A boiler make-up water treatment system and method based on modified reverse osmosis membranes

Abstract

A boiler makeup water treatment system and method based on modified reverse osmosis membrane belong to the technical field of water treatment systems. The treatment system comprises a pretreatment unit, a reverse osmosis unit, a resin unit, a TOC online detection unit, a early warning unit, a reverse osmosis membrane modification unit and a modified reverse osmosis membrane regeneration unit. The treatment method comprises S1. pretreatment; S2. primary reverse osmosis; S3. secondary reverse osmosis; S4. resin adsorption; S5. TOC online analysis; and S6. regeneration treatment. The present application modifies the reverse osmosis membranes differently for primary reverse osmosis and secondary reverse osmosis, so that the membrane surface properties of the two reverse osmosis stages change respectively, and the organic matter with different charged properties in raw water is treated; by modifying the reverse osmosis membrane, the compactness of the separation layer of the reverse osmosis membrane is increased, and the separation effect on organic matter is increased. The present application monitors the modified effluent quality in real time through the early warning system, discovers the performance change of the modified reverse osmosis membrane in time, and regenerates the modified reverse osmosis membrane.

Description

Technical Field

[0001] This invention belongs to the field of water treatment system technology, specifically relating to a boiler feedwater treatment system and method based on a modified reverse osmosis membrane. Background Technology

[0002] Boilers play a crucial role in thermal power generation. Through long-term theoretical and practical experience, it has been recognized that the quality of boiler feedwater is a key factor in ensuring its safe and economical operation. Boilers typically use two water sources: untreated natural water, such as groundwater, spring water, or reservoir water; and wastewater treated by industrial water recycling plants. Although the latter is treated, it still contains high concentrations of salt, especially chloride, sodium, and ammonium ions, a certain amount of organic matter, and small amounts of calcium and magnesium ions. At the same time, untreated natural water contains various impurities, such as salt and microorganisms. Poor boiler water quality leads to widespread scaling and corrosion problems on heating surfaces. Even treated water with high salt content can cause steam to carry moisture and steam-water co-flushing, which not only increases blowdown volume but also affects the safe and economical operation of the boiler. Therefore, effectively treating boiler water to ensure it meets appropriate standards is of paramount practical importance and urgency.

[0003] Traditional boiler feedwater treatment processes mainly include coagulation, sedimentation, ultrafiltration pretreatment units, and reverse osmosis and ion exchange resin desalination units. Pretreatment aims to remove large particulate matter, suspended solids, and partially dissolved solids from the water to protect downstream equipment. Reverse osmosis, a highly efficient desalination technology, uses pressure to force water molecules through a semi-permeable membrane, separating salts and other dissolved substances. Reverse osmosis can significantly reduce total dissolved solids (TDS) and total organic carbon (TOC), improving water quality. Finally, resin treatment, also known as ion exchange, removes residual hardness ions (such as calcium and magnesium) and partially dissolved salts from the water. The resin bed adsorbs these ions, softening the water and reducing the risk of boiler scaling. The entire treatment process requires precise control to ensure that the final feedwater meets the boiler's safe and economical operation requirements.

[0004] Traditional boiler feedwater treatment processes in thermal power plants can ensure that the salinity meets national standards. However, with increasingly serious organic pollution in water sources and excessive cleaning of reverse osmosis membranes leading to reduced membrane performance, traditional boiler feedwater treatment processes frequently encounter problems with excessive organic matter concentration in the effluent. Once organic matter enters the boiler, it undergoes changes under high temperature and pressure, producing substances that can cause corrosion of the boiler and turbine unit's metal materials.

[0005] Traditional boiler feedwater treatment processes primarily rely on the removal efficiency of reverse osmosis membranes for organic matter removal. While reverse osmosis membranes typically have a relatively high removal rate for organic matter, they are less effective at removing small-molecule organic compounds. Organic matter that cannot be removed by primary reverse osmosis often remains unremoved even after secondary or subsequent stages of reverse osmosis, ultimately ending up in the permeate phase of the reverse osmosis system.

[0006] Therefore, as the concentration of organic matter in the influent increases and the composition of pollutants becomes more complex, the TOC of the effluent often fails to meet the standards. Summary of the Invention

[0007] This invention addresses the issues of poor removal of small-molecule organic matter by reverse osmosis in traditional boiler feedwater treatment processes, and the failure to remove certain types of organic matter due to the lack of differentiated removal by two-stage or even multi-stage reverse osmosis. It provides a boiler feedwater treatment system and method based on a modified reverse osmosis membrane to solve the problem of excessive TOC concentration in the effluent from traditional boiler feedwater treatment processes.

[0008] The technical solution adopted in this invention is:

[0009] A boiler feedwater treatment system based on a modified reverse osmosis membrane, comprising:

[0010] The pretreatment unit, connected to the reverse osmosis unit, is used to pretreat the raw water to be treated;

[0011] The reverse osmosis unit, connected to the resin unit, is used to perform reverse osmosis treatment on the raw water to be treated.

[0012] The resin units are connected to the desalination permeate tank and are used for mixed-bed resin treatment of the reverse osmosis permeate.

[0013] The TOC online detection unit is used for online TOC analysis of desalination permeate.

[0014] The early warning unit is connected to the TOC online detection unit.

[0015] The reverse osmosis membrane modification unit is connected to the reverse osmosis unit and controlled by the early warning unit. It is used to modify the reverse osmosis membrane in the reverse osmosis unit.

[0016] The modified reverse osmosis membrane regeneration unit is connected to the reverse osmosis unit and controlled by the early warning unit. It is used for the regeneration of the modified reverse osmosis membrane in the reverse osmosis unit.

[0017] A method for treating boiler feedwater based on a modified reverse osmosis membrane includes the following steps:

[0018] S1. Pretreatment: Remove suspended solid particles, including colloids, from the raw water to obtain pretreated effluent;

[0019] S2. First-stage reverse osmosis: The pretreated effluent is subjected to first-stage reverse osmosis treatment based on a type of modified reverse osmosis membrane to obtain first-stage reverse osmosis treated permeate;

[0020] S3. Secondary reverse osmosis: The primary reverse osmosis permeate is subjected to secondary reverse osmosis treatment based on a type II modified reverse osmosis membrane to obtain reverse osmosis permeate;

[0021] S4. Resin adsorption: Reverse osmosis permeate is treated with mixed-bed resin to obtain desalinated permeate;

[0022] S5. TOC Online Analysis: Perform online TOC analysis on the desalination permeate. If (TOCt1-TOCt0) / TOCt0>25%, proceed to S6; otherwise, the desalination permeate enters the desalination permeate tank. Here, t0 is the initial time of the system, t1 is the current time, TOCt0 is the TOC of the permeate at the initial time of the system, and TOCt1 is the TOC of the permeate at the current time.

[0023] S6. Regeneration treatment: Regeneration treatment is performed on both Type I and Type II modified reverse osmosis membranes.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention modifies the reverse osmosis membranes of the first-stage and second-stage reverse osmosis stages differently, causing changes in the membrane surface characteristics of each stage, resulting in different surface charge characteristics, and thus treating organic matter with different charge characteristics in the raw water. By modifying the reverse osmosis membranes, the density of the reverse osmosis membrane separation layer is increased, thereby improving the separation effect of organic matter.

[0026] 2. This invention uses an early warning system to monitor the modified effluent quality in real time, promptly detect changes in the performance of the modified reverse osmosis membrane, and regenerate the modified reverse osmosis membrane. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the processing system structure of the present invention;

[0028] Figure 2 This is a flowchart of the processing method of the present invention;

[0029] Figure 3 This is a flowchart of a method for modifying a type of reverse osmosis membrane according to the present invention;

[0030] Figure 4 This is a flowchart of the method for modifying the second type of reverse osmosis membrane according to the present invention;

[0031] Figure 5 This is a flowchart of the regeneration process of the modified reverse osmosis membrane of the present invention;

[0032] The components include: 1. Pretreatment unit; 2. Reverse osmosis unit; 3. Reverse osmosis membrane modification unit; 4. Resin unit; 5. TOC online detection unit; 6. Early warning unit; 7. Modified reverse osmosis membrane regeneration unit; 201. Primary reverse osmosis module; 202. Secondary reverse osmosis module. Detailed Implementation

[0033] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0034] This invention is based on reverse osmosis treatment. By modifying the reverse osmosis membrane, the density of the membrane separation layer is increased, thereby improving the separation effect of organic matter. Two-stage or multi-stage reverse osmosis uses different modification methods to change the surface properties of the membrane, in order to treat organic matter with different charge characteristics in the raw water. At the same time, an early warning system monitors the quality of the effluent in real time to detect changes in the performance of the modified reverse osmosis membrane in a timely manner, and regenerates the modified reverse osmosis membrane, so that the TOC of the system effluent meets the target.

[0035] like Figure 1 As shown, the present invention provides a boiler feedwater treatment system based on a modified reverse osmosis membrane, including...

[0036] Pretreatment unit 1, connected to reverse osmosis unit 2, is used to pretreat the raw water to be treated;

[0037] Reverse osmosis unit 2 is connected to resin unit 4 and is used to perform reverse osmosis treatment on the raw water to be treated.

[0038] Resin unit 4 is connected to the desalination permeate tank and is used for mixed bed resin treatment of reverse osmosis permeate.

[0039] TOC online detection unit 5 is used to perform online TOC analysis on desalination permeate; its installation location depends on the actual situation of the plant, as long as it can detect the desalination permeate.

[0040] Early warning unit 6 is connected to TOC online detection unit 5.

[0041] The reverse osmosis membrane modification unit 3 is connected to the reverse osmosis unit 2 and controlled by the early warning unit 6. It is used to modify the reverse osmosis membrane in the reverse osmosis unit 2.

[0042] The modified reverse osmosis membrane regeneration unit 7 is connected to the reverse osmosis unit 2 and controlled by the early warning unit 6. It is used to regenerate the modified reverse osmosis membrane in the reverse osmosis unit 2.

[0043] The pretreatment unit 1 includes a coagulation system, a sedimentation system, and a filtration system. The coagulation system includes a rapid mixing module and a slow mixing module, and the filtration system includes sand filtration and ultrafiltration.

[0044] The pretreatment unit 1 also includes a softening module preceding the coagulation system.

[0045] The reverse osmosis membrane modification unit 3 includes components that are connected to the first module, the second module, and the third module; the first modified reagent tank outlet of the first module, the second modified reagent tank outlet of the second module, and the third modified reagent tank outlet of the third module are connected, and each outlet is equipped with a switching valve.

[0046] The first module includes a first modified reagent tank and a first reagent dosing pump connected to the first modified reagent tank; the second module includes a second modified reagent tank and a second reagent dosing pump connected to the second modified reagent tank; and the third module includes a third modified reagent tank and a third reagent dosing pump connected to the third modified reagent tank.

[0047] like Figure 1 As shown, the reverse osmosis unit 2 includes a first-stage reverse osmosis module 201 and a second-stage reverse osmosis module 202; the raw water to be treated passes sequentially through the pretreatment unit 1, the first-stage reverse osmosis module 201, the second-stage reverse osmosis module 202 and the resin unit 4; the first-stage reverse osmosis module 201 is composed of a first-stage reverse osmosis membrane, and the second-stage reverse osmosis module 202 is composed of a second-stage reverse osmosis membrane;

[0048] The inlet of the first-stage reverse osmosis module 201 is connected to the outlet of the pretreatment unit 1, the outlet of the first module of the reverse osmosis membrane modification unit 3, and the outlet of the second module of the reverse osmosis membrane modification unit 3, respectively.

[0049] The inlet of the secondary reverse osmosis module 202 is connected to the product outlet of the primary reverse osmosis module 201, the outlet of the first module of the reverse osmosis membrane modification unit 3, and the outlet of the third module of the reverse osmosis membrane modification unit 3, respectively.

[0050] The inlet of the first-stage reverse osmosis module 201 is connected to the modified reverse osmosis membrane regeneration unit 7;

[0051] The outlet of the secondary reverse osmosis module 202 is connected to the modified reverse osmosis membrane regeneration unit 7; the outlet of the secondary reverse osmosis module 202 is connected to the resin unit 4.

[0052] The reverse osmosis unit 2 can be increased to include multiple stages of reverse osmosis;

[0053] The piping material connected to the reverse osmosis membrane modification unit 3 is one of PVC-U, PE pipe, or sanitary stainless steel.

[0054] The modified reverse osmosis membrane regeneration module includes a regeneration reagent tank and a regeneration reagent dosing pump connected to the regeneration reagent tank. The regeneration reagent tank is connected to the inlet of the first-stage reverse osmosis module 201 and the outlet of the second-stage reverse osmosis module 202. The regeneration reagent is a NaOH solution. The regeneration reagent enters from the inlet of the first-stage reverse osmosis module 201, exits from the first-stage concentrate outlet, then enters the inlet of the second-stage reverse osmosis module 202, exits from the second-stage concentrate outlet, and finally returns to the regeneration reagent tank.

[0055] The early warning unit 6 includes a signal collection module, a data processing module, and a signal output module. The signal collection module is used to collect or manually input TOC detection data, the data processing module is used to process the signal collection module to obtain the processing result, and the signal output module is used to output the processing result of the signal processing module.

[0056] like Figure 2 As shown, a boiler feedwater treatment method based on a modified reverse osmosis membrane includes the following steps:

[0057] S1. Pretreatment: The raw water is pretreated to remove suspended solid particles, including colloids, to obtain pretreated effluent;

[0058] S2. First-stage reverse osmosis: The pretreated effluent is subjected to first-stage reverse osmosis treatment based on a type of modified reverse osmosis membrane to obtain first-stage reverse osmosis treated permeate;

[0059] S3. Secondary reverse osmosis: The primary reverse osmosis permeate is subjected to secondary reverse osmosis treatment based on a type II modified reverse osmosis membrane to obtain reverse osmosis permeate;

[0060] S4. Resin adsorption: Reverse osmosis permeate is treated with mixed-bed resin to obtain desalinated permeate;

[0061] S5. TOC Online Analysis: Online TOC analysis of desalination permeate.

[0062] If (TOCt1-TOCt0) / TOCt0>25%, proceed to S6; otherwise, the desalination permeate enters the desalination permeate tank. Here, t0 is the initial time of the system, t1 is the current time, TOCt0 is the TOC of the permeate at the initial time of the system, and TOCt1 is the TOC of the permeate at the current time.

[0063] S6. Regeneration treatment: Regeneration treatment is performed on both Type I and Type II modified reverse osmosis membranes.

[0064] like Figure 3 As shown, in step S2, a modified reverse osmosis membrane is obtained by modifying a reverse osmosis membrane. This modification method includes the following steps:

[0065] S21. Perform a clean water forward rinse and a product water rinse on the first-stage reverse osmosis membrane to remove the residual protective solution on the surface of the initial first-stage reverse osmosis membrane;

[0066] S22. The circulating treatment using a modified agent to a single-stage reverse osmosis membrane is controlled by a pump body to circulate both permeate and concentrate within a modified agent tank, with the average permeate flux controlled at 25-50 LMH.

[0067] S23. The primary reverse osmosis membrane is circulated using modified reagent II. Both permeate and concentrate are circulated within the modified reagent II tank by a pump, with the average permeate flux controlled at 25-50 LMH.

[0068] like Figure 4 As shown, in step S3, the modified reverse osmosis membrane is obtained by modifying a type II reverse osmosis membrane. This modification method includes the following steps:

[0069] S31. Perform a forward rinse with clean water and a permeate rinse on the secondary reverse osmosis membrane to remove the residual protective solution on the surface of the initial secondary reverse osmosis membrane;

[0070] S32. Circulation treatment using a modified agent for a two-stage reverse osmosis membrane, where both permeate and concentrate are circulated within a modified agent tank controlled by a pump, with an average permeate flux of 25-50 LMH.

[0071] S33. The modified reagent is used for circulation treatment of two-stage reverse osmosis membranes. Both permeate and concentrate are circulated in the modified reagent tank by the pump body, and the average permeate flux is controlled to be 25-50 LMH.

[0072] The modified agent is one or more of sulfobetaine, carboxybetaine, polyvinyl alcohol, and alanine.

[0073] The second modified agent is one or more of polyacrylic acid, anionic polyacrylamide, polystyrene sulfonic acid, maleic acid-acrylic acid copolymer, salicylic acid, and tannic acid.

[0074] The modified agent three is one or more of polyimide, polyethyleneimine, polyaniline, polylysine salicylic acid, and tannic acid.

[0075] like Figure 5 As shown, in step S6, the regeneration process includes the following steps:

[0076] S61. The reverse osmosis membrane is modified by alkaline washing, rinsing and soaking under pH 12 conditions, with a water temperature of 25-35 degrees Celsius. First, it is circulated and rinsed for 0.5 hours, then soaked for 6-12 hours, and finally circulated and rinsed for 0.5-1 hour.

[0077] S62. Modify the primary and secondary reverse osmosis membranes with Class I and Class II reverse osmosis membranes respectively to obtain regenerated Class I modified reverse osmosis membranes and Class II modified reverse osmosis membranes.

[0078] Example 1

[0079] In this embodiment, the first-stage reverse osmosis module 201 uses a 6-core pressure vessel arranged in a 4:2 ratio; the second-stage reverse osmosis module 202 uses a 6-core pressure vessel arranged in a 3:1 ratio. Both the first-stage and second-stage reverse osmosis membranes underwent modification treatment.

[0080] 1. Modify the primary reverse osmosis membrane. Perform a clean water forward flush and a permeate flush at a feed rate of 30 cubic meters per hour to remove residual protective solution from the initial primary reverse osmosis membrane surface. Continuously flush for 1 hour. Modifier one uses 500 ppm sulfobetaine to circulate the primary reverse osmosis membrane. Both permeate and concentrate are circulated to the modifier one tank, controlling the average permeate flux at 30 LMH. Modifier two uses 500 ppm polyacrylic acid with a molecular weight of 3000 to circulate the primary reverse osmosis membrane. Both permeate and concentrate are circulated to the modifier two tank, controlling the average permeate flux at 30 LMH.

[0081] 2. Modify the secondary reverse osmosis membrane. Perform a clean water forward flush and a permeate flush at a feed rate of 15 cubic meters per hour to remove residual protective solution from the initial secondary reverse osmosis membrane surface. Continuously flush for 1 hour. Modifier one uses 500 ppm sulfobetaine to circulate the secondary reverse osmosis membrane. Both permeate and concentrate are circulated to the modifier one tank, controlling the average permeate flux at 30 LMH. Modifier three uses 500 ppm polyethyleneimine with a molecular weight of 2500 to circulate the secondary reverse osmosis membrane. Both permeate and concentrate are circulated to the modifier three tank, controlling the average permeate flux at 30 LMH.

[0082] The method provided by this invention is used to treat boiler feedwater. This embodiment provides the treatment method and effects of the boiler feedwater disclosed in this patent. The raw boiler feedwater volume is 50 t / h, and the main water quality is shown in Table 1.

[0083] TOC (mg / L) 23 Turbidity (NTU) 1.58 Total hardness (mg / L, as CaCO3) 43.5 pH 7.30

[0084] After pretreatment, primary and secondary reverse osmosis, and resin adsorption treatment, the effluent underwent a series of processes including coagulation clarification, multi-media filtration, and sand filtration. The treatment results are shown in Table 2. The final effluent TOC content was less than 0.2 mg / L, meeting the effluent standards.

[0085]

[0086] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for treating boiler feedwater based on a modified reverse osmosis membrane, characterized in that: Includes the following steps: S1. Pretreatment: Remove suspended solid particles, including colloids, from the raw water to obtain pretreated effluent; S2. First-stage reverse osmosis: The pretreated effluent is subjected to first-stage reverse osmosis treatment based on a type of modified reverse osmosis membrane to obtain first-stage reverse osmosis treated permeate; S3. Secondary reverse osmosis: The primary reverse osmosis permeate is subjected to secondary reverse osmosis treatment based on a type II modified reverse osmosis membrane to obtain reverse osmosis permeate; S4. Resin adsorption: Reverse osmosis permeate is treated with mixed-bed resin to obtain desalinated permeate; S5. TOC Online Analysis: Perform online TOC analysis on the desalination permeate. If (TOCt1-TOCt0) / TOCt0>25%, proceed to S6; otherwise, the desalination permeate enters the desalination permeate tank. Here, t0 is the initial time of the system, t1 is the current time, TOCt0 is the TOC of the permeate at the initial time of the system, and TOCt1 is the TOC of the permeate at the current time. S6. Regeneration Treatment: Regeneration treatment is performed on both Type I and Type II modified reverse osmosis membranes. In step S2, a modified reverse osmosis membrane is obtained by modifying a reverse osmosis membrane. The modification method includes the following steps: S21. Perform a clean water forward rinse and a product water rinse on the first-stage reverse osmosis membrane to remove the residual protective solution on the surface of the initial first-stage reverse osmosis membrane; S22. The circulating treatment using a modified chemical agent to a single-stage reverse osmosis membrane is controlled by a pump body to circulate both permeate and concentrate within the modified chemical agent tank. S23. The primary reverse osmosis membrane is circulated using modified reagent II, with both permeate and concentrate circulated within the modified reagent II tank by a pump. In step S3, the type II modified reverse osmosis membrane is obtained through a type II reverse osmosis membrane modification process. This modification method includes the following steps: S31. Perform a forward rinse with clean water and a permeate rinse on the secondary reverse osmosis membrane to remove the residual protective solution on the surface of the initial secondary reverse osmosis membrane; S32. The circulating treatment using a modified chemical agent for a two-stage reverse osmosis membrane is controlled by a pump body to circulate both permeate and concentrate within the modified chemical agent tank. S33. The circulating treatment using modified reagent three pairs of two-stage reverse osmosis membranes is controlled by the pump body to circulate both permeate and concentrate within the modified reagent three water tank; The modified agent is one or more of sulfobetaine, carboxybetaine, polyvinyl alcohol, and alanine. The second modified agent is one or more of polyacrylic acid, anionic polyacrylamide, polystyrene sulfonic acid, maleic acid-acrylic acid copolymer, salicylic acid, and tannic acid. The modified agent three is one or more of polyimide, polyethyleneimine, polyaniline, polylysine salicylic acid, and tannic acid; The method is implemented based on a makeup water treatment system, which includes... The pretreatment unit (1) is connected to the reverse osmosis unit (2) and is used to pretreat the raw water to be treated; The reverse osmosis unit (2) is connected to the resin unit (4) and is used to perform reverse osmosis treatment on the raw water to be treated; The resin unit (4) is connected to the desalination permeate tank and is used for mixed bed resin treatment of reverse osmosis permeate. The TOC online detection unit (5) is used for online TOC analysis of desalination permeate. The early warning unit (6) is connected to the TOC online detection unit (5). The reverse osmosis membrane modification unit (3) is connected to the reverse osmosis unit (2) and controlled by the early warning unit (6) for modifying the reverse osmosis membrane in the reverse osmosis unit (2); The modified reverse osmosis membrane regeneration unit (7) is connected to the reverse osmosis unit (2) and controlled by the early warning unit (6) for regenerating the modified reverse osmosis membrane in the reverse osmosis unit (2).

2. The boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 1, characterized in that: The reverse osmosis membrane modification unit (3) includes a first module, a second module, and a third module; the outlets of the first module, the second module, and the third module are connected, and each outlet is equipped with a switching valve. The first module includes a first modified reagent tank and a first reagent dosing pump connected to the first modified reagent tank; the second module includes a second modified reagent tank and a second reagent dosing pump connected to the second modified reagent tank; and the third module includes a third modified reagent tank and a third reagent dosing pump connected to the third modified reagent tank.

3. The boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 2, characterized in that: The reverse osmosis unit (2) includes a primary reverse osmosis module (201) and a secondary reverse osmosis module (202); the primary reverse osmosis module (201) is composed of a primary reverse osmosis membrane, and the secondary reverse osmosis module (202) is composed of a secondary reverse osmosis membrane; The inlet of the first-stage reverse osmosis module (201) is connected to the outlet of the pretreatment unit (1), the outlet of the first module of the reverse osmosis membrane modification unit (3), and the outlet of the second module of the reverse osmosis membrane modification unit (3), respectively. The inlet of the secondary reverse osmosis module (202) is connected to the product outlet of the primary reverse osmosis module (201), the outlet of the first module of the reverse osmosis membrane modification unit (3), and the outlet of the third module of the reverse osmosis membrane modification unit (3), respectively. The inlet of the first-stage reverse osmosis module (201) is connected to the modified reverse osmosis membrane regeneration unit (7), and the outlet of the second-stage reverse osmosis module (202) is connected to the modified reverse osmosis membrane regeneration unit (7). The outlet of the secondary reverse osmosis module (202) is connected to the resin unit (4).

4. The boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 3, characterized in that: The modified reverse osmosis membrane regeneration unit (7) includes a regeneration reagent tank and a regeneration reagent dosing pump connected to the regeneration reagent tank; the regeneration reagent tank is connected to the inlet of the first-stage reverse osmosis module (201) and the outlet of the second-stage reverse osmosis module (202).

5. A boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 1, characterized in that: The early warning unit (6) includes a signal collection module, a data processing module and a signal output module; the signal collection module is used to collect or manually input TOC detection data, the data processing module is used to process the signal collection module to obtain the processing result, and the signal output module is used to output the processing result of the signal processing module.

6. The boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 1, characterized in that: In S22, the average water production flux is controlled at 25-50 LMH; in S23, the average water production flux is controlled at 25-50 LMH.

7. A boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 1, characterized in that: In S32, the average water production flux is controlled at 25-50 LMH; in S33, the average water production flux is controlled at 25-50 LMH.

8. A boiler feedwater treatment method based on a modified reverse osmosis membrane according to claim 1, characterized in that: In step S6, the regeneration process includes the following steps: S61. The reverse osmosis membrane is modified by alkaline washing, rinsing and soaking under pH 12 conditions, with a water temperature of 25-35 degrees Celsius. First, it is circulated and rinsed for 0.5 hours, then soaked for 6-12 hours, and finally circulated and rinsed for 0.5-1 hour. S62. Modify the primary and secondary reverse osmosis membranes with Class I and Class II reverse osmosis membranes respectively to obtain regenerated Class I modified reverse osmosis membranes and Class II modified reverse osmosis membranes.

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