An open feed liquid concentration system and a method of feed liquid concentration

Abstract

The application discloses an open type feed liquid concentration system and a feed liquid concentration method, and relates to the technical field of metallurgy. The system comprises a flow divider, an MVR system, a high-temperature absorption tower, a partition wall type condenser, a first anti-corrosion heat exchanger, a second anti-corrosion heat exchanger, a first superheating heat exchanger unit, a mixed liquid device, a low-temperature absorption tower, a second superheating heat exchanger unit, a heat recovery unit, a regeneration tower, a cooling unit, a cooler and a solid-liquid separator. The system can reduce the temperature of the pre-evaporation liquid going to the second leaching process and reduce the energy consumption of the MVR technology for processing the pre-evaporation liquid.

Description

Technical Field

[0001] This invention relates to the technical field of the metallurgical industry, and more specifically, to an open-type liquid concentrate system and a method for liquid concentrate. Background Technology

[0002] The metallurgical industry faces the core technological requirement of pre-evaporation liquid concentration and volume reduction during production, while also encountering energy consumption and process compatibility issues arising from traditional treatment technologies. This presents numerous challenges to the application of related technologies. Firstly, relying solely on MVR technology to treat pre-evaporation liquid suffers from extremely high power consumption and can lead to excessively high pre-evaporation liquid temperatures, affecting the normal progress of the second-stage leaching process and hindering efficient volume reduction and synergistic compatibility with subsequent processes. Secondly, the new energy industry's demands for production energy efficiency and process stability are continuously increasing, and traditional single MVR technology can no longer meet the industry's core requirements for low energy consumption and process adaptability. Therefore, developing a pre-evaporation liquid concentration treatment technology that features low power consumption, precise temperature control, and strong compatibility with subsequent processes has significant practical application value and market potential.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide an open-type liquid concentration system and a method for liquid concentration to reduce the temperature of the liquid before evaporation in the second-stage leaching process and reduce the energy consumption of MVR technology in treating the liquid before evaporation.

[0005] This invention is implemented as follows: In a first aspect, the present invention provides an open-type liquid concentration system, which includes a distributor, an MVR system, a high-temperature absorption tower, a partitioned condenser, a first corrosion-resistant heat exchanger, a second corrosion-resistant heat exchanger, a first superheated heat exchanger unit, a mixing device, a low-temperature absorption tower, a second superheated heat exchanger unit, a regenerator unit, a regeneration tower, a cooling unit, a cooler, and a solid-liquid separator. The distributor connects to a first branch and a second branch. The first branch connects to the MVR system, which is connected to the spray device in the high-temperature absorption tower via a pre-evaporation liquid delivery pipeline. The high-temperature absorption tower also has a circulating air inlet and a circulating air outlet. The circulating air inlet is connected in sequence to the first superheated heat exchanger and the indirect condenser to introduce circulating air into the high-temperature absorption tower. The circulating air outlet is connected to the indirect condenser. The high-temperature absorption tower also has a circulating liquid outlet and a circulating liquid inlet. The circulating liquid outlet, the first superheated heat exchanger, and the circulating liquid inlet are connected to achieve the concentration and circulation of the pre-evaporation liquid. The MVR system is also connected to the second corrosion-resistant heat exchanger via a condensate pipe. The indirect-contact condenser has a process leachate outflow pipe connected to the second corrosion-resistant heat exchanger to achieve the heating of the process leachate in the second corrosion-resistant heat exchanger. The high-temperature absorption tower has a concentrated liquid outlet connected to a mixing device, and a second branch line connected to the mixing device. The mixing device has a liquid outlet connected to a low-temperature absorption tower. The low-temperature absorption tower, the regenerator unit, and the second superheated heat exchanger unit are connected to achieve circulation of the concentrated liquid. The second superheated heat exchanger unit has a concentrated liquid outlet connected to the second-stage leaching process equipment. The second-stage leaching process equipment is connected to a solid-liquid separator. The solid-liquid separator has a liquid outlet connected to a first corrosion-resistant heat exchanger. The first corrosion-resistant heat exchanger has a process leachate pipeline connected to a partitioned condenser to achieve heat exchange and temperature rise in the partitioned condenser. The first corrosion-resistant heat exchanger has a second-stage process leachate outlet connected to a cooler. The low-temperature absorption tower is equipped with a circulating air inlet and a circulating air outlet. The circulating air inlet is connected to the regeneration tower, and the circulating air outlet is connected to the second superheat heat exchanger and the regeneration tower in sequence to realize the circulation of circulating air. The regeneration tower has a clean water outlet and a clean water inlet. The clean water outlet is connected in sequence to the regenerator unit and the cooling unit, and then connected to the regeneration tower through the cooling unit to achieve clean water circulation. The cooling unit also has a cooling water outlet connected to the cooler.

[0006] The high-temperature open-loop evaporation absorption wastewater purification system consists of a distributor, an MVR system, a high-temperature absorption tower, a partition condenser, a first corrosion-resistant heat exchanger, a second corrosion-resistant heat exchanger, a first superheated heat exchanger unit, and a mixing device.

[0007] The low-temperature absorption tower, the second superheated heat exchanger, the regenerator, the regeneration tower, the cooling unit, the cooler, and the solid-liquid separator constitute a low-temperature open-loop evaporation absorption wastewater purification system.

[0008] In the above system, the liquid before evaporation after being evaporated by the MVR system enters the high-temperature absorption tower, where it is sprayed at a certain circulation rate and comes into direct contact with the circulating working fluid air in the high-temperature absorption tower. Heat and moisture are carried away, thereby achieving the effects of concentration, volume reduction, and cooling.

[0009] The pre-evaporation liquid from the high-temperature absorption tower mixes with the remaining pre-evaporation liquid at the outlet of the distributor and enters the low-temperature absorption tower. The mixed pre-evaporation liquid is sprayed at a certain spray ratio and comes into direct contact with the humidified air (circulating air). The moisture and heat are carried by the air and then exit the low-temperature absorption tower to enter the second-stage leaching process. The second-stage leaching liquid enters the anti-corrosion heat exchanger to heat the leaching liquid in the plant process, and then enters the cooler to be cooled twice by cooling water.

[0010] In the above system, the process leachate first enters the first corrosion-resistant heat exchanger to exchange heat with the second stage leachate to achieve a temperature increase. Then, it enters the partition condenser to exchange heat with the humidified air that has absorbed the heat of the liquid before evaporation to achieve a second temperature increase. After that, it goes to the second corrosion-resistant heat exchanger to exchange heat with the condensate from the MVR system to complete the third heating.

[0011] In the above system, a stream of humidified air absorbs heat and moisture from the pre-evaporation liquid at the MVR outlet in the high-temperature absorption tower, increasing its temperature and moisture content. It then enters the indirect-containment condenser, where it exchanges heat with the process leachate in the indirect-containment condenser, transferring the heat to the process leachate. The cooled purified water is then discharged and returns to the high-temperature absorption tower to continue heat and mass transfer with the pre-evaporation liquid, in a continuous cycle.

[0012] In the above system, a stream of humidified air absorbs heat and moisture from the mixed pre-evaporation liquid in the low-temperature absorption tower. After the temperature and moisture content increase, it enters the regeneration tower and comes into direct contact with the circulating purified water sprayed in the regeneration tower, transferring heat and moisture to the circulating purified water. After that, it returns to the low-temperature absorption tower and continues to transfer heat and mass with the mixed pre-evaporation liquid, in a continuous cycle.

[0013] In the above system, the circulating purified water absorbs heat and moisture from the humidified air in the regeneration tower. The purified water produced in this process is discharged for other process uses. Afterward, the circulating purified water enters the cooling unit, transfers heat to the cooling water, and then returns to the regeneration tower, repeating the cycle.

[0014] In the above system, the cooling water first enters the cooling unit to cool the circulating purified water, and then enters the cooler to further cool the second-stage leachate from the first anti-corrosion heat exchanger.

[0015] The condensate from the pre-evaporation product of the MVR concentrate enters the second corrosion-resistant heat exchanger to transfer heat to the process leachate coming out of the indirect condenser.

[0016] In a preferred embodiment of the present invention, the first corrosion-resistant heat exchanger is further provided with a process leachate inlet.

[0017] Secondly, the present invention also provides a method for open-loop liquid concentration. The open-loop liquid concentration system described above is used for liquid concentration. The pre-evaporation liquid is introduced into a distributor, and after being split by the distributor, a portion of the pre-evaporation liquid enters the MVR system via the first branch for concentration treatment. The pre-evaporation liquid treated by the MVR system enters a high-temperature absorption tower for concentration and cooling. The concentrated liquid is then discharged through a concentration circulation to a mixing device, where it is mixed with another portion of the pre-evaporation liquid from the second branch and introduced into a low-temperature absorption tower for concentration and cooling. The concentrated liquid is then discharged through a concentration circulation to a second-stage leaching process device, where it is mixed with acid and minerals. After separation by a solid-liquid separator, a second-stage leaching solution is obtained and discharged into a first corrosion-resistant heat exchanger for external process leaching. The second-stage leaching solution, after heat exchange in the first corrosion-resistant heat exchanger, is then introduced into a cooler for cooling. The circulating air circulates in the partition condenser and the high-temperature absorption tower, and exchanges heat with the process leachate from the first corrosion-resistant heat exchanger in the partition condenser; the condensate of the MVR system exchanges heat with the process leachate from the partition condenser in the second corrosion-resistant heat exchanger.

[0018] In a preferred embodiment of the present invention, another stream of circulating air circulates between the low-temperature absorption tower and the regeneration tower, and exchanges heat with the purified water from the cooling unit in the regeneration tower.

[0019] In a preferred embodiment of the present invention, the flow rate ratio of the pre-evaporation liquid in the first branch to the second branch is 280±10:260±10. By splitting the flow, the amount of pre-evaporation liquid directly supplied by the MVR for evaporation and concentration is reduced, which helps to reduce the processing load of the MVR system and reduce energy consumption.

[0020] In a preferred embodiment of the present invention, the concentrated liquid flowing out of the high-temperature absorption tower exchanges heat with the circulating air from the first superheated heat exchange unit and the indirect-flow condenser, then is introduced back into the high-temperature absorption tower for concentration and circulation, and finally discharged to the mixing device. The mixing device is, for example, a mixing tank, mixing trough, or mixing pool.

[0021] In a preferred embodiment of the present invention, the concentrated liquid flowing out of the low-temperature absorption tower exchanges heat with a regenerator unit and a second superheater heat exchanger unit. It then exchanges heat with the circulating air coming out of the low-temperature absorption tower in the second superheater heat exchanger unit, and is then introduced into the low-temperature absorption tower for concentration and circulation by the second superheater heat exchanger unit, before being discharged into the leaching stage II process equipment.

[0022] In a preferred embodiment of the present invention, the cooling unit introduces purified water into the regeneration tower, where it exchanges heat with the circulating air. The purified water from the regeneration tower is then introduced into the regenerator unit to exchange heat with the concentrated liquid from the low-temperature absorption tower. The purified water after heat exchange is then introduced into the cooling unit to achieve purified water circulation.

[0023] Thirdly, the present invention also provides the application of an open-type liquid concentration system in liquid concentration.

[0024] The present invention has the following beneficial effects: This invention provides an open-loop feed concentration system based on the principle of an open absorption heat pump. First, a portion of the pre-evaporation liquid is evaporated through an MVR system. The remaining liquid after evaporation is then introduced into a high-temperature absorption tower for concentration. This process involves repeated circulation and concentration to obtain a concentrated solution. During this process, a second and a first corrosion-resistant heat exchanger are used to recover heat from the high-temperature condensate generated by the MVR system. This heat can be used to heat another stream or an external process leachate, achieving partial concentration and volume reduction of the pre-evaporation liquid, thus reducing the power consumption of the MVR system. The remaining pre-evaporation liquid is mixed with the concentrated solution discharged from the high-temperature absorption tower and then circulated and concentrated in a low-temperature absorption tower. This further reduces the material throughput of direct evaporation and concentration using the MVR system, thus lowering energy consumption. Further concentration and volume reduction of the remaining pre-evaporation liquid in the low-temperature absorption tower significantly lowers the temperature of the pre-evaporation liquid heading to the second-stage leaching process, thereby solving the problem of high outlet temperature in the second-stage leaching process and effectively protecting the reaction equipment in the second-stage leaching stage.

[0025] Therefore, by innovatively coupling two concentration systems (high-temperature open-loop evaporation and absorption wastewater purification system and low-temperature open-loop evaporation and absorption wastewater purification system) through open-loop evaporation and absorption technology, dual concentration of the liquid before evaporation is achieved.

[0026] This invention achieves the simultaneous heating of another process leachate while concentrating and cooling the pre-evaporation liquid, thereby reducing the enterprise's heat consumption and providing multiple technical advantages. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is one of the schematic diagrams of an open-type liquid concentration system; Figure 2 This is the second schematic diagram of an open-type liquid concentration system.

[0029] Explanation of reference numerals in the attached diagram: 1-MVR system; 2-High temperature absorption tower; 3-Indirect wall condenser; 4-Second anti-corrosion heat exchanger; 5-First superheated heat exchanger unit; 6-First anti-corrosion heat exchanger unit; 7-Mixing tank; 8-Diverter; 9-First stage leaching process; 10-Low temperature absorption tower; 11-Second superheated heat exchanger unit; 12-Second stage leaching process; 13-Solid-liquid separator; 14-Cooler; 15-Cooling unit; 16-Regenerator unit; 17-Regeneration tower. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0031] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0032] Example 1 This embodiment provides an open-loop liquid concentration system, the results of which are illustrated in the diagram below. Figure 1 and Figure 2 As shown.

[0033] The system includes: a distributor 8, an MVR system 1, a high-temperature absorption tower 2, a partitioned condenser 3, a first corrosion-resistant heat exchanger 6, a second corrosion-resistant heat exchanger 4, a first superheated heat exchanger unit 5, a mixing tank 7, a low-temperature absorption tower 10, a second superheated heat exchanger unit 11, a regenerator unit 16, a regeneration tower 17, a cooling unit 15, a cooler 14, and a solid-liquid separator 13; The distributor 8 is connected to a first branch and a second branch. The first branch connects to the MVR system 1, which is connected to the spray device in the high-temperature absorption tower 2 via a pre-evaporation liquid delivery pipeline. The high-temperature absorption tower 2 also has a circulating air inlet and a circulating air outlet. The circulating air inlet is connected to the first superheated heat exchanger 5 and the indirect condenser 3 to introduce circulating air into the high-temperature absorption tower 2. The circulating air outlet is connected to the indirect condenser 3. The high-temperature absorption tower 2 also has a circulating liquid outlet and a circulating liquid inlet. The circulating liquid outlet, the first superheated heat exchanger 5, and the circulating liquid inlet are connected to achieve the concentration and circulation of the pre-evaporation liquid until a concentrated liquid with a preset concentration and temperature is obtained, for example, a concentrated liquid at 75°C. Before evaporation in the high-temperature absorption tower 2, spraying occurs at a certain circulation rate, directly contacting the circulating working fluid (i.e., circulating air) within the high-temperature absorption tower 2. Heat and moisture are carried away, thereby achieving the effects of concentration reduction and cooling. The circulating working fluid is air.

[0034] The MVR system 1 is also connected to the second corrosion-resistant heat exchanger 4 via a condensate pipe. The indirect-flow condenser 3 has a process leachate outlet pipe connected to the second corrosion-resistant heat exchanger 4 to raise the temperature of the process leachate in the second corrosion-resistant heat exchanger 4. In this way, the excess heat from the hot condensate generated by the MVR is used to heat another stream of process leachate, achieving efficient heat utilization.

[0035] The high-temperature absorption tower 2 has a concentrated liquid outlet connected to a mixing device, and a second branch line connected to the mixing device; the mixing device has a liquid outlet connected to the low-temperature absorption tower 10, and the low-temperature absorption tower 10, the regenerator unit 16, and the second superheated heat exchanger unit 11 are connected to realize the circulation of the concentrated liquid.

[0036] Specifically, the pre-evaporation liquid from the high-temperature absorption tower 2 is mixed with the remaining pre-evaporation liquid from the outlet of the distributor 8 and then enters the low-temperature absorption tower 10. The mixed pre-evaporation liquid is sprayed at a certain spray ratio and comes into direct contact with the humidified air. The moisture and heat are carried away by the air, thereby achieving further concentration of the pre-evaporation liquid.

[0037] The second superheated heat exchanger unit 11 has a concentrated liquid outlet connected to the leaching second stage process 12 equipment. At this time, the concentrated liquid of the second superheated heat exchanger unit 11 can be introduced into the leaching second stage process 12 equipment for leaching second stage process 12. Acid and mineral can be added.

[0038] The leaching stage 12 equipment is connected to a solid-liquid separator 13 to separate the solid from the second-stage leachate, with the solid being discharged as slag. The solid-liquid separator 13 has a liquid outlet connected to a first corrosion-resistant heat exchanger 6. The first corrosion-resistant heat exchanger 6 has a process leachate pipeline connected to a partition condenser 3 to achieve initial heat exchange and temperature increase of the process leachate in the partition condenser 3, and initial cooling of the second-stage leachate. The first corrosion-resistant heat exchanger 6 has a second-stage process leachate outlet connected to a cooler 14, where the second-stage leachate is further cooled. The first corrosion-resistant heat exchanger 6 is also equipped with a process leachate inlet.

[0039] The low-temperature absorption tower 10 is equipped with a circulating air inlet and a circulating air outlet. The circulating air inlet is connected to the regeneration tower 17, and the circulating air outlet is connected in sequence to the second superheat heat exchanger unit 11 and the regeneration tower 17 to realize the circulation of circulating air. The circulating air is used to remove water from the liquid before evaporation, thereby achieving low-temperature concentration.

[0040] The regeneration tower 17 has a clean water outlet and a clean water inlet. The clean water outlet is connected in sequence to the regenerator unit 16 and the cooling unit 15, and then connected to the regeneration tower 17 via the cooling unit 15 to achieve clean water circulation. Cooling unit 15 also has a cooling water outlet connected to cooler 14.

[0041] The specific process for open-loop liquid concentration is as follows: (1) Liquid flow before evaporation The pre-evaporation liquid from the leaching process is divided into two streams by splitter 8, one stream being 280m³. 3The liquid before evaporation from the MVR system 1 is directly fed into the MVR system 1 for concentration. The liquid before evaporation from the MVR outlet enters the high-temperature absorption tower 2, where it is sprayed at a certain circulation rate and comes into direct contact with the circulating working fluid in the high-temperature absorption tower 2. Heat and moisture are carried away, thereby achieving the effects of concentration, volume reduction, and cooling. The liquid before evaporation from the high-temperature absorption tower 2 is mixed with the remaining liquid before evaporation (260m³) at the outlet of the distributor 8. 3 After mixing, the mixture enters the low-temperature absorption tower 10. The pre-evaporation liquid is sprayed at a certain spray ratio and comes into direct contact with the humidified air. The moisture and heat are carried by the air. The concentrate is then discharged from the low-temperature absorption tower 10 and enters the second-stage leaching process 12. The second-stage leaching liquid enters the first anti-corrosion heat exchanger 6 to heat a batch of in-plant process leaching liquid. After that, it enters the cooler 14 and is cooled twice by cooling water.

[0042] (2) Process leachate flow The process leachate first enters the first corrosion-resistant heat exchanger 6 to exchange heat with the second stage leachate to achieve a temperature increase. Then it enters the partition condenser 3 to exchange heat with the humidified air that has absorbed the heat of the liquid before evaporation to achieve a second temperature increase. After that, it goes to the second corrosion-resistant heat exchanger 4 to exchange heat with the condensate from the MVR to complete the third heating.

[0043] (3) Circulating working fluid air flow After a stream of humidified air absorbs heat and moisture from the pre-evaporation liquid at the MVR outlet in the high-temperature absorption tower 2, its temperature and moisture content increase. It then enters the indirect-contact condenser 3 to exchange heat with the process leachate in the indirect-contact condenser 3, transferring heat to the process leachate and cooling the purified water produced. The purified water then returns to the high-temperature absorption tower 2 to continue heat and mass transfer with the pre-evaporation liquid, and the cycle repeats.

[0044] A stream of humidified air absorbs heat and moisture from the mixed pre-evaporation liquid in the low-temperature absorption tower 10. After the temperature and moisture content increase, it enters the regeneration tower 17 and comes into direct contact with the circulating purified water sprayed in the regeneration tower 17, transferring heat and moisture to the circulating purified water. After that, it returns to the low-temperature absorption tower 10 and continues to transfer heat and mass with the mixed pre-evaporation liquid, in a continuous cycle.

[0045] (4) Circulating water purification process The circulating purified water absorbs heat and moisture from the humidified air in the regeneration tower 17. The purified water produced in this process is discharged for other process uses. Afterward, the circulating purified water enters the cooling unit 15, transfers heat to the cooling water, and then returns to the regeneration tower 17, repeating the cycle.

[0046] (5) Cooling water / condensate flow: The cooling water first enters the cooling unit 15 to cool the circulating purified water, and then enters the cooler 14 to further cool the second-stage leachate from the first anti-corrosion heat exchanger 6.

[0047] The condensate from the pre-evaporation product of the MVR concentrate enters the second corrosion-resistant heat exchanger 4 to transfer heat to the process leachate coming out of the indirect condenser 3.

[0048] Example 2 In this embodiment, the liquid before evaporation is concentrated and cooled in the metallurgical industry, and the process leachate is heated.

[0049] 1. Processing media The liquid before evaporation has an initial temperature of 65℃ and a total feed flow rate of 540m³ / h. It contains acidic components and requires corrosion protection. After the target concentration, the flow rate is maintained at 435m³ / h, and the temperature of the liquid entering the second stage of leaching process 12 drops to 58℃.

[0050] 2. Operating pressure MVR system 1 operates at the original process pressure. The high-temperature absorption tower 2, the indirect-contact condenser 3, the low-temperature absorption tower 10, and the regeneration tower 17 of the open-loop evaporation absorption (LOADS) system all operate at atmospheric pressure and are compatible with the air circulation system.

[0051] 3. Key temperature parameters: The liquid temperature before evaporation at the outlet of MVR system 1 is 85℃; the liquid temperature before evaporation after heat exchange in high-temperature absorption tower 2 is 75℃; and the liquid temperature before evaporation at the outlet of low-temperature absorption tower 10 is 58℃ and the outlet temperature is 73℃.

[0052] 4. Auxiliary media parameters: The process leachate flow rate is 220 m³ / h, the initial temperature is 55℃, and the target heating temperature is 70℃; the cooling water flow rate is 600 m³ / h, and the temperature range is 32℃~47℃; the MVR system 1 condensate flow rate is 115 t / h, and the temperature is 75℃.

[0053] 5. Core Operating Process (1) Process of liquid concentration and cooling before evaporation The 540 m³ / h, 65°C pre-evaporation liquid discharged from the first leaching process 9 is divided into two streams by the splitter 8: one stream enters the MVR system 1 for preliminary concentration, and the 190 m³ / h, 85°C pre-evaporation liquid at the outlet is fed into the high-temperature absorption tower 2, where it is sprayed at a preset circulation ratio and comes into direct contact with the circulating working fluid air inside the tower. The heat and moisture are carried away by the working fluid air, achieving concentration and volume reduction while cooling to 75°C; the other stream of pre-evaporation liquid that does not enter the MVR system 1 is mixed with the pre-evaporation liquid discharged from the high-temperature absorption tower 2 in the mixing tank 7. The mixed pre-evaporation liquid with a flow rate of 442 m³ / h and a temperature of 69.2°C enters the low-temperature absorption tower 10, where it is sprayed at a set spray ratio and comes into direct contact with the humidified air for further concentration and cooling. Finally, it enters the second leaching process 12 at a state of 435 m³ / h and 58°C. The two LOADS systems together achieve a pre-evaporation liquid concentration and volume reduction of 18 t / h (~15 m³ / h), replacing part of the output of the MVR system 1.

[0054] (2) Process leachate heating process The 200 m³ / h, 55°C process leachate first enters the first corrosion-resistant heat exchanger 6, where it exchanges heat with the high-temperature leachate discharged from the second leaching stage 12 to raise its temperature to 60°C. Then it enters the partition condenser 3, where it exchanges heat a second time with the humidified air that has absorbed the heat from the liquid before high-temperature evaporation to raise its temperature to 65°C. Finally, it is introduced into the second corrosion-resistant heat exchanger 4, where it exchanges heat a third time with the 75°C, 115 t / h condensate discharged from the MVR system 1, and finally raises its temperature to 70°C before proceeding to the subsequent processes.

[0055] (3) Circulating working fluid air circulation process High-temperature circulating working fluid air: After absorbing heat and moisture from the liquid before evaporation at 85℃ in the high-temperature absorption tower 2, the temperature and moisture content increase. Then it enters the indirect wall condenser 3, which transfers heat to the process leachate, cools down and precipitates water (producing 3.5t / h of discharged clean water), and then returns to the high-temperature absorption tower 2 to continue participating in the heat and mass transfer cycle.

[0056] Low-temperature circulating working fluid air: Absorbs the heat and moisture of the liquid before evaporation after mixing in the low-temperature absorption tower 10. After the temperature and moisture content increase, it enters the low-temperature regeneration tower 17, directly contacts the circulating purified water sprayed in the tower, transfers heat and moisture, and then returns to the low-temperature absorption tower 10 for circulation.

[0057] (4) Circulating water purification and discharge process The circulating purified water absorbs heat and moisture from the low-temperature circulating working fluid in the low-temperature regeneration tower 17, producing 7.5t / h of discharged purified water (which can be used for other processes in the plant); then the circulating purified water enters the cooling unit 15, transfers heat to the cooling water, and returns to the regeneration tower 17 for continuous circulation.

[0058] (5) Cooling water and condensate utilization process Cooling water: 1100m³ / h, 32℃~40℃ cooling water first enters the cooling unit 15 cooling circulation clean water, and then enters the cooler 14 to further cool the second-stage leachate after heat exchange in the first anti-corrosion heat exchanger 6.

[0059] MVR condensate: The 115t / h, 75℃ condensate generated by the concentrated evaporation liquid in MVR system 1 enters the second anti-corrosion heat exchanger 4 to transfer heat to the process leachate. After the heat exchange is completed, it is discharged according to the original process.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An open-type liquid concentration system, characterized in that, It includes a distributor, an MVR system, a high-temperature absorption tower, a partitioned condenser, a first corrosion-resistant heat exchanger, a second corrosion-resistant heat exchanger, a first superheated heat exchanger unit, a mixing device, a low-temperature absorption tower, a second superheated heat exchanger unit, a regenerator unit, a regeneration tower, a cooling unit, a cooler, and a solid-liquid separator. The distributor is connected to a first branch and a second branch. The first branch is connected to the MVR system. The MVR system is connected to the spray device in the high-temperature absorption tower via a pre-evaporation liquid delivery pipeline. The high-temperature absorption tower also has a circulating air inlet and a circulating air outlet. The circulating air inlet is connected in sequence to the first superheated heat exchanger and the indirect-contact condenser to introduce circulating air into the high-temperature absorption tower. The circulating air outlet is connected to the indirect-contact condenser. The high-temperature absorption tower has a circulating liquid outlet and a circulating liquid inlet. The circulating liquid outlet, the first superheated heat exchanger, and the circulating liquid inlet are connected to achieve the concentration and circulation of the pre-evaporation liquid. The MVR system is also connected to the second corrosion-resistant heat exchanger via a condensate pipe. The indirect-contact condenser has a process leachate outflow pipe connected to the second corrosion-resistant heat exchanger to achieve heating of the process leachate in the second corrosion-resistant heat exchanger. The high-temperature absorption tower has a concentrated liquid outlet connected to the mixing device, and the second branch is connected to the mixing device; the mixing device has a liquid outlet connected to the low-temperature absorption tower, and the low-temperature absorption tower, the regenerator unit, and the second superheated heat exchanger unit are connected to achieve circulation of the concentrated liquid; the second superheated heat exchanger unit has a concentrated liquid outlet connected to the second-stage leaching process equipment, the second-stage leaching process equipment is connected to the solid-liquid separator, the solid-liquid separator has a liquid outlet connected to the first corrosion-resistant heat exchanger, the first corrosion-resistant heat exchanger has a process leaching liquid pipeline connected to the indirect-wall condenser to achieve heat exchange and temperature rise in the indirect-wall condenser; the first corrosion-resistant heat exchanger has a second-stage process leaching liquid outlet connected to the cooler. The low-temperature absorption tower is provided with a circulating air inlet and a circulating air outlet. The circulating air inlet is connected to the regeneration tower, and the circulating air outlet is connected in sequence to the second superheat heat exchanger and the regeneration tower to realize the circulation of circulating air. The regeneration tower has a clean water outlet and a clean water inlet. The clean water outlet is connected in sequence to the regenerator unit and the cooling unit, and is connected to the regeneration tower through the cooling unit to realize clean water circulation. The cooling unit also has a cooling water outlet connected to the cooler.

2. The open-type liquid concentration system according to claim 1, characterized in that, The first corrosion-resistant heat exchanger is also equipped with a process leachate inlet.

3. A method for concentrating open-loop liquid feed, characterized in that, The open-type liquid concentration system according to any one of claims 1-2 is used for liquid concentration. The liquid before evaporation is introduced into a distributor. After being divided by the distributor, part of the liquid before evaporation enters the MVR system for concentration treatment through the first branch. The liquid before evaporation after treatment by the MVR system enters the high-temperature absorption tower for concentration and cooling. The concentrated liquid is discharged to the mixing device after concentration circulation. In the mixing device, it is mixed with another part of the liquid before evaporation from the second branch and then introduced into the low-temperature absorption tower for concentration and cooling. The concentrated liquid is discharged to the second stage leaching process equipment after concentration circulation. It is mixed with acid and minerals and separated by a solid-liquid separator to obtain the second stage leaching solution. It is then led to the first anti-corrosion heat exchanger for external process leaching solution heat exchange. The second stage leaching solution after heat exchange in the first anti-corrosion heat exchanger is introduced into the cooler for cooling. The circulating air circulates in the partition condenser and the high-temperature absorption tower, and exchanges heat with the process leachate from the first corrosion-resistant heat exchanger in the partition condenser; the condensate of the MVR system exchanges heat with the process leachate from the partition condenser in the second corrosion-resistant heat exchanger.

4. The method for open-loop liquid concentration according to claim 3, characterized in that, Another stream of circulating air circulates between the low-temperature absorption tower and the regeneration tower, and exchanges heat with the purified water from the cooling unit in the regeneration tower.

5. The method for open-loop liquid concentration according to claim 3, characterized in that, The flow rate ratio of the pre-evaporation liquid in the first branch and the second branch is 280±10:260±10.

6. The method for open-loop liquid concentration according to claim 3, characterized in that, The concentrated liquid flowing out of the high-temperature absorption tower exchanges heat with the circulating air from the first superheated heat exchanger unit and the indirect condenser, and then is introduced into the high-temperature absorption tower for concentration and circulation, and then discharged to the mixing device.

7. The method for open-loop liquid concentration according to claim 3, characterized in that, The concentrated liquid flowing out of the low-temperature absorption tower exchanges heat with the regenerator unit and the second superheater heat exchanger unit. It then exchanges heat with the circulating air coming out of the low-temperature absorption tower in the second superheater heat exchanger unit, and is then introduced into the low-temperature absorption tower for concentration and circulation by the second superheater heat exchanger unit before being discharged into the leaching stage II process equipment.

8. The method for open-loop liquid concentration according to claim 3, characterized in that, The cooling unit introduces purified water into the regeneration tower, where it exchanges heat with the circulating air. The purified water from the regeneration tower is then introduced into the reheat unit for heat exchange with the concentrated liquid from the low-temperature absorption tower. The purified water after heat exchange is then introduced into the cooling unit to achieve purified water circulation.

9. The application of the open-type liquid concentration system as described in any one of claims 1-2 in liquid concentration.

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