet is used to introduce the liquid to be flashed, the liquid outlet is used to discharge the liquid after flashing, and the exhaust port is used to discharge the vapor generated during flashing.

5. The flash preheating equipment according to claim 4, characterized in that, The number of flash tanks is three, namely the first flash tank, the second flash tank and the third flash tank, which are connected in sequence.

6. The flash preheating equipment according to claim 5, characterized in that, The system includes two annular baffles that divide the interlayer region into a first steam region, a second steam region, and a third steam region. The third steam region, the second steam region, and the first steam region are arranged along the slurry transport direction. The first steam region is connected to the exhaust port of the first flash tank, the second steam region is connected to the exhaust port of the second flash tank, and the third steam region is connected to the exhaust port of the third flash tank.

7. The flash preheating equipment according to claim 3, characterized in that, The annular baffle is equipped with a one-way valve at the through hole, which only allows steam to flow in the opposite direction to the transport of the ore.

8. The flash preheating equipment according to claim 6, characterized in that, The inner cylinder is provided with a first pipe, a second pipe, and a third pipe. The two ends of the first pipe are connected to the first steam area, the two ends of the second pipe are connected to the second steam area, and the two ends of the third pipe are connected to the third steam area.

9. The flash preheating equipment according to claim 7, characterized in that, The inner cylinder is made of a thermally conductive material.

10. The flash preheating equipment according to claim 7, characterized in that, The outer sleeve is covered with heat-insulating cotton.

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