Multi-effect evaporation device for reducing corrosion of corrosive ions

Abstract

The utility model discloses a multi-effect evaporation device for reducing corrosion of corrosive ions. The multi-effect evaporation device comprises a feeding unit, a first-effect evaporation unit, a second-effect evaporation unit and a third-effect evaporation unit, the feeding unit comprises feeding pH value adjusting equipment; the first-effect evaporation unit comprises a first-effect heater, a first-effect separator, a first-effect steam purification tower and a first-effect pH value adjusting device; the second-effect evaporation unit comprises a second-effect heater, a second-effect separator, a second-effect steam purification tower and second-effect pH value adjusting equipment; the triple-effect evaporation unit comprises a triple-effect heater, a triple-effect separator, a triple-effect steam purification tower and triple-effect pH value adjusting equipment. The multi-effect evaporation device can reduce corrosion of corrosive ions (such as fluorine ions) to the evaporation device.

Description

Technical Field

[0001] The utility model relates to a multi-effect evaporation device, in particular to a multi-effect evaporation device capable of reducing corrosive ion corrosion. Background Art

[0002] The conventional treatment process for high-magnesium ammonium sulfate wastewater generated during rare earth ore production relies on evaporation and crystallization, with the primary equipment constructed from titanium. Due to the large amount of impurity ions in the wastewater, particularly high fluoride ion content, fluoride ions accumulate in the secondary steam during evaporation. This secondary steam, during heat exchange, can cause corrosion in the evaporator's heat exchange tubes. To minimize corrosion, the mother liquor enriched during the evaporation and crystallization process must be discharged in large quantities and treated separately. This requires significant equipment investment and high treatment costs, and the resulting secondary steam condensate is also high in fluoride ions.

[0003] Existing techniques typically adjust the pH of the solution directly by adding an alkaline solution. However, in practice, high localized alkalinity can cause crystals to form in the solution, clogging the heat exchange tubes. Furthermore, during reevaporation, the pH decreases as the solution hydrolyzes, causing corrosion to the evaporator. Conventional gas-liquid separation devices offer poor separation performance, and the fluoride ion content of the resulting secondary steam condensate can still reach 20-50 ppm.

[0004] CN106966365A discloses a triple-effect evaporation waste acid treatment system, comprising an elevated tank for storing raw materials. The raw materials in the elevated tank pass through a primary preheater, a secondary preheater, and a tertiary preheater, followed by a triple-effect evaporator, a second-effect evaporator, and a first-effect evaporator for concentration and evaporation. The first-effect evaporator is connected to a cooling reactor, which is connected to a solid-liquid separation device. The triple-effect evaporator includes a triple-effect gas-liquid separator and a triple-effect heater arranged in a vertically staggered manner. The second-effect evaporator includes a second-effect gas-liquid separator and a second-effect heater arranged in a vertically staggered manner. The first-effect evaporator includes a first-effect gas-liquid separator and a first-effect heater arranged in a vertically staggered manner, with the gas-liquid separator at the top and the heater at the bottom. The gas outlet of the first-effect preheater is connected to the gas inlet of a condenser, which is connected to a vacuum pump that maintains negative pressure throughout the system. This patent document does not involve multi-point pH adjustment or secondary steam purification.

[0005] CN217838420U discloses a triple-effect evaporation system for treating high-salinity wastewater, comprising an evaporation unit, a crystallization unit, and a steam condensate recovery unit. The evaporation unit includes a feed pump, a primary evaporation module, a secondary evaporation module, and a tertiary evaporation module. Each evaporation module includes a heater, a separator, and a forced circulation pump. The crystallization unit includes a discharge pump, a thickener, a centrifuge, a mother liquor tank, and a mother liquor reflux pump. The steam condensate recovery unit includes a raw steam condensate recovery module and a secondary steam condensate recovery module. This patent document also does not address multi-point pH adjustment or secondary steam purification.

[0006] CN219058765U discloses a phenol-containing wastewater treatment system, comprising a raw liquid tank, which is fixedly connected to a raw liquid pump via a connecting pipe, which is fixedly connected to a pH adjustment tank via a connecting pipe, which is fixedly connected to a neutralization tank discharge pump via a connecting pipe, which is fixedly connected to an integrated device. The system employs multi-stage demisting using a single-effect demister, a second-effect demister, and a third-effect demister, resulting in high demisting efficiency and protecting subsequent equipment from corrosion. This patent document utilizes a multi-effect demister to reduce corrosion by demisting. The patent document only addresses initial pH adjustment of the raw liquid and does not address multi-point pH adjustment within the multi-effect system. Utility Model Content

[0007] In view of this, the purpose of the present invention is to provide a multi-effect evaporation device that reduces corrosive ion corrosion, which can inhibit the generation of corrosive ions in the secondary steam of each effect, and purify the secondary steam to reduce the corrosive ion content in the secondary steam, thereby reducing the corrosion of the corrosive ions on the heat exchange equipment.

[0008] The present invention adopts the following technical solutions to achieve the above-mentioned purpose.

[0009] The utility model provides a multi-effect evaporation device for reducing corrosive ion corrosion, comprising a feeding unit, a first-effect evaporation unit, a second-effect evaporation unit and a third-effect evaporation unit;

[0010] The feeding unit is connected to the first-effect evaporation unit and is used to supply the raw material liquid to be concentrated to the first-effect evaporation unit; the feeding unit includes a feed pH value adjustment device, which is used to adjust the pH value of the raw material liquid to a predetermined range;

[0011] The single-effect evaporation unit includes a single-effect heater, a single-effect separator, a single-effect steam purification tower, and a single-effect pH value adjustment device; the lower portion of the single-effect separator receives the pH-adjusted raw material liquid from the feeding unit through a pipeline; the lower portion of the single-effect separator is also connected to the bottom of the single-effect heater and the single-effect pH value adjustment device through pipelines; the top of the single-effect separator is connected to the bottom of the single-effect steam purification tower through a pipeline;

[0012] The second-effect evaporation unit includes a second-effect heater, a second-effect separator, a second-effect steam purification tower and a second-effect pH value adjustment device; the lower part of the second-effect separator is connected to the bottom of the first-effect separator, the bottom of the second-effect heater and the second-effect pH value adjustment device through pipelines; the top of the second-effect separator is connected to the bottom of the second-effect steam purification tower through a pipeline; the upper part of the second-effect heater is connected to the upper part of the first-effect steam purification tower through a pipeline;

[0013] The triple-effect evaporation unit includes a triple-effect heater, a triple-effect separator, a triple-effect steam purification tower and a triple-effect pH value adjustment device; the lower part of the triple-effect separator is connected to the bottom of the second-effect separator, the bottom of the triple-effect heater and the triple-effect pH value adjustment device through pipelines; the top of the triple-effect separator is connected to the bottom of the triple-effect steam purification tower through a pipeline; the upper part of the triple-effect heater is connected to the upper part of the second-effect steam purification tower through a pipeline.

[0014] According to the multi-effect evaporation device of the present invention, preferably:

[0015] The feeding unit also includes a feeding pump and a feeding pH value measuring device;

[0016] The single-effect evaporation unit further includes a preheater, a single-effect circulation pump, a single-effect material transfer pump and a single-effect pH value measuring device; wherein,

[0017] The feed pump is connected to the preheater through a pipeline and is used to pump the raw material liquid after adjusting the pH value into the preheater; the feed pH value measuring device is provided on the pipeline connecting the preheater and the feed pump and is used to measure the pH value of the liquid entering the preheater;

[0018] The upper part of the preheater is connected to the lower part of the first-effect heater through a pipeline, and is used to receive steam condensate from the first-effect heater, thereby preheating the liquid in the preheater;

[0019] The first-effect circulation pump is connected to the first-effect separator and the first-effect heater respectively through pipelines; the first-effect material transfer pump is connected to the bottom of the first-effect separator and the lower part of the second-effect separator respectively through pipelines; the first-effect pH value measuring device is arranged on the pipeline connecting the first-effect steam purification tower and the second-effect heater.

[0020] According to the multi-effect evaporation device of the present invention, preferably, the second-effect evaporation unit further includes a second-effect circulation pump, a second-effect material transfer pump and a second-effect pH value measuring device; wherein the second-effect circulation pump is connected to the second-effect heater and the second-effect separator respectively through pipelines; the second-effect material transfer pump is connected to the bottom of the second-effect separator and the lower part of the triple-effect separator respectively through pipelines; and the second-effect pH value measuring device is arranged on the pipeline connecting the second-effect steam purification tower and the triple-effect heater.

[0021] According to the multi-effect evaporation device of the present invention, preferably, the triple-effect evaporation unit further includes a triple-effect circulation pump, a triple-effect material transfer pump and a triple-effect pH value measuring device; wherein the triple-effect circulation pump is connected to the triple-effect heater and the triple-effect separator respectively through pipelines; the triple-effect material transfer pump is connected to the bottom of the triple-effect separator through a pipeline; and the triple-effect pH value measuring device is connected to the upper part of the triple-effect steam purification tower through a pipeline.

[0022] According to the multi-effect evaporation device of the present invention, preferably, it further includes a condensing unit, which includes a condenser and a vacuum pump; the upper part of the condenser is connected to the upper part of the triple-effect heater, the upper part of the second-effect heater and the upper part of the first-effect heater through pipelines respectively; the upper part of the condenser is also connected to the upper part of the triple-effect steam purification tower through a pipeline, and the triple-effect pH value measuring device is arranged on the pipeline connecting the condenser and the triple-effect steam purification tower; the vacuum pump is connected to the upper part of the condenser through a pipeline.

[0023] According to the multi-effect evaporation device of the present invention, preferably, the condensing unit further comprises a steam condensate tank and a steam condensate pump; the steam condensate tank is respectively connected to the lower part of the condenser and the steam condensate pump through pipelines.

[0024] According to the multi-effect evaporation device of the present invention, preferably, the lower portion of the condenser is further connected to the lower portion of the second-effect heater and the lower portion of the triple-effect heater via pipelines.

[0025] According to the multi-effect evaporation device of the present invention, preferably, it further includes a discharge unit, which includes a discharge concentration meter and a receiving tank; the discharge concentration meter is connected to the three-effect transfer pump and the receiving tank through pipelines, respectively, and is used to measure the concentration of the final concentrated liquid discharged from the three-effect separator.

[0026] According to the multi-effect evaporation device of the present invention, preferably, the receiving tank is further connected to the lower part of the second-effect separator through a pipeline.

[0027] According to the multi-effect evaporation device described in the utility model, preferably, it also includes a cooling water supply unit and a raw steam supply unit; the raw steam supply unit is connected to the single-effect heater through a pipeline, and is used to supply raw steam to the single-effect heater; the cooling water supply unit is connected to the condenser through a pipeline, and is used to supply cooling water to the condenser.

[0028] The multi-effect evaporation device of the utility model can adjust the pH value of the feed liquid in the multi-effect evaporation system at multiple points in real time, suppressing the generation of corrosive ions (such as fluoride ions) in the secondary steam of each effect. At the same time, the secondary steam is effectively purified by the steam purification tower of each effect, which basically ensures that the content of corrosive ions in the secondary steam is reduced, and basically avoids the corrosion of the evaporation device by the corrosive ions in the secondary steam, especially avoids the corrosion of the heat exchange equipment, thereby improving the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an overall schematic diagram of a multi-effect evaporation device of the present utility model.

[0030] The following are the descriptions of the reference numerals:

[0031] 1-single-effect evaporation unit, 11-preheater, 12-single-effect heater, 13-single-effect separator, 14-single-effect steam purification tower, 15-single-effect pH value adjustment equipment, 16-single-effect circulation pump, 17-single-effect material transfer pump, 18-single-effect pH value measuring equipment;

[0032] 2-second-effect evaporation unit, 22-second-effect heater, 23-second-effect separator, 24-second-effect steam purification tower, 25-second-effect pH value adjustment equipment, 26-second-effect circulation pump, 27-second-effect material transfer pump, 28-second-effect pH value measuring equipment 28;

[0033] 3-Triple-effect evaporation unit, 32-Triple-effect heater, 33-Triple-effect separator, 34-Triple-effect steam purification tower, 35-Triple-effect pH value adjustment equipment, 36-Triple-effect circulation pump, 37-Triple-effect material transfer pump, 38-Triple-effect pH value measuring equipment;

[0034] 4- condensing unit, 41- condenser, 42- vacuum pump, 43- steam condensate tank, 44- steam condensate pump;

[0035] 8-feeding unit, 81-feeding pH value adjusting device, 82-feeding pump, 83-feeding pH value measuring device; 51-discharge concentration meter;

[0036] A represents the preheater condensate outlet, B represents the raw steam supply unit inlet, C and D represent the cooling water supply inlet and cooling water outlet respectively, and E represents the secondary steam condensate outlet. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0038] The utility model provides a multi-effect evaporation device for reducing corrosive ion corrosion, which can be used to concentrate a raw material liquid (the raw material liquid to be concentrated can be saline wastewater to be treated), thereby reducing the corrosion of heat exchange equipment by corrosive ions. The corrosive ions can be halide ions, i.e., fluoride ions, chloride ions, bromide ions, etc., for example, fluoride ions.

[0039] The multi-effect evaporation device for reducing corrosive ion corrosion of the present invention includes a feed unit, a first-effect evaporation unit, a second-effect evaporation unit, a third-effect evaporation unit, a condensation unit, and a discharge unit. Optionally, it also includes a cooling water supply unit and a live steam supply unit. This is described in detail below.

[0040] <Feeding unit>

[0041] The feed unit of the utility model is connected to the first-effect evaporation unit for providing the first-effect evaporation unit with a raw material liquid to be concentrated. For example, the raw material liquid can be high-magnesium ammonium sulfate wastewater generated in the rare earth ore production process.

[0042] In the present invention, the feed unit includes a feed pH adjustment device, a feed pump, and a feed pH measuring device. The preheater of the single-effect evaporation unit is connected to the feed pump via a pipeline, which can be referred to as a feed pipeline. The feed pH measuring device is arranged on the feed pipeline connected between the preheater and the feed pump of the single-effect evaporation unit, and is used to measure the pH value of the feed liquid entering the preheater. The feed pH adjustment device is connected to the feed pipeline. The feed pH adjustment device is used to adjust the pH value of the raw material liquid (e.g., ammonium sulfate waste liquid with a high magnesium content) to a predetermined range. The feed pump is used to provide power to the preheater of the single-effect evaporation unit, thereby pumping the raw material liquid after pH adjustment into the preheater of the single-effect evaporation unit.

[0043] In certain embodiments, the feed pH adjustment device and the feed pH measurement device are interlocked, which can ensure that the pH value of the raw material liquid entering the single-effect evaporation unit is maintained within a set range.

[0044] <Single-effect evaporation unit>

[0045] The single-effect evaporation unit of the present invention includes a single-effect heater, a single-effect separator, a single-effect steam purification tower, and a single-effect pH adjustment device. Preferably, it also includes a preheater, a single-effect circulation pump, a single-effect material transfer pump, and a single-effect pH measurement device. This not only allows for the production of a preliminarily concentrated feed liquid, but also allows for the purification of the single-effect secondary steam and the control of the pH value of the single-effect secondary steam within a set range, thereby reducing the risk of corrosive ions on the device.

[0046] In the present invention, a preheater is used to preheat the raw material liquid after pH adjustment. The bottom of the preheater is connected to the feed pH value measuring device via a pipeline, thereby receiving the raw material liquid after pH adjustment from the feed unit. The upper part of the preheater is connected to the lower part of the single-effect heater via a pipeline, and is used to receive steam condensate from the single-effect heater as the heat source of the preheater. In this way, the steam condensate formed after heat exchange in the single-effect heater can be reused, saving costs. The lower part of the preheater is provided with a preheater condensate outlet for discharging the primary steam condensate.

[0047] In the present invention, the lower portion of the first-effect separator is connected to the bottom of the preheater via a pipeline, for receiving preheated raw material liquid from the preheater. The first-effect pH adjustment device is connected to the lower portion of the first-effect separator via a pipeline, for providing a regulating liquid into the first-effect separator. This regulating liquid can neutralize the liquid in the first-effect separator, adjust the pH value of the liquid, and further adjust the pH value of the first-effect secondary steam discharged from the first-effect steam purification tower to the second-effect heater.

[0048] The lower portion of the primary separator is also connected to the bottom of the primary heater via a pipe. A primary circulation pump is connected to the bottom of the primary separator and the bottom of the primary heater via pipes. This allows the liquid entering the primary separator to circulate between the primary heater and the primary separator, facilitating cyclic concentration and achieving initial concentration.

[0049] The top of the first-effect separator is connected to the bottom of the first-effect steam purification tower by a pipeline. In this way, the secondary steam separated by the first-effect separator can be purified by the first-effect steam purification tower. For example, the content of corrosive ions (such as fluoride ions) in the secondary steam can be reduced by purification. The upper part of the first-effect steam purification tower is connected to the upper part of the second-effect heater by a pipeline, and the pipeline can be called a first-effect steam purification pipeline. In this way, a heat source for heat exchange (i.e., first-effect secondary steam) can be provided to the second-effect heater. The first-effect pH value measuring device is connected to the upper part of the first-effect steam purification tower and the upper part of the second-effect heater by pipelines, that is, the first-effect pH value measuring device is arranged on the first-effect steam purification pipeline. In this way, the pH value of the heat source (i.e., first-effect secondary steam) passed into the second-effect heater can be measured.

[0050] In certain embodiments, the first-effect pH value adjusting device and the first-effect pH value measuring device are interlocked to ensure the pH value of the first-effect secondary steam.

[0051] In the present invention, the upper portion of the first-effect heater is connected to the condenser and vacuum pump of the condensing unit via pipes, thereby creating a negative pressure in the first-effect evaporation unit and discharging non-condensable gases. The upper portion of the first-effect heater is also connected to a live steam supply unit via pipes. This allows live steam to be supplied to the first-effect heater via the live steam supply unit, thereby providing a heat source for the first-effect heater.

[0052] In the utility model, the first-effect transfer pump is connected to the bottom of the first-effect separator and the lower part of the second-effect separator through pipelines, so that the preliminary concentrated liquid obtained by the first-effect separator can be quickly transferred to the second-effect separator.

[0053] <Second-effect evaporation unit>

[0054] The second-effect evaporation unit of the present invention includes a second-effect heater, a second-effect separator, a second-effect steam purification tower, and a second-effect pH adjustment device. Preferably, it also includes a second-effect circulation pump, a second-effect material transfer pump, and a second-effect pH measurement device. This not only allows for the production of re-concentrated liquid, but also allows for purification of the second-effect steam and for the pH value of the second-effect steam to be controlled within a set range, thereby reducing corrosion to the equipment caused by corrosive ions (e.g., fluoride ions).

[0055] In the present invention, the lower portion of the secondary separator is connected to the bottom of the primary separator via a pipeline, to which a primary transfer pump is connected. This allows the secondary separator to receive the preliminarily concentrated liquid feed from the primary separator. A secondary pH adjustment device is connected to the lower portion of the secondary separator via a pipeline and is used to supply a regulating liquid to the secondary separator. This regulating liquid neutralizes the liquid feed within the secondary separator, regulating its pH, and thereby regulating the pH of the secondary steam discharged from the secondary steam purification tower to the triple-effect heater.

[0056] The lower portion of the secondary separator is connected to the bottom of the secondary heater via a pipe. A secondary circulation pump is connected to the bottom of the secondary separator and the bottom of the secondary heater via pipes. This allows the initially concentrated liquid entering the secondary separator to circulate between the secondary heater and the secondary separator, achieving re-concentration.

[0057] The top of the second-effect separator is connected to the bottom of the second-effect steam purification tower by a pipeline. In this way, the second-effect secondary steam separated by the second-effect separator can be purified by the second-effect steam purification tower. For example, the corrosive ion (such as fluoride ion) content in the second-effect secondary steam can be reduced by purification. The upper part of the second-effect steam purification tower is connected to the upper part of the triple-effect heater by a pipeline, and the pipeline can be called a second-effect steam purification pipeline. In this way, a heat source (i.e., second-effect secondary steam) can be provided to the triple-effect heater. A second-effect pH value measuring device is respectively connected to the upper part of the second-effect steam purification tower and the upper part of the triple-effect heater by pipelines, that is, the second-effect pH value measuring device is arranged on the second-effect steam purification pipeline. In this way, the pH value of the heat source (i.e., second-effect secondary steam) passed into the triple-effect heater can be measured.

[0058] In certain embodiments, the second-effect pH value adjusting device and the second-effect pH value measuring device are interlocked to ensure the pH value of the second-effect secondary steam condensate.

[0059] The upper portion of the second-effect heater is also connected to the condenser and vacuum pump of the condensing unit in sequence through pipes, thereby creating a negative pressure in the second-effect evaporation unit and discharging non-condensable gas. In the present utility model, the upper portion of the first-effect heater and the upper portion of the second-effect heater can be connected in parallel to the pipes connected to the condenser.

[0060] The secondary effect transfer pump is connected to the bottom of the secondary effect separator and the lower part of the tertiary effect separator through pipelines, so that the re-concentrated liquid obtained from the secondary effect separator can be quickly transferred to the tertiary effect separator.

[0061] In certain embodiments, the lower portion of the secondary effect separator may also be connected to a discharge unit via a pipeline, so as to discharge the liquid that has reached the re-concentration target to a receiving tank.

[0062] <Triple-effect evaporation unit>

[0063] The triple-effect evaporation unit of the present invention includes a triple-effect heater, a triple-effect separator, a triple-effect steam purification tower, and a triple-effect pH adjustment device. Preferably, it also includes a triple-effect circulation pump, a triple-effect material transfer pump, and a triple-effect pH measurement device. This not only produces a final concentrated liquid feed, but also allows for purification of the triple-effect secondary steam and controls the pH of the triple-effect secondary steam within a set range, thereby reducing corrosion to the equipment caused by corrosive ions (e.g., fluoride ions).

[0064] In the present invention, the lower portion of the triple-effect separator is connected to the bottom of the secondary-effect separator via a pipeline, to which a secondary-effect transfer pump is connected. This allows the triple-effect separator to receive the re-concentrated liquid from the secondary-effect separator. A triple-effect pH adjustment device is connected to the lower portion of the triple-effect separator via a pipeline and is used to provide a regulating liquid into the triple-effect separator. This regulating liquid can neutralize the liquid in the triple-effect separator, adjusting the pH of the liquid, thereby adjusting the pH of the triple-effect secondary steam discharged from the triple-effect steam purification tower to the condenser.

[0065] The lower portion of the triple-effect separator is connected to the bottom of the triple-effect heater via a pipe. A triple-effect circulation pump is connected to the bottom of the triple-effect separator and the bottom of the triple-effect heater via pipes, respectively. This allows the re-concentrated liquid entering the triple-effect separator to circulate between the triple-effect heater and the triple-effect separator, achieving final concentration.

[0066] The top of the triple-effect separator is connected to the bottom of the triple-effect steam purification tower by a pipeline. In this way, the triple-effect secondary steam separated by the triple-effect separator can be purified by the triple-effect steam purification tower, for example, the corrosive ion (such as fluoride ion) content in the triple-effect secondary steam can be reduced by purification. The top of the triple-effect steam purification tower is connected to the top of the condenser of the condensing unit by a pipeline, and this pipeline can be called the triple-effect steam purification pipeline, so that the triple-effect steam purified by the triple-effect steam purification tower can be cooled. A triple-effect pH value measuring device is respectively connected to the top of the triple-effect steam purification tower and the top of the condenser by a pipeline, that is, the triple-effect pH value measuring device is arranged on the triple-effect steam purification pipeline. In this way, the pH value of the triple-effect secondary steam passed into the condenser can be measured.

[0067] In certain embodiments, the triple-effect pH adjustment device and the triple-effect pH measurement device are interlocked to ensure the pH value of the triple-effect secondary steam.

[0068] The upper portion of the triple-effect heater is also connected to the condenser and vacuum pump of the condensing unit via pipes, thereby creating a negative pressure within the triple-effect evaporation unit and discharging non-condensable gases. In the present invention, the upper portions of the first-effect heater, the second-effect heater, and the triple-effect heater can be connected in parallel to the pipes connected to the condenser, thereby creating a negative pressure within the entire evaporation system, discharging non-condensable gases, and making the overall structure more compact.

[0069] In the utility model, the triple-effect steam purification tower and the upper part of the triple-effect heater are connected to the condenser in parallel.

[0070] The three-effect transfer pump is connected to the bottom of the three-effect separator through a pipeline, so that the final concentrated liquid can be discharged to the receiving tank of the discharge unit.

[0071] According to one embodiment of the present invention, a discharge concentration meter may be provided on the pipeline connecting the triple-effect transfer pump and the receiving tank to measure the concentration of the final concentrated liquid (i.e. the liquid discharged to the receiving tank).

[0072] In the utility model, the high-salt secondary steam condensate separated by the first-effect steam purification tower, the second-effect steam purification tower, and the third-effect steam purification tower can be returned to the evaporation system, and the clean secondary steam condensate is returned to the heat exchange system for reuse.

[0073] <Condensation unit and cooling water supply unit>

[0074] The condensing unit of the utility model comprises a condenser, a vacuum pump, a steam condensing water tank and a steam condensing water pump.

[0075] In the present invention, the upper portion of the condenser is connected to the upper portion of the first-effect heater, the upper portion of the second-effect heater, the upper portion of the third-effect heater, and the upper portion of the third-effect steam purification tower via pipes. This allows the third-effect secondary steam discharged from the third-effect steam purification tower to be cooled, and the non-condensable gas discharged from the first-effect heater, the second-effect heater, and the third-effect heater to be further cooled or discharged.

[0076] The vacuum pump is connected to the upper part of the condenser through a pipeline, which is conducive to forming negative pressure in the evaporation system and discharging non-condensable gas.

[0077] The steam condensate tank is connected to the lower part of the condenser and the steam condensate pump through pipelines, so that cooled secondary steam condensate can be obtained.

[0078] In certain embodiments, the lower portion of the condenser is further connected to the lower portion of the second-effect heater and the lower portion of the triple-effect heater through pipelines, so that the secondary steam discharged from the second-effect heater and the triple-effect heater can be cooled.

[0079] In the present invention, the cooling water supply unit is connected to the bottom of the condenser and is used to supply cooling water to the condenser.

[0080] <Raw Steam Supply Unit>

[0081] In the present invention, the raw steam supply unit is connected to the first-effect heater of the first-effect evaporation unit through a pipeline, and is used to supply raw steam to the first-effect heater, that is, to provide a heat source.

[0082] Example 1

[0083] Figure 1 This is an overall schematic diagram of a multi-effect evaporation device of the present utility model.

[0084] like Figure 1As shown, a multi-effect evaporation device for reducing corrosive ion corrosion in this embodiment includes a first-effect evaporation unit 1, a second-effect evaporation unit 2, a third-effect evaporation unit 3, a condensation unit 4, a discharge unit, a cooling water supply unit (not shown), a raw steam supply unit (not shown) and a feed unit 8.

[0085] The feed unit 8 includes a feed pH adjustment device 81, a feed pump 82, and a feed pH measuring device 83. The feed pH measuring device 83 is located on the pipeline connecting the preheater 11 of the first-effect evaporation unit 1 and the feed pump 82, and is used to measure the pH of the feed liquid entering the preheater 11. The feed pH adjustment device 81 is used to adjust the pH value of the raw material liquid (e.g., ammonium sulfate waste liquid with a high magnesium content) to a predetermined range. The feed pH adjustment device 81 is connected to the pipeline connecting the feed pump 82 and the first-effect evaporation unit 1. The feed pump 82 is used to pump the raw material liquid into the preheater 11 of the first-effect evaporation unit 1. The feed pH adjustment device 81 is located between the feed pH measuring device 83 and the feed pump 82. In this embodiment, the feed pH adjustment device 81 and the feed pH measuring device 83 can be interlocked and controlled.

[0086] The single-effect evaporation unit 1 includes a preheater 11 , a single-effect heater 12 , a single-effect separator 13 , a single-effect steam purification tower 14 , a single-effect pH value adjustment device 15 , a single-effect circulation pump 16 , a single-effect material transfer pump 17 and a single-effect pH value measuring device 18 .

[0087] The bottom of the preheater 11 is connected to the feed pH measuring device 83 via a pipe. The upper portion of the preheater 11 is connected to the lower portion of the primary heater 12 via a pipe. This pipe receives steam condensate from the primary heater 12 after heat exchange, thereby preheating the feed liquid entering the preheater 11. This reduces costs. A preheater condensate outlet A is provided at the bottom of the preheater 11 for discharging the primary steam condensate.

[0088] The lower portion of the first-effect separator 13 is connected to the bottom of the preheater 11 via a pipeline, and is used to receive the preheated raw material liquid from the preheater 11. The first-effect pH adjustment device 15 is connected to the lower portion of the first-effect separator 13 via a pipeline, and is used to provide a regulating liquid into the first-effect separator 13. This regulating liquid can neutralize the liquid in the first-effect separator 13, adjust the pH value of the liquid, and further adjust the pH value of the first-effect secondary steam.

[0089] The lower portion of the first-effect separator 13 is also connected to the bottom of the first-effect heater 12 via a pipe. A first-effect circulation pump 16 is connected to the bottom of the first-effect separator 13 and the bottom of the first-effect heater 12 via pipes, respectively. This allows the feed liquid entering the first-effect separator 13 to circulate between the first-effect heater 12 and the first-effect separator 13, thereby achieving preliminary concentration.

[0090] The top of the first-effect separator 13 is connected to the bottom of the first-effect steam purification tower 14 via a pipeline. A first-effect pH measuring device 18 is connected to the upper portion of the first-effect steam purification tower 14 and the upper portion of the second-effect heater 22 via pipelines, respectively. This allows the pH value of the first-effect secondary steam entering the second-effect heater 22 to be measured. The first-effect secondary steam serves as the heat source for the second-effect heater 22. In this embodiment, the first-effect pH adjusting device 15 and the first-effect pH measuring device 18 can be interlocked and controlled.

[0091] An effective transfer pump 17 is connected to each other through a pipeline with the bottom of the first effect separator 13 and the bottom of the second effect separator 23. The preliminary concentrated feed liquid obtained by the first effect separator 13 can be transferred to the second effect separator 23 quickly like this.

[0092] The second-effect evaporation unit 2 includes a second-effect heater 22 , a second-effect separator 23 , a second-effect steam purification tower 24 , a second-effect pH value adjustment device 25 , a second-effect circulation pump 26 , a second-effect material transfer pump 27 and a second-effect pH value measuring device 28 .

[0093] The lower portion of the secondary separator 23 is connected to the bottom of the primary separator 13 via a pipeline, to which the primary transfer pump 17 is connected. A secondary pH adjustment device 25 is connected to the lower portion of the secondary separator 23 via a pipeline and is used to provide a regulating liquid into the secondary separator 23. This regulating liquid can neutralize the feed liquid in the secondary separator 23, adjust the pH value of the feed liquid, and thus adjust the pH value of the secondary steam from the secondary effect.

[0094] The lower portion of the secondary effect separator 23 is also connected to the bottom of the secondary effect heater 22 via a pipe. A secondary effect circulation pump 26 is connected to the bottom of the secondary effect heater 22 and the bottom of the secondary effect separator 23 via pipes. This allows the preliminarily concentrated liquid entering the secondary effect separator 23 to circulate between the secondary effect heater 22 and the secondary effect separator 23, thereby achieving re-concentration.

[0095] The top of the second-effect separator 23 is connected to the bottom of the second-effect steam purification tower 24 via a pipeline. The upper portion of the second-effect steam purification tower 24 is connected to the upper portion of the triple-effect heater 32 via a pipeline. A second-effect pH measuring device 28 is provided on this pipeline to measure the pH value of the second-effect secondary steam entering the triple-effect heater 32. The second-effect secondary steam serves as the heat source for the triple-effect heater 32. In this embodiment, the second-effect pH adjusting device 25 and the second-effect pH measuring device 28 can be interlocked.

[0096] The upper portion of the second-effect heater 22 is connected to the upper portion of the first-effect steam purification tower 14 through a pipeline, and is used to receive the first-effect secondary steam from the first-effect steam purification tower 14 .

[0097] The secondary-effect transfer pump 27 is connected to the bottom of the secondary-effect separator 23 and the lower part of the tertiary-effect separator 33 through pipelines, and is used to quickly transfer the re-concentrated liquid obtained from the secondary-effect separator 23 into the tertiary-effect separator 33.

[0098] In this embodiment, the lower portion of the secondary effect separator 23 may also be connected to a discharge unit via a pipeline, so as to discharge the liquid that has reached the re-concentration target to a receiving tank.

[0099] In this embodiment, the lower portion of the second-effect heater 22 is also connected to the lower portion of the condenser 41 of the condensing unit through a pipeline. In this way, when the re-concentrated target liquid is discharged to the receiving tank, the secondary steam condensate can be discharged from the condensing unit 4.

[0100] The triple-effect evaporation unit 3 includes a triple-effect heater 32 , a triple-effect separator 33 , a triple-effect steam purification tower 34 , a triple-effect pH value adjustment device 35 , a triple-effect circulation pump 36 , a triple-effect material transfer pump 37 and a triple-effect pH value measuring device 38 .

[0101] The bottom of the triple effect separator 33 is connected to the bottom of the second effect separator 23 by a pipeline, and the pipeline is connected to the second effect transfer pump 27. This helps the triple effect separator 33 receive the re-concentrated feed liquid from the second effect separator 23.

[0102] The triple-effect pH value regulating device 35 is connected to the lower part of the triple-effect separator 33 through a pipeline, and is used to provide a regulating liquid into the triple-effect separator 33. The regulating liquid can neutralize the feed liquid in the triple-effect separator 33, regulate the pH value of the feed liquid, and further regulate the pH value of the triple-effect secondary steam.

[0103] The lower portion of the triple-effect separator 33 is connected to the bottom of the triple-effect heater 32 via a pipe. A triple-effect circulation pump 36 is connected to the bottom of the triple-effect separator 33 and the bottom of the triple-effect heater 32 via pipes, respectively. This allows the feed liquid in the two to circulate, thereby facilitating final concentration.

[0104] The top of the triple-effect separator 33 is connected to the bottom of the triple-effect steam purification tower 34 via a pipeline. The triple-effect pH value measuring device 38 is connected to the upper portion of the triple-effect steam purification tower 34 and the upper portion of the condenser 41 of the condensing unit 4 via pipelines, so that the pH value of the triple-effect secondary steam entering the condenser 41 can be measured. In this embodiment, the triple-effect pH value adjusting device 35 and the triple-effect pH value measuring device 38 can be interlocked and controlled.

[0105] The upper portion of the triple-effect heater 32 is also connected to the upper portion of the second-effect steam purification tower 24 via a pipeline, and the second-effect pH value measuring device 25 is installed on this pipeline. The triple-effect transfer pump 37 is connected to the bottom of the triple-effect separator 33 via a pipeline and is used to discharge the final concentrated liquid in the triple-effect separator 33 to the receiving tank of the discharge unit.

[0106] The condensing unit 4 includes a condenser 41, a vacuum pump 42, a steam condensate tank 43, and a steam condensate pump 44. The upper portion of the condenser 41 is connected to the upper portion of the first-effect heater 12, the upper portion of the second-effect heater 22, and the upper portion of the triple-effect heater 32 via pipes. The upper portion of the condenser 41 is also connected to the upper portion of the triple-effect steam purification tower 34 via pipes, and a triple-effect pH value measuring device 38 is located on the pipe connecting the condenser 41 and the triple-effect steam purification tower 34. This facilitates the formation of negative pressure within the system and the discharge of non-condensable gases. The vacuum pump 42 is connected to the upper portion of the condenser 41 via pipes. The steam condensate tank 43 is connected to the lower portion of the condenser 41 and the steam condensate pump 44 via pipes. The steam condensate pump 44 provides power to discharge the secondary steam condensate from the steam condensate tank 43 and discharges it to a designated device through the secondary steam condensate outlet E. The lower portion of the condenser 41 is also connected to the lower portion of the second-effect heater 22 and the lower portion of the triple-effect heater 32 through pipelines.

[0107] The discharge unit includes a discharge concentration meter 51 and a receiving tank (not shown). The discharge concentration meter 51 is positioned between the triple-effect transfer pump 37 and the receiving tank. In this embodiment, the receiving tank can also be connected to the lower portion of the secondary separator 23 via a pipeline. The receiving tank is used to receive the concentrated liquid after it has reached the desired concentration target.

[0108] The cooling water supply unit is connected to the bottom of the condenser 41 through a pipe, and is used to supply cooling water to the condenser 41. The bottom of the condenser is provided with a cooling water supply inlet C (for introducing cooling water) and a cooling water outlet D (for discharging the cooling water after heat exchange).

[0109] The raw steam supply unit is connected to the upper portion of the single-effect heater 12 through a pipeline, and is used to supply raw steam to the single-effect heater 12 . Figure 1 B in the figure indicates the inlet of the raw steam supply unit.

[0110] The application of the multi-effect evaporation device for reducing corrosive ion corrosion of this embodiment is described as follows:

[0111] The high-magnesium ammonium sulfate solution with a salt content of 10 wt% produced during the rare earth ore production process is adjusted to a pH value between 4 and 5 using ammonia water (as a regulating liquid) through the feed pH regulating device 81 and then pumped into the preheater 11.

[0112] After being preheated in preheater 11, the steam enters primary separator 13, where it circulates and concentrates between primary separator 13 and primary heater 12. The secondary steam from primary separator 13 is adjusted to a pH of 9-10 by primary pH adjustment device 15 before entering primary steam purification tower 14. High-salt condensate with a conductivity of ≥1000 μs / cm produced by primary steam purification tower 14 is returned to the evaporation system (first to primary separator 13). The purified secondary steam enters secondary heater 22 as a heat source for heat exchange. A preliminarily concentrated feed liquid is obtained in primary evaporation unit 1.

[0113] The initially concentrated liquid is transferred from the first-effect separator 13 to the second-effect separator 23. The secondary steam from the second-effect separator 23 is adjusted to a pH of 9-10 by the second-effect pH adjustment device 25 before entering the second-effect steam purification tower 24. The high-salt condensate with a conductivity of 1500 μs / cm or higher produced by the second-effect steam purification tower 24 is returned to the evaporation system (first to the second-effect separator 23). The purified secondary steam enters the third-effect heater 32 as a heat source for heat exchange. A re-concentrated liquid is obtained in the second-effect evaporation unit 2.

[0114] The re-concentrated liquid is transferred from the secondary separator 23 to the tertiary separator 33. The secondary steam from the tertiary separator 33 is adjusted to a pH of 9-10 by the tertiary pH adjustment device 35 and then enters the tertiary steam purification tower 34. The high-salt condensate with a conductivity of ≥2000 μs / cm produced by the tertiary steam purification tower 34 is returned to the evaporation system (first returning to the tertiary separator 33). The purified secondary steam enters the condenser 41. The secondary steam condensate has a conductivity of ≤200 μs / cm and a fluoride ion content of less than 5 ppm. It is finally discharged from the evaporation system through the condensation unit 4. The finally concentrated liquid is transferred from the tertiary separator 33 to the receiving tank of the discharge unit.

[0115] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement, and substitution that can be thought of by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A multi-effect evaporation device for reducing corrosive ion corrosion, characterized in that: It includes a feeding unit, a first-effect evaporation unit, a second-effect evaporation unit and a third-effect evaporation unit; The feeding unit is connected to the first-effect evaporation unit and is used to supply the raw material liquid to be concentrated to the first-effect evaporation unit; the feeding unit includes a feed pH value adjustment device, which is used to adjust the pH value of the raw material liquid to a predetermined range; The single-effect evaporation unit includes a single-effect heater, a single-effect separator, a single-effect steam purification tower, and a single-effect pH value adjustment device; the lower portion of the single-effect separator receives the pH-adjusted raw material liquid from the feeding unit through a pipeline; the lower portion of the single-effect separator is also connected to the bottom of the single-effect heater and the single-effect pH value adjustment device through pipelines; the top of the single-effect separator is connected to the bottom of the single-effect steam purification tower through a pipeline; The second-effect evaporation unit includes a second-effect heater, a second-effect separator, a second-effect steam purification tower and a second-effect pH value adjustment device; the lower part of the second-effect separator is connected to the bottom of the first-effect separator, the bottom of the second-effect heater and the second-effect pH value adjustment device through pipelines; the top of the second-effect separator is connected to the bottom of the second-effect steam purification tower through a pipeline; the upper part of the second-effect heater is connected to the upper part of the first-effect steam purification tower through a pipeline; The triple-effect evaporation unit includes a triple-effect heater, a triple-effect separator, a triple-effect steam purification tower and a triple-effect pH value adjustment device; the lower part of the triple-effect separator is connected to the bottom of the second-effect separator, the bottom of the triple-effect heater and the triple-effect pH value adjustment device through pipelines; the top of the triple-effect separator is connected to the bottom of the triple-effect steam purification tower through a pipeline; the upper part of the triple-effect heater is connected to the upper part of the second-effect steam purification tower through a pipeline.

2. The multi-effect evaporation device according to claim 1, characterized in that: The feeding unit also includes a feeding pump and a feeding pH value measuring device; The single-effect evaporation unit further includes a preheater, a single-effect circulation pump, a single-effect material transfer pump and a single-effect pH value measuring device; wherein, The feed pump is connected to the preheater through a pipeline and is used to pump the raw material liquid after adjusting the pH value into the preheater; the feed pH value measuring device is provided on the pipeline connecting the preheater and the feed pump and is used to measure the pH value of the liquid entering the preheater; The upper part of the preheater is connected to the lower part of the first-effect heater through a pipeline, and is used to receive steam condensate from the first-effect heater, thereby preheating the liquid in the preheater; The first-effect circulation pump is connected to the first-effect separator and the first-effect heater respectively through pipelines; the first-effect material transfer pump is connected to the bottom of the first-effect separator and the lower part of the second-effect separator respectively through pipelines; the first-effect pH value measuring device is arranged on the pipeline connecting the first-effect steam purification tower and the second-effect heater.

3. The multi-effect evaporation device according to claim 1, characterized in that: The second-effect evaporation unit further includes a second-effect circulation pump, a second-effect material transfer pump and a second-effect pH value measuring device; wherein the second-effect circulation pump is connected to the second-effect heater and the second-effect separator respectively through pipelines; the second-effect material transfer pump is connected to the bottom of the second-effect separator and the lower part of the three-effect separator respectively through pipelines; the second-effect pH value measuring device is arranged on the pipeline connecting the second-effect steam purification tower and the three-effect heater.

4. The multi-effect evaporation device according to claim 1, characterized in that: The triple-effect evaporation unit further includes a triple-effect circulation pump, a triple-effect material transfer pump and a triple-effect pH value measuring device; wherein the triple-effect circulation pump is connected to the triple-effect heater and the triple-effect separator respectively through pipelines; the triple-effect material transfer pump is connected to the bottom of the triple-effect separator through a pipeline; and the triple-effect pH value measuring device is connected to the upper part of the triple-effect steam purification tower through a pipeline.

5. The multi-effect evaporation device according to claim 4, characterized in that: It also includes a condensing unit, which includes a condenser and a vacuum pump; the upper part of the condenser is connected to the upper part of the triple-effect heater, the upper part of the second-effect heater and the upper part of the first-effect heater through pipelines respectively; the upper part of the condenser is also connected to the upper part of the triple-effect steam purification tower through a pipeline, and the triple-effect pH value measuring device is arranged on the pipeline connecting the condenser and the triple-effect steam purification tower; the vacuum pump is connected to the upper part of the condenser through a pipeline.

6. The multi-effect evaporation device according to claim 5, characterized in that: The condensing unit further comprises a steam condensing water tank and a steam condensing water pump; the steam condensing water tank is connected to the lower part of the condenser and the steam condensing water pump respectively through pipelines.

7. The multi-effect evaporation device according to claim 6, characterized in that: The lower portion of the condenser is also connected to the lower portion of the second-effect heater and the lower portion of the triple-effect heater through pipelines.

8. The multi-effect evaporation device according to claim 5, characterized in that: It also includes a discharge unit, which includes a discharge concentration meter and a receiving tank; the discharge concentration meter is connected to the three-effect transfer pump and the receiving tank through pipelines, and is used to measure the concentration of the final concentrated liquid discharged from the three-effect separator.

9. The multi-effect evaporation device according to claim 8, characterized in that: The receiving tank is also connected to the lower part of the second-effect separator through a pipeline.

10. The multi-effect evaporation device according to any one of claims 5 to 9, characterized in that: It also includes a cooling water supply unit and a raw steam supply unit; the raw steam supply unit is connected to the single-effect heater through a pipeline, and is used to supply raw steam to the single-effect heater; the cooling water supply unit is connected to the condenser through a pipeline, and is used to supply cooling water to the condenser.

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