A high-pressure leaching residual heat power generation system for laterite nickel ore

Abstract

This application relates to a waste heat power generation system for high-pressure leaching of lateritic nickel ore, comprising a high-pressure reactor, a flash evaporation unit, a gas-liquid separator, and a steam generator. The flash evaporation unit includes a flash tank with an inlet, an outlet, and a steam outlet. The inlet of the flash tank is connected to the slurry outlet of the high-pressure reactor, and the steam outlet of the flash tank is sequentially connected to the gas-liquid separator and the steam generator. Compared with the prior art, the waste heat power generation system for high-pressure leaching of lateritic nickel ore provided by this application utilizes a gas-liquid separator to remove sulfuric acid mist contained in the steam, avoiding corrosion of the generator by sulfuric acid. Furthermore, only anti-corrosion treatment is required on the pipeline before the gas-liquid separator, reducing pipeline corrosion costs. Simultaneously, the sulfuric acid separated by the gas-liquid separator can be recycled, reducing sulfuric acid usage costs.

Description

Technical Field

[0001] This application relates to the field of chemical equipment technology, and in particular to a high-pressure leaching waste heat power generation system for laterite nickel ore. Background Technology

[0002] Flash evaporation refers to the process where high-pressure slurry from a high-pressure reactor enters a lower-pressure container, where the sudden pressure drop transforms the slurry into saturated steam and saturated slurry. Since the boiling point of a substance is directly proportional to its pressure, depressurization lowers the boiling point of the high-pressure, high-temperature slurry, allowing it to enter the flash evaporation process. The function of a flash evaporator is to provide a space for rapid vaporization and gas-liquid separation of fluids.

[0003] In the hydrometallurgical process for laterite nickel ore, ore slurry, sulfuric acid, and steam are typically injected into a high-pressure reactor for leaching of high-valence metals from the laterite nickel ore under high pressure. The reacted ore slurry and sulfuric acid are then introduced into a flash tank for depressurization. The high-temperature steam generated during depressurization can be used for preheating and power generation to avoid energy waste.

[0004] However, while generating steam, some sulfuric acid droplets are also agitated by the vibrations during steam generation, forming acid mist that is discharged along with the steam. This causes corrosion of steam pipes and generators, as well as additional consumption of sulfuric acid. Furthermore, compared to pipes, generators are more difficult to treat for acid corrosion.

[0005] Application content

[0006] In view of this, it is necessary to provide a high-pressure leaching waste heat power generation system for laterite nickel ore to solve the technical problem in the prior art where the steam generated by the flash tank contains sulfuric acid mist, which causes corrosion of pipelines and generators.

[0007] This application provides a high-pressure leaching waste heat power generation system for laterite nickel ore. The system includes a high-pressure reactor, a flash evaporation unit, a gas-liquid separator, and a steam generator. The flash evaporation unit includes a flash tank with an inlet, an outlet, and a steam outlet. The inlet of the flash tank is connected to the slurry outlet of the high-pressure reactor, and the steam outlet of the flash tank is connected in sequence to the gas-liquid separator and the steam generator.

[0008] Furthermore, the flash unit includes several flash tanks connected in series. The inlet of the first flash tank is connected to the slurry outlet of the high-pressure reactor, and the outlet of the flash tank is connected to the inlet of the next flash tank. The steam outlet of each flash tank is connected to a gas-liquid separator, and at least some of the gas-liquid separators are connected to a steam generator.

[0009] Furthermore, the gas-liquid separator includes a first gas-liquid separator and a second gas-liquid separator. Along the direction of slurry movement, the forward part of the flash tank is connected to a steam generator through the first gas-liquid separator, and the steam outlet of the remaining flash tanks is connected to the second gas-liquid separator.

[0010] Furthermore, it also includes a preheating unit, which includes a preheating tower, a second gas-liquid separator, and the outlet of a steam generator connected to the preheating tower to preheat the slurry with waste steam.

[0011] Furthermore, the preheating unit includes multiple preheating towers connected in series, with the last preheating tower connected to the slurry inlet of the high-pressure reactor, and the gas-liquid separator connected to each preheating tower in a corresponding manner.

[0012] Furthermore, the gas-liquid separator includes a shell and a liquid-separating baffle. The shell has a separation chamber inside and also forms an air inlet, an air outlet, and a liquid outlet that connect the separation chamber. The liquid-separating baffle is arranged on the airflow path between the air inlet and the air outlet, and the liquid outlet is located below the liquid-separating baffle. The air inlet is connected to the steam outlet of the flash tank, and the air outlet is connected to the steam generator.

[0013] Furthermore, the bottom surface of the outer shell is sloped, and the liquid outlet is located at the lowest point of the slope.

[0014] Furthermore, the separating baffle has multiple bends to divide the flow into multiple bends within the separation chamber. When water vapor passes through the flow, sulfuric acid droplets will impact the separating baffle and drip off.

[0015] Furthermore, the gas-liquid separator also includes a liquid storage tank, with an outlet connected to the upper end of the tank and a closable drain port at the lower end.

[0016] Furthermore, it also includes a sulfuric acid collection tank, with the drain outlet connected to the sulfuric acid collection tank via a sulfuric acid pipe, which is equipped with a valve.

[0017] Compared with the prior art, the high-pressure leaching waste heat power generation system of laterite nickel ore provided in this application uses a gas-liquid separator to remove sulfuric acid mist contained in the steam, which avoids the generator being corroded by sulfuric acid. Moreover, only the pipeline located in front of the gas-liquid separator needs to be treated with anti-corrosion, which reduces the cost of pipeline anti-corrosion. At the same time, the sulfuric acid separated by the gas-liquid separator can be recycled, which reduces the cost of sulfuric acid use.

[0018] 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

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 is a schematic diagram of a preferred embodiment of the waste heat power generation system for high-pressure leaching of laterite nickel ore provided in this application.

[0021] Figure 2 for Figure 1 Cross-sectional view of a gas-liquid separator. Detailed Implementation

[0022] The preferred embodiments of this application are described in detail below with reference to the accompanying drawings, which constitute a part of this application and are used together with the embodiments of this application to illustrate the principles of this application, but are not intended to limit the scope of this application.

[0023] Please see Figure 1 This application provides a high-pressure leaching waste heat power generation system for laterite nickel ore. This high-pressure leaching waste heat power generation system for laterite nickel ore can be applied to the smelting of laterite nickel ore to recover sulfuric acid from the steam generated by the flash tank, thus avoiding sulfuric acid corrosion of the generator when using steam to generate electricity.

[0024] It should be noted that the high-pressure leaching waste heat power generation system for laterite nickel ore of this application is used, but not limited to, in the smelting of laterite nickel ore, and can also be applied to other smelting production processes that require sulfuric acid and flash tanks. In this application, only the application of the high-pressure leaching waste heat power generation system for laterite nickel ore smelting is used as an example for illustration. The principle of the high-pressure leaching waste heat power generation system for laterite nickel ore smelting is essentially the same as that applied to the smelting of laterite nickel ore, and will not be elaborated here.

[0025] This high-pressure leaching waste heat power generation system for laterite nickel ore includes a high-pressure reactor 1, a flash evaporation unit 2, a gas-liquid separator 3, and a steam generator 4. The flash evaporation unit 2 includes a flash tank, which has a feed inlet, a discharge outlet, and a steam outlet. The feed inlet of the flash tank is connected to the slurry outlet of the high-pressure reactor 1, and the steam outlet of the flash tank is connected in sequence to the gas-liquid separator 3 and the steam generator 4.

[0026] After the slurry reacts in the high-pressure reactor 1, it enters the flash tank for depressurization. The steam generated by depressurization enters the gas-liquid separator 3 through the steam outlet, where sulfuric acid is removed. The steam then enters the steam generator 4 to generate electricity. This effectively avoids corrosion of the generator by sulfuric acid, and only requires anti-corrosion treatment of the pipeline before the gas-liquid separator 3, reducing pipeline anti-corrosion costs. At the same time, recovering sulfuric acid from the steam also reduces sulfuric acid waste.

[0027] In some embodiments, the flash evaporation unit 2 includes several flash tanks connected in series. The inlet of the first flash tank is connected to the slurry outlet of the high-pressure reactor 1, and the outlet of the flash tank is connected to the inlet of the next flash tank. Each flash tank's steam outlet is correspondingly connected to a gas-liquid separator 3, and at least a portion of the gas-liquid separator 3 is connected to a steam generator 4.

[0028] As the pressure and temperature of the steam generated in each flash tank gradually decrease, considering the power generation efficiency of the steam generator 4, only the steam generated by the first few flash tanks is suitable for power generation. Therefore, the gas-liquid separator 3 includes a first gas-liquid separator 3A and a second gas-liquid separator 3B. Along the direction of slurry movement, the first few flash tanks are connected to the steam generator 4 through the first gas-liquid separator 3A, and the steam outlets of the remaining flash tanks are connected to the second gas-liquid separator 3B.

[0029] Combination Figure 1 In this embodiment, the flash evaporation unit 2 includes three flash tanks connected in series. Based on their position relative to the high-pressure reactor 1, i.e., the direction of slurry flow, they are named the first flash tank 21, the second flash tank 22, and the third flash tank 23. Due to the high pressure inside the high-pressure reactor, the slurry can be driven to flow sequentially between the tanks solely by this pressure and the height difference between them. The slurry reacted in the high-pressure reactor 1 first enters the first flash tank 21 for the first flash evaporation, then enters the second flash tank 22 for the second flash evaporation, and finally enters the third flash tank 23 for the third flash evaporation. The first flash tank 21 and the second flash tank 22 are connected to the first gas-liquid separator 3A, and the third flash tank 23 is connected to the second gas-liquid separator 3B.

[0030] In this embodiment, the flash unit 2 is a three-stage structure containing three flash tanks. In other embodiments, it may include other numbers of flash tanks, with connections similar to this embodiment. The first few flash tanks are selected based on the temperature and pressure of the generated steam and connected to the first gas-liquid separator 3A, using the generated steam for power generation. The remaining flash tanks are connected to the second gas-liquid separator 3B to remove sulfuric acid from the steam. This portion of steam is unsuitable for power generation due to its lower temperature and pressure, but it still contains a certain amount of waste heat, making it worthwhile to recover and reuse.

[0031] The steam generator 4 can generate electricity using steam. In some embodiments, the steam generator 4 includes a turbine, which is driven by high-pressure steam to rotate, thereby generating electrical energy.

[0032] In some embodiments, the system further includes a preheating unit 6, which includes a preheating tower. The outlet of the second gas-liquid separator 3B and the steam generator 4 are connected to the preheating tower to preheat the slurry with waste steam. The steam is introduced into the preheating tower to directly contact the slurry, allowing the slurry to fully absorb the heat from the steam. Alternatively, a heat exchanger can be used for heat exchange.

[0033] In some embodiments, the preheating unit 6 includes a plurality of preheating towers connected in series, with the last preheating tower connected to the slurry inlet of the high-pressure reactor 1. Pumps are provided between adjacent preheating towers to pressurize the slurry and drive its flow.

[0034] Combination Figure 1 In this embodiment, the preheating unit 6 includes three preheating towers connected in series, named first preheating tower 61, second preheating tower 62, and third preheating tower 63 according to the direction of slurry flow. The slurry first enters the first preheating tower 61 for the first preheating, then enters the second preheating tower 62 for the second preheating, then enters the third preheating tower 63 for the third preheating, and finally enters the high-pressure reactor 1 for reaction. The first flash tank 21 is connected to the first preheating tower 61 through the first preheater 3A and the steam generator 4, the second flash tank 22 is connected to the second preheating tower 62 through the first preheater 3A and the steam generator 4, and the third flash tank 23 is connected to the third preheating tower 63 through the second preheater 3B.

[0035] Some flash tanks generate steam at excessively high temperatures, making them unsuitable for preheating slurry. To address this, steam generators (4) are installed for these flash tanks. The steam is cooled to a suitable temperature after passing through these generators and then introduced into the corresponding preheating towers to preheat the slurry. This method fully utilizes the energy in the steam.

[0036] Please see Figure 2 In this embodiment, the first gas-liquid separator 3A and the second gas-liquid separator 3B can adopt the same structural form, including a shell 31 and a liquid-separating baffle 32. The shell 31 has a separation chamber inside and also forms an air inlet 33, an air outlet 34, and a liquid outlet 35 that communicate with the separation chamber. The liquid-separating baffle 32 is disposed on the airflow path between the air inlet 33 and the air outlet 34, which can block the steam airflow so that sulfuric acid droplets collide with the liquid-separating baffle 32 and converge into large droplets that flow down. The liquid outlet 35 is located below the liquid-separating baffle and is used to discharge the separated sulfuric acid. The air inlet 34 is connected to the steam outlet of the flash tank, and the air outlet 35 is connected to the steam inlet of the steam generator 4.

[0037] In some embodiments, the bottom surface 31 of the outer casing is a slope, and the outlet 35 is located at the lowest point of the slope so that sulfuric acid can be collected at the outlet 35.

[0038] In some embodiments, the diverting baffle 32 has multiple bends to divide the separation chamber into multiple bends in the flow channel. When water vapor passes through the flow channel, sulfuric acid droplets will impact the diverting baffle 32 and drip off. This multi-bend structure can effectively separate sulfuric acid droplets from the water vapor, ensuring that the water vapor discharged from the outlet 34 does not contain sulfuric acid.

[0039] In some embodiments, the gas-liquid separator 3 further includes a storage tank 36, with an outlet 35 connected to the upper end of the storage tank 36 and a closable drain port 37 at the lower end. The separated sulfuric acid is collected in the storage tank 36 for temporary storage. When a certain amount is stored, the drain port 37 is opened to discharge it. Since the gas-liquid separator 3 is filled with high-pressure steam, the pressure of the high-pressure steam can automatically push out the sulfuric acid after the drain port 37 is opened.

[0040] In some embodiments, the system further includes a sulfuric acid collection tank 7, with a drain outlet 37 connected to the sulfuric acid collection tank 7 via a sulfuric acid pipe. A valve is installed on the sulfuric acid pipe to close the drain outlet 37. The sulfuric acid separated by the first gas-liquid separator 3A and the second gas-liquid separator 3B can be collected in the same sulfuric acid collection tank 7 for centralized collection, recycling, and reuse. It is readily understood that the sulfuric acid collection tank 7 includes the necessary discharge structure to discharge the collected sulfuric acid.

[0041] Compared with the prior art, the high-pressure leaching waste heat power generation system of laterite nickel ore provided in this application uses a gas-liquid separator to remove sulfuric acid mist contained in the steam, which avoids the generator being corroded by sulfuric acid. Moreover, only the pipeline located in front of the gas-liquid separator needs to be treated with anti-corrosion, which reduces the cost of pipeline anti-corrosion. At the same time, the sulfuric acid separated by the gas-liquid separator can be recycled, which reduces the cost of sulfuric acid use.

[0042] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A waste heat power generation system for high-pressure leaching of laterite nickel ore, characterized in that, It includes: The system includes a high-pressure reactor, a flash evaporation unit, a gas-liquid separator, and a steam generator. The flash evaporation unit includes a flash tank with an inlet, an outlet, and a steam outlet. The inlet of the flash tank is connected to the slurry outlet of the high-pressure reactor, and the steam outlet of the flash tank is connected in sequence to the gas-liquid separator and the steam generator.

2. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 1, characterized in that, The flash unit includes several flash tanks connected in series. The inlet of the first flash tank is connected to the slurry outlet of the high-pressure reactor. The outlet of the flash tank is connected to the inlet of the next flash tank. The steam outlet of each flash tank is connected to a gas-liquid separator. At least part of the gas-liquid separator is connected to the steam generator.

3. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 2, characterized in that, The gas-liquid separator includes a first gas-liquid separator and a second gas-liquid separator. Along the direction of slurry movement, the front part of the flash tank is connected to the steam generator through the first gas-liquid separator, and the steam outlet of the remaining flash tanks is connected to the second gas-liquid separator.

4. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 3, characterized in that, It also includes a preheating unit, which includes a preheating tower. The outlet of the second gas-liquid separator and the steam generator are connected to the preheating tower to preheat the slurry with waste steam.

5. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 4, characterized in that, The preheating unit includes multiple preheating towers connected in series, with the last preheating tower connected to the slurry inlet of the high-pressure reactor. The gas-liquid separator is connected to each of the preheating towers in a corresponding manner.

6. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 1, characterized in that, The gas-liquid separator includes a shell and a liquid-separating baffle. The shell has a separation chamber and also forms an air inlet, an air outlet, and a liquid outlet that communicate with the separation chamber. The liquid-separating baffle is disposed on the airflow path between the air inlet and the air outlet, and the liquid outlet is located below the liquid-separating baffle. The air inlet is connected to the steam outlet of the flash tank, and the air outlet is connected to the steam generator.

7. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 6, characterized in that, The bottom surface of the outer shell is a slope, and the liquid outlet is located at the lowest point of the slope.

8. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 6, characterized in that, The liquid-separating baffle has multiple bends to divide the separation chamber into multiple bends in the flow channel. When water vapor passes through the flow channel, sulfuric acid droplets will hit the liquid-separating baffle and drip off.

9. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 6, characterized in that, The gas-liquid separator also includes a liquid storage tank, the upper end of which is connected to the liquid outlet, and the lower end of which has a closable drain port.

10. The high-pressure leaching waste heat power generation system for laterite nickel ore according to claim 9, characterized in that, It also includes a sulfuric acid collection tank, and the drain outlet is connected to the sulfuric acid collection tank through a sulfuric acid pipe, which is equipped with a valve.

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