Desalted water treatment system

Abstract

The invention discloses a desalted water treatment system which comprises a hot desalted water system and a cold desalted water system, and a first communication pipeline with a communication valve is arranged between an EDI feed pump outlet in the cold desalted water system and a process condensate tank in the hot desalted water system. And the condensate in the process condensate tank is cooled through the liquid flowing back through the first communication pipeline. The problem that the heat exchange efficiency of the heat exchanger is low due to insufficient circulating water and small heat exchange area of the heat exchanger can be solved, and the problem that the exchange capacity and the service life of the resin are affected due to thermal decomposition of anion and cation resin caused by over-high condensate temperature can also be solved.

Description

Technical Field

[0001] The invention relates to the technical field of desalted water systems, and in particular to a desalted water processing system. Background Art

[0002] At present, our company's desalination system consists of a hot desalination system and a cold desalination system. The cold desalination water is raw water, and the hot desalination water is the condensate produced by the flash evaporation system and the ORC power generation system. Since this part of the condensate is a high-temperature liquid, it is not suitable for direct treatment by the hot desalination system. Therefore, a circulating water heat exchanger is set before the condensate enters the condensate water tank. The cold medium of the heat exchanger is 20-30℃ circulating water. The specific process of desalination is as follows:

[0003] Cold desalinated water:

[0004] Production water (raw water) → raw water tank → raw water pump → steam-water heat exchanger → multi-media filter → laminated filter → ultrafiltration device → ultrafiltration water tank → first-level reverse osmosis water feed pump → first-level security filter → first-level high-pressure pump → first-level reverse osmosis device → decarbonizer → first-level reverse osmosis water production tank → second-level reverse osmosis water feed pump → second-level security filter → second-level high-pressure pump → second-level reverse osmosis device → second-level reverse osmosis water production tank → EDI water feed pump → EDI security filter → EDI device → desalted water tank → high (low) pressure desalted water pump → high (low) pressure desalted water heat exchanger → high (low) pressure user.

[0005] Thermal desalination water:

[0006] Process condensate → high (low) pressure desalted water heat exchanger → circulating water heat exchanger → process condensate tank → process condensate pump → iron removal filter → pre-cation bed → cation bed resin catcher → refined mixed bed → refined mixed bed resin catcher → desalted water tank → high (low) pressure desalted water pump → high (low) pressure desalted water heat exchanger → high (low) pressure user.

[0007] During the startup phase, the cold desalted water system operates relatively stably, but the hot desalted water system often has problems:

[0008] 1. Insufficient circulating water and small heat exchange area of ​​the heat exchanger result in low heat exchange efficiency of the heat exchanger. High-temperature condensate will cause thermal decomposition of the yin and yang resins, and will also affect the exchange capacity and service life of the resin;

[0009] 2. There is no water purification device in the front-end process of the condensate tank, which causes iron, manganese, suspended matter or organic matter in the incoming water to contaminate the resin. After these substances enter the resin layer, they will form an oxide film or other sediments on the surface of the resin, causing the resin to become hardened, thereby affecting production.

[0010] 3. The amount of condensate fluctuates greatly. Long-term large flow of condensate entering the condensate tank will cause the condensate tank to overflow and increase production costs.

[0011] 4. Although scale inhibitors, hydrochloric acid, reducing agents, non-oxygen bactericides, etc. are added to the water for treatment before entering the primary security filtration, the primary reverse osmosis device will still be blocked after a long period of reverse osmosis operation. The conventional solution is to use a reverse osmosis flushing pump for flushing. However, when the existing backwashing pump is flushing, the flushed sewage is generally discharged directly to the outside, resulting in a waste of water resources.

[0012] In order to continuously and stably produce qualified desalted water, a solution is urgently needed to solve the production problems caused by condensate temperature and water quality. Summary of the invention

[0013] In order to solve one or some technical problems existing in the prior art, the purpose of the present application is to provide a desalted water treatment system, which can not only solve the problem of insufficient circulating water volume and small heat exchange area of ​​the heat exchanger resulting in low heat exchange efficiency of the heat exchanger, but also solve the problem of excessive condensate temperature causing thermal decomposition of yin and yang resins, thereby affecting the exchange capacity and service life of the resin.

[0014] In order to solve the above existing technical problems, one of the purposes of this application is achieved by adopting the following technical solution:

[0015] A desalted water treatment system, comprising a hot desalted water system and a cold desalted water system,

[0016] The process flow of the cold desalted water system includes production water → raw water tank → raw water pump → steam-water heat exchanger → multi-media filter → laminated filter → ultrafiltration device → ultrafiltration water tank → primary reverse osmosis water pump → primary security filter → primary high-pressure pump → primary reverse osmosis device → decarbonizer → primary reverse osmosis water production tank → secondary reverse osmosis water pump → secondary security filter → secondary high-pressure pump → secondary reverse osmosis device → secondary reverse osmosis water production tank → EDI water pump → EDI security filter → EDI device → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user;

[0017] The hot desalted water system includes process condensate → high or low pressure desalted water heat exchanger → circulating water heat exchanger → process condensate tank → process condensate pump → iron removal filter → pre-cation bed → cation bed resin catcher → refined mixed bed → refined mixed bed resin catcher → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user. A first connecting pipeline with a connecting valve is provided between the outlet of the EDI water feed pump in the cold desalted water system and the process condensate tank in the hot desalted water system. The liquid refluxed through the first connecting pipeline cools down the condensate in the process condensate tank.

[0018] Preferably, the condensate inlet pipe of the process condensate is provided with an online monitoring conductivity and TOC meter, and when the conductivity and TOC meter detects that the data exceeds the set value, the connecting valve on the first connecting pipeline is opened to cut out the condensate.

[0019] Preferably, the opening condition of the connecting valve on the first connecting pipeline is: when the condensate temperature at the outlet of the circulating water heat exchanger exceeds the design value of 45° C., the valve of the connecting valve is opened to cool the condensate.

[0020] Preferably, the circulating water supply system of the circulating water heat exchanger includes a circulating water cooling tower, a circulating water pump, a circulating water supply pipe and a circulating water return pipe arranged between the circulating water cooling tower and the circulating water heat exchanger. The hot water in the circulating water cooling tower is sprayed from top to bottom into small water droplets, forming a water film on the surface of the filler and flowing downward. The air flows in the tower from bottom to top. The surface of the hot water is in direct contact with the air, and the water temperature is lowered by conduction heat dissipation and radiation heat dissipation.

[0021] Preferably, a temperature sensor is provided at the discharge port of the circulating water cooling tower, and a cooling fan linked to the circulating water cooling tower is provided on one side of the circulating water cooling tower. The cooling fan can automatically start to dissipate heat after the temperature is set by the temperature sensor.

[0022] Preferably, a second connecting pipeline with a connecting valve is provided on the condensate inlet side of the circulating water heat exchanger in the hot desalted water system and the circulating water return pipe side of the circulating water station, and the liquid returning through the second connecting pipeline cools the condensate in the process condensate tank.

[0023] Preferably, the opening condition of the connecting valve on the second connecting pipeline is: the condensate temperature at the outlet of the circulating water heat exchanger is still too high after the connecting valve on the first connecting pipeline is opened, and at the same time, when the water quality of the condensate inlet water exceeds the design value, the condensate is cooled by opening the connecting valve on the second connecting pipeline.

[0024] Preferably, the first-level reverse osmosis device is externally connected to a reverse osmosis flushing pump, the water inlet pipe of the reverse osmosis flushing pump is connected to the first-level reverse osmosis water production pool, and a concentrate tank is also provided on the sewage pipe of the first-level reverse osmosis device. A concentrate water supply pump and a concentrate water safety filter are respectively provided between the concentrate water tank and the first-level reverse osmosis water production pool. The sewage in the concentrate water tank is transported to the concentrate water safety filter by the concentrate water supply pump for filtration and then flows back to the first-level reverse osmosis water production pool.

[0025] Preferably, a concentrate high-pressure pump and a concentrate reverse osmosis device are provided between the concentrate security filtration and the primary reverse osmosis water production pool, and hydrochloric acid and scale inhibitor are added to the water inlet end of the concentrate security filtration.

[0026] Preferably, a concentrate return pipe is provided between the concentrate reverse osmosis device and the ultrafiltration water tank, and a concentrate return pipe is also provided between the EDI device and the primary reverse osmosis water production tank.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] A first connecting pipeline with a connecting valve is added between the outlet of the EDI water pump in the cold desalted water system and the process condensate tank in the hot desalted water system. A pipeline is designed through the outlet of the EDI water pump to connect to the process condensate tank to solve the problem of excessive temperature. The liquid refluxed through the first connecting pipeline can effectively cool the condensate in the process condensate tank, thereby solving the problem of low heat exchange efficiency of the heat exchanger caused by insufficient circulating water and small heat exchange area of ​​the heat exchanger, so that the condensate temperature reaches a reasonable range, and will no longer cause thermal decomposition of the yin and yang resins, thereby no longer affecting the exchange capacity and service life of the resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a process flow chart of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the circulating water supply system in the present invention;

[0031] Figure 3 This is the original flow chart after improvement of the circulating water heat exchanger, process condensate tank and EDI device in this valve;

[0032] Figure 4 It is the original flow chart of the circulating water heat exchanger, process condensate tank and EDI device in the present invention;

[0033] In the figure: 1. Circulating water cooling tower; 2. Cooling fan; 3. Second connecting pipeline; 4. Circulating water heat exchanger; 5. Circulating water pump; 6. Temperature sensor. DETAILED DESCRIPTION

[0034] Below, the present application is further described in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0035] In the description of the present application, it should be understood that the terms "up", "down", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0036] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0037] like Figure 1 As shown, a desalted water treatment system includes a hot desalted water system and a cold desalted water system.

[0038] The process flow of the cold desalted water system includes production water → raw water tank → raw water pump → steam-water heat exchanger → multi-media filter → laminated filter → ultrafiltration device → ultrafiltration water tank → primary reverse osmosis water pump → primary security filter → primary high-pressure pump → primary reverse osmosis device → decarbonizer → primary reverse osmosis water production tank → secondary reverse osmosis water pump → secondary security filter → secondary high-pressure pump → secondary reverse osmosis device → secondary reverse osmosis water production tank → EDI water pump → EDI security filter → EDI device → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user;

[0039] The hot desalted water system includes process condensate → high or low pressure desalted water heat exchanger → circulating water heat exchanger → process condensate tank → process condensate pump → iron removal filter → pre-cation bed → cation bed resin catcher → refined mixed bed → refined mixed bed resin catcher → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user. A first connecting pipeline with a connecting valve is provided between the outlet of the EDI water feed pump in the cold desalted water system and the process condensate tank in the hot desalted water system. The liquid refluxed through the first connecting pipeline cools down the condensate in the process condensate tank.

[0040] In the cold desalted water system, the water quality standards for primary reverse osmosis, secondary reverse osmosis, EDI produced water and condensate inlet water are shown in Table 1:

[0041] Table 1

[0042]

[0043]

[0044] Since the current desalted water treatment system is in the startup stage, the cold desalted water system operates relatively stably, but the hot desalted water system often has problems such as insufficient circulating water and small heat exchange area of ​​the heat exchanger, resulting in low heat exchange efficiency of the heat exchanger. As a result, high-temperature condensate will cause thermal decomposition of the yin and yang resins, and will also affect the exchange capacity and service life of the resin; therefore, the existing system needs to be improved. As can be seen from Table 1, the water quality of the first-stage reverse osmosis, second-stage reverse osmosis, and EDI produced water is better than the condensate inlet water quality. Introducing cold desalted water into the process condensate water tank to cool the process condensate is a feasible method. Figure 4 As shown, the temperature of the cation bed can only be controlled by plate exchange at present, but due to the uncontrollable condensate and limited circulating water volume, the temperature sometimes cannot reach the expected target (cation bed inlet water temperature ≤ 50°C). In order to avoid such a situation, the temperature and condensate volume of the condensate are unstable during operation, resulting in the failure of the resin, the failure of the cation bed, and the discharge of the condensate, which will cause it to generate unnecessary production costs. In order to reduce this series of losses, a first connecting pipeline with a connecting valve is added between the outlet of the EDI feed water pump in the cold desalted water system and the process condensate tank in the hot desalted water system. A pipeline is designed through the outlet of the EDI feed water pump to connect to the process condensate tank to solve the problem of excessive temperature. The liquid refluxed through the first connecting pipeline can effectively cool the condensate in the process condensate tank, thereby solving the problem of low heat exchange efficiency of the heat exchanger due to insufficient circulating water and small heat exchange area of ​​the heat exchanger, so that the condensate temperature reaches a reasonable range, and will no longer cause thermal decomposition of the cation resin, thereby no longer affecting the exchange capacity and service life of the resin. At the same time, the first connecting pipeline also solves the problem of large fluctuations in the amount of condensate, and the problem of increased production costs after the condensate tank overflows due to a long-term large flow of condensate entering the condensate tank.

[0045] A further improvement is that the condensate inlet pipe of the process condensate is provided with an online monitoring conductivity and TOC meter. When the conductivity and TOC meter detects that the data exceeds the set value, the connecting valve on the first connecting pipeline is opened to cut out the condensate. Table 2 is the condensate inlet water quality standard, and Table 3 is the raw water tank inlet and secondary water production indicators;

[0046] Table 2:

[0047] serial number Project Name unit index 1 Conductivity μs / cm ≤100 2 ph - 7 3 Full Iron Mg / L 1 4 Process condensate inlet TOC mg / l ≤0.3

[0048] Table 3:

[0049] serial number Project Name unit index 1 Conductivity μs / cm ≤5 2 ph - 6.5～7.5 3 Raw water temperature at outlet of steam-water heat exchanger ℃ 20～25

[0050] There is no water purification device in the front-end process of the condensate tank, which causes the iron, manganese, suspended matter or organic matter in the inlet water to contaminate the resin. After these substances enter the resin layer, they will form an oxide film or other sediments on the resin surface, causing the resin to become hardened, thereby affecting production. Therefore, online monitoring conductivity and TOC meters are installed on the condensate inlet pipes of the two process condensates. When the conductivity and TOC meters detect that the data exceeds the set value, the connecting valve on the first connecting pipeline is opened to cut the condensate out to the pipeline at the outlet of the EDI water pump, thereby preventing the iron, manganese, suspended matter or organic matter in the inlet water from contaminating the resin.

[0051] A further improvement is that the opening condition of the connecting valve on the first connecting pipeline is: when the condensate temperature at the outlet of the circulating water heat exchanger exceeds the design value of 45°C, the valve of the connecting valve is opened to cool the condensate.

[0052] Since the operating temperature of the cation bed and mixed bed is ≤60℃, the water inlet temperature of the cation bed is currently controlled to be ≤50℃. Therefore, when the condensate inlet water volume or temperature exceeds the design value of the plate exchanger, causing the condensate temperature at the circulating water heat exchanger outlet to exceed the design value of 45℃, open the valve to cool the condensate.

[0053] A further improvement is that the circulating water supply system of the circulating water heat exchanger 4 includes a circulating water cooling tower 1, a circulating water pump 5, a circulating water supply pipe and a circulating water return pipe arranged between the circulating water cooling tower 1 and the circulating water heat exchanger 4 for heat exchange, the hot water in the circulating water cooling tower 1 is sprayed from top to bottom into small water droplets, a water film is formed on the surface of the filler and flows downward, the air flows from bottom to top in the tower, the surface of the hot water is in direct contact with the air, the heat is dissipated by conduction and radiation, and the water temperature is reduced.

[0054] A further improvement is that a temperature sensor 6 is provided at the discharge port of the circulating water cooling tower 1, and a cooling fan 2 linked to the circulating water cooling tower 1 is provided on one side of the circulating water cooling tower 1. The cooling fan 2 can automatically start heat dissipation after the temperature is set by the temperature sensor 6.

[0055] If the temperature is still ≥30℃ after natural cooling, the fan needs to be started to accelerate heat exchange to reduce the temperature to within the control range.

[0056] A further improvement is that a second connecting pipeline 3 with a connecting valve is provided on the condensate inlet side of the circulating water heat exchanger 4 in the hot desalted water system and the circulating water return pipe side of the circulating water station, and the liquid refluxed through the second connecting pipeline 3 cools the condensate in the process condensate tank.

[0057] By adding a second connecting pipeline 3 with a connecting valve on the condensate inlet side and the circulating water return pipe side of the circulating water heat exchanger 4, excess condensate and unqualified condensate can be discharged into the circulating water through the height difference between the pipelines, which can solve the problem that the condensate tank and the desalted water tank cannot accommodate the unqualified condensate or the condensate amount is too much, and effectively solves the problem of large fluctuations in the condensate amount, long-term large flow of condensate entering the condensate tank, causing the condensate tank to overflow, and increased production costs.

[0058] The water quality standards of the circulating water heat exchanger are shown in Table 4 below:

[0059] Table 4

[0060]

[0061] As can be seen from Table 4, if the water quality permits, condensate can be used as supplementary water to enter the circulating water system. Introducing condensate to cool the process condensate in the process condensate tank is also a feasible method. Through the combination of two pipelines, not only a first connecting pipeline with a connecting valve is designed between the EDI feed water pump outlet and the process condensate tank, but also a second connecting pipeline with a connecting valve is designed between the condensate inlet side of the circulating water heat exchanger and the circulating water return pipe. This method can help cool down and has two other functions.

[0062] Function 1: Eliminate unqualified condensate:

[0063] like Figure 4 As shown in the figure, if this pipeline is not added, the condensate will directly enter the condensate tank and the cation bed, and there will be a problem that cannot be avoided. When the condensate inlet water quality exceeds the standard, it will directly enter the condensate tank and the cation bed through the heat exchanger, causing the cation bed resin to be contaminated and quickly fail. Figure 3 As shown, part of the design of the condensate entering the circulating water return pipeline is to avoid such situations. When the condensate does not meet the indicators, it can enter the circulating water through this connecting pipeline.

[0064] Function 2: Cooling:

[0065] From the original process Figure 4 It can be seen that in the original process, the condensate can only be heat exchanged through the plate heat exchanger, but due to the limited amount of circulating water used for cooling, when there is a large amount of high-temperature condensate, it cannot reach the predetermined index (the cation bed inlet water temperature ≤ 50℃). The EDI feed water pump outlet pipeline can solve this problem. According to the raw water tank inlet water index, it can be seen that the raw water temperature at the steam-water heat exchanger outlet is between 20 and 25℃ and there is no heating process in the desalted water. Therefore, the secondary water production temperature can fully achieve the cooling effect and can be obtained through the secondary water production index. Its water quality is also within the allowable range of the condensate tank inlet water index. Therefore, such measures can achieve the expected goals.

[0066] One problem that needs to be noted in the second function is that when a large amount of high-temperature condensate enters the condensate tank, a large amount of cold water will be needed to cool it down. The volume of the condensate tank and the desalted water tank will be unable to accommodate the condensate. In order to avoid such problems, a pipeline is added to the condensation inlet of the circulating water heat exchanger and the circulating water return pipeline, so that the condensate that cannot be cooled can enter the circulating water for replenishment. Cold water is configured through the outlet of the EDI feed water pump to cool it to the expected temperature; the production cost is reduced, and the production water consumption is reduced to a certain extent by replenishing the circulating water, reducing the production water consumption cost and the condensate loss; the failure cycle of the positive mixed bed is reduced, and the unqualified condensate can be timely introduced into the circulating water by adding condensate water to the circulating water, avoiding the rapid failure of the positive mixed bed.

[0067] A further improvement is that the opening condition of the connecting valve on the second connecting pipeline is: the condensate temperature at the outlet of the circulating water heat exchanger is still too high after the connecting valve on the first connecting pipeline is opened, and at the same time, when the condensate inlet water quality exceeds the design value, the condensate is cooled by opening the connecting valve on the second connecting pipeline.

[0068] That is, when the outlet distribution pipeline of the EDI water pump cannot meet the use requirements (the temperature cannot be lowered or the liquid level in the desalted water tank is too high and the water balance cannot be achieved), open the connecting valve to introduce part of the condensate into the circulating water supply system, reduce the heat medium flow of the heat exchanger to control the temperature of the condensate water tank entering the process. Among them, when it is opened, it is also necessary to meet the condensate inlet water quality exceeding the design value (conductivity>100μS / cm, SiO2>20μg / L, total iron>1mg / L, TOC>300μg / L, suspended solids>0.1mg / L), and then the unqualified condensate (as circulating water replenishment) can be sent to the circulating water supply system for replenishment. After the above improvements, we can not only achieve our original purpose of cooling, but also reduce the loss of condensate and production costs.

[0069] A further improvement is that the first-level reverse osmosis device is externally connected to a reverse osmosis flushing pump, the water inlet pipe of the reverse osmosis flushing pump is connected to the first-level reverse osmosis water production pool, and a concentrate tank is also provided on the sewage pipe of the first-level reverse osmosis device. A concentrate water supply pump and a concentrate water safety filter are provided between the concentrate water tank and the first-level reverse osmosis water production pool in sequence. The sewage in the concentrate water tank is transported to the concentrate water safety filter by the concentrate water supply pump for filtration and then flows back to the first-level reverse osmosis water production pool.

[0070] In order to solve the problem that the first-stage reverse osmosis device may be blocked after a long period of reverse osmosis operation, a reverse osmosis flushing pump is added between the first-stage reverse osmosis device and the first-stage reverse osmosis water production pool, thereby solving the blockage problem. However, in order to avoid waste of water resources, the water inlet pipe of the reverse osmosis flushing pump is connected to the first-stage reverse osmosis water production pool, thereby solving the water source problem. At the same time, the sewage under backwashing is collected by the concentrated water tank, and then transported to the concentrated water security filter by the concentrated water supply pump for filtration, so that the filtered water can be reused, so that the water can be directly returned to the first-stage reverse osmosis water production pool for use, effectively solving the problem of secondary water waste caused by the first-stage reverse osmosis device during backwashing.

[0071] A further improvement is that a concentrate high-pressure pump and a concentrate reverse osmosis device are provided between the concentrate security filter and the primary reverse osmosis water production pool, and hydrochloric acid and scale inhibitor are added to the water inlet end of the concentrate security filter.

[0072] Adding hydrochloric acid and scale inhibitors at the water inlet of the concentrate security filtration can make the water quality meet the standards, and it is less likely to be blocked when filtering through the concentrate security filtration and the concentrate reverse osmosis device. When the sewage after the concentrate security filtration is transported backward, it is transported by a concentrate high-pressure pump, which can make the water flow smoother and the water supply more sufficient. After passing through the concentrate reverse osmosis device, the sewage can meet the reuse standards.

[0073] A further improvement is that a concentrate return pipe is provided between the concentrate reverse osmosis device and the ultrafiltration water tank, and a concentrate return pipe is also provided between the EDI device and the primary reverse osmosis water production tank.

[0074] Through two brine return pipes, the brine discharged from the brine reverse osmosis device and the EDI device can be returned to the primary reverse osmosis water production pool for dilution and repeated use, thereby reducing the generation of external sewage. In particular, the sewage discharged from the brine reverse osmosis device is returned to the ultrafiltration water tank through the brine return pipe for re-filtration, so that the sewage discharged from the EDI device can be directly returned for use without passing through the primary safety filtration.

[0075] In view of the problem that the condensate in the desalted water treatment system has a series of problems that will cause unnecessary production costs, such as resin failure, cation mixed bed failure, and condensate discharge, due to the unstable temperature and condensate volume during operation, a pipeline is designed through the outlet of the EDI feed water pump to connect to the condensate tank to solve the problem of excessive temperature, and then a pipeline is designed from the condensate inlet to the circulating water outlet to discharge the excess condensate and unqualified condensate into the circulating water through the height difference between the pipelines to solve the problem that the condensate is unqualified or the condensate volume is too much and cannot be loaded in the condensate tank and the desalted water tank. The design principle is:

[0076] 1. The key point for condensate to be poured into circulating water is whether the design of the pipeline from the circulating water exchanged by the condensate tank to the circulating water pool can meet the demand. Since the desalted water station and the circulating water station are not together, the design of this pipeline has become the key point to the success of this method. To make the condensate return to the circulating water, its liquid level must be at a high level first, and secondly, the design of the pipeline must comply with the principle of "water flows to a low place", otherwise the condensate cannot be transported to the circulating water by this method.

[0077] 2. The liquid level must meet the standard. When the condensate needs to be cooled by the water in the secondary water tank, the liquid level in the secondary water tank must meet the pump start level because the pipeline is installed at the outlet of the EDI water pump. The design of the other pipeline also requires the condensate tank to meet the standard, otherwise the condensate cannot be reversed.

[0078] From the above, it can be seen that the implementation of this design scheme can not only achieve our original cooling purpose, but also reduce the loss of condensate and production costs.

[0079] The above-mentioned implementation modes are only preferred implementation modes of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present application shall fall within the scope of protection required by the present application.

Claims

1. A desalted water treatment system, comprising a hot desalted water system and a cold desalted water system, wherein the process flow of the cold desalted water system comprises produced water → raw water tank → raw water pump → steam-water heat exchanger → multi-media filter → laminated filter → ultrafiltration device → ultrafiltration water tank → primary reverse osmosis water pump → primary security filter → primary high-pressure pump → primary reverse osmosis device → decarbonizer → primary reverse osmosis water production pool → secondary reverse osmosis water pump → secondary security filter → secondary high-pressure pump → secondary reverse osmosis device → secondary reverse osmosis water production tank → EDI Feed water pump → EDI security filter → EDI device → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user; the hot desalted water system includes process condensate → high or low pressure desalted water heat exchanger → circulating water heat exchanger → process condensate tank → process condensate pump → iron removal filter → pre-cation bed → cation bed resin catcher → refined mixed bed → refined mixed bed resin catcher → desalted water tank → high or low pressure desalted water pump → high or low pressure desalted water heat exchanger → high or low pressure user, characterized in that: A first connecting pipeline with a connecting valve is provided between the outlet of the EDI water pump in the cold desalted water system and the process condensate tank in the hot desalted water system, and the liquid refluxed through the first connecting pipeline cools the condensate in the process condensate tank.

2. A desalted water treatment system according to claim 1, characterized in that: The opening condition of the connecting valve on the first connecting pipeline is: when the condensate temperature at the outlet of the circulating water heat exchanger exceeds the design value of 45° C., the valve of the connecting valve is opened to cool the condensate.

3. A desalted water treatment system according to claim 1, characterized in that: The circulating water supply system of the circulating water heat exchanger includes a circulating water cooling tower, a circulating water pump, a circulating water supply pipe and a circulating water return pipe arranged between the circulating water cooling tower and the circulating water heat exchanger. The hot water in the circulating water cooling tower is sprayed from top to bottom into small water droplets, forming a water film on the surface of the filler and flowing downward. The air flows in the tower from bottom to top. The surface of the hot water is in direct contact with the air, and the water temperature is reduced by conduction heat dissipation and radiation heat dissipation.

4. A desalted water treatment system according to claim 3, characterized in that: A temperature sensor is provided at the discharge port of the circulating water cooling tower, and a cooling fan linked to the circulating water cooling tower is provided at one side of the circulating water cooling tower. The cooling fan can automatically start to dissipate heat after the temperature is set by the temperature sensor.

5. A desalted water treatment system according to claim 3, characterized in that: A second connecting pipeline with a connecting valve is provided on the condensate inlet side of the circulating water heat exchanger in the hot desalted water system and the circulating water return pipe side of the circulating water station, and the liquid returning through the second connecting pipeline cools the condensate in the process condensate tank.

6. A desalted water treatment system according to claim 5, characterized in that: The opening condition of the connecting valve on the second connecting pipeline is: the condensate temperature at the outlet of the circulating water heat exchanger is still too high after the connecting valve on the first connecting pipeline is opened, and at the same time, when the water quality of the condensate inlet water exceeds the design value, the condensate is cooled by opening the connecting valve on the second connecting pipeline.

7. A desalted water treatment system according to claims 1 to 6, characterized in that: The first-level reverse osmosis device is externally connected to a reverse osmosis flushing pump, the water inlet pipe of the reverse osmosis flushing pump is connected to the first-level reverse osmosis water production pool, and a concentrate tank is also provided on the sewage pipe of the first-level reverse osmosis device. A concentrate water supply pump and a concentrate water safety filter are provided between the concentrate water tank and the first-level reverse osmosis water production pool in sequence. The sewage in the concentrate water tank is transported to the concentrate water safety filter by the concentrate water supply pump for filtration and then flows back to the first-level reverse osmosis water production pool.

8. A desalted water treatment system according to claim 7, characterized in that: A high-pressure concentrate pump and a reverse osmosis device are also provided between the concentrate security filter and the primary reverse osmosis water production pool, and hydrochloric acid and scale inhibitor are added to the water inlet of the concentrate security filter.

9. A desalted water treatment system according to claim 8, characterized in that: A concentrate return pipe is provided between the concentrate reverse osmosis device and the ultrafiltration water tank, and a concentrate return pipe is also provided between the EDI device and the primary reverse osmosis water production tank.

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