Treatment system for directly recycling wastewater of middle-high pressure boiler

Abstract

The utility model provides a system for directly recycling wastewater of a medium-high pressure boiler. The system comprises a collecting and regulating tank, a heat exchanger, a coagulation clarifier, a multi-medium filter, an ultrafiltration system, a secondary reverse osmosis system, an EDI (Electronic Data Interchange) device, a mixed bed and a user high-purity water tank which are connected in sequence, the second-stage reverse osmosis system comprises a first-stage reverse osmosis system and a second-stage reverse osmosis system, the first-stage reverse osmosis system comprises a first-stage RO raw water tank, a precision filter and a first-stage RO device, effluent of the ultrafiltration system enters the first-stage RO raw water tank and then enters the precision filter to be filtered, and water produced by the precision filter is fed into the first-stage RO device; the second-stage reverse osmosis system comprises a second-stage RO raw water tank and a second-stage RO device, fresh water produced by the first-stage RO device is fed into the second-stage RO raw water tank and then enters the second-stage RO device, and fresh water produced by the second-stage RO device is fed into the EDI device to be treated. According to the utility model, a full-flow treatment system is developed aiming at the water quality condition of the wastewater of the medium-high pressure boiler, and the finished water can stably meet the water supply requirements of the medium-high pressure boiler.

Description

TECHNICAL FIELD

[0001] The utility model relates to a boiler wastewater treatment system, concretely relates to a treatment system of medium and high pressure boiler wastewater direct reuse. BACKGROUND

[0002] With the development of industrial enterprises, water resources are increasingly scarce in China, and it is increasingly difficult to obtain water resources. With the tension of natural water bodies, mixed treatment of industrial waste water of different qualities is used as an alternative water source for industrial water, without grading treatment. While saving water, it also leads to further increase in water production cost of industrial water supply system. Although the practice of simply using industrial high-quality drainage as secondary system water is an effective method in water saving, for enterprises, water resources are not reasonably utilized, and the large circulation of enterprise water resources causes a large amount of repeated treatment, which brings great waste in cost to enterprises.

[0003] Boiler system is widely used in industrial field as a main power source, but boiler feed water has a high standard, and the treatment cost is high. With the increase of boiler operating pressure, the requirement for water quality of medium and high pressure boiler is more stringent, and the problem is more prominent. In the process of boiler operation, with the concentration of ions and the addition of water quality stabilizing agent, the ions are enriched to a certain standard and need to be discharged, and new water is supplemented to ensure the stability of water quality in the boiler. The long-distance transportation of new water has the risk of water quality fluctuation and even environmental pollution. Only a few indicators in the boiler drainage increase slightly, such as being discharged into the secondary user for water supplement. The treatment cost in the early stage is a great waste, and in order to meet the requirements of the secondary user, technical measures such as temperature reduction, turbidity reduction and removal of specific ions are still needed, which increases the cost of cascade water resource reuse and has low economic benefit. Therefore, effective treatment of boiler drainage water to meet the water supply index of medium and high pressure boiler and direct treatment and reuse nearby are the needs to be realized by current enterprise users.

[0004] The current mainstream boiler drainage water treatment system adopts the mode of temperature reduction and desalination for secondary users and discharge of thick water after coagulation and sedimentation. Although it can improve the water quality of reuse, it still cannot be directly reused for medium and high pressure boiler, and a large amount of thick water is discharged. At the same time, due to the existence of hardness, alkalinity and dissolved silicate in the drainage water, the risk of scaling and clogging is increased for the reverse osmosis system. The irreversible reaction of dissolved silicate on the membrane surface is difficult to clean, which greatly reduces the service life of the membrane element, and causes serious adverse effects on production safety and operating cost. CONTENT OF THE UTILITY MODEL

[0005] Based on the technical problems existing in the prior art, the utility model provides a treatment system for direct reuse of medium and high pressure boiler wastewater, which realizes the goal of in-situ treatment and direct reuse of medium and high pressure boiler wastewater.

[0006] The above object is achieved by the following solution:

[0007] A treatment system for direct reuse of medium-high pressure boiler wastewater, characterized in that the system comprises, in sequence, a collection and adjustment tank, a heat exchanger, a coagulation clarifier, a multi-medium filter, an ultrafiltration system, a two-stage reverse osmosis system, an EDI device, a mixed bed, and a user high-purity water tank; the two-stage reverse osmosis system comprises a first-stage reverse osmosis system and a second-stage reverse osmosis system, the first-stage reverse osmosis system comprises a first-stage RO raw water tank, a precision filter, and a first-stage RO device, the ultrafiltration system outlet water enters the first-stage RO raw water tank, then enters the precision filter for filtration, and the precision filter product water is fed into the first-stage RO device; the second-stage reverse osmosis system comprises a second-stage RO raw water tank and a second-stage RO device, the first-stage RO device product water is fed into the second-stage RO raw water tank, then enters the second-stage RO device, and the second-stage RO device product water is fed into the EDI device for treatment; the EDI device product water enters the mixed bed through system excess pressure, carries out precision desalination through ion exchange, and then is fed into the user high-purity water tank for medium-high pressure boiler water inlet use.

[0008] The system as described above, characterized in that the first-stage reverse osmosis system further comprises a conductivity transmitter, the first-stage RO device product concentrated water is fed into the conductivity transmitter, the conductivity transmitter is linked with a solenoid valve: when the conductivity exceeds the standard, the solenoid valve opens, and the concentrated water is discharged into a plant area turbid circulating water treatment system; when the conductivity reaches the standard, the solenoid valve is closed, and the concentrated water is returned to the first-stage RO raw water tank.

[0009] The system as described above, characterized in that the second-stage RO device product concentrated water is returned to the first-stage RO raw water tank.

[0010] The system as described above, characterized in that the EDI device product concentrated water is returned to the second-stage RO raw water tank.

[0011] The system as described above, characterized in that the first-stage RO device and the second-stage RO device adopt a polyamide composite membrane, the composite membrane is composed of three layers: a polyester material reinforced non-woven fabric, about 110-130 μm thick; a porous polysulfone material middle support layer, about 35-45 μm thick; and a polyamide material ultra-thin separation layer, about 0.1-0.3 μm thick; the first-stage reverse osmosis system and the second-stage reverse osmosis system both adopt a three-stage configuration mode, and the configuration ratio of each stage membrane element is 3:2:1.

[0012] The system as described above, characterized in that a static mixer is further arranged between the heat exchanger and the coagulation clarifier; and a flocculation reaction zone is arranged in the coagulation clarifier.

[0013] The system as claimed in claim 1, characterized in that the ultraviolet disinfection device adopts 253.7nm wavelength ultraviolet light to disinfect the water line output by the secondary RO device, and the water is sent into the EDI device after the microorganisms in the water are removed.

[0014] The system as claimed in claim 1, characterized in that the water output by the EDI device is sent into the TOC-UV device to remove the residual TOC components in the water, and the water is disinfected by using 185nm wavelength ultraviolet light, the residual CO2 in the water is removed by the carbon dioxide degassing device, and then the water is sent into the mixed bed by using the system residual pressure.

[0015] The system as claimed in claim 1, characterized in that the three filter materials of anthracite, quartz sand and manganese sand are used in the multi-medium filter; the particle size of the anthracite is 0.8-1.8mm, the filter layer thickness is 600mm; the particle size of the quartz sand is 0.5-1.2mm, K80<2.0, the filter layer thickness is 300-400mm; the particle size of the manganese sand is 0.5-1.2mm, the filter layer thickness is 300mm; and the filtration speed is 6m / h.

[0016] The system as claimed in claim 1, characterized in that the PVDF material hollow fiber membrane with a nominal pore size of 0.03um is used in the ultrafiltration system, the pH range of the external pressure type ultrafiltration membrane cleaning is 1-14, and the sodium hypochlorite cleaning is 5,000ppm.

[0017] The utility model discloses the beneficial effect:

[0018] Compared with the prior art, the above technical scheme has the following advantages: (1) the pretreatment, depth treatment and precision desalination improve the water quality, meet the water quality requirements of the medium and high pressure boiler, reduce the discharge of high-quality "clean wastewater", improve the recycling rate, reduce the cost of boiler feed water preparation, improve the water recycling rate of the user, and reduce the water consumption per product; (2) the phosphoric acid root ions, dissolved silica, alkalinity and hardness in the wastewater are effectively removed, and the high purity of the water quality is ensured through reverse osmosis, EDI and ion exchange technology; (3) the chemical reaction of specific ions effectively controls the amount of reagent, and reduces the cost; (4) the instrument control improves the product water recovery rate, improves the water production rate of the system, and effectively reduces the amount of discharged water; (5) through cascade utilization, the discharged water is effectively utilized, the water recycling rate of the system is ensured, and the consumption of new water is reduced.

[0019] The utility model discloses a special water quality condition of medium and high pressure boiler drainage, through the coupling type coagulation clarification filtration pretreatment of all wastewater, the effective treatment of hardness, alkalinity, dissolved silicate is realized, and special concentrated water recycling mode is used on the desalination method to realize higher recovery rate, reduces the concentrated water of external discharge, and after desalination, through electrodialysis + mixed bed polishing or ultraviolet light + electrodialysis + mixed bed polishing process, ion and trace organic pollutants are further removed to salted water, and the finished water can reach the strict water quality requirement of medium and high pressure boiler feed water. Compared with the traditional boiler drainage system, the medium and high pressure boiler wastewater in situ treatment direct reuse system of the utility model, its device configuration is more perfect, and the finished water is directly used as the make-up water of medium and high pressure boiler, reduces the demand of boiler system to external supply deionized water and ultrapure water, and the system operation cost and equipment maintenance period are greatly improved, the plant sewage discharge is greatly reduced, the sewage treatment load is reduced, the operation cost and fixed asset investment are saved, and the water reuse rate of boiler system is improved, which provides strong support and realization means for enterprise sewage zero emission, energy saving and carbon emission reduction, effectively reduces the water resource consumption quota of user unit product, and has wide market demand and application value. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the structure schematic diagram of the utility model system. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantage of the utility model more clear, the following will combine the specific embodiment of the utility model and the corresponding drawing to clearly and completely describe the technical scheme of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the ordinary skill in the art without making creative labor belong to the range of protection of the utility model.

[0022] It also needs to be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawing, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device, component or structure must have a particular orientation, be constructed or operated in a particular orientation, and cannot be understood as a limitation on the utility model.

[0023] In the utility model, unless another definite provision and limitation, the terms "mount", "link", "connect", "fix" and so on terms should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through intermediate medium, can be two element internal communication or two element mutual action relation. For ordinary skilled person in the art, the above terms can be understood according to the specific meaning in the utility model.

[0024] The utility model provides a technical scheme, which will be described in detail below in combination with the accompanying drawings. Figure 1 , detailed description is provided to the technical scheme of the utility model.

[0025] As shown in Figure 1 , the utility model discloses a high pressure boiler wastewater direct reuse treatment system including collection and regulation pool, heat exchanger, coagulation clarifier, multi -media filter, ultrafiltration system, two -stage reverse osmosis system, EDI device, mixed bed, user high -purity water tank that connect in proper order. Two -stage reverse osmosis system includes first -stage reverse osmosis system and second -stage reverse osmosis system, and first -stage reverse osmosis system includes primary RO raw water tank, precision filter and primary RO device, and the water of ultrafiltration system enters primary RO raw water tank, then enters precision filter and is filtered, and the water of precision filter is sent into primary RO device;Second -stage reverse osmosis system includes secondary RO raw water tank and secondary RO device, and the fresh water of primary RO device is sent into secondary RO raw water tank, then enters secondary RO device, and the fresh water of secondary RO device is sent into EDI device and is handled;The pure water of EDI device is sent into mixed bed through system residual pressure, and is desalted through ion exchange, then is sent into user high -purity water tank, and is used for high pressure boiler water.

[0026] First -stage reverse osmosis system further includes conductivity transmitter, and the concentrated water of primary RO device is sent into the conductivity transmitter, and the conductivity transmitter is linked with electromagnetic valve:when conductivity is overproof, electromagnetic valve opens, and concentrated water is discharged into factory area turbid ring water treatment system;When conductivity is up to standard, electromagnetic valve is closed, and concentrated water returns to primary RO raw water tank.

[0027] The concentrated water of secondary RO device returns to primary RO raw water tank;The concentrated water of EDI device returns to secondary RO raw water tank.

[0028] Primary RO device and secondary RO device adopt polyamide composite membrane, and the composite membrane is composed of three layers: polyester material reinforced non -woven fabric, about 110-130 μm thick;Polysulfone material porous middle support layer, about 35-45 μm thick;Polyamide material ultrathin separation layer, about 0.1-0.3 μm thick;First -stage reverse osmosis system and second -stage reverse osmosis system all adopt the configuration mode of primary three sections, and the configuration ratio of each section membrane element of each stage is 3:2:1.

[0029] The medium-high pressure boiler wastewater is closed discharged into a collection and regulation tank, and is sent into a heat exchanger for cooling treatment by a booster pump, and the outlet water temperature is controlled at 20-40℃. The purpose of setting the collection and regulation tank is mainly to stabilize the boiler drainage system, and the water quantity and temperature periodically fluctuate greatly. The continuous regulation of the flow and water temperature by the collection and regulation tank can make the subsequent treatment system stably inlet water, and achieve the effects of stable treatment effect and stable outlet water quality. The heat exchanger is used to cool the high temperature wastewater, so as to meet the temperature requirements of the coagulation clarification and subsequent reverse osmosis treatment. The outlet water of the heat exchanger enters the coagulation clarifier, and the dosing agent and wastewater are fully mixed through an online pipeline mixer, and the water flow velocity gradient is 500-1000s -1 , the reaction time is 15-30s, the coagulation reaction is completed by using the hydraulic mixing effect. The coagulation clarifier is provided with a flocculation reaction zone, and the fluid after the coagulation reaction enters the flocculation reaction zone to react with the coagulation aid, and the water flow velocity gradient is controlled at 30s -1 , and the reaction time is 15-30min. The clarification zone is provided with a slanting pipe, and the clarified outlet water is collected through a finger-shaped water collecting tank. Calcium chloride, polyaluminum chloride, polyacrylamide, a composite removal agent, sodium hydroxide solution, sulfuric acid or hydrochloric acid are added into the coagulation clarifier, so as to remove the phosphate ions, dissolved silica and part of metal cations in the water. The calcium chloride addition amount is 12-20mg / L, the polyaluminum chloride addition amount is 100-300μg / L (converted into the content of aluminum oxide), the polyacrylamide addition amount is 0.1mg / L, and the sulfuric acid (or hydrochloric acid, nitric acid) and sodium hydroxide (or Ca(OH)2, K(OH) and the like) solution are controlled according to the pH value of the water quality. The pH value is adjusted at the outlet end of the coagulation clarifier.

[0030] The anthracite, quartz sand and manganese sand are used in the multi-medium filter; the anthracite particle size is 0.8-1.8mm, the filter layer thickness is 600mm; the quartz sand particle size is 0.5-1.2mm, K80<2.0, the filter layer thickness is 300-400mm; the manganese sand particle size is 0.5-1.2mm, the filter layer thickness is 300mm; and the filtration speed is 6m / h.

[0031] The PVDF material hollow fiber membrane with a nominal pore size of 0.03μm is used in the ultrafiltration system, the pH range of the external pressure type ultrafiltration membrane cleaning is 1-14, and the sodium hypochlorite cleaning is 5,000ppm. The ultrafiltration system produces water which is filtered through a multi-filter core safety filter by a booster pump, and then enters the reverse osmosis system for desalination treatment. At the inlet of the secondary reverse osmosis system, sodium hydroxide is added to remove carbon dioxide in the water, so as to meet the inlet water requirements of the subsequent process.

[0032] The fresh water produced by the secondary RO device is first sent to an ultraviolet disinfection device for disinfection by using 253.7 nm wavelength ultraviolet light, and then sent to the EDI device after removing the microorganisms in the water. Under the action of the electric field of the EDI device, the charged particles migrate directionally into the concentrated water side, and meanwhile, selective ion exchange resins are added between the electrodes and membranes in a targeted manner to accelerate the removal rate of the ions in the water, thereby improving the purity and resistivity of the produced water. According to the water quantity, a plurality of EDI devices are arranged in parallel, and the minimum number of devices is not less than 2, so as to ensure continuous water supply during equipment failure, and the processing capacity of a single device is not less than 70% of the water production quantity. Meanwhile, conductivity meters and silicon dioxide online monitoring instruments are arranged at the water outlet ends of the two parallel EDI devices, and when the conductivity and silicon dioxide indicators show an increasing trend, a predictive alarm is given, and when the indicators reach the set values, the corresponding water inlet and outlet valves are automatically locked and closed, and an alarm telephone and alarm message are sent to the operation and maintenance personnel and the person in charge for timely treatment.

[0033] The water produced by the EDI device is first sent to a TOC-UV device to remove the residual TOC components in the water, and then disinfected by using 185 nm wavelength ultraviolet light, and then sent to a carbon dioxide degassing device to remove the residual CO2 in the water. Subsequently, the produced water is sent to a mixed bed by using the system residual pressure, so that the produced water reaches 15-18 MΩ.

[0034] Overall, the system for directly recycling the medium and high pressure boiler wastewater works according to the following steps:

[0035] (1) After the medium and high pressure boiler wastewater is discharged, it is sent to a collection and adjustment tank, and then sent to a heat exchanger by a booster pump for cooling treatment; the treated wastewater is sent to a coagulation clarifier by using the system residual pressure, and a coagulant is added in the coagulation clarifier to form flocs and clarify the water;

[0036] (2) The clarified water is sent to a multi-medium filter by a booster pump to remove small particles, colloids and other impurities; the water produced by the multi-medium filter is sent to an ultrafiltration system to further remove suspended solids and colloids, so as to control the SDI of the produced water to meet the requirements of the reverse osmosis water inlet;

[0037] (3) The water produced by the ultrafiltration system is sent to a secondary reverse osmosis system, and the fresh water produced by the secondary reverse osmosis system is sent to an EDI device for treatment by a booster pump;

[0038] (4) The pure water produced by the EDI device is sent to a mixed bed by using the system residual pressure, and then sent to a user high-purity water tank for use as the water inlet of the medium and high pressure boiler.

[0039] The above-mentioned embodiments are not limited to the above-mentioned examples, and other combinations of related devices are also within the protection scope of the present application. The above-mentioned embodiments are only used for illustrating the present application, and are not used for limiting the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore all equivalent technical solutions should also belong to the scope of the present application.

Claims

1. A treatment system for direct reuse of medium-high pressure boiler wastewater, characterized in that, The system comprises a collecting and adjusting tank, a heat exchanger, a coagulation clarifier, a multi-medium filter, an ultrafiltration system, a two-stage reverse osmosis system, an EDI device, a mixed bed and a user high-purity water tank connected in sequence; the two-stage reverse osmosis system comprises a first-stage reverse osmosis system and a second-stage reverse osmosis system; the first-stage reverse osmosis system comprises a first-stage RO raw water tank, a precision filter and a first-stage RO device; the ultrafiltration system outlet water enters the first-stage RO raw water tank, then enters the precision filter for filtration, and the precision filter outlet water is sent to the first-stage RO device; the second-stage reverse osmosis system comprises a second-stage RO raw water tank and a second-stage RO device; the first-stage RO device outlet fresh water is sent to the second-stage RO raw water tank, then enters the second-stage RO device, and the second-stage RO device outlet fresh water is sent to the EDI device for treatment; the EDI device outlet pure water enters the mixed bed through system excess pressure, is subjected to ion exchange for fine desalination, then is sent to the user high-purity water tank and is used for high-pressure boiler inlet water.

2. The system of claim 1, wherein, The first-stage reverse osmosis system further comprises a conductivity transmitter, and the first-stage RO device outlet concentrated water is sent to the conductivity transmitter; the conductivity transmitter is linked with a solenoid valve; when the conductivity exceeds the standard, the solenoid valve is opened, and the concentrated water is discharged into a plant area turbid circulating water treatment system; when the conductivity reaches the standard, the solenoid valve is closed, and the concentrated water is returned to the first-stage RO raw water tank.

3. The system of claim 2, wherein, The second-stage RO device outlet concentrated water is returned to the first-stage RO raw water tank.

4. The system of claim 3, wherein, The EDI device outlet concentrated water is returned to the second-stage RO raw water tank.

5. The system of claim 1, wherein, The first-stage RO device and the second-stage RO device adopt a polyamide composite membrane which is composed of three layers: a polyester material reinforced non-woven fabric with a thickness of about 110-130 μm, a porous polysulfone material middle support layer with a thickness of about 35-45 μm and a polyamide material ultra-thin separation layer with a thickness of about 0.1-0.3 μm; the first-stage reverse osmosis system and the second-stage reverse osmosis system both adopt a three-stage configuration mode, and the configuration ratio of each stage membrane element is 3:2:

1.

6. The system of claim 1, wherein, A static mixer is further arranged between the heat exchanger and the coagulation clarifier; a flocculation reaction zone is arranged in the coagulation clarifier.

7. The system of claim 1, wherein, The second-stage RO device outlet fresh water is sent to an ultraviolet disinfection device to be disinfected by 253.7 nm wavelength ultraviolet light, and is sent to the EDI device after microorganisms in the water are removed.

8. The system of claim 1, wherein, The EDI device outlet water is first sent to a TOC-UV device to remove residual TOC components in the water, is disinfected by 185 nm wavelength ultraviolet light, is removed of residual CO2 by a carbon dioxide degassing device, and then is sent to the mixed bed by system excess pressure.

9. The system of claim 1, wherein, The multi-medium filter adopts anthracite, quartz sand and manganese sand as filter materials; the anthracite has a particle size of 0.8-1.8 mm and a filter layer thickness of 600 mm; the quartz sand has a particle size of 0.5-1.2 mm, a K80 of less than 2.0 and a filter layer thickness of 300-400 mm; the manganese sand has a particle size of 0.5-1.2 mm and a filter layer thickness of 300 mm; and the filter speed is 6 m / h.

10. The system of claim 1, wherein, The ultrafiltration system adopts PVDF material hollow fiber membrane, nominal pore size 0.03 μm, external pressure type ultrafiltration membrane cleaning pH range 1-14, sodium hypochlorite cleaning 5,000 ppm.

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