A low temperature concentration apparatus

Abstract

The utility model belongs to chemical equipment technical field discloses a low temperature concentration equipment. The low temperature concentration equipment includes the main circuit of forming the closed loop, is provided with the glass lining circulating tank, the feed pump, the security filter, the high pressure pump, the circulating pump, the nanofiltration water removal membrane group and the heat exchanger in proper order on the main circuit, is equipped with the glass lining storage tank of collecting finished product on the main circuit, still includes the glass lining cleaning tank, and the glass lining cleaning tank is connected through the cleaning branch between the main circuit. In the utility model, the ethanol solution of sulfuric acid to be handled is through nanofiltration membrane group, realizes the primary water removal, and after continuously removing water in the circulating system, realizes the effective concentration of the ethanol solution of sulfuric acid.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, and in particular to a low-temperature concentration device. Background Technology

[0002] In the production of products such as isaconazole sulfate in the pharmaceutical industry, solutions containing ethanol and other components require concentration and dehydration. Traditional concentration methods, such as evaporation concentration, are not only energy-intensive but also prone to damaging heat-sensitive components due to high temperatures. They are also unsuitable for the concentration requirements of specific low-temperature products (sensitive to temperature and purity), leading to unstable product quality, long production cycles, and high costs. Existing membrane concentration equipment and processes on the market are not designed for GMP requirements and specific product production process conditions, exhibiting the following defects: the piping design connecting each unit is not entirely reasonable, leading to uneven flow and residual material accumulation in solution delivery, affecting the continuity and effectiveness of concentration; cleaning pipelines are missing or inadequate, resulting in the accumulation of impurities in the pipelines and equipment after long-term operation, reducing concentration accuracy and equipment lifespan; and the insulation and temperature control design of pipelines for low-temperature environments is insufficient, making it impossible to stably maintain a suitable concentration temperature, thus hindering product quality improvement.

[0003] Therefore, there is an urgent need for a process with a reasonable pipeline layout, suitable for the concentration of specific low-temperature products, capable of efficient water removal, and easy to clean and maintain, in order to solve existing technical problems and meet the needs of high-quality production. Utility Model Content

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a low-temperature concentration device with a reasonable layout, high degree of automation, and suitability for low-temperature product concentration. This device can achieve efficient, continuous, and stable low-temperature concentration and is easy to clean and maintain.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A low-temperature concentration device includes a main circuit forming a closed loop, on which a glass-lined circulating tank, a feed pump, a security filter, a high-pressure pump, a circulating pump, a nanofiltration membrane assembly, and a heat exchanger are sequentially arranged; the main circuit is equipped with a glass-lined storage tank for collecting the finished product.

[0007] It also includes a glass-lined cleaning tank, which is connected to the main circuit via a cleaning branch.

[0008] Furthermore, the top of the glass-lined circulating tank is provided with a circulating tank purified water inlet pipe for raising the liquid level inside the tank, and the circulating tank purified water inlet pipe is provided with a circulating tank purified water inlet valve;

[0009] The top of the glass-lined circulating tank is also equipped with a raw material inlet pipe, a circulating tank nitrogen inlet pipe and a circulating tank exhaust pipe. The circulating tank nitrogen inlet pipe is equipped with a circulating tank air inlet valve, and the circulating tank exhaust pipe is equipped with a circulating tank exhaust valve.

[0010] Furthermore, the connecting pipeline between the glass-lined circulating tank and the feeding pump is a first pipeline, which is equipped with a bottom valve and an outlet valve of the circulating tank. The bottom valve of the circulating tank is located near the discharge end of the glass-lined circulating tank.

[0011] Furthermore, the connecting pipeline between the feed pump and the security filter is a second pipeline, and the second pipeline is equipped with a feed pump outlet valve and a filter inlet valve;

[0012] A receiving pipeline and a nitrogen inlet pipe are connected on the pipeline between the outlet valve of the feed pump and the inlet valve of the filter. The receiving pipeline is connected to the inlet of the glass-lined storage tank and is equipped with a concentrated hydraulic fluid outlet valve. A nitrogen inlet valve is installed on the nitrogen inlet pipe.

[0013] Furthermore, a high-pressure pump inlet valve is provided on the pipeline between the security filter and the high-pressure pump.

[0014] Furthermore, the connecting pipeline between the high-pressure pump and the circulating pump is a third pipeline, the connecting pipeline between the nanofiltration membrane assembly and the heat exchanger is a fourth pipeline, and a fifth pipeline is provided between the third and fourth pipelines; the fourth pipeline is provided with a concentrated liquid outflow regulating valve, which is located near the heat exchanger inlet; the fifth pipeline is provided with a nanofiltration membrane circulation pipeline valve.

[0015] Furthermore, the connecting pipeline between the heat exchanger and the glass-lined circulating tank is a sixth pipeline, which is equipped with a reflux valve and a circulating tank reflux valve, with the reflux valve located close to the glass-lined circulating tank.

[0016] Furthermore, the glass-lined storage tank is connected to a stainless steel spiral plate condenser via a pipeline, and the outlet of the stainless steel spiral plate condenser is connected to a stainless steel receiving tank via a pipeline.

[0017] Furthermore, the top of the glass-lined cleaning tank is provided with a return pipeline connected to the main circuit, and a cleaning tank return valve is provided on the return pipeline;

[0018] The bottom of the glass-lined cleaning tank is provided with a cleaning tank drain circuit and a first branch circuit connected to the main circuit. The cleaning tank drain circuit is provided with a cleaning tank drain valve, and the first branch circuit is provided with a cleaning tank outlet valve.

[0019] Furthermore, the wastewater outlet of the nanofiltration membrane module is provided with a wastewater pipeline, which is connected to a second branch and a third branch respectively. The second branch is connected to the waste liquid tank, and the third branch is connected to the glass-lined cleaning tank. The second branch is provided with a clear liquid drain valve, and the third branch is provided with a membrane reflux valve.

[0020] The beneficial effects of this utility model are as follows: This utility model has a simple structure and reasonable design, and has the following advantages:

[0021] (1) When the liquid level in the glass-lined circulating tank drops to the low dialysis liquid level, the purified water inlet valve is automatically opened to replenish water, which can prevent the circulating pump and other equipment from cavitation due to air intake, prevent pump damage, and extend the service life of the equipment; at the same time, it can also prevent the nanofiltration membrane from dry burning due to lack of water, avoid irreversible damage to the membrane module, and ensure the long-term stable operation of the nanofiltration system; when the high dialysis liquid level is reached, the valve is automatically closed to prevent the liquid level in the circulating tank from being too high and causing excessive pressure, which could damage the tank, pipes and related connecting parts, and ensure that the pressure of the entire system is within a safe and controllable range;

[0022] (2) A stable liquid level helps ensure a stable liquid intake of the circulating pump, thereby maintaining a stable flow rate and pressure in the circulating system; this is crucial for the normal operation of the nanofiltration machine, ensuring the stability of membrane separation efficiency and effect during nanofiltration, enabling the isaconazole sulfate solution to be continuously and effectively concentrated, and ensuring the consistency of product quality.

[0023] (3) Automated liquid level control eliminates the need for operators to constantly monitor liquid level changes and manually operate valves, greatly reducing the workload of operators.

[0024] (4) For products that require low-temperature concentration, temperature fluctuations can lead to increased ethanol volatilization or changes in sulfuric acid activity. Automated control stabilizes the circulating liquid level and coordinates with the temperature regulation of the heat exchanger to ensure that the circulating liquid operates stably in the low-temperature range, avoiding a decrease in heat exchange efficiency of the heat exchanger due to too low a liquid level or insufficient cooling due to too high a liquid level, and ultimately protecting the chemical stability of the product at low temperatures. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] In the diagram: 1. Enameled circulating tank, 2. Enameled cleaning tank, 3. Nanofiltration membrane assembly, 4. Heat exchanger, 5. Stainless steel receiving tank, 6. Enameled storage tank, 7. Feed pump, 8. Security filter, 9. High-pressure pump, 10. Circulating pump, 11. Stainless steel spiral plate condenser, 12. Purified water inlet valve of circulating tank, 13. Air inlet valve of circulating tank, 14. Reflux valve, 15. Bottom valve of circulating tank, 16. Outlet valve of circulating tank, 17. Drain valve of cleaning tank, 18. Outlet valve of cleaning tank, 19. Outlet valve of feed pump, 20. Nitrogen inlet valve, 21. Concentrated hydraulic fluid outlet valve 22. Filter inlet valve, 23. High-pressure pump inlet valve, 24. Concentrate outflow regulating valve, 25. Circulation tank reflux valve, 26. Cleaning tank reflux valve, 27. Heat exchanger refrigeration inlet valve, 28. Discharge valve, 29. Circulation tank exhaust valve, 30. Nanofiltration membrane circulation pipeline valve, 31. Membrane reflux valve, 32. Clarified liquid drain valve, 33. First pipeline, 34. Second pipeline, 35. Third pipeline, 36. Fourth pipeline, 37. Fifth pipeline, 38. Sixth pipeline, 39. Receiving pipeline, 40. First branch, 41. Second branch, 42. Third branch. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] like Figure 1 The image shows a low-temperature concentration device. Figure 1 In the diagram, the red pipeline is the main circuit for low-temperature concentration of materials, and the black pipeline is the cleaning branch circuit.

[0032] The equipment includes a main circuit forming a closed loop, on which are sequentially arranged a glass-lined circulation tank 1, a feed pump 7, a security filter 8, a high-pressure pump 9, a circulation pump 10, a nanofiltration membrane assembly 3, and a heat exchanger 4; a glass-lined storage tank 6 for collecting finished products is provided on the main circuit; and a glass-lined cleaning tank 2 is also included, which is connected to the main circuit via a cleaning branch.

[0033] Nanofiltration membrane module 3 is an acid-resistant, wide-channel spiral wound polyamide nanofiltration membrane module, specifically composed of four polyamide membrane modules connected in parallel. Heat exchanger 4 is a titanium tubular heat exchanger, feed pump 7 is a fluoroplastic feed pump, high-pressure pump 9 is a titanium high-pressure pump, and circulation pump 10 is a titanium circulation pump.

[0034] The top of the glass-lined circulating tank 1 is equipped with a circulating tank purified water inlet pipe for raising the liquid level inside the tank, and the circulating tank purified water inlet pipe is equipped with a circulating tank purified water inlet valve 12; the top of the glass-lined circulating tank 1 is also equipped with a raw material inlet pipe, a circulating tank nitrogen inlet pipe and a circulating tank exhaust pipe, the circulating tank nitrogen inlet pipe is equipped with a circulating tank air inlet valve 13 and the circulating tank exhaust pipe is equipped with a circulating tank exhaust valve 29.

[0035] The connecting pipeline between the glass-lined circulating tank 1 and the feeding pump 7 is the first pipeline 33. The first pipeline 33 is equipped with a circulating tank bottom valve 15 and a circulating tank outlet valve 16. The circulating tank bottom valve 15 is located near the discharge end of the glass-lined circulating tank 1.

[0036] The connection between the feed pump 7 and the security filter 8 is a second pipeline 34, which is equipped with a feed pump outlet valve 19 and a filter inlet valve 22. A receiving pipeline 39 and a nitrogen inlet pipe are connected between the feed pump outlet valve 19 and the filter inlet valve 22. The receiving pipeline 39 is connected to the inlet of the glass-lined storage tank 6, and a concentrated hydraulic fluid outlet valve 21 is installed on the receiving pipeline 39. A nitrogen inlet valve 20 is installed on the nitrogen inlet pipe.

[0037] A high-pressure pump inlet valve 23 is installed on the pipeline between the security filter 8 and the high-pressure pump 9.

[0038] The connection between the high-pressure pump 9 and the circulating pump 10 is the third pipeline 35, and the connection between the nanofiltration membrane group 3 and the heat exchanger 4 is the fourth pipeline 36. A fifth pipeline 37 is provided between the third pipeline 35 and the fourth pipeline 36. A concentrated liquid outflow regulating valve 24 is provided on the fourth pipeline 36, and the concentrated liquid outflow regulating valve 24 is located near the feed inlet of the heat exchanger 4. A nanofiltration membrane circulation pipeline valve 30 is provided on the fifth pipeline 37.

[0039] The connection between heat exchanger 4 and glass-lined circulating tank 1 is the sixth pipe 38. The sixth pipe 38 is equipped with a reflux valve 14 and a circulating tank reflux valve 25. The reflux valve 14 is located close to the glass-lined circulating tank 1.

[0040] The glass-lined storage tank 6 is connected to a stainless steel spiral plate condenser 11 via a pipeline, and the outlet of the stainless steel spiral plate condenser 11 is connected to a stainless steel receiving tank 5 via a pipeline.

[0041] The top of the glass-lined cleaning tank 2 is provided with a return pipe connected to the sixth pipe 38, and a cleaning tank return valve 26 is provided on the return pipe; the bottom of the glass-lined cleaning tank 2 is provided with a cleaning tank drain pipe and a first branch pipe 40 connected to the first pipe 33, a cleaning tank drain valve 17 is provided on the cleaning tank drain pipe, and a cleaning tank outlet valve 18 is provided on the first branch pipe 40.

[0042] The nanofiltration membrane module 3 has a wastewater outlet with a wastewater pipeline and a discharge valve. The wastewater pipeline is connected to a second branch 41 and a third branch 42. The second branch 41 is connected to the waste liquid tank, and the third branch 42 is connected to the glass-lined cleaning tank 2. The second branch 41 is equipped with a clear liquid drain valve 32, and the third branch 42 is equipped with a membrane reflux valve 31.

[0043] The heat exchanger 4 is equipped with a refrigeration inlet valve 27.

[0044] The specific process of low-temperature concentration of materials is as follows:

[0045] Confirm that the sulfuric acid ethanol solution has entered the glass-lined circulating tank 1, and open the valves on the main solution delivery circuit: circulating tank exhaust valve 29, circulating tank bottom valve 15, circulating tank outlet valve 16, clear liquid drain valve 32, feed pump outlet valve 19, filter inlet valve 22, high-pressure pump inlet valve 23, circulating tank reflux valve 25, heat exchanger refrigeration inlet valve, nanofiltration membrane circulating pipeline valve, concentrate outflow pipeline regulating valve, and circulating tank reflux valve; close the circulating tank purified water inlet valve 12, cleaning tank reflux valve 26, cleaning tank drain valve 17, cleaning tank outlet valve 18, membrane reflux valve 31, concentrated liquid outlet pipeline valve 21, and other drain valves.

[0046] Start the feed pump 7. When the liquid is observed passing through the sight glass after the tubular heat exchanger 4 (system venting complete), start the high-pressure pump 9. First, allow the material to pass through the freezer for cooling. After a few seconds, start the circulation pump 10 to allow the material to pass through the nanofiltration membrane group 3 to begin nanofiltration. Water is discharged through the discharge valve 28 and the clear liquid discharge valve 32. The sulfuric acid ethanol solution is concentrated through the main circuit.

[0047] To ensure the liquid level in the glass-lined circulating tank 1 remains within the safe process range, guaranteeing continuous, stable, and efficient nanofiltration concentration operation, the purified water inlet valve 12 automatically opens and starts timing the dialysis process when the tank level drops to the low dialysis level. It automatically closes when the tank level reaches the high dialysis level, repeating this cycle. The opening and closing states of other valves remain consistent with those during equipment operation.

[0048] The entire cryogenic concentration equipment is equipped with a pressure interlock alarm function. When the outlet pressure P of the feed pump 7 is... S When the high or low pressure alarm values ​​are reached, the feed pump outlet pressure will trigger a high or low alarm; when the circulating pump 10 outlet pressure P C When the pressure reaches the high alarm or very high alarm value, the circulating pump outlet pressure will trigger a high alarm or very high alarm; when the concentrate outlet pressure P... CO When the high or low pressure alarm values ​​are reached, the concentrate outlet pressure will trigger a high or low alarm. The pressure of the pipelines before and after the high-pressure pump 9 and the nanofiltration membrane group 3 will be monitored in real time to prevent material blockage in the membrane and material leakage caused by pipeline pressure.

[0049] The entire low-temperature concentration equipment is equipped with a temperature interlock alarm function. When the inlet temperature T of heat exchanger 4 reaches the high temperature alarm or high-high alarm value, the heat exchanger inlet temperature will be alarmed. When the inlet temperature T of heat exchanger reaches the valve auto-opening value or auto-closing value, the chilled water inlet valve of the heat exchanger will automatically open or close to prevent the product from being adversely affected by the increase in the internal circulating temperature of the equipment.

[0050] After concentration, the liquid from the glass-lined circulation tank 1 is transferred to the glass-lined storage tank 6, which is accomplished in three steps, as follows:

[0051] (1) The liquid material in the glass-lined circulating tank 1 is transferred to the glass-lined storage tank 6.

[0052] When the set concentration time is reached, and the nanofiltration low-temperature concentration ends, the circulation pump 10 is stopped first, the high-pressure pump 9 is stopped after a few seconds, and the feed pump 7 is stopped after another few seconds. At this time, the concentration is terminated. The filter inlet valve 22 is closed, and the circulation tank outlet valve 16, the feed pump outlet valve 19, the concentrated hydraulic fluid outlet pipe valve 21, and the circulation tank air inlet valve 13 are opened. Nitrogen gas is introduced into the nitrogen inlet pipe of the circulation tank, and the nanofiltration completed liquid in the glass-lined circulation tank 1 is transferred to the glass-lined storage tank 6 through the first pipe 33, the second pipe 34, and the receiving pipe 39 in sequence.

[0053] (2) The residual liquid in the main circuit pipeline is transferred to the glass-lined circulating tank 1.

[0054] Nitrogen gas is used to push the liquid out of the glass-lined circulating tank 1. At this time, there is still residual liquid in the main circuit pipeline. Close the purified water inlet valve 12, circulating tank outlet valve 16, clear liquid drain valve 32, cleaning tank outlet valve 18, cleaning tank drain valve 17, cleaning tank reflux valve 26, membrane reflux valve 31, feed pump outlet valve 19, concentrated liquid outlet pipeline valve 21, and all drain valves in the system. Open the circulating tank reflux valve 25, reflux valve 14, filter inlet valve 22, high-pressure pump inlet valve 23, concentrated liquid outlet pipeline regulating valve 24, and nanofiltration membrane circulating pipeline valve 30. Open the nitrogen inlet valve 20 after feed pump 7 to push the liquid in the main circuit pipeline back to the glass-lined circulating tank 1. When it is observed from the sight glass after the tubular heat exchanger 4 that all the liquid has passed through, close the nitrogen inlet valve 20.

[0055] (3) The liquid in the glass-lined circulating tank 1 is transferred back into the glass-lined storage tank 6.

[0056] Close the filter inlet valve 22, open the circulation tank outlet valve 16, the feed pump outlet valve 19, the concentrated hydraulic fluid outlet valve 21, and the circulation tank inlet valve 13, and introduce nitrogen gas into the circulation tank nitrogen inlet pipe at the top of the glass-lined circulation tank 1 to transfer the filtered liquid in the glass-lined circulation tank 1 into the glass-lined storage tank 6.

[0057] After the concentrate is ejected, a small amount of liquid will often remain in the pipeline of the nanofiltration water removal membrane group 3. At this time, a small amount of purified water can be added to the glass-lined circulation tank 1, and the operation can be repeated according to steps (1) to (3) to incorporate the purified water washing liquid into the glass-lined storage tank 6, collect the liquid remaining in the pipeline, and improve the product yield.

[0058] After each batch of material is processed, the nanofiltration membrane module 3 needs to be cleaned to restore membrane flux. The specific working process is as follows:

[0059] First, close the purified water inlet valve 12 of the circulating tank, the outlet valve 16 of the circulating tank, the reflux valve 25 of the circulating tank, the clear liquid drain valve 32, the cleaning tank drain valve 17, the refrigeration inlet valve 27 of the heat exchanger, the concentrated liquid outlet valve 21, and all drain valves in the system; then open the cleaning tank outlet valve 18, the cleaning tank reflux valve 26, the membrane reflux valve 31, the feed pump outlet valve 19, the filter inlet valve 22, the high-pressure pump inlet valve 23, the concentrated liquid outlet regulating valve 24, and the nanofiltration membrane circulation pipeline valve 30.

[0060] Then, add about 1 / 2 volume of purified water to the glass-lined cleaning tank 2, start the feed pump 7, and when the liquid is observed to pass through the sight glass after the tubular heat exchanger 4 (the system exhaust is completed), start the high pressure pump 9. After a few seconds, start the circulation pump 10. After cleaning for 3 minutes, turn off the circulation pump 10, the high pressure pump 9, and the feed pump 7 in sequence.

[0061] Finally, open the drain valve 17 of the cleaning tank to drain the cleaning solution in the glass-lined cleaning tank 2, and then close the drain valve 17 of the cleaning tank.

[0062] After confirming that the feed liquid and purified water washing liquid in the glass-lined circulating tank 1 have been completely transferred to the glass-lined storage tank 6, ethyl acetate and dichloromethane are pumped into the glass-lined storage tank 6, and stirring is started. After stirring, the mixture is allowed to stand and separate into phases. The lower organic phase is discarded, and the aqueous phase is retained in the reactor. Stirring is started, the jacket is refrigerated, and vacuum is applied to continue the depressurization concentration. The small amount of solvent remaining in the feed liquid is vaporized into gas during the depressurization process. The gas is liquefied through the stainless steel spiral plate condenser 11 and finally collected by the stainless steel receiving tank 5, thus realizing the low-temperature concentration process of the entire product.

[0063] In summary, this utility model has a simple structure, consisting of a glass-lined circulating tank 1, a feed pump 7, a security filter pump 8, a high-pressure pump 9, a circulating pump 10, a nanofiltration membrane module 3, a heat exchanger 4, a glass-lined cleaning tank 2, a stainless steel receiving tank 5, a glass-lined storage tank 6, and a stainless steel spiral plate condenser 11, connected sequentially via pipelines. In this utility model, the sulfuric acid ethanol solution to be treated undergoes preliminary water removal through the nanofiltration membrane module, and then continuous water removal through the circulating system, thereby achieving effective concentration of the sulfuric acid ethanol solution.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A low-temperature concentration device, characterized in that: The equipment includes a main circuit forming a closed loop, on which a glass-lined circulating tank (1), a feed pump (7), a security filter (8), a high-pressure pump (9), a circulating pump (10), a nanofiltration membrane assembly (3), and a heat exchanger (4) are arranged in sequence; a glass-lined storage tank (6) for collecting finished products is provided on the main circuit; It also includes a glass-lined cleaning tank (2), which is connected to the main circuit via a cleaning branch.

2. The low-temperature concentration equipment according to claim 1, characterized in that: The top of the glass-lined circulating tank (1) is provided with a circulating tank purified water inlet pipe for raising the liquid level inside the tank, and the circulating tank purified water inlet pipe is provided with a circulating tank purified water inlet valve (12); The top of the glass-lined circulating tank (1) is also provided with a raw material inlet pipe, a circulating tank nitrogen inlet pipe and a circulating tank exhaust pipe. The circulating tank nitrogen inlet pipe is provided with a circulating tank air inlet valve (13) and the circulating tank exhaust pipe is provided with a circulating tank exhaust valve (29).

3. The low-temperature concentration equipment according to claim 1, characterized in that: The connecting pipeline between the glass-lined circulating tank (1) and the feeding pump (7) is the first pipeline (33). The first pipeline (33) is equipped with a bottom valve (15) and a outlet valve (16) of the circulating tank. The bottom valve (15) of the circulating tank is located near the discharge end of the glass-lined circulating tank (1).

4. The low-temperature concentration equipment according to claim 1, characterized in that: The connecting pipeline between the feed pump (7) and the security filter (8) is a second pipeline (34), and the second pipeline (34) is equipped with a feed pump outlet valve (19) and a filter inlet valve (22); A receiving pipeline (39) and a nitrogen inlet pipe are connected on the pipeline between the feed pump outlet valve (19) and the filter inlet valve (22). The receiving pipeline (39) is connected to the feed port of the glass-lined storage tank (6). A concentrated hydraulic pressure outlet valve (21) is provided on the receiving pipeline (39). A nitrogen inlet valve (20) is installed on the nitrogen inlet pipe.

5. The low-temperature concentration equipment according to claim 1, characterized in that: A high-pressure pump inlet valve (23) is provided on the pipeline between the security filter (8) and the high-pressure pump (9).

6. The low-temperature concentration equipment according to claim 1, characterized in that: The connection between the high-pressure pump (9) and the circulating pump (10) is the third pipeline (35), and the connection between the nanofiltration membrane group (3) and the heat exchanger (4) is the fourth pipeline (36). A fifth pipeline (37) is provided between the third pipeline (35) and the fourth pipeline (36). A concentrated liquid outflow regulating valve (24) is provided on the fourth pipeline (36), and the concentrated liquid outflow regulating valve (24) is located near the feed inlet of the heat exchanger (4). A nanofiltration membrane circulation pipeline valve (30) is provided on the fifth pipeline (37).

7. The low-temperature concentration equipment according to claim 1, characterized in that: The connection between the heat exchanger (4) and the glass-lined circulating tank (1) is the sixth pipeline (38). The sixth pipeline (38) is equipped with a reflux valve (14) and a circulating tank reflux valve (25). The reflux valve (14) is located close to the glass-lined circulating tank (1).

8. The low-temperature concentration equipment according to claim 1, characterized in that: The glass-lined storage tank (6) is connected to a stainless steel spiral plate condenser (11) via a pipeline, and the outlet of the stainless steel spiral plate condenser (11) is connected to a stainless steel receiving tank (5) via a pipeline.

9. A low-temperature concentration device according to claim 1, characterized in that: The top of the glass-lined cleaning tank (2) is provided with a return pipe connected to the main circuit, and a cleaning tank return valve (26) is provided on the return pipe; The bottom of the glass-lined cleaning tank (2) is provided with a cleaning tank drain circuit and a first branch circuit (40) connected to the main circuit. A cleaning tank drain valve (17) is provided on the cleaning tank drain circuit, and a cleaning tank outlet valve (18) is provided on the first branch circuit (40).

10. A low-temperature concentration apparatus according to claim 1, characterized in that: The nanofiltration membrane module (3) has a wastewater outlet with a wastewater pipeline. The wastewater pipeline is connected to a second branch (41) and a third branch (42). The second branch (41) is connected to the waste liquid tank, and the third branch (42) is connected to the glass-lined cleaning tank (2). The second branch (41) is equipped with a clear liquid drain valve (32), and the third branch (42) is equipped with a membrane reflux valve (31).

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