CN114671558A - Heat supply network circulating water treatment system and method with electrochemical softening coupled with electric flocculation - Google Patents

Abstract

The invention discloses a heat supply network circulating water treatment system and method with electrochemical softening coupled with electric flocculation, wherein the system comprises a pressurizing unit, an electrochemical softening unit, an electric flocculation unit, a clarification unit and a sludge treatment unit, wherein the pressurizing unit, the electrochemical softening unit, the electric flocculation unit and the clarification unit are sequentially arranged along the water flow direction of circulating water of a heat supply network; the electric flocculation unit comprises a first polar plate, a second polar plate and a first control device; the first polar plate and the second polar plate are alternately matched; a first gap is arranged between the first polar plate and the adjacent second polar plate; the first polar plate and the second polar plate are electrically connected with a first control device, and the first control device can enable the first polar plate and the second polar plate to be reversed. The first polar plate and the second polar plate are soluble electrodes. The system can simultaneously realize softening of the circulating water of the heat supply network, combined removal of suspended particles and metal corrosion product impurities in the suspended particles, and is reasonable in design, convenient to use and not easy to generate secondary pollution.

Description

Heat supply network circulating water treatment system and method with electrochemical softening coupled with electric flocculation

Technical Field

The invention belongs to the technical field of heat supply network circulating water treatment, and relates to a heat supply network circulating water treatment system and method based on electrochemical softening coupling electric flocculation.

Background

At present, the economic growth form of China is good, the national economy is greatly developed, the living standard of residents is continuously improved, and for northern areas of China, central heating is a very important civil engineering and is directly related to the living quality of residents. So-called central heating is through the transport of heat supply pipeline to use water or vapor to send the heat into resident's family as the medium to replace traditional individual heating mode to realize central heating. The medium that ultimately delivers heat to the inhabitant's home is typically water.

The heat supply pipe network system belongs to a special system in industrial production, and has the problems of high water temperature, easy scaling, corrosion and the like. According to the current standards CJJ34-2010 urban heat supply network design specifications and GB/T12145 2016 Water and steam quality standards for thermal power generating units and steam power equipment, the hardness of the make-up water in the hot water thermal power network using thermal power plants and regional boiler houses as heat sources is not more than 0.60 mmol/L. However, the territory of China is vast, members are vast, a heat supply pipe network system is huge generally, if the water quality in the standard specification is completely adopted, the first-stage reverse osmosis effluent or the first-stage desalted water of a power plant needs to be used for replenishing the circulating water of the heat supply network, and most power plants and heat supply companies are difficult to bear the water production cost. Therefore, at present, most of heating water directly adopts tap water, circulating water, even reclaimed water and other raw water which is not softened, the scaling and corrosion problems of the water side of the heating pipe network system under the condition can be more serious, and the scaling can cause the efficiency reduction of the heating system and even the blocking phenomenon.

The results of analyzing the scale sample in the heat exchange tube of a certain heat supply pipe network system show that the main components of the scale sample are calcium magnesium scale and corrosion products of iron, wherein the calcium magnesium scale accounts for 83 percent, and the corrosion products of iron account for 17 percent. The hardness of the heat supply network circulating water of the heat supply pipeline network system reaches more than 4mmol/L, a large amount of corrosion products of suspended iron exist, the turbidity is 110-150 NTU, and the iron content is 4-7 mg/L. Because the hardness of the heat supply network circulating water is higher, the scaling phenomenon is easy to occur in the heat supply network heater with higher temperature in the operation process, a large amount of iron corrosion products and scale in the circulating water are combined together, so that the scaling condition is gradually worsened, and finally, a heat exchange tube of the heat supply network heater is blocked.

In order to solve the problems of scaling and corrosion of the heat supply pipe network system, part of power plants or heat supply companies treat the supplementary water of the heat supply pipe network system by putting in operation sodium beds, and Ca in the water is treated by using ion exchange resin²⁺、Mg²⁺Replacement of the scaling ions by Na⁺The purpose of softening and supplementing water is achieved, but the ion exchange resin is easy to lose efficacy due to pollution and poisoning, the requirement on water inflow is high, regeneration is needed, the operation is relatively complex, and the treatment cost of high-salinity wastewater generated during regeneration is relatively high; the scale and corrosion inhibitor is added into a heat supply pipeline network system by a power plant or a heat supply company to inhibit the growth and deposition of scale and simultaneously slow down corrosion, but because the water temperature of heating water is higher and the water quality is poorer, the added agent not only maintains the scale inhibition rate and corrosion inhibition performance required by the system at high temperature, but also needs to have good stability and is not suitable for decomposition at high temperature, and the scale and corrosion inhibitor capable of meeting the requirements is usually a phosphorus scale and corrosion inhibitor, wherein the phosphorus content is higher, so that the scale and corrosion inhibitor can be used for a long timeThe use of the paint is easy to cause secondary pollution and is not beneficial to environmental protection.

The electrochemical softening is to put an electrode loaded with low-voltage direct current into water, and the scaling ions in the water are crystallized and separated out near a cathode so as to be removed, thereby achieving the purpose of softening and inhibiting scale. However, part of calcium carbonate and magnesium hydroxide suspended particles generated in the electrochemical softening process of calcium and magnesium ions cannot be well precipitated, and metal corrosion products in the circulating water of the heat supply network cannot be removed through the electrochemical softening treatment process, so that the heat supply network system still has the risk of scaling and blocking.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a system and a method for treating the circulating water of a heat supply network by electrochemical softening coupling electrocoagulation, so that softening of the circulating water in the heat supply network and effective settlement removal of suspended particulate matters and metal corrosion products are realized simultaneously, the normal use of the heat supply network is ensured, and the service life of the heat supply network is effectively prolonged.

The invention is realized by the following technical scheme:

a heat supply network circulating water treatment system with electrochemical softening coupled with electric flocculation comprises a pressurization unit, an electrochemical softening unit, an electric flocculation unit, a clarification unit and a sludge treatment unit; the pressurizing unit, the electrochemical softening unit, the electric flocculation unit and the clarification unit are sequentially arranged along the water flow direction of circulating water of the heat supply network;

the heat supply network circulating water treatment system is arranged on a bypass of the heat supply network circulating system;

the electrochemical softening unit, the electric flocculation unit and the clarification unit are communicated with the sludge treatment unit;

the electric flocculation unit comprises a plurality of first polar plates, a plurality of second polar plates and a first control device; the first polar plates and the second polar plates are alternately matched; a first gap is formed between the first polar plate and the adjacent second polar plate; the plurality of first polar plates and the plurality of second polar plates are electrically connected with a first control device;

the first polar plate and the second polar plate are both soluble electrodes.

Preferably, the electric flocculation unit further comprises a first conductive rod and a second conductive rod; the plurality of first polar plates are uniformly arranged at intervals along the axial direction of the first conducting rod, and the plurality of second polar plates are uniformly arranged at intervals along the axial direction of the second conducting rod;

the first conducting rod and the second conducting rod are electrically connected with the first control device; when the first conducting rod is communicated with the positive pole of the first control device and the second conducting rod is communicated with the negative pole of the first control device, the plurality of first pole plates are anodes and the plurality of second pole plates are cathodes; when the first conducting rod is communicated with the negative electrode of the first control device and the second conducting rod is communicated with the positive electrode of the first control device, the plurality of first polar plates are cathodes and the plurality of second polar plates are anodes.

Preferably, a turbidity monitoring device is further arranged at the water outlet of the clarification unit, a first pipeline and a second pipeline are arranged at the water outlet of the turbidity monitoring device, the first pipeline is communicated with the water inlet of the clarification unit, and the second pipeline is connected to the heat supply network circulating system.

Preferably, the electric flocculation unit is also provided with a first exhaust port, a first access port and a first sewage discharge port; the first exhaust port is communicated with the outside atmosphere and is used for exhausting gas generated in the electric flocculation unit; the first sewage discharge port is used for discharging sediments in the electric flocculation unit and communicated with the sludge treatment unit; the first access hole is used for overhauling the electric flocculation unit.

Preferably, the electric flocculation unit further comprises a first driving motor and a first rotating shaft connected with the first driving motor; the first driving motor is electrically connected with the first control device; through holes are formed in the first polar plates and the second polar plates, the first rotating shaft penetrates through the through holes, and second gaps are formed between the first rotating shaft and the through holes.

Preferably, a plurality of first rotary scrapers are arranged at intervals along the axial direction of the first rotary shaft; a number of the first rotary scrapers extend in a radial direction of the first rotary shaft.

Preferably, the first rotary scraper is arranged at the first gap; and the first rotary scraper is provided with cutting edges at one side close to the first polar plate and at one side close to the second polar plate.

Preferably, the first electrode plate and the second electrode plate are one of iron electrodes or aluminum electrodes.

The method for treating the circulating water of the heat supply network by electrochemical softening coupled electrocoagulation is characterized in that the treatment system is adopted to purify the circulating water of the heat supply network, and the surface current density of the first polar plate or the second polar plate is controlled to be 30-300A/m in the purification process²(ii) a And after the electric flocculation unit operates for 5-30 min, the connection modes of the first polar plate, the second polar plate and the control device are exchanged.

Compared with the prior art, the invention has the following beneficial technical effects:

in an electrochemical softening unit, calcium and magnesium ions in the circulating water of the heat supply network respectively react on the surface of a cathode of the electrochemical softening unit to generate calcium carbonate and magnesium hydroxide suspended particles. Soluble anode of soluble electrode of the electric flocculation unit loses electrons after being electrified with high-voltage pulse direct current to form metal cations and OH in solution^-The flocculating group with high activity is generated in a combined mode, the flocculating group has strong adsorption performance, calcium carbonate and magnesium hydroxide suspended particulate matters in the heat supply network circulating water and impurities such as original metal corrosion products in the heat supply network circulating water are changed into large particles by utilizing the functions of adsorption bridging, network capturing, rolling and sweeping and the like of the flocculating group, the large particles are subjected to coprecipitation with the large particles, the heat supply network circulating water containing the coprecipitation sediments enters a clarification unit for sedimentation, and supernatant liquid is obtained and returns to the heat supply pipeline network system again. The softening of the circulating water of the heat supply network, the combined removal of suspended particles and metal corrosion product impurities in the particles can be realized simultaneously, the system design is reasonable, the automation degree is high, secondary pollution is not easy to generate, and the method is environment-friendly.

Furthermore, the first pole plate and the second pole plate can be more conveniently installed through the first conducting rod and the second conducting rod; the connection modes of the first conducting rod and the second conducting rod and the first control device can be interchanged, so that the surface dirt on the first polar plate and the second polar plate can be effectively reduced, and the service life of the device is prolonged.

Furthermore, the turbidity monitoring device is convenient for monitor the quality of water after purifying to control the quality of circulating water. When quality of water accords with the requirement, the circulating water after the purification gets into the heat supply network circulation system through the second pipeline, if the quality of water after the purification does not accord with the requirement, then get into clarification unit again through first pipeline and handle until meeting the requirement, rethread second pipeline gets into the heat supply network circulation system, can be so that the circulating water effectively satisfies the actual requirement.

Furthermore, the first exhaust port is communicated with the outside atmosphere, so that gas generated in the electric flocculation unit can be discharged in time, and the use safety of the system is ensured. The first sewage draining port and the first overhauling port can effectively prolong the service life of the device.

Furthermore, the first rotating shaft facilitates installation of the first rotating scraper, and the first rotating scraper can effectively remove sediments on the surfaces of the first polar plate and the second polar plate, so that the current efficiency of the electric flocculation unit is improved, and the energy consumption is reduced. Meanwhile, the stirring effect can be effectively achieved, the turbulence degree of water flow on the surfaces of the first polar plate and the second polar plate is improved, so that concentration polarization is eliminated, and the current efficiency is effectively improved.

Furthermore, the first rotating scraper is provided with cutting edges at one side close to the first polar plate and one side close to the second polar plate, so that the deposits on the surfaces of the first polar plate and the second polar plate can be thoroughly scraped.

Furthermore, the first polar plate and the second polar plate are one of iron electrodes or aluminum electrodes, the flocculation effect is good, and meanwhile, the installation cost of the device can be effectively reduced.

A method for treating circulating water in a heat supply network by electrochemical softening coupled electrocoagulation is characterized in that the surface current density of a first polar plate or a second polar plate is controlled to be 30-300A/m in the treatment process²(ii) a The current density in the electric flocculation process determines the elution amount of metal ions on the metal electrode, and the elution amount is increased to a certain extentThe current density on the surface of the polar plate can improve the precipitation amount of metal cations, so that the generation rate of the flocculating agent is accelerated, and the electric flocculation effect is enhanced along with the increase of the current density, but the high current density simultaneously means high energy consumption, and along with the increase of the current density, the polarization and passivation phenomena of the electrode are more serious, so that the generation condition of the flocculating agent is worsened, and the electric flocculation effect is reduced along with the increase of the current density. The current density is selected by comprehensively considering factors such as pH, temperature, flow rate and the like so as to ensure that the electric flocculation unit operates at higher current efficiency. The current density on the surface of the polar plate is controlled to be 30-300A/m²The maximization of the electric flocculation effect can be realized. The treatment process has the characteristics of higher automation degree, simpler operation, active descaling mode, difficult generation of secondary pollution and environmental friendliness.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a processing system according to the present invention;

FIG. 2 is a schematic structural diagram of an electric flocculation unit in the invention;

fig. 3 is a schematic view of the structure of an electrochemical softening unit according to the present invention.

Wherein: 1. a pressurizing unit, 2, an electrochemical softening unit, 20, a second air outlet, 211, a cathode supporting frame, 212, a cathode, 221, an anode supporting frame, 222, an anode, 24, a second control device, 231, a second driving motor, 232, a second rotating shaft, 233, a scraper connecting rod, 234, a second rotating scraper, 25, a second access hole, 26, a backwashing water inlet, 27, a second sewage outlet, 3, an electric flocculation unit, 31, a first polar plate, 32, a second polar plate, 33, a first control device, 311, a first conducting rod, 321, a second conducting rod, 34, a first air outlet, 35, a first access hole, 36, a first sewage outlet, 37, a first driving motor, 38, a first rotating shaft, 381, a first rotating scraper, 4, a clarification unit, 41, a clarification unit sewage outlet, 5, a sludge treatment unit, 6, a turbidity monitoring device, 61, a first pipeline, 62. a second pipeline, 7, a valve.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship which the product of the present invention is used to usually place, it is only for convenience of describing the present invention and simplifying the description, but it is not necessary to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

Furthermore, the term "horizontal", if present, does not mean that the component is required to be absolutely horizontal, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The invention is described in further detail below with reference to the accompanying drawings:

as shown in fig. 1, a heat supply network circulating water treatment system with electrochemical softening coupled with electric flocculation comprises a pressurizing unit 1, an electrochemical softening unit 2, an electric flocculation unit 3, a clarification unit 4 and a sludge treatment unit 5, wherein the pressurizing unit 1, the electrochemical softening unit 2, the electric flocculation unit 3 and the clarification unit 4 are sequentially arranged along the flow direction of circulating water of a heat supply network. A bypass water outlet of the heat supply pipe network system is connected with a water inlet of the pressurizing unit 1, a water outlet of the pressurizing unit 1 is divided into two paths, one path is connected to a first water inlet of the electrochemical softening unit 2, the other path is connected to a backwashing water inlet of the electrochemical softening unit, and a backwashing water outlet of the electrochemical softening unit is connected with a water inlet of the sludge treatment unit 5; the water inlet of the electric flocculation unit 3 is connected with the water outlet of the electrochemical softening unit 2; the water inlet of the clarification unit 4 is connected with the water outlet of the electric flocculation unit 3, the water outlet of the clarification unit is connected with the water inlet of the online turbidity monitoring device 6, the outlet of the online turbidity monitoring device 6 is divided into two paths, one path is connected with the bypass water return port of the heat supply pipeline network system through the second pipeline 62, and the other path is connected with the water inlet of the clarification unit 4 through the first pipeline 61. The clarifying unit 4 is provided with a clarifying unit drain outlet 41, and the clarifying unit drain outlet 41 is communicated with the sludge treatment unit 5, so that the inside cleanness of the unit can be ensured, and the phenomenon of dirt blockage of the unit is avoided. Preferably, the heat supply network circulating water treatment system is arranged on a bypass of the heat supply pipeline network system; the pressurizing unit 1 is communicated with a bypass water outlet of the heat supply pipeline network system, and a water outlet of the clarifying unit 4 is communicated with a bypass water inlet of the heat supply pipeline network system. The bottom of the clarifying unit 4 is of a funnel type structure, so that bottom mud can be discharged conveniently.

As shown in fig. 2, the electric flocculation unit 3 is of a parallel plate type modular design, and specifically includes a plurality of first polar plates 31, a plurality of second polar plates 32, and a first control device 33; the electroflocculation unit 3 further comprises a first conductive rod 311 and a second conductive rod 321; the plurality of first polar plates 31 are uniformly and fixedly arranged at intervals along the axial direction of the first conducting rod 311, and the plurality of second polar plates 32 are uniformly and fixedly arranged at intervals along the axial direction of the second conducting rod 321; the first conductor bar 311 and the second conductor bar 321 are electrically connected to the first control device 33; when the first conductive rods 311 are connected with the positive electrode of the first control device 33 and the second conductive rods 321 are connected with the negative electrode of the first control device 33, the plurality of first pole plates 311 are anodes and the plurality of second pole plates 321 are cathodes; when the first conductive rod 311 is connected to the negative electrode of the first control device 33 and the second conductive rod 321 is connected to the positive electrode of the first control device 33, the first electrode plates 311 are cathodes and the second electrode plates 321 are anodes. The electrode inverting function is used to reduce the formation of dirt on the surface of the electrode. The first polar plates 31 and the second polar plates 32 are circular, and the plurality of first polar plates 31 and the plurality of second polar plates 32 are alternately matched; a first gap is arranged between the first polar plate 31 and the adjacent second polar plate 32; the electrocoagulation unit 3 is also provided with a first exhaust port 34, a first access port 35 and a first sewage discharge port 36; the first exhaust port 34 is communicated with the outside atmosphere for exhausting the gas generated in the electrocoagulation unit 3; the first sewage discharge port 36 is used for discharging sediments in the electric flocculation unit 3, and the first sewage discharge port 36 is communicated with the sludge treatment unit 5; the first access opening 35 is used for servicing the electric flocculation unit 3. The electrocoagulation unit 3 further includes a first drive motor 37 and a first rotation shaft 38 connected to the first drive motor 37; the first driving motor 37 is electrically connected to the first control device 33; the first polar plate 31 and the plurality of second polar plates 32 are provided with through holes, which may be circular holes, the first rotating shaft 38 penetrates the through holes, and second gaps are provided between the first rotating shaft 38 and the through holes. A plurality of first rotary scrapers 381 are provided at intervals in the axial direction of the first rotary shaft 38; a number of first rotary scrapers 381 extend in the radial direction of the first rotary shaft 38. The first rotating scraper 381 is disposed at the first gap; the first rotating scraper 381 is provided with a blade on one side close to the first pole plate 31 and a blade on one side close to the second pole plate 32. The first electrode plate 31 and the second electrode plate 32 are soluble electrodes such as iron electrodes or aluminum electrodes. The material of the housing of the electric flocculation unit 3 is rubber-lined carbon steel, and the material of the first rotating shaft 38 and the first rotating blade 381 is 304 stainless steel.

As shown in fig. 3, the electrochemical softening unit 2 adopts a coaxial electrode cartridge type modular design, and specifically includes a cathode support frame 211, a cathode 212, an anode support frame 221, an anode 222, and a second control device 24; the cathode support frame 211 is matched with the anode support frame 221, and an arc-shaped hole is formed in the cathode support frame so that the anode support frame can penetrate through the cathode support frame; the cathode 212 is disposed in cooperation with the anode 222, the cathode 212 includes a cylindrical wall of the electrochemical processing unit and a curved cathode above the cathode support frame, the anode 222 is a curved anode above the anode support frame 221, and a gap is formed between the anode 222 and the curved cathode and the cylindrical wall. The electrochemical softening unit 2 further comprises a second scale scraping device, the second scale scraping device comprises a second driving motor 231, a second rotating shaft 232, a scraper connecting rod 233 and a second rotating scraper 234, an extension line of the second rotating shaft 232 is coincident with central axes of the cathode 212 and the anode 222, a middle part of the second rotating shaft 232 is connected with a middle part of the scraper connecting rod 233, the second rotating scraper 234 is installed at the lower part of the scraper connecting rod 233, the second rotating scraper 234 is located in a gap between the anode 222 and a curved cathode inside the anode 222 and a cylinder wall outside the anode, the second rotating scraper 234 is symmetrically arranged about the axes of the cathode 212 and the anode 222, and a blade edge of the second rotating scraper 234 faces the cathode direction. The second scale scraping device can effectively remove the deposit on the surface of the cathode, improve the current efficiency of the electrochemical softening unit and reduce the energy consumption. The control device 24 is electrically connected to the cathode 212, the anode 222, and the second drive motor 231. The electrochemical softening unit 2 is also provided with a second air outlet 20 and a second access hole 25, and the second air outlet 20 is connected with the outside atmosphere and used for discharging the gas generated in the electrochemical softening unit so as to ensure the safety of the device; the second manhole 25 is used for service and maintenance work of the electrochemical softening unit. The cathode of the electrochemical softening unit is made of stainless steel or carbon steel, the anode of the electrochemical softening unit is a titanium electrode, and the surface of the titanium electrode is coated with a ruthenium-iridium or iridium-tantalum mixed metal oxide coating. The second scale scraping device is made of 304 stainless steel. Be provided with backwash water inlet 26 and second drain 27 on the electrochemistry softening unit 2, backwash water import 26 is used for wasing electrochemistry softening installation, and the backwash water is arranged to sludge treatment unit 5 in through second drain 27, but extension device's life.

And valves 7 are arranged among the units and are used for controlling the opening and closing of the pipelines. The inlet of the bypass booster pump is connected with a heat supply pipe network system through a bypass outlet valve, one path of the bypass booster pump is connected to the water inlet of the electrochemical softening unit through an inlet valve of the electrochemical softening unit, the other path of the bypass booster pump is connected to the backwashing water inlet of the electrochemical softening unit through a backwashing water inlet valve of the electrochemical softening unit, a backwashing water outlet of the electrochemical softening unit is connected to the inlet of the sludge treatment device through a backwashing water discharge valve, a second air outlet of the electrochemical softening unit is directly connected with the atmosphere through a second air discharge valve, and a water production port of the electrochemical softening unit is connected to the water inlet of the electrocoagulation unit through a water inlet valve of the electrocoagulation unit; a second exhaust port of the electric flocculation unit is connected with the atmosphere through a second exhaust valve, a drain outlet of the electric flocculation unit is connected with an inlet of the sludge treatment device through a drain valve, and a water production port of the electric flocculation unit is connected with a water inlet of the clarification unit through an inlet valve of the clarification unit; the water pump entry is produced with the clarification unit to the water mouth of producing of clarification unit links to each other, and the pump export is produced with online turbidity monitoring devices to the clarifier, and online turbidity monitoring devices's export is divided into two the tunnel, and one of them is linked to each other with heat supply pipe network system through the bypass return valve, and another way returns the clarifier backward flow mouth through the clarifier return valve, and the clarifier bottom mud outlet passes through the inlet of clarification tank bottom bar valve and sludge treatment device and links to each other. The electrochemical softening unit and the electric flocculation unit are both prefabricated modular design, the number of modules can be customized according to the field requirements, and the electrochemical softening unit and the electric flocculation unit are simple and convenient to construct and flexible to assemble.

When the system for treating the circulating water of the heat supply network by electrochemical coupling electric flocculation is used for purifying the circulating water of the heat supply network, the specific treatment process is as follows:

under the action of a bypass booster pump, circulating water of a heat supply network is pumped into the electrochemical softening unit 2 and enters from a water inlet below the side of the electrochemical softening unit 2, the electrochemical softening unit 2 operates in a constant current mode, and the surface current density of the cathode plate is controlled to be 5-30A/m during the operation of a softening program²Keeping the water inlet valve of the electrochemical softening unit 2, the water outlet valve of the electrochemical softening unit 2 and the exhaust valve of the electrochemical softening unit 2 in an open state, and keeping the cleaning water inlet valve, the blowdown valve and the driving scraper motor of the electrochemical softening unit 2 in a closed state, wherein the reactions shown in the formulas 1 and 2 occur on the surface of the cathode of the electrochemical softening unit:

2H₂O+4e^-+O₂→4OH^-formula 1

2H₂O+2e^-→2OH^-+H₂↓2

OH formed^-Forming an alkaline region near the cathode to increase CO in water₂While promoting the HCO in the original solution₃-generation of CO₃ ^2-The reaction is shown in formula 3 and formula 4:

CO₂+OH^-→HCO₃-formula 3

HCO₃-+OH^-→H₂O+CO₃ ^2-Formula 4

Ca in water accompanying the electrolysis reaction²⁺、Mg²⁺Migrate to the cathode under the action of the electric field and react with a large amount of CO near the cathode₃ ^2-And (3) reacting, bonding, crystallizing, separating out precipitate and removing the precipitate, wherein the reaction is shown as a formula 5 and a formula 6.

CO₃ ^2-+Ca²⁺→CaCO₃Formula 5

2OH^-+Mg²⁺→Mg(OH)₂Formula 6

And operating the automatic cleaning program of the electrochemical softening unit every 90 min: closing a water inlet valve, a water outlet valve and an exhaust valve of the electrochemical softening unit 2, opening a backwashing water inlet valve, a backwashing water discharge valve and a driving scraper motor of the electrochemical softening unit 2, driving scrapers to scrape scales on the barrel wall of the softening unit and the curved cathode inside the softening unit by the driving scraper motor, backwashing the electrochemical softening unit by the circulating water of the heat supply network entering from the backwashing water inlet valve of the electrochemical softening unit 2, and discharging the backwashing water to the sludge treatment unit 5 from the backwashing water discharge valve of the electrochemical softening unit 2.

The softened produced water enters the water inlet of the electric flocculation unit 3 through the water inlet valve of the electric flocculation unit 3, and the current density on the surface of the polar plate is controlled to be 30-300A/m during the operation of the electric flocculation unit 3²Under the action of high-voltage pulse direct current, soluble anodes of the electrocoagulation unit 3 lose electrons to form metal cations Fe²⁺With OH in solution^-The metal corrosion products in the circulating water of the heat supply network are adsorbed and co-precipitated to be removed by utilizing the functions of adsorption bridging, network capturing, rolling, sweeping and the like of the flocculation groups with high activity, which are combined and generated, and the adsorption capacity of the flocculation groups is very strong. The electric flocculation unit driving motor continuously operates to drive the rotary scraper in the electric flocculation unit 3 to continuously rotate, and the electrode reversing period of the control electrode during the operation of the electric flocculation unit is 5-30 min. And opening a drain outlet at the bottom of the electric flocculation unit once every 7-30 days, wherein the drain time is 10-30 min, and closing the drain outlet at the bottom of the electric flocculation unit after the drain is finished.

Circulating water treated by the electric flocculation unit 3 enters a clarification unit 4, the circulating water of the heat supply network treated by the clarification unit 4 is divided into two paths after the turbidity is measured by an online turbidity monitoring device 6, a bypass return valve is closed and a clarification unit return valve is opened under the condition that the turbidity of the produced water of the clarification unit is higher, the produced water of the clarification unit is returned to a water inlet of the clarification unit for further clarification treatment, the clarification unit return valve is closed and the bypass return valve is opened after the turbidity of the discharged water of the clarification unit is reduced to be below 5NTU, and the circulating water of the heat supply network subjected to purification treatment is returned to a heat supply pipeline network system. The bottom discharge valve of the clarification unit is opened regularly every day to discharge sludge at the bottom of the clarification unit, the sewage discharge time is 10-20 min, and the bottom discharge valve of the clarification unit is closed after sewage discharge.

A system for treating heat supply network circulating water by electrochemical softening coupling electric flocculation is characterized in that calcium and magnesium ions in the heat supply network circulating water respectively react on the surface of a cathode of an electrochemical softening unit to generate calcium carbonate and magnesium hydroxide suspended particulate matters, impurities such as the calcium carbonate and the magnesium hydroxide suspended particulate matters and original metal corrosion products in the heat supply network circulating water are changed into large particles by the electric flocculation unit, the heat supply network circulating water containing the large particles enters a clarification unit to be precipitated, and supernatant is obtained and returned to a heat supply pipeline network system again. The softening of the circulating water of the heat supply network and the removal of impurities of metal corrosion products in the circulating water can be realized simultaneously, the system is reasonable in design, high in automation degree, not easy to generate secondary pollution and environment-friendly.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. A heat supply network circulating water treatment system with electrochemical softening coupled with electric flocculation is characterized by comprising a pressurizing unit (1), an electrochemical softening unit (2), an electric flocculation unit (3), a clarification unit (4) and a sludge treatment unit (5); the pressurizing unit (1), the electrochemical softening unit (2), the electric flocculation unit (3) and the clarifying unit (4) are sequentially arranged along the flow direction of circulating water of the heat supply network;

the heat supply network circulating water treatment system is arranged on a bypass of the heat supply network circulating system;

the electrochemical softening unit (2), the electric flocculation unit (3) and the clarification unit (4) are communicated with the sludge treatment unit (5);

the electric flocculation unit (3) comprises a plurality of first polar plates (31), a plurality of second polar plates (32) and a first control device (33); the plurality of first polar plates (31) and the plurality of second polar plates (32) are alternately matched; a first gap is formed between the first polar plate (31) and the adjacent second polar plate (32); the plurality of first polar plates (31) and the plurality of second polar plates (32) are electrically connected with the first control device (33);

the first polar plate (31) and the second polar plate (32) are both soluble electrodes.

2. The system for treating circulating water of a heat supply network by coupling electrochemical softening and electrocoagulation with the claim 1, wherein the electrocoagulation unit (3) further comprises a first conductive rod (311) and a second conductive rod (321); the plurality of first polar plates (31) are uniformly arranged at intervals along the axial direction of the first conducting rod (311), and the plurality of second polar plates (32) are uniformly arranged at intervals along the axial direction of the second conducting rod (321);

the first conducting rod (311) and the second conducting rod (321) are electrically connected with the first control device (33); when the first conducting rod (311) is connected with the positive electrode of the first control device (33) and the second conducting rod (321) is connected with the negative electrode of the first control device (33), the plurality of first polar plates (311) are anodes, and the plurality of second polar plates (321) are cathodes; when the first conducting rod (311) is connected with the negative electrode of the first control device (33) and the second conducting rod (321) is connected with the positive electrode of the first control device (33), the plurality of first polar plates (31) are cathodes, and the plurality of second polar plates (32) are anodes.

3. The system for treating circulating water of a heat supply network of electrochemical softening coupled electrocoagulation according to claim 1, wherein a turbidity monitoring device (6) is further disposed at the water outlet of the clarification unit (4), a first pipeline (61) and a second pipeline (62) are disposed at the water outlet of the turbidity monitoring device (6), the first pipeline (61) is communicated with the water inlet of the clarification unit (4), and the second pipeline (62) is connected to the heat supply network circulation system.

4. The system for treating the circulating water of the heat supply network by coupling electrochemical softening and electrocoagulation with the claim 1, wherein the electrocoagulation unit (3) is further provided with a first exhaust port (34), a first access port (35) and a first drain port (36); the first exhaust port (34) is communicated with the outside atmosphere and used for exhausting gas generated in the electric flocculation unit (3); the first sewage discharge port (36) is used for discharging sediments in the electric flocculation unit (3), and the first sewage discharge port (36) is communicated with the sludge treatment unit (5); the first access hole (35) is used for overhauling the electric flocculation unit (3).

5. The system for treating circulating water in a heat supply network by coupling electrochemical softening and electrocoagulation with the claim 1, wherein the electrocoagulation unit (3) further comprises a first driving motor (37) and a first rotating shaft (38) connected with the first driving motor (37); the first drive motor (37) is electrically connected with the first control device (33); through holes are formed in the first pole plates (31) and the second pole plates (32), the first rotating shaft (38) penetrates through the through holes, and second gaps are formed between the first rotating shaft (38) and the through holes.

6. The system for circulating water in the heat supply network for electrochemical softening coupled electrocoagulation according to claim 5, wherein a plurality of first rotating scrapers (381) are arranged at intervals along the axial direction of the first rotating shaft (38); several of said first rotating scrapers (381) extend in radial direction of the first rotating shaft (38).

7. The system for circulating water in a heat supply network for electrochemical softening coupled electrocoagulation according to claim 6, wherein the first rotating scraper (381) is disposed at the first gap; and the first rotating scraper (381) is provided with a blade on one side close to the first polar plate (31) and one side close to the second polar plate (32).

8. The system for circulating water in a heat supply network for electrochemical softening coupled with electrocoagulation as recited in claim 1, wherein the first plate (31) and the second plate (32) are one of iron electrode and aluminum electrode.

9. A method for treating circulating water of a heat supply network by electrochemical softening coupled electrocoagulation, which is characterized in that the treatment system of any one of claims 1 to 8 is adopted to purify the circulating water of the heat supply network, and the surface current density of the first polar plate (31) or the second polar plate (32) is controlled to be 30-300A/m in the purification process²(ii) a And after the electric flocculation unit (3) operates for 5-30 min, the connection modes of the first polar plate (31), the second polar plate (32) and the control device (33) are exchanged.

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