Desalted water system for power plant

Abstract

The utility model provides a power plant demineralized water system, and relates to the technical field of water treatment. The utility model provides a power plant demineralized water system which comprises a filtering device, a first reverse osmosis device and an EDI device which are sequentially communicated along a water treatment direction, the filtering device is used for removing suspended matters in the water to be treated; the first reverse osmosis device produces water at two ends, and a concentrated water end water producing port is communicated with a water inlet of the first reverse osmosis device and is used for enabling the concentrated water end water producing port to flow back to the water inlet of the first reverse osmosis device; a water outlet at the water inlet end of the first reverse osmosis device is communicated with the EDI device; the EDI device is used for carrying out EDI treatment on the produced water from the first reverse osmosis device. The demineralized water system for the power plant is simple in structure, a secondary reverse osmosis process is omitted, a traditional resin process is replaced by an EDI process, and the acid and alkali consumption and the treatment cost of cleaning water are greatly saved.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology, and in particular to a demineralized water system for power plants. Background Technology

[0002] Boilers, steam turbines, and other thermal equipment used in power plants have very high requirements for water quality, particularly low salinity. Directly drawing untreated natural water from the outside environment results in high salinity, causing corrosion, abrasion, scaling, and salt buildup in the equipment. This negatively impacts the economic efficiency and reliability of the equipment, increases maintenance costs, and shortens its lifespan. Therefore, power plants utilize various water treatment processes to remove suspended solids, colloids, and inorganic anions and cations from the raw water to obtain demineralized water with the required salinity. Conventional power plant demineralization systems use river water or tap water as raw water, employing processes such as pretreatment sedimentation + sand filtration + ultrafiltration + two-stage reverse osmosis + ion exchange resin to achieve demineralized water requirements. This process is complex, costly, and has a water recovery rate of less than 60%, resulting in a large discharge of concentrated wastewater and wasted water resources.

[0003] In view of the above, this utility model is hereby proposed. Utility Model Content

[0004] The purpose of this invention is to provide a power plant demineralized water system to at least solve some of the aforementioned technical problems.

[0005] To achieve the above objectives, the following technical solution is adopted:

[0006] In one aspect, this utility model provides a power plant demineralized water system, which, along the water treatment direction, includes a filter device, a first reverse osmosis device, and an EDI (electrodeionization) device connected in sequence.

[0007] The filtration device is used to remove suspended solids from the water to be treated;

[0008] The first reverse osmosis device produces water at both ends. The concentrate end water outlet is connected to the inlet of the first reverse osmosis device to return the concentrate end water to the inlet of the first reverse osmosis device. The inlet end water outlet of the first reverse osmosis device is connected to the EDI device.

[0009] The EDI device is used to perform EDI treatment on the permeate from the first reverse osmosis unit.

[0010] As a further technical solution, along the water treatment direction, the filtration device sequentially includes a flocculation sedimentation tank and a sand filter.

[0011] As a further technical solution, the flocculation sedimentation tank is equipped with a flocculant inlet for adding flocculant.

[0012] As a further technical solution, the concentrate outlet of the EDI device is connected to the inlet of the sand filter device.

[0013] As a further technical solution, nanofiltration devices are also included;

[0014] The inlet of the nanofiltration device is connected to the concentrate outlet of the first reverse osmosis device, and is used to perform nanofiltration treatment on the concentrate after the first reverse osmosis device has been treated.

[0015] As a further technical solution, a second reverse osmosis unit is also included;

[0016] The inlet of the second reverse osmosis unit is connected to the outlet of the nanofiltration unit, and is used to perform reverse osmosis treatment on the permeate obtained by the nanofiltration unit.

[0017] The product water outlet of the second reverse osmosis unit is connected to the inlet water outlet of the first reverse osmosis unit.

[0018] As a further technical solution, the concentrate outlet of the second reverse osmosis device is connected to the inlet of the nanofiltration device.

[0019] As a further technical solution, a concentration device is also included for concentrating the concentrated water obtained from the nanofiltration device.

[0020] As a further technical solution, the concentration device includes an evaporation and concentration device.

[0021] As a further technical solution, the water to be treated includes river water or tap water.

[0022] Compared with existing technologies, the power plant demineralized water system provided by this utility model has the following beneficial effects:

[0023] The first reverse osmosis unit is equipped with two ends for producing water. The concentrate end of the product water is returned to the feed water side of the first-stage reverse osmosis unit to improve the quality of the product water. This eliminates the need for the second-stage reverse osmosis process and saves costs.

[0024] 2. The first reverse osmosis unit uses EDI technology to produce water, replacing the traditional resin process, which can save on acid and alkali consumption and cleaning water treatment costs. 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 1This is a structural diagram of the first reverse osmosis device of this utility model;

[0027] Figure 2 The power plant demineralized water system provided in Embodiment 1 of this utility model;

[0028] Figure 3 This is a power plant demineralized water system provided in Embodiment 2 of the present invention;

[0029] Figure 4 The power plant demineralized water system provided in Embodiment 3 of this utility model.

[0030] Icons: 1-Flocculation sedimentation tank; 2-Sand filter device; 3-First reverse osmosis device; 31-Inlet of the first reverse osmosis device; 32-Concentrate of the first reverse osmosis device; 33-Product water inlet; 34-Product water inlet; 4-EDI device; 5-Nanofiltration device; 6-Second reverse osmosis device; 7-Concentration device. Detailed Implementation

[0031] The embodiments and examples of this utility model will be described in detail below. However, those skilled in the art will understand that the following embodiments and examples are only for illustrating this utility model and should not be considered as limiting the scope of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Unless otherwise specified, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0032] In the first aspect, this utility model provides a power plant demineralized water system, which, along the water treatment direction, includes a filter device, a first reverse osmosis device 3, and an EDI device 4 connected in sequence.

[0033] The filtration device is used to remove suspended solids from the water to be treated in order to meet the requirements of reverse osmosis;

[0034] The first reverse osmosis device 3 produces water at both ends. The concentrate end water outlet 34 is connected to the inlet 31 of the first reverse osmosis device and is used to return the concentrate end water to the inlet 31 of the first reverse osmosis device. The inlet end water outlet 33 of the first reverse osmosis device 3 is connected to the EDI device 4.

[0035] The EDI device 4 is used to perform EDI treatment on the permeate from the first reverse osmosis device 3.

[0036] In this utility model, such as Figure 1As shown, "permeable water at both ends" refers to the process where, during reverse osmosis treatment, the water to be treated flows from the inlet to the concentrate outlet. Simultaneously, under pressure, the water permeates through the reverse osmosis membrane to produce permeate, which then flows out from both ends of the membrane. As the water flows towards the concentrate outlet, the salt concentration in the solution gradually increases. This increased salt concentration leads to a deterioration in the quality of the permeate passing through the reverse osmosis membrane in that area. Consequently, the permeate flowing out from the inlet outlet 33 is of good quality, while the permeate flowing out from the concentrate outlet 34 is of poor quality.

[0037] The power plant demineralized water system provided by this utility model has a first reverse osmosis device 3 with two ends producing water. The concentrated water is returned to the feed water side of the first-stage reverse osmosis to improve the quality of the produced water, thereby eliminating the need for the second-stage reverse osmosis process and saving costs. The produced water of the first reverse osmosis device 3 adopts the EDI process, which replaces the traditional resin process, and can save on the amount of acid and alkali used and the cost of cleaning water treatment.

[0038] In some alternative embodiments, along the water treatment direction, the filtration device sequentially includes a flocculation sedimentation tank 1 and a sand filter device 2;

[0039] The flocculation sedimentation tank 1 is used to flocculate the water to be treated and remove large particulate suspended matter;

[0040] The sand filter device 2 is used to further remove suspended solids from the water in order to meet the requirements of reverse osmosis.

[0041] In some optional embodiments, the flocculation sedimentation tank 1 is provided with a flocculant inlet for adding flocculant.

[0042] This invention does not impose specific limitations on the flocculant; any flocculant well-known to those skilled in the art can be used.

[0043] In some alternative embodiments, the concentrate outlet of the EDI device 4 is connected to the inlet of the sand filter device 2 to recirculate the concentrate generated by the EDI device 4, which helps to improve the water recovery rate.

[0044] In some alternative implementations, a nanofiltration device 5 is also included;

[0045] The inlet of the nanofiltration device 5 is connected to the concentrate outlet 32 ​​of the first reverse osmosis device, and is used to perform nanofiltration treatment on the concentrate after the first reverse osmosis device 3 has been treated.

[0046] The permeate obtained from nanofiltration can be returned to the inlet 31 of the first reverse osmosis unit for reflux treatment, or it can be further purified.

[0047] The concentrated water obtained from nanofiltration can be discharged directly or further concentrated and recycled.

[0048] In some alternative implementations, a second reverse osmosis unit 6 is also included;

[0049] The inlet of the second reverse osmosis device 6 is connected to the outlet of the nanofiltration device 5, and is used to perform reverse osmosis treatment on the permeate obtained by the nanofiltration device 5.

[0050] The product water outlet of the second reverse osmosis device 6 is connected to the inlet water outlet 31 of the first reverse osmosis device.

[0051] By combining nanofiltration unit 5 and second reverse osmosis unit 6, the overall recovery rate of the system can be effectively improved.

[0052] In some alternative embodiments, the concentrate outlet of the second reverse osmosis unit 6 is connected to the inlet of the nanofiltration unit 5.

[0053] In some alternative embodiments, a concentration device 7 is also included for concentrating the concentrate obtained from the nanofiltration device 5.

[0054] In some alternative embodiments, the concentration device 7 includes, but is not limited to, an evaporation and concentration device.

[0055] In some alternative implementations, the water to be treated includes, but is not limited to, river water or tap water.

[0056] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are only for more detailed illustration and should not be construed as limiting the present invention in any way.

[0057] Example 1

[0058] A power plant demineralized water system, such as Figure 1 and Figure 2 As shown, along the water treatment direction, it includes a flocculation sedimentation tank 1, a sand filter device 2, a first reverse osmosis device 3, and an EDI device 4 connected in sequence.

[0059] Among them, the flocculation sedimentation tank 1 is used to flocculate the water to be treated and remove large particulate suspended matter. The flocculation sedimentation tank 1 is equipped with a flocculant inlet for adding flocculant.

[0060] Sand filter 2 is used to further remove suspended solids from the water in order to meet the requirements of reverse osmosis;

[0061] The first reverse osmosis unit 3 produces water at both ends. The concentrate end water outlet 34 is connected to the inlet 31 of the first reverse osmosis unit and is used to return the concentrate end water to the inlet 31 of the first reverse osmosis unit. The inlet end water outlet 33 of the first reverse osmosis unit 3 is connected to the EDI unit 4.

[0062] EDI device 4 is used to perform EDI treatment on the permeate from the first reverse osmosis device 3. The concentrate outlet of EDI device 4 is connected to the inlet of the sand filter device 2 so as to recirculate the concentrate produced by EDI device 4.

[0063] Example 2

[0064] A power plant demineralized water system, such as Figure 1 and 3 As shown, along the water treatment direction, it includes a flocculation sedimentation tank 1, a sand filter device 2, a first reverse osmosis device 3, and an EDI device 4 connected in sequence.

[0065] Among them, the flocculation sedimentation tank 1 is used to flocculate the water to be treated and remove large particulate suspended matter. The flocculation sedimentation tank 1 is equipped with a flocculant inlet for adding flocculant.

[0066] Sand filter 2 is used to further remove suspended solids from the water in order to meet the requirements of reverse osmosis;

[0067] The first reverse osmosis unit 3 produces water at both ends. The concentrate end water outlet 34 is connected to the inlet 31 of the first reverse osmosis unit and is used to return the concentrate end water to the inlet 31 of the first reverse osmosis unit. The inlet end water outlet 33 of the first reverse osmosis unit 3 is connected to the EDI unit 4.

[0068] EDI device 4 is used to perform EDI treatment on the permeate from the first reverse osmosis device 3. The concentrate outlet of EDI device 4 is connected to the inlet of the sand filter device 2 so as to recirculate the concentrate produced by EDI device 4.

[0069] In this scheme, the power plant demineralized water system also includes a nanofiltration unit 5 and a second reverse osmosis unit 6;

[0070] The inlet of the nanofiltration device 5 is connected to the concentrate outlet 32 ​​of the first reverse osmosis device, and is used to perform nanofiltration treatment on the concentrate after the first reverse osmosis device 3.

[0071] The inlet of the second reverse osmosis device 6 is connected to the outlet of the nanofiltration device 5, and is used to perform reverse osmosis treatment on the permeate obtained by the nanofiltration device 5; the outlet of the second reverse osmosis device 6 is connected to the inlet 31 of the first reverse osmosis device; the outlet of the second reverse osmosis device 6 is connected to the inlet of the nanofiltration device 5.

[0072] Example 2

[0073] A power plant demineralized water system, such as Figure 1 and 3 As shown, along the water treatment direction, it includes a flocculation sedimentation tank 1, a sand filter device 2, a first reverse osmosis device 3, and an EDI device 4 connected in sequence.

[0074] Among them, the flocculation sedimentation tank 1 is used to flocculate the water to be treated and remove large particulate suspended matter. The flocculation sedimentation tank 1 is equipped with a flocculant inlet for adding flocculant.

[0075] Sand filter 2 is used to further remove suspended solids from the water in order to meet the requirements of reverse osmosis;

[0076] The first reverse osmosis unit 3 produces water at both ends. The concentrate end water outlet 34 is connected to the inlet 31 of the first reverse osmosis unit and is used to return the concentrate end water to the inlet 31 of the first reverse osmosis unit. The inlet end water outlet 33 of the first reverse osmosis unit 3 is connected to the EDI unit 4.

[0077] EDI device 4 is used to perform EDI treatment on the permeate from the first reverse osmosis device 3. The concentrate outlet of EDI device 4 is connected to the inlet of the sand filter device 2 so as to recirculate the concentrate produced by EDI device 4.

[0078] In this scheme, the power plant demineralized water system also includes a nanofiltration unit 5 and a second reverse osmosis unit 6;

[0079] The inlet of the nanofiltration device 5 is connected to the concentrate outlet 32 ​​of the first reverse osmosis device, and is used to perform nanofiltration treatment on the concentrate after the first reverse osmosis device 3.

[0080] The inlet of the second reverse osmosis device 6 is connected to the outlet of the nanofiltration device 5, and is used to perform reverse osmosis treatment on the permeate obtained by the nanofiltration device 5; the outlet of the second reverse osmosis device 6 is connected to the inlet 31 of the first reverse osmosis device; the outlet of the second reverse osmosis device 6 is connected to the inlet of the nanofiltration device 5.

[0081] Comparative Example 1

[0082] A power plant demineralized water system differs from Embodiment 2 in that the first reverse osmosis device 3 produces water at both ends, but the water produced at both ends is mixed and flows into the EDI device 4 for EDI treatment.

[0083] Experimental Example 1

[0084] River water was used as the water to be treated (inlet parameters are shown in Table 1). The power plant demineralized water systems of Example 2 and Comparative Example 1 were used for treatment. The inlet and outlet water quality of the first reverse osmosis unit 3 and EDI unit 4 were tested respectively, and the results are shown in Table 1.

[0085] Table 1

[0086]

[0087] As can be seen from Table 1, the conductivity of the product water from the first reverse osmosis unit 3 in the power plant demineralized water system of Example 2 is significantly lower than that in Comparative Example 1, and the final product water quality is also better than that in Comparative Example 1.

[0088] Example 3

[0089] A power plant demineralized water system, such as Figure 1 and 4 As shown, along the water treatment direction, it includes a flocculation sedimentation tank 1, a sand filter device 2, a first reverse osmosis device 3, and an EDI device 4 connected in sequence.

[0090] Among them, the flocculation sedimentation tank 1 is used to flocculate the water to be treated and remove large particulate suspended matter. The flocculation sedimentation tank 1 is equipped with a flocculant inlet for adding flocculant.

[0091] Sand filter 2 is used to further remove suspended solids from the water in order to meet the requirements of reverse osmosis;

[0092] The first reverse osmosis unit 3 produces water at both ends. The concentrate end water outlet 34 is connected to the inlet 31 of the first reverse osmosis unit and is used to return the concentrate end water to the inlet 31 of the first reverse osmosis unit. The inlet end water outlet 33 of the first reverse osmosis unit 3 is connected to the EDI unit 4.

[0093] EDI device 4 is used to perform EDI treatment on the permeate from the first reverse osmosis device 3. The concentrate outlet of EDI device 4 is connected to the inlet of the sand filter device 2 so as to recirculate the concentrate produced by EDI device 4.

[0094] In this scheme, the power plant demineralized water system also includes a nanofiltration unit 5, a second reverse osmosis unit 6, and a concentration unit 7;

[0095] The inlet of the nanofiltration device 5 is connected to the concentrate outlet 32 ​​of the first reverse osmosis device, and is used to perform nanofiltration treatment on the concentrate after the first reverse osmosis device 3.

[0096] The inlet of the second reverse osmosis device 6 is connected to the outlet of the nanofiltration device 5, and is used to perform reverse osmosis treatment on the permeate obtained by the nanofiltration device 5; the outlet of the second reverse osmosis device 6 is connected to the inlet 31 of the first reverse osmosis device; the concentrate outlet of the second reverse osmosis device 6 is connected to the inlet of the nanofiltration device 5.

[0097] The concentration unit 7 is used to concentrate the concentrated water obtained from the nanofiltration unit 5. In this scheme, the concentration unit 7 is an evaporation concentration unit.

[0098] 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 power plant demineralized water system characterized by, In the water treatment direction, the filter device, the first reverse osmosis device (3) and the EDI device (4) are sequentially connected. The filter device is used for removing suspended solids in the water to be treated. The first reverse osmosis device (3) is a water production device at both ends, and a concentrated water outlet (34) at the concentrated water end is communicated with a water inlet (31) of the first reverse osmosis device, and is used for returning the concentrated water at the concentrated water end to the water inlet (31) of the first reverse osmosis device; a water outlet (33) at the water inlet end of the first reverse osmosis device (3) is communicated with the EDI device (4). The EDI device (4) is used for EDI treatment of the water produced from the first reverse osmosis device (3).

2. The power plant demineralized water system of claim 1, wherein, In the water treatment direction, the filter device sequentially comprises a flocculation sedimentation tank (1) and a sand filter device (2).

3. The power plant demineralized water system of claim 2, wherein, The flocculation sedimentation tank (1) is provided with a flocculant adding port for adding flocculant.

4. The power plant demineralized water system of claim 2, wherein, A concentrated water outlet of the EDI device (4) is communicated with a water inlet of the sand filter device (2).

5. The power plant demineralized water system of claim 1, wherein, Further comprising a nanofiltration device (5); A water inlet of the nanofiltration device (5) is communicated with a concentrated water outlet (32) of the first reverse osmosis device, and is used for nanofiltration treatment of the concentrated water treated by the first reverse osmosis device (3).

6. The power plant demineralized water system of claim 5, wherein, Further comprising a second reverse osmosis device (6); A water inlet of the second reverse osmosis device (6) is communicated with a water outlet of the nanofiltration device (5), and is used for reverse osmosis treatment of the water produced by the nanofiltration device (5); A water outlet of the second reverse osmosis device (6) is communicated with the water inlet (31) of the first reverse osmosis device.

7. The power plant demineralized water system of claim 6, wherein, A concentrated water outlet of the second reverse osmosis device (6) is communicated with the water inlet of the nanofiltration device (5).

8. The power plant demineralized water system of claim 5, wherein, Further comprising a concentration device (7) for concentration treatment of the concentrated water treated by the nanofiltration device (5).

9. The power plant demineralized water system of claim 8, wherein, The concentration device (7) comprises an evaporation concentration device.

10. The power plant demineralized water system of claim 1, wherein, The water to be treated comprises river water or tap water.

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