A method and apparatus for treating ammonia-rich condensate from a power plant

Abstract

The application discloses a method and device for treating ammonia-rich condensed water of a power plant to solve the problems of complicated traditional process operation, large reagent consumption, high environmental protection pressure and high cost. A two-stage treatment of a cation bed-electric mixed bed is adopted, the cation bed is filled with weak acid resin for ammonia removal and cation and anion balance in pretreatment, and the electric mixed bed is filled with an easy-to-regenerate mixed resin of anions and cations for deep impurity removal, and the two are regenerated and cleaned synchronously in series; the device is of an integrated sealed structure, and the cation bed, an acid adding assembly and an electric mixed bed are sequentially arranged from top to bottom; water flows from top to bottom in treatment, and water flows from bottom to top in regeneration and cleaning. Compared with a traditional mixed bed, the application has the advantages of simple operation, no need for alkali regenerant, acid consumption being only 25%-33% of that of the traditional method, no high-concentration acid and alkali wastewater and low treatment cost.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a method and apparatus for treating ammonia-rich condensate from power plants. It employs a two-stage treatment technology combining a cation exchange bed and an electro-mixed bed, which is suitable for the efficient treatment of ammonia-rich condensate from power plants. Background Technology

[0002] Condensate generated during power plant production contains impurities such as sodium ions, chloride ions, and silicate ions, which can have adverse effects on the power plant's thermal system. Therefore, it is necessary to carry out in-depth purification treatment.

[0003] Currently, the industry commonly uses mixed-bed condensate treatment, which involves mixing cation exchange resins and anion exchange resins to remove impurity ions from the water through ion exchange reactions. However, this technology has significant drawbacks: regeneration requires sequential steps such as backwashing and stratification, separate acid and alkali regeneration, residual reagent cleaning, and resin remixing, making the regeneration operation quite complex, and each regeneration typically takes 4-5 hours. To ensure thorough resin regeneration, the actual acid and alkali dosages are usually 3-4 times and 4-5 times the theoretical requirements, respectively, resulting in high reagent consumption, high treatment costs, and the generation of large amounts of acid and alkali wastewater, which is detrimental to environmental protection. Furthermore, due to layout constraints, most power plants have their fine treatment mixed-bed and resin regeneration units located in different areas, requiring frequent resin transport via pipelines, which is not only cumbersome but also causes resin friction damage.

[0004] While electrodeionization (EDI) technology is considered a potential direction for condensate treatment, the ion exchange membranes it relies on are temperature-sensitive, and the temperature of power plant condensate is typically high, which can easily lead to membrane performance degradation. The use of EDI to treat power plant condensate is currently still in the research stage and has not yet been implemented on a large scale in industry.

[0005] As the third deep desalination technology following mixed-bed and conventional EDI, electro-mixed-bed desalination does not rely on ion exchange membranes, overcoming the temperature sensitivity of conventional EDI. It can effectively treat condensate with relatively low ammonia content and a conductivity typically around 2-3 μS / cm. However, to suppress corrosion in thermal systems, many power plants, especially some small and medium-sized thermal power plants, add a large amount of ammonia to boiler feedwater, resulting in relatively high ammonia content in condensate, with conductivity typically reaching 5-10 μS / cm, and sometimes even exceeding 20 μS / cm. This ammonia-rich condensate is characterized by a significantly higher molar ratio of cations and molecular ammonia than anions, leading to a severe imbalance between cations and anions, making direct treatment with an electro-mixed-bed desalination unsustainable. Because the cation and anion resins in the electro-mixed-bed undergo simultaneous in-situ regeneration, when the condensate is ammonia-rich, the pH of the regeneration water flow within the resin layer becomes significantly alkaline, hindering the effective regeneration of the degraded cation resin. This ultimately affects the removal of cationic impurities, making it difficult to consistently meet effluent quality standards. Summary of the Invention

[0006] To address the problems existing in the background technology, the present invention aims to provide a method and apparatus for treating ammonia-rich condensate from power plants in a two-stage series treatment of "cation bed-electro-mixed bed". By pre-treating with a cation bed to adsorb excess ammonia and adjust the water quality to near neutrality, the anion and cation content is balanced, enabling the subsequent electro-mixed bed to operate efficiently. This method can replace the traditional mixed bed, significantly simplifying operation, greatly reducing acid and alkali consumption, and alleviating environmental pressure.

[0007] The technical solution of the present invention is as follows: A method for treating ammonia-rich condensate from power plants employs a two-stage treatment process: a cation exchange bed and an electro-mixed bed. The cation exchange bed is filled with a weakly acidic resin for pretreatment, removing excess ammonia from the ammonia-rich condensate, balancing cations and anions, and removing corrosion products. The electro-mixed bed is filled with a mixed cation and anion resin for further treatment of the pretreated water, removing ionic and ionizable molecular impurities. The electro-mixed bed and the cation exchange bed are regenerated and cleaned synchronously in series.

[0008] In the treatment method of this application, for ammonia-rich condensate from power plants, a two-stage process of "cationized bed pretreatment - electro-mixed bed deep treatment" is adopted, combined with in-situ synchronous series regeneration and cleaning. The core points are: Operating method: Each operating cycle consists of three steps: treatment, regeneration and cleaning, which are repeated continuously. During treatment, the water flows from top to bottom, while during regeneration and cleaning, the water flows from bottom to top.

[0009] Secondary treatment division of labor: The cation exchange bed is filled with weakly acidic resin to remove excess ammonia and corrosion products, transforming the water quality from relatively high alkalinity to near neutrality, balancing anions and cations, and laying a reliable foundation for subsequent treatment; the electro-mixed bed is responsible for deep impurity removal of the pretreated water to ensure that the effluent meets the standards.

[0010] Regeneration / Cleaning Design: The electro-mixed bed and the cation exchange bed are regenerated and cleaned synchronously in series. When the effluent quality drops to a preset threshold, purified water after deep treatment flows through the resin layer of the electro-mixed bed. At the same time, direct current is applied to the anode and cathode of the electro-mixed bed to promote the regeneration of the electro-mixed bed resin and generate electro-mixed bed regeneration concentrate. The electro-mixed bed regeneration concentrate is immediately mixed with external acid to form an acidic regeneration solution. The acidic regeneration solution then flows through the weakly acidic resin layer of the cation exchange bed to chemically regenerate the weakly acidic resin and generate cation exchange bed regeneration concentrate. After regeneration, the purified water after deep treatment continues to flow sequentially through the electro-mixed bed and the cation bed to rinse away residual impurities until the quality of the effluent meets the preset requirements.

[0011] This application also provides a device for treating ammonia-rich condensate from power plants to implement the method, which adopts an integrated structure and includes three core units from top to bottom: a cation bed, an acid addition component, and an electro-mixed bed. The three units are connected in a sealed manner to form a whole. The cation bed is provided with a cover plate, an upper box, a first water distribution component, and a second water distribution component; the cover plate is rectangular in shape, with a first reinforcing rib at the top and an upper pipe interface at the center; the upper box is located below the cover plate, open at both the top and bottom, with a second reinforcing rib on the outside and a cuboid shape inside; the first water distribution component and the second water distribution component are located at the upper and lower ends of the upper box, respectively, and a weakly acidic resin is filled between them to form a cation bed resin layer; The acid addition component is a rectangular clamp-shaped structure with an acid input interface on one of its edges and a water collection hole in the center of the plate. An annular acid tank is arranged around the water collection hole. The annular acid tank is connected to the acid input interface by an acid channel. An annular acid tank cover plate is provided on the lower side of the annular acid tank, and the annular acid tank cover plate has a small acid inlet hole. The electro-mixed bed comprises a lower chamber, a third water distribution assembly, a fourth water distribution assembly, an anode, and a cathode. The upper end of the lower chamber is open, and the lower end has a base plate with a central lower pipe interface. The interior is rectangular, and the outer side wall has a third reinforcing rib and supporting feet. The lower side of the base plate has a fourth reinforcing rib. The third and fourth water distribution assemblies are located at the upper and lower ends of the lower chamber, respectively. The anode and cathode are respectively installed in close contact with two opposite inner side walls of the lower chamber. The cavity formed by the anode, cathode, the other two inner side walls of the lower chamber, and the third and fourth water distribution assemblies is filled with a mixture of anion and cathode resin to form an electro-mixed bed resin layer. During treatment, no DC power is applied to the electro-mixed bed, and the water flow direction is from top to bottom; during synchronous series regeneration, DC power is applied to the electro-mixed bed, and acid is added through the acid addition component, with the water flow direction from bottom to top; during synchronous series cleaning, the water flow direction is the same as that during synchronous series regeneration.

[0012] The integrated structural device of this application comprises three core units from top to bottom: a cation bed, an acid addition component, and an electro-mixed bed, which are connected in a sealed manner to form a whole. Through an integrated and synchronous series regeneration and cleaning design, the process is simplified, effective treatment time is increased, and space is saved. Compared with traditional mixed beds, it has advantages such as simple operation, no need for alkali regenerant, acid consumption of only 25%-33% of the traditional method, no high-concentration acid or alkali wastewater, and low treatment cost. The regeneration concentrate and cleaning effluent flowing from the top pipe interface are nearly neutral, with an average conductivity typically below 500 μS / cm, and most of them can be recycled after reverse osmosis treatment.

[0013] During processing, the water flow direction is from top to bottom: water to be treated → upper pipe interface → first water distribution component → cation bed resin layer → second water distribution component → water collection hole → third water distribution component → electro-mixed bed resin layer (no DC power applied) → fourth water distribution component → lower pipe interface → output purified water after treatment.

[0014] During synchronous series regeneration, the water flow direction is from bottom to top: purified water → lower pipe interface → fourth water distribution component → electro-mixed bed resin layer (applied DC current) → third water distribution component (the electro-regeneration concentrate and the added acid solution are mixed in the internal area of ​​the third water distribution component) → water collection hole → second water distribution component → cation bed resin layer → first water distribution component → upper pipe interface → discharge of concentrated acid regeneration water.

[0015] During synchronous series cleaning, the water flow direction is the same as that during synchronous series regeneration.

[0016] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0017] Optionally, the outer edges of the upper and lower housings are flange structures; the outer edges of the cover plate and the acid adding assembly are both provided with matching flange holes; a first sealing gasket is sandwiched between the lower side of the cover plate and the upper end of the upper housing, and the connection is secured by a first bolt group; a second sealing gasket is sandwiched between the lower end of the upper housing and the upper side of the acid adding assembly, and a third sealing gasket is sandwiched between the lower side of the acid adding assembly and the upper end of the lower housing, and the connections are secured by a second bolt group.

[0018] Optionally, the cation bed is a shallow high-speed cation bed with a resin layer height of only 0.2-0.5m and a processing flow rate of 100-120m / h.

[0019] Optionally, the filling height of the electric mixed bed resin layer is 0.3-0.8m.

[0020] Optionally, each of the two opposite side walls of the lower housing is provided with an anode terminal through hole and a cathode terminal through hole for passing through the corresponding terminals. The anode terminals and cathode terminals are assembled through the corresponding through holes; the anode and cathode are electrically connected to the corresponding terminals.

[0021] Optionally, the inner walls of the upper and lower housings, as well as the through holes of the anode and cathode terminals, are all made of insulating material, or the entire housing is made of insulating material to achieve insulation isolation between the inside and outside of the housing; insulating glue is used to seal the back of the anode and cathode with the inner wall of the lower housing, the anode terminals with the anode terminals through holes, and the cathode terminals with the cathode terminals through holes.

[0022] Optionally, the anodes are electrically connected to each other and the cathodes are electrically connected to each other by direct electric welding.

[0023] Optionally, the wiring terminals are secured to the outer wall of the enclosure with nuts and washers.

[0024] Optionally, the annular acid tank is formed by slotting a plate and then sealing it with an annular acid tank cover plate with small acid injection holes by welding or acid and alkali resistant waterproof sealant. The diameter of the small acid injection holes is 1-5mm, the number is 6-100, and the center-to-center distance between two adjacent small acid injection holes is about 10-30mm, and they are evenly distributed.

[0025] Optionally, the second and third water distribution components are fixedly connected to the top and bottom surfaces of the clamping plate, respectively; the first water distribution component is fixedly connected to the bottom surface of the cover plate, and the fourth water distribution component is fixedly connected to the top surface of the base plate.

[0026] Optionally, the first, second, third, and fourth water distribution components each include a slit plate for intercepting resin, a frame, and 10-30 cylindrical support members with a diameter of 20-30mm and a central bolt hole. These support members are respectively tightly fixed to the inner side of the cover plate, the upper and lower sides of the acid addition component, and the inner side of the base plate using high-strength insulating bolts or acid and alkali resistant waterproof sealant.

[0027] The treatment method of this application employs a two-stage series connection of a cation exchange bed and an electro-mixed bed. The cation exchange bed and the electro-mixed bed can be connected in series as independent devices, or they can be connected using a uniquely designed integrated device, preferably a self-designed integrated device. When the method of this application for treating ammonia-rich condensate from power plants utilizes the aforementioned integrated device, it includes a cyclic process: deal with: The ammonia-rich condensate from the power plant is fed into the cation exchange bed through the upper pipeline interface. The weakly acidic resin in the cation exchange bed removes ammonia from the condensate to pretreat and balance the anions and cations. The pretreated condensate enters the electric mixed bed through the water collection hole, and after being deeply purified by the resin layer of the electric mixed bed, it is discharged through the lower pipe interface. regeneration: When the effluent quality drops to a preset threshold, the purified water after deep treatment is sent into the electro-mixed bed through the lower pipe interface. At the same time, DC current is applied to the anode and cathode to promote the regeneration of the electro-mixed bed resin layer and generate electro-mixed bed regeneration concentrate. The electro-mixed bed regeneration concentrate is mixed with the acid solution sent by the acid addition component to form an acidic regeneration solution. The acidic regeneration solution enters the cation bed through the water collection hole, flows through the cation bed resin layer, chemically regenerates the cation bed resin layer and generates cation bed regeneration concentrate, which is discharged through the upper pipe interface. Cleaning: After regeneration, the deeply treated purified water continues to be sent into the electro-mixed bed through the lower pipe interface. The purified water flows through the electro-mixed bed resin layer and the cation bed resin layer in sequence and is discharged through the upper pipe interface to rinse away residual impurities until the quality of the effluent meets the preset requirements.

[0028] Optionally, the flow rate during treatment is 100~120 m / h; the current density during regeneration is 100~200 A / m. 2 The average voltage is 250-450V; the flow rate during regeneration and cleaning is 30-70 m / h; the processing time in each operating cycle is 200-400 minutes, and the regeneration and cleaning times are 15-20 minutes and 1-3 minutes, respectively.

[0029] Optionally, regeneration can be initiated when the conductivity of the effluent from the electro-mixed bed exceeds a preset threshold.

[0030] The actual amount of acid added during regeneration is close to the theoretical requirement.

[0031] Compared with the prior art, this application has at least one of the following beneficial effects: (1) Higher efficiency and wider application range: By adding a cation bed filled with weak acid resin for pretreatment, excess ammonia in ammonia-rich condensate can be removed efficiently, balancing the anions and cations in the water, significantly improving the regeneration efficiency and treatment capacity of the electro-mixed bed, and effectively expanding its application scenarios.

[0032] (2) Simple operation, saving time and effort: Traditional mixed bed regeneration requires complicated steps such as resin transportation, hydraulic stratification of cation and anion resins, independent regeneration and cleaning of cation and anion resins, and remixing of cation and anion resins, which takes up to 4-5 hours in total. The electric mixed bed and cation bed of this application adopt the in-situ synchronous series regeneration and cleaning mode, which is simple to operate and only takes about 20 minutes in total. It supports unattended operation and greatly reduces labor costs.

[0033] (3) Saves reagents and is environmentally friendly: In traditional mixed bed regeneration, the actual consumption of acid and alkali regenerators is usually 3-4 times and 4-5 times the theoretical value, respectively, and high-concentration acid and alkali wastewater is generated, which puts great pressure on the environment. This application does not require the use of alkali regenerators, and the actual consumption of acid regenerators is close to the theoretical value, which is only 25%-33% of that of traditional mixed beds. The regeneration process does not generate high-concentration acid and alkali wastewater. The regeneration concentrate and cleaning effluent are close to neutral, and the average conductivity is usually less than 500μs / cm. Most of them can be recycled after reverse osmosis treatment, which saves water resources and is also beneficial to the environment. Attached Figure Description

[0034] Figure 1 This is a process flow diagram of the processing method in this application.

[0035] Figure 2 This is a front view of the integrated device.

[0036] Figure 3 This is a left view of the integrated device.

[0037] Figure 4 This is a top view of the integrated device.

[0038] Figure 5 for Figure 2 Sectional view along the middle II direction.

[0039] Figure 6 for Figure 5 A magnified view of part A in the middle.

[0040] Figure 7 for Figure 6 A magnified view of part B in the middle section.

[0041] The reference numerals in the figure are as follows: 1. Acid bed: 101. Cover plate, 102. Upper box body, 103. First water distribution component, 104. Second water distribution component, 105. First reinforcing rib, 106. Upper pipe interface, 107. Second reinforcing rib, 108. Acid bed resin layer, 109. First sealing gasket, 110. Second sealing gasket. 2. Acid addition assembly: 201, acid input interface, 202, water collection hole, 203, annular acid tank, 204, acid channel, 205, annular acid tank cover, 206, acid injection hole, 207, clamping plate; 3. Electric Mixed Bed: 301. Lower Box, 302. Third Water Distribution Component, 303. Fourth Water Distribution Component, 304. Anode, 305. Cathode, 306. Lower Pipe Interface, 307. Base Plate, 308. Third Reinforcing Rib, 309. Fourth Reinforcing Rib, 310. Electric Mixed Bed Resin Layer, 311. Anode Terminal, 312. Anode Terminal Through Hole, 313. Anode Terminal Nut, 314. Anode Terminal Gasket, 315. Cathode Terminal, 316. Cathode Terminal Through Hole, 317. Cathode Terminal Nut, 318. Cathode Terminal Gasket, 319. Third Sealing Gasket, 320. Support Leg; 4. First bolt group; 5. Second bolt group. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0044] A method for treating ammonia-rich condensate from power plants, the process flow of which is as follows: Figure 1 As shown, a series connection of anionic bed and electric mixed bed is used for treatment, regeneration, and cleaning: Treatment: The ammonia-rich condensate from the power plant is sent to the cation exchange bed for pretreatment, and then enters the electro-mixed bed for deep purification. The purified water is then discharged.

[0045] regeneration: When the effluent quality drops to a preset threshold, the purified water after deep treatment is sent into the electric mixed bed. At the same time, direct current is applied to the anode and cathode in the electric mixed bed to promote the regeneration of the resin layer and generate electric mixed bed regeneration concentrate. The electric mixed bed regeneration concentrate mixes with the externally supplied acid solution to form an acidic regeneration solution, which then enters the cation bed, flows through the cation bed resin layer, chemically regenerates the cation bed resin layer, generates cation bed regeneration concentrate, and is discharged. Cleaning: After regeneration, the deeply treated purified water continues to be fed into the electro-mixed bed. The purified water flows through the electro-mixed bed and the cation bed in sequence to clean the resin layers of the electro-mixed bed and the cation bed until the quality of the effluent meets the preset requirements.

[0046] The processing method of this application involves connecting the cation bed and the electro-mixed bed in series for series processing, regeneration, and cleaning. In some embodiments, the cation bed and the electro-mixed bed can be two independent devices connected in series, and the acid addition component is used to add acid to the electro-mixed bed. In other embodiments, an integrated device with a unique design of this application is used.

[0047] like Figures 2-5 As shown, an integrated device for treating ammonia-rich condensate in an electric field includes an cation bed 1 and an electric mixed bed 3 connected in series from top to bottom. An acid addition component 2 is provided between the cation bed and the electric mixed bed. The cation bed 1, the acid addition component 2, and the electric mixed bed 3 are sequentially and sealed together as a whole.

[0048] The cation bed 1 includes an upper housing 102, a cover plate 101, a first water distribution component 103, a second water distribution component 104, and a cation bed resin layer 108. The upper housing has side walls, and its top is sealed to the cover plate. An upper pipe interface 106 is provided on the cover plate. The first water distribution component 103 is located at the top of the upper housing, and the second water distribution component is located at the bottom of the upper housing. The space between the first water distribution component and the second water distribution component is filled with a weakly acidic resin to form the cation bed resin layer 108.

[0049] The electric mixed bed 3 includes a lower chamber 301, a third water distribution component 302, a fourth water distribution component 303, an anode 304, a cathode 305, and an electric mixed bed resin layer 310. The lower chamber has a bottom plate 307 and side walls. The bottom plate is provided with a lower pipe interface 306. The third water distribution component 302 is provided at the top of the lower chamber, and the fourth water distribution component 303 is provided at the bottom of the lower chamber. The space between the third water distribution component and the fourth water distribution component is filled with anode and cathode mixed resin to form the electric mixed bed resin layer 310. An anode 304 and a cathode 305 are respectively provided on one pair of opposite inner side walls of the lower chamber.

[0050] The acid adding component 2 is sealed to both the upper housing 102 and the lower housing 301, and the acid adding component 2 has a water collection hole 202 that connects the upper housing and the lower housing, as well as an acid distribution component arranged around the water collection hole.

[0051] The acid addition assembly is used to introduce acidic liquid into the device during regeneration. As one embodiment of the acid addition assembly, see [link to relevant documentation]. Figures 5-7 The acid addition component 2 includes: The clamping plate 207 is clamped between the upper box 102 and the lower box 301 and is sealed to the side walls of the upper box and the lower box respectively. The water collection hole 202 passes through the center of the clamping plate 207. The outer side wall of the clamping plate has an acid input interface 201. An annular acid tank 203 is arranged around the water collection hole 202 and located on the bottom surface of the clamping plate 207. The annular acid tank 203 is connected to the acid input interface 201 through the acid channel 204 located inside the clamping plate. An annular acid tank cover plate 205 is used to enclose the opening of the annular acid tank 203, and small acid injection holes 206 are evenly opened on the annular acid tank cover plate 205.

[0052] The annular acid tank and the annular acid tank cover plate constitute the aforementioned acid distribution component, and the clamping plate can be a rectangular plate.

[0053] As a processing method for acid addition components: after the plate body of the clamp is grooved to form an annular acid tank, an annular acid tank cover plate with acid injection holes is used to seal it by welding or acid and alkali resistant waterproof sealant. The diameter of the acid injection holes is 1-5mm, the number is 6-100, and the center distance between two adjacent acid injection holes is about 10-30mm.

[0054] In some embodiments, the top and bottom of the upper tank are both open structures, with the top closed by a cover plate. The top of the lower tank is also open, while the bottom is an integral structure with the base plate. Support feet 320 are provided at the bottom of the lower tank. The upper and lower tanks are separated by a clamping plate of the acid-adding assembly and connected by a water collection hole in the center of the clamping plate. The second water distribution assembly 104 is fixed to the top surface of the clamping plate, the third water distribution assembly 302 is fixed to the bottom surface of the clamping plate, the first water distribution assembly 103 is fixed to the bottom surface of the cover plate 101, and the fourth water distribution assembly 303 is fixed to the top surface of the base plate 307.

[0055] The first, second, third, and fourth water distribution components all adopt the same structure, which can be based on the existing water distribution structure in an electro-mixed bed. For example, a combined structure including a slotted plate, a support frame, and support columns can be used. The slotted plate serves both for water distribution and resin interception. The support frame and support columns of each water distribution component are supported between the slotted plate and the corresponding cover plate, clamping plate, and bottom plate. The support frame is located at the edge of the slotted plate, and the support column is located within the area enclosed by the support frame. Each water distribution component is tightly fixed to its corresponding connecting surface using high-strength insulated bolts and / or acid- and alkali-resistant waterproof sealant. After the water distribution components are assembled, each slotted plate comes into contact with the corresponding resin layer.

[0056] The cation exchange bed is a shallow, high-speed cation exchange bed, with weakly acidic resin packed between the first and second water distribution components at a height of 0.2-0.5m, and a treatment flow rate of 100-120m / h. The filling height of the cation-anion mixed resin in the electro-mixed bed is 0.3-0.8m.

[0057] Both the upper and lower housings are cubic enclosures. The anode and cathode are respectively located on a pair of opposite side walls of the lower housing. To facilitate connection between the anode and cathode and an external power source, each of the opposite side walls of the lower housing has a through hole for passing through the corresponding terminal block. The anode and cathode terminals are assembled through the corresponding through holes and sealed with waterproof sealant. The anode and cathode are electrically connected to their corresponding terminals, for example, by direct welding. The terminals are secured to the outer wall of the housing with nuts and washers.

[0058] For details, see Figure 5A through hole 312 for anode terminals is provided on the side wall where the anode is installed. An anode terminal 311 penetrates the through hole and is welded to the anode. A waterproof sealant is used to seal the anode terminal 311 with the inner wall of the through hole. The anode terminal is fastened to the outside of the side wall by an anode terminal nut 313 and an anode terminal washer 314. A through hole 316 for cathode terminals is provided on the side wall where the cathode is installed. A cathode terminal 315 penetrates the through hole and is welded to the cathode. A waterproof sealant is used to seal the cathode terminal 315 with the inner wall of the through hole. The cathode terminal is fastened to the outside of the side wall by a cathode terminal nut 317 and a cathode terminal washer 318.

[0059] To enhance the overall strength of the device, reinforcing ribs are provided on the outer walls of the upper housing and the top surface of the cover plate; reinforcing ribs are also provided on the outer walls of the lower housing and the bottom surface of the base plate. Specifically, a first reinforcing rib 105 is provided on the top surface of the cover plate 101, a second reinforcing rib 107 is provided on the outer walls of the upper housing 102, a third reinforcing rib 308 is provided on the outer walls of the lower housing 301, and a fourth reinforcing rib 309 is provided on the bottom surface of the base plate 307. The reinforcing ribs are evenly distributed vertically on the outer sides of the side walls, and evenly intersectingly distributed along the length and width directions on the outer sides of the base plate and cover plate.

[0060] The upper and lower housing inner walls, anode terminal through holes, and cathode terminal through holes are all made of insulating material, or the entire housing is made of insulating material to achieve insulation isolation between the inside and outside of the housing. Insulating adhesive is used to seal the gaps between the back of the anode and cathode and the inner wall of the lower housing, between the anode terminals and their through holes, and between the cathode terminals and their through holes. Both the upper and lower pipe interfaces use flange structures, and the sealing surfaces of the flanges and the inner sides of the pipe sections are made of insulating material.

[0061] The cation bed 1, acid addition assembly 2, and electric mixing bed 3 are sequentially and sealed together. In one connection method, the outer edges of the upper and lower housings are flange structures; the outer edges of the cover plate and clamping plate are opened with matching flange holes; a first sealing gasket is sandwiched between the lower side of the cover plate and the upper end of the upper housing and is fastened and sealed by the first bolt group 4; a second sealing gasket is sandwiched between the lower end of the upper housing and the upper side of the clamping plate, and a third sealing gasket is sandwiched between the lower side of the clamping plate and the upper end of the lower housing; the upper housing, clamping plate, and lower housing are fastened and sealed together by the second bolt group 5.

[0062] When the above-mentioned integrated device is used for condensate treatment, the treatment process is as follows: deal with: The ammonia-rich condensate from the power plant is fed into the cation exchange bed through the upper pipeline interface. The weakly acidic resin in the cation exchange bed removes ammonia from the condensate to pretreat and balance the anions and cations. The pretreated condensate enters the electro-mixed bed through the water collection hole, and after being deeply purified by the resin layer of the electro-mixed bed, it is discharged through the lower pipe interface.

[0063] During treatment, the water flow direction is from top to bottom: water to be treated → upper pipe interface → first water distribution component → cation bed resin layer → second water distribution component → water collection hole → third water distribution component → electro-mixed bed resin layer (no DC power applied) → fourth water distribution component → lower pipe interface → output purified water after treatment.

[0064] regeneration: When the effluent quality drops to a preset threshold, the purified water after deep treatment is sent into the electro-mixed bed through the lower pipe interface. At the same time, direct current is applied to the anode and cathode to promote the regeneration of the electro-mixed bed resin layer and generate electro-mixed bed regeneration concentrate. The electro-mixed bed regeneration concentrate mixes with the acid solution sent by the acid addition component to form an acidic regeneration solution. The acidic regeneration solution enters the cation bed through the water collection hole, flows through the cation bed resin layer, chemically regenerates the cation bed resin layer and generates cation bed regeneration concentrate, which is discharged through the upper pipe interface.

[0065] During synchronous series regeneration, the water flow direction is from bottom to top: purified water → lower pipe interface → fourth water distribution component → electro-mixed bed resin layer (applied DC current) → third water distribution component (the electro-regeneration concentrate and the added acid solution are mixed in the internal area of ​​the third component) → water collection hole → second water distribution component → cation bed resin layer → first water distribution component → upper pipe interface → discharge of concentrated acid regeneration water.

[0066] Cleaning: After regeneration, the deeply treated purified water is sent into the electro-mixed bed through the lower pipe interface. The purified water flows sequentially through the electro-mixed bed resin layer and the cation exchange bed resin layer before being discharged through the upper pipe interface, rinsing away residual impurities until the quality of the effluent meets the preset requirements. That is, during synchronous series cleaning, the water flow direction is the same as during synchronous series regeneration.

[0067] The processes of treatment, regeneration, and cleaning are repeated continuously.

[0068] The flow rate during controlled treatment is 100~120 m / h; the current density during regeneration is 100~200 A / m. 2 The average voltage is 250-450V; the flow rate during regeneration and cleaning is 30-70 m / h; the processing time in each operating cycle is 200-400 minutes, with regeneration and cleaning lasting 15-20 minutes and 1-3 minutes respectively. Regeneration is initiated when the conductivity of the effluent from the electro-mixed bed exceeds a preset threshold.

[0069] Acid regeneration dosage control during regeneration: Condensate typically has relatively low impurity ion content, and the conductivity of ammonia-rich condensate is mainly contributed by ammonium and hydroxide ions. Based on fundamental data such as the molar conductivity of ammonium and hydroxide ions at different temperatures, the ionization equilibrium constant of ammonia, and ionization equilibrium theory, combined with real-time acquisition of conductivity, pH, and temperature signals of the cation exchange bed influent, and utilizing the programming calculation function of a PLC or DCS control system, the total amount of ammonia adsorbed by the cation exchange bed in one treatment cycle is automatically calculated based on a 90% ammonia removal efficiency. Then, a reference value for the acid dosage required for cation exchange bed regeneration is further calculated based on a 1:1 amino acid molar ratio. Based on these calculations, and combined with real-time acquisition of water quality signals from the electro-mixed bed effluent, the required acid regeneration dosage is further automatically optimized and corrected through a PLC or DCS control system. This achieves automatic and precise control of the acid regeneration agent dosage in the cation exchange bed, thereby improving treatment efficiency, saving acid regeneration agent consumption, and reducing environmental pressure.

[0070] Example 1: The simulated ammonia-rich condensate from a power plant with a conductivity of approximately 10 µS / cm was treated in a secondary process using the integrated "cation bed-electro-mixed bed" device described in this application. The cation bed was filled with a weakly acidic resin with a resin layer height of 0.24 m; the electro-mixed bed was filled with a uniformly mixed, easily electroregenerable cation and anion resins in a volume ratio of approximately 1:1, with a resin layer height of 0.6 m.

[0071] Operating conditions are as follows: processing flow rate 110 m³ / h; processing flow rate 70 m³ / h. 3 / h; Regeneration current density 150A / m 2 Average voltage 380V; regeneration and cleaning flow rate 55 m / h; regeneration and cleaning flow rate 35 m³ / h. 3 / h; the processing time in each cycle is 280 minutes, with regeneration and cleaning lasting 18 minutes and 2 minutes respectively. The acid added during each regeneration cycle is 4.7L of 30% hydrochloric acid. The operating results are as follows: Cation bed effluent conductivity: 0.4-1.4 µS / cm; Electro-mixed bed effluent conductivity: 0.07-0.08 µS / cm; Regeneration concentrate and rinsing effluent are close to neutral; Water recovery rate: 96.4%; DC power consumption: approximately 0.03 kWh / m³. 3 water.

[0072] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An apparatus for treating ammonia-rich condensate from power plants, characterized in that: It adopts an integrated structure, which consists of three core units from top to bottom: a cation bed, an acid addition component, and an electro-mixing bed. The three are connected in a sealed manner to form a whole. The cation bed is provided with a cover plate, an upper box, a first water distribution component, and a second water distribution component; the cover plate is rectangular in shape, with a first reinforcing rib at the top and an upper pipe interface at the center; the upper box is located below the cover plate, open at both the top and bottom, with a second reinforcing rib on the outside and a cuboid shape inside; the first water distribution component and the second water distribution component are located at the upper and lower ends of the upper box, respectively, and a weakly acidic resin is filled between them to form a cation bed resin layer; The acid addition component is a rectangular clamp-shaped structure with an acid input interface on one of its edges and a water collection hole in the center of the plate. An annular acid tank is arranged around the water collection hole. The annular acid tank is connected to the acid input interface by an acid channel. An annular acid tank cover plate is provided on the lower side of the annular acid tank, and the annular acid tank cover plate has a small acid inlet hole. The electro-mixed bed comprises a lower chamber, a third water distribution assembly, a fourth water distribution assembly, an anode, and a cathode. The upper end of the lower chamber is open, and the lower end has a base plate with a central lower pipe interface. The interior is rectangular, and the outer side wall has a third reinforcing rib and supporting feet. The lower side of the base plate has a fourth reinforcing rib. The third and fourth water distribution assemblies are located at the upper and lower ends of the lower chamber, respectively. The anode and cathode are respectively installed in close contact with two opposite inner side walls of the lower chamber. The cavity formed by the anode, cathode, the other two inner side walls of the lower chamber, and the third and fourth water distribution assemblies is filled with a mixture of anion and cathode resin to form an electro-mixed bed resin layer. During treatment, no DC power is applied to the electro-mixed bed, and the water flow direction is from top to bottom; during synchronous series regeneration, DC power is applied to the electro-mixed bed, and acid is added through the acid addition component, with the water flow direction from bottom to top; during synchronous series cleaning, the water flow direction is the same as that during synchronous series regeneration.

2. The apparatus according to claim 1, characterized in that, The upper and lower housings have flange structures on their outer edges; the cover plate and the outer edge of the acid adding assembly both have matching flange holes; a first sealing gasket is sandwiched between the lower side of the cover plate and the upper end of the upper housing, and the connection is secured by a first bolt group; a second sealing gasket is sandwiched between the lower end of the upper housing and the upper side of the acid adding assembly, and a third sealing gasket is sandwiched between the lower side of the acid adding assembly and the upper end of the lower housing, and the connections between them are secured by a second bolt group.

3. The apparatus according to claim 1, characterized in that, The cation bed is a shallow high-speed cation bed with a resin layer height of only 0.2-0.5m and a processing flow rate of 100-120m / h.

4. The apparatus according to claim 1, characterized in that, The lower housing has two opposite side walls, each with an anode terminal through hole and a cathode terminal through hole for passing through the corresponding terminals. The anode and cathode terminals are assembled through the corresponding through holes; the anode and cathode are electrically connected to the corresponding terminals.

5. The apparatus according to claim 4, characterized in that, The inner walls of the upper and lower housings, as well as the through holes of the anode and cathode terminals, are all made of insulating material, or the entire housing is made of insulating material to achieve insulation isolation between the inside and outside of the housing; the back of the anode and cathode is sealed with insulating glue between the inner wall of the lower housing, between the anode terminals and the anode terminals, and between the cathode terminals and the cathode terminals.

6. The apparatus according to claim 4, characterized in that, The anodes are electrically connected to each other and the cathodes are electrically connected to each other by direct electric welding.

7. The apparatus according to claim 1, characterized in that, The annular acid tank is formed by slotting a plate and then sealing it with an annular acid tank cover plate with small acid injection holes by welding or acid and alkali resistant waterproof sealant. The diameter of the small acid injection holes is 1-5mm, the number is 6-100, and the center-to-center distance between two adjacent small acid injection holes is 10-30mm, and they are evenly distributed.

8. The apparatus according to claim 1, characterized in that, The first, second, third, and fourth water distribution components each include a slit plate for intercepting resin, a frame, and 10-30 cylindrical support members with a diameter of 20-30mm and a central bolt hole. These support members are respectively tightly fixed to the inner side of the cover plate, the upper and lower sides of the acid addition component, and the inner side of the base plate using high-strength insulating bolts or acid and alkali resistant waterproof sealant.

9. A method for treating ammonia-rich condensate from a power plant, characterized in that: The process is carried out using the apparatus described in any one of claims 1 to 8, employing a two-stage "cation bed-electro-mixed bed" treatment; the cation bed is filled with a weakly acidic resin for pretreatment to remove excess ammonia from the ammonia-rich condensate, balance the anions and cations, and also remove corrosion products; The electro-mixed bed is filled with a cation-cation mixed resin for deep treatment of pretreated water, removing ionic and ionizable molecular impurities from the water; the electro-mixed bed and the cation bed are regenerated and cleaned synchronously in series. Each operating cycle consists of three steps: treatment, regeneration, and cleaning. The cycle repeats continuously. During treatment, the water flows from top to bottom, while during regeneration and cleaning, the water flows from bottom to top. Regeneration / Cleaning: The electro-mixed bed and the cation exchange bed are regenerated and cleaned synchronously in series. When the effluent quality drops to a preset threshold, purified water after deep treatment flows through the resin layer of the electro-mixed bed. At the same time, direct current is applied to the anode and cathode of the electro-mixed bed to promote the regeneration of the electro-mixed bed resin and generate electro-mixed bed regeneration concentrate. The electro-mixed bed regeneration concentrate is immediately mixed with external acid to form an acidic regeneration solution. The acidic regeneration solution then flows through the weakly acidic resin layer of the cation exchange bed to chemically regenerate the weakly acidic resin and generate cation exchange bed regeneration concentrate. After regeneration, the purified water after deep treatment continues to flow sequentially through the electro-mixed bed and the cation bed to rinse away residual impurities until the quality of the effluent meets the preset requirements.

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