CN114735771A - Water quality control method for cooling circulating water system - Google Patents
Water quality control method for cooling circulating water system Download PDFInfo
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- CN114735771A CN114735771A CN202210316059.6A CN202210316059A CN114735771A CN 114735771 A CN114735771 A CN 114735771A CN 202210316059 A CN202210316059 A CN 202210316059A CN 114735771 A CN114735771 A CN 114735771A
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
- C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/22—Means for preventing condensation or evacuating condensate
- F24F13/222—Means for preventing condensation or evacuating condensate for evacuating condensate
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F5/00—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
- F24F5/0007—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning
- F24F5/0017—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning using cold storage bodies, e.g. ice
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/02—Non-contaminated water, e.g. for industrial water supply
- C02F2103/023—Water in cooling circuits
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/40—Liquid flow rate
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Abstract
The invention provides a water quality control method of a cooling circulating water system, relates to the technical field of cooling circulating water treatment, and is used for realizing energy-saving, low-carbon and environment-friendly operation of the system. The water quality control method comprises the following steps: concentrating and enriching anions and cations in the cooling circulating water, releasing the concentrated and enriched anions and cations to form concentrated water to be discharged out of the system, namely increasing the concentration of the concentrated water discharged out of the system, reducing the amount of discharged sewage, reducing the amount of water supplement supplemented into the cooling tower and achieving the aim of saving water resources; the concentration multiple is reduced, and chemical agents such as corrosion inhibition, scale inhibition and dispersing agents are prevented from being added; the concentrated water generated by the deionization system is recycled, for example, the concentrated water is introduced into a toilet flushing system, and the concentrated water can be used for other purposes. When the water quality control method of the cooling circulating water system is applied to the air conditioning system, the condensed water generated by the air conditioning system can be collected into the cooling water pool to be used as the circulating water for supplementing water, so that the water resource can be saved.
Description
Technical Field
The invention relates to the technical field of cooling circulating water treatment, in particular to a water quality control method of a cooling circulating water system.
Background
Under the guidance of the policy of 'carbon peak reaching and carbon neutralization', the energy saving and emission reduction work of various industries is going deep.
In the operation process of a cooling circulating water system, due to the evaporation of water and dust brought into air, the conditions of water quality concentration of the system and increase of the concentration of accumulated harmful ions exist, so that a series of problems of scaling of a heat exchanger, corrosion of a pipeline, breeding of bacteria and algae and the like occur, and the safe operation of the system is seriously influenced. The treatment method of the cooling circulating water treatment system comprises the following steps:
when the accumulated concentration of harmful ions reaches a certain concentration (according to engineering experience, the hardness of circulating water (calculated by CaCO 3) must be controlled below 500 mg/L), we are forced to discharge part of the running cooling circulating water out of the system, and at the same time, fresh water is replenished into the system to balance and reduce the concentration of water quality in the cooling circulating water system, namely, the water quality is maintained through continuous blowdown-replenishment. According to research, the discharge capacity of the existing cooling circulating water system per hour is about 0.5 percent of the circulating water quantity in the whole system, and the water replenishing quantity of the cooling circulating water system per hour is 1.2 to 1.5 percent of the circulating water quantity in the whole system. Referring to fig. 1 and 2, for the water quality treatment scheme of the existing cooling circulating water system, the problems of scaling of a heat exchanger and the like are reduced by continuously controlling the quality of discharged sewage and supplementing new water to control the water quality and by a circulating water quality treatment system (comprising chemical method treatment equipment, physical and chemical combination method treatment equipment and the like).
The concentration of the circulating water in the cooling circulating water system is balanced through the pollution discharge-water supplement mode, namely the water quality balance control, so that large pollution discharge is caused, and the water quality is good compared with municipal sewage, and the water enters a municipal sewage pipe network and is mixed with the sewage to finally form the municipal sewage. Generally, COD, ammonia nitrogen, total nitrogen and the like in the discharged water of the cooling circulating water are very low compared with urban sewage, and the difference is dozens of times. After sewage discharged by the cooling circulating water system is mixed into the sewage pipe network, on one hand, the total amount of the sewage is increased, and on the other hand, the concentration of the sewage is diluted. Both of these aspects are very disadvantageous for municipal sewage treatment.
In general, for sewage treatment, the sewage amount in summer is higher than that in autumn and winter, and the water quality concentration is generally lower than that in autumn and winter, so that the operation cost is brought to sewage treatment of various governments. (concretely, for example, if the total area of office buildings currently stored in Beijing is 5000 ten thousand square meters, and the average building area of each building is 5 ten thousand square meters, then 1000 office buildings and office buildings are manufactured in Beijing, according to the circulation volume of cooling circulating water of each building being 400 tons per hour, the discharge volume is considered according to 0.5% of the circulation volume of cooling circulating water, 20 tons of wastewater are generated per hour and enter a sewage municipal pipe network, 20 hours a day is calculated, 400 tons of wastewater are generated, 4 months is calculated in an air-conditioning season every year, 4800 ten thousand tons of wastewater are generated, the wastewater directly enters a sewage treatment plant, the total amount of the wastewater of the sewage treatment plant is increased, the pollutant concentration of the wastewater is reduced, the difficulty is increased for biological treatment, and the treatment efficiency is reduced.
In addition, when fresh water is supplied to the cooling circulation water system, the water is usually softened (by adding a water softener) before water supply, and the softening treatment only reduces the content of cations (such as calcium and magnesium) in the supplied water, and anions (chloride ions) are not removed, so that the chloride ions are inevitably brought into the system during the softening treatment, and the chloride ions are concentrated. At present, in the treatment of water quality, the hardness index of calcium and magnesium ions is focused to control the heat exchange efficiency of a heat exchanger, and the corrosion of anions to a system, particularly to copper and stainless steel, is neglected.
Based on the method, the invention provides a water quality control method of a cooling circulating water system, so as to reduce the sewage discharge amount, reduce the water supplement amount and ensure the safe, stable, energy-saving, low-carbon, green and environment-friendly operation of the system.
Disclosure of Invention
The invention aims to provide a water quality control method of a cooling circulating water system, which is used for realizing energy-saving, low-carbon and environment-friendly operation of the system. The technical effects that can be produced by the preferred technical scheme in the technical schemes provided by the invention are described in detail in the following.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides a water quality control method of a cooling circulating water system, which comprises the following steps: concentrating and enriching anions and cations in the cooling circulating water; releasing the concentrated and enriched anions and cations to form concentrated water out of the system; the concentration of the concentrated water is greater than the required value of the system operating concentration, the required value of the system operating concentration is the required value of the circulating water ion concentration when the cooling circulating water system normally operates, namely, the discharge capacity and the water replenishing capacity of the cooling circulating water system are reduced by increasing the concentration of the concentrated water discharged out of the system.
Furthermore, a bypass pipeline is formed on the cooling circulating water system, a deionization system is arranged on the bypass pipeline, part of cooling water discharged from the cooling tower is purified after passing through the deionization system, fresh water generated after the purification treatment flows back to the cooling tower, and formed concentrated water is discharged out of the system.
Further, the ion concentration of circulating water in the cooling circulating water system is monitored, and the circulating water flow flowing to the deionization system is controlled, or the deionization efficiency of the deionization system is controlled, or the working time of the deionization system is controlled.
Further, the deionization system adopts an electrodialysis method, an electric adsorption method, a reverse osmosis method or a distillation method.
Further, the concentration multiple N of the cooling circulating water is controlled to be 1.5-3, wherein the concentration of water externally supplemented to the system is C1The required value of the system operation concentration is C2Concentration factor N ═ C2C1。
Further, the concentrated water discharged out of the system is secondarily used.
Further, the generated concentrated water is used for flushing a toilet or for sprinkling water on streets.
Further, the cooling circulation water system is a cooling circulation water system of air conditioning equipment, and the water quality control method further comprises the following steps: collecting condensed water generated when the air conditioning equipment operates, and then guiding the collected condensed water to a cooling tower for supplementing water to the cooling tower.
And further, monitoring the water quantity of the cooling tower, preferentially controlling the condensed water to be led to the cooling tower when the cooling tower needs to be supplemented with water, and if the cooling tower still needs to be supplemented with water, controlling the water outside the system to be led into the cooling tower, wherein the water outside the system is tap water or rainwater or reclaimed water.
Further, the water quality control method also comprises the following steps: and purifying the circulating water in the cooling circulating water system by adopting a physical method and a physicochemical method.
The invention can achieve the following beneficial effects:
(1) the concentration of the concentrated water outside the discharge system is increased, the discharged sewage quantity can be reduced, the pressure of a sewage treatment plant is reduced, the quantity of the water supplement to the cooling tower is reduced, the water resource can be saved, and the water quality control method is energy-saving, water-saving, low-carbon and environment-friendly;
(2) the corrosion problem caused by the fact that the chloride ions cannot be removed due to softening water replenishing is avoided;
(3) the operation with low concentration multiple is mainly based on a physical method, and the addition of chemical agents such as corrosion inhibition, scale inhibition and dispersing agents is reduced or even avoided;
(4) when the cooling circulating water system is cooling circulating water of an air conditioner, condensed water generated by the air conditioner system is collected by the condensed water system and then enters the cooling tower to be used as circulating water for supplementing water, so that the external water supplementing amount can be reduced, and the salt content of the condensed water is low.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a method for controlling the water quality of a cooling circulating water system in the prior art;
FIG. 2 is a structural frame diagram of a cooling circulation water system in the prior art;
FIG. 3 is a schematic flow chart of a method for controlling water quality of a cooling circulation water system according to an embodiment of the present invention;
FIG. 4 is a structural frame diagram of a cooling circulation water system according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of water balance of a prior art air conditioner circulating water system;
fig. 6 is a schematic diagram of water balance of an air-conditioning cooling circulation water system according to an embodiment of the present invention.
FIG. 1-cooling tower; 2-a heat exchanger; 3-a circulating pump; 4-water treatment equipment; 5-ion balancer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.
Example 1:
referring to fig. 1 and fig. 2, a water quality control method of a cooling circulating water system in the prior art is shown, when the concentration of harmful ions accumulated reaches a certain concentration (according to engineering experience, the hardness of circulating water (calculated as CaCO 3) must be controlled below 500 mg/L), a part of running cooling circulating water is forced to be discharged out of the system, and meanwhile, fresh water is added into the system to reduce the concentration of water quality in the cooling circulating water system in a balanced manner, namely, the water quality is maintained by continuous blowdown-water supplement, and by adopting the existing water quality control method, a large amount of blowdown is caused, and the water quantity supplemented into a cooling tower 1 needs to be large. The invention provides a water quality control method of a cooling circulating water system, which comprises the following steps: concentrating and enriching anions and cations in the cooling circulating water; releasing the concentrated and enriched anions and cations to form concentrated water out of the system; the concentration of the concentrated water is greater than the required value of the system operating concentration, and the required value of the system operating concentration is the required value of the circulating water ion concentration when the cooling circulating water system normally operates, namely, the discharge capacity and the water replenishing capacity of the cooling circulating water system are reduced by increasing the concentration of the concentrated water discharged out of the system. Referring to fig. 3, a schematic flow chart of a water quality control method for a cooling circulating water system provided by the present invention is shown, and since the concentration of the discharged concentrated water is greater than the required system operating concentration value (for example, the required system operating concentration value may be set to be less than 500mg/L, calculated as CaCO 3), the concentration of the concentrated water discharged from the system is increased, the amount of discharged sewage is reduced, the pressure of the sewage treatment plant is reduced, the amount of water supplied to the cooling tower 1 is reduced, and water resources are saved.
Specifically, referring to fig. 3, a bypass pipeline is formed on the cooling circulation water system, a deionization system is arranged on the bypass pipeline, a part of cooling water discharged from the cooling tower 1 is purified by the deionization system, and fresh water generated after the purification treatment flows back to the cooling tower, and the formed concentration is discharged out of the system. The deionization system comprises an ion balancer 5, see fig. 3, ion balancer 5.
Monitoring the ion concentration of circulating water in the cooling circulating water system, controlling the flow rate of the circulating water flowing to the deionization system or controlling the deionization efficiency of the deionization system or controlling the working time of the deionization system. Cooling water discharged from the cooling tower 1 is divided into two branches, one branch flows back to the cooling tower 1 after being purified by the deionization system, and the other branch flows to the cooling tower 1 through the heat exchanger 2; monitoring the flow rate of the cooling water discharged from the cooling tower 1 to the deionization system and the heat exchanger 2, respectively; the ratio of the flow to the deionization system and to the heat exchanger 2 is controlled. The salt content of the cooling water in the cooling tower 1 is monitored to control the flow ratio of the water flow to the deionization system and to the heat exchanger 2. Of course, it is also possible to control the operation time of the deionization system according to the monitored condition of the salt content in the cooling tower 1, and when the deionization system does not work, the deionization system does not have the function of removing salt from the circulating water passing through the deionization system. Or, according to the monitored salt content of the cooling tower 1, the deionization efficiency of the deionization system in unit time is controlled.
The ion balancer calculates the total ion amount to be collected, concentrated and discharged out of the system according to the water retention amount of the cooling circulating water system and the ion concentration rate in the actual operation process, and reversely deduces the treated water amount and the working time of the ion balancer, wherein the treated water amount of the ion balancer per hour is 0.5-1% of the circulating water amount of the system under the normal condition. In addition, in normal operation, the fresh water production rate of the ion balancer can reach more than 80%, and the concentrated water is less than 20%, so compared with a cooling circulating water system, the discharge capacity of the ion balancer is only 0.05%, the discharge capacity of a conventional cooling circulating water system per hour is about 0.5% of the circulating water quantity in the whole system, and the discharge capacity is reduced by about 10 times.
Controlling the concentration multiple N of the cooling circulating water to be 1.5-3, wherein the concentration of water supplemented to the system from the outside is C1The required value of the system operation concentration is C2Concentration factor N ═ C2C1. According to engineering experience, the hardness (calculated by CaCO 3) of the circulating water needs to be controlled below 500mg/L, and the concentration multiple is calculated by combining the hardness index of the quality of the make-up water, and generally, the concentration multiple of the circulating water of the conventional system is about 3. The water quality control method of the cooling circulating water system provided by the invention can reduce the concentration multiple and a series of problems of scaling of a heat exchanger, corrosion of a pipeline, breeding of bacteria and algae and the like.
The water quality control method also comprises the following steps: and purifying the circulating water in the cooling circulating water system by adopting a physical method and a physical and chemical method. Referring to fig. 1 and 2, a cooling circulating water quality system in the prior art comprises a continuous sewage treatment system and a circulating water quality treatment system, wherein the circulating water quality treatment system comprises chemical method treatment equipment, physical method treatment equipment and post-physicochemical method treatment equipment. The chemical sewage treatment method is to add chemical agents such as corrosion inhibitor, scale inhibitor and dispersant into circulating cooling water, and the addition of the chemical agents can cause secondary pollution. The invention adopts a physical method and a physical and chemical method to purify the circulating water in the cooling circulating water system, and can also realize the stable operation of the system, because the deionization system is utilized, the concentration multiple of the circulating cooling water can be reduced, and the low concentration multiple operation can be realized, thus, the normal and stable operation of the system can be ensured without adopting a chemical method. Furthermore, chemical agents such as corrosion inhibitors, dispersants, scale inhibitors and the like do not need to be added into the cooling water, the discharged concentrated water is from raw water, and a system does not generate new discharge, so that the problem of secondary pollution is avoided, and the system is environment-friendly.
As an optional implementation mode, the concentrated water discharged out of the system is recycled, and zero emission of the system is realized. For example, the concentrated water is introduced into a toilet flushing system and connected to a water supply pipeline of a toilet and sanitary ware. Specifically, the deionization system comprises an ion balancer 5, wherein the ion balancer 5 is connected with a fresh water tank, the fresh water tank is connected with a cooling tower through a pipeline, and a fresh water pump is arranged on the pipeline connecting the fresh water tank and the cooling tower; the ion balance equipment is connected with a concentrated water tank, and a constant-pressure water supply pump is arranged on the concentrated water tank and a pipeline of the toilet flushing system. In addition, the concentrated water can be used for other purposes, is not limited to be used for flushing toilets, can also be used for street watering and the like, and realizes zero emission of the system "
The deionization system can adopt an electrodialysis method, an electric adsorption method, a reverse osmosis method or a distillation method. The deionization system preferably uses an electric adsorption method, and as described below, the deionization system forms an electrostatic field between electrodes by applying a voltage, and charged particles are forced to move to an electrode plate having opposite charges by an electrostatic force in the electrostatic field, and an electric double layer is formed on the surface of the electrode plate, and the charged particles are adsorbed and temporarily stored in the electric double layer, by using the principle of the ion balance technique. When the adsorption process reaches the equilibrium, the electric field is removed or the power supply is reversely connected, and the ions adsorbed on the electrode return to the solution to achieve the purpose of desorption.
Example 2:
a water quality control method for an air-conditioning cooling circulating water system comprises the following steps: concentrating and enriching anions and cations in the cooling circulating water; releasing the concentrated and enriched anions and cations to form concentrated water out of the system; the concentration of the concentrated water is greater than the required value of the system operating concentration, and the required value of the system operating concentration is the required value of the circulating water ion concentration when the cooling circulating water system normally operates, namely, the discharge capacity and the water replenishing capacity of the cooling circulating water system are reduced by increasing the concentration of the concentrated water discharged out of the system. Referring to fig. 3, a schematic flow chart of a water quality control method for a cooling circulating water system provided by the present invention is shown, and since the concentration of the discharged concentrated water is greater than the required system operating concentration value (for example, the required system operating concentration value may be set to be less than 500mg/L, calculated as CaCO 3), the concentration of the concentrated water discharged from the system is increased, the amount of discharged sewage is reduced, the pressure of the sewage treatment plant is reduced, the amount of water supplied to the cooling tower 1 is reduced, and water resources are saved. And collecting condensed water generated when the air conditioning equipment is operated, and then guiding the collected condensed water to the cooling tower for replenishing water for the cooling tower. Condensed water generated by the air conditioning system is collected by the condensed water system and then enters the cooling tower 1 to be used as the water supplement of the circulating water, so that the external water supplement amount can be reduced, and the salt content of the condensed water is low.
Specifically, referring to fig. 3, a bypass pipeline is formed on the cooling circulation water system, a deionization system is arranged on the bypass pipeline, a part of cooling water discharged from the cooling tower 1 is purified by the deionization system, and fresh water generated after the purification treatment flows back to the cooling tower, and the formed concentration is discharged out of the system. The deionization system comprises an ion balancer 5, see fig. 3, ion balancer 5.
Monitoring the ion concentration of circulating water in the cooling circulating water system, controlling the flow rate of the circulating water flowing to the deionization system or controlling the deionization efficiency of the deionization system or controlling the working time of the deionization system. Cooling water discharged from the cooling tower 1 is divided into two branches, one branch flows back to the cooling tower 1 after being purified by the deionization system, and the other branch flows to the cooling tower 1 through the heat exchanger 2; monitoring the flow rate of the cooling water discharged from the cooling tower 1 to the deionization system and the heat exchanger 2, respectively; the ratio of the flow to the deionization system and to the heat exchanger 2 is controlled. The salt content of the cooling water in the cooling tower 1 is monitored to control the flow ratio of the water flow to the deionization system and to the heat exchanger 2. Of course, it is also possible to control the operation time of the deionization system according to the monitored condition of the salt content in the cooling tower 1, and when the deionization system does not work, the deionization system does not have the function of removing salt from the circulating water passing through the deionization system. Or, according to the monitored salt content of the cooling tower 1, the deionization efficiency of the deionization system in unit time is controlled.
The ion balancer calculates the total ion amount to be collected, concentrated and discharged out of the system according to the water retention amount of the cooling circulating water system and the ion concentration rate in the actual operation process, and reversely deduces the treated water amount and the working time of the ion balancer, wherein the treated water amount of the ion balancer per hour is 0.5-1% of the circulating water amount of the system under the normal condition. In addition, in normal operation, the fresh water production rate of the ion balancer can reach more than 80%, and the concentrated water is less than 20%, so compared with a cooling circulating water system, the discharge capacity of the ion balancer is only 0.05%, the discharge capacity of a conventional cooling circulating water system per hour is about 0.5% of the circulating water quantity in the whole system, and the discharge capacity is reduced by about 10 times.
Controlling the concentration multiple N of the cooling circulating water to be 1.5-3, wherein the concentration of water supplemented to the system from the outside is C1The required value of the system operation concentration is C2Concentration factor N ═ C2C1. According to engineering experience, the hardness (calculated by CaCO 3) of circulating water must be controlled below 500mg/L, and the concentration factor is calculated by combining with the hardness index of the quality of make-up water, and generally, the concentration factor of circulating water of the conventional system is about 3. The water quality control method of the cooling circulating water system provided by the invention can reduce the concentration multiple and a series of problems of heat exchanger scaling, pipeline corrosion, bacterial and algae breeding and the like.
The water quality control method also comprises the following steps: and purifying the circulating water in the cooling circulating water system by adopting a physical method and a physical and chemical method. Referring to fig. 1 and 2, a cooling circulating water quality system in the prior art comprises a continuous sewage treatment system and a circulating water quality treatment system, wherein the circulating water quality treatment system comprises chemical method treatment equipment, physical method treatment equipment and post-physicochemical method treatment equipment. The chemical sewage treatment method is to add chemical agents such as corrosion inhibitor, scale inhibitor and dispersant into circulating cooling water, and the addition of the chemical agents can cause secondary pollution. The invention adopts a physical method and a physical and chemical method to purify the circulating water in the cooling circulating water system, and can also realize the stable operation of the system, because the deionization system is utilized, the concentration multiple of the circulating cooling water can be reduced, and the low concentration multiple operation can be realized, thus, the normal and stable operation of the system can be ensured without adopting a chemical method. Furthermore, chemical agents such as corrosion inhibitors, dispersants, scale inhibitors and the like do not need to be added into the cooling water, the discharged concentrated water is from raw water, and a system does not generate new discharge, so that the problem of secondary pollution is avoided, and the system is environment-friendly.
As an optional implementation mode, the concentrated water discharged out of the system is secondarily utilized, and zero emission of the system is realized. For example, the concentrated water is introduced into a toilet flushing system and connected to a water supply pipeline of a toilet and sanitary ware. Specifically, the deionization system comprises an ion balancer 5, wherein the ion balancer 5 is connected with a fresh water tank, the fresh water tank is connected with a cooling tower through a pipeline, and a fresh water pump is arranged on the pipeline connecting the fresh water tank and the cooling tower; the ion balance equipment is connected with a concentrated water tank, and a constant-pressure water supply pump is arranged on the concentrated water tank and a pipeline of the toilet flushing system. In addition, the concentrated water can be used for other purposes, is not limited to be used for flushing toilets, can also be used for street watering and the like, and realizes zero emission of the system "
The deionization system can adopt an electrodialysis method, an electric adsorption method, a reverse osmosis method or a distillation method. The deionization system preferably uses an electric adsorption method, and as described below, the deionization system forms an electrostatic field between electrodes by applying a voltage, and charged particles are forced to move to an electrode plate having opposite charges by an electrostatic force in the electrostatic field, and an electric double layer is formed on the surface of the electrode plate, and the charged particles are adsorbed and temporarily stored in the electric double layer, by using the principle of the ion balance technique. When the adsorption process reaches balance, the electric field is removed or the power supply is reversely connected, and the ions adsorbed on the electrode return to the solution, so that the desorption purpose is achieved.
Monitoring the water quantity of the cooling tower, preferentially controlling to guide condensed water to the cooling tower when the cooling tower needs to be supplemented with water, and controlling to guide water outside the system into the cooling tower if the cooling tower still needs to be supplemented with water, wherein the water outside the system is tap water or rainwater or reclaimed water. In the air-conditioning cooling circulating water system, water evaporation and drift exist (the evaporation amount and the drift amount of circulating water can be calculated according to civil cooling tower water saving management standard (DB 11/T1770-2020)), and in addition, concentrated water needs to be discharged from the air-conditioning cooling circulating water system, if the cooling tower 1 needs to be kept in a fixed amount, the water needs to be supplemented into the cooling tower 1 from the outside only by supplementing condensed water, and the water needs to be supplemented into the cooling tower 1 from the outside. But the condensed water is recycled to the cooling tower 1, so that the water quantity input to the cooling tower 1 from the outside can be reduced, and the purpose of saving water resources is achieved.
Because the water quantity in the cooling tower 1 is a fixed value, the water quantity of condensed water introduced into the cooling tower 1 and the water quantity supplemented into the cooling tower 1 from the outside need to be controlled, when the cooling tower 1 is supplemented with water, the condensed water collected by a condensed water system is preferably supplemented into the cooling tower 1, and the supplemented condensed water quantity is monitored, and if the water quantity in the cooling tower 1 does not reach the required value at the moment, the water is supplemented into the cooling tower 1 from the outside is controlled, and the water supplementing quantity is monitored.
The following is a data comparison explanation of the existing cooling circulating water quality control system and the cooling circulating water quality control system provided by the invention, taking the central air-conditioning system of Beijing subway as an example:
(I) calculating concentration multiple, evaporation capacity of circulating water, water supplement capacity and drift amount
1. Determination of the concentration factor
When the pure physical method is adopted to treat the cooling circulating water, corresponding water quality indexes must be controlled in order to ensure the heat exchange efficiency of the heat exchanger, ensure no corrosion and no scaling. According to engineering experience, the hardness (calculated as CaCO 3) of the circulating water must be controlled below 500mg/L, and the concentration times are calculated by combining with the hardness index of the quality of the make-up water.
When the water hardness is 167mg/L according to the water quality of a certain area of Beijing, the tap water concentration factor N is 500/167 and is approximately equal to 3, and the concentration factor is 3.
2. Calculation of evaporation capacity, water supply capacity and drift quantity of circulating water
And (4) calculating the evaporation capacity, the water supplement capacity and the drift capacity of the circulating water according to the civil cooling tower water saving management specification (DB 11/T1770-2020).
(1) Calculating the evaporation capacity: according to civil cooling tower water saving management specification (DB11/T1770-2020), the evaporation capacity is
In the formula:
qr- -circulation water flow, m3/h
Delta t- -temperature difference between cooling circulating water entering and leaving a cooling tower, DEG C
k- -evaporation loss coefficient, taken from a table, calculated by interpolation at an intermediate temperature, 1/deg.C
h- -time period of operation
Coefficient of evaporation loss
Circulating water flow 200m3The average temperature of the evaporation rate is 1.5m, the average temperature of the evaporation rate is 5 ℃ and the average temperature of the evaporation rate is 0.00138 (21 ℃ in 6 months, 24 ℃ in 7 months, 23 ℃ in 8 months, 17 ℃ in 9 months, 9 ℃ in 10 months, the average temperature of the evaporation rate is calculated by interpolation method month by month to obtain the average value), and the evaporation rate is 1.5m3/h。
(2) Calculating the dispersion amount: the drift amount is Qp-Qr multiplied by Pp multiplied by h according to civil cooling tower water saving management specification (DB11/T1770-2020)
In the formula: pp is the percent loss by wind, taken as 0.01% when test data is absent.
The amount of scattering is 0.02m3/h。
(3) And (3) calculating the sewage discharge amount: according to the civil cooling tower water saving management specification (DB11/T1770-2020), the discharge capacity is Qw-Qe/(N-1) -Qp
In the formula: n is concentration multiple.
The concentration multiple of the circulating water is 3 times, and the sewage discharge capacity is 0.87m3/h。
(4) And (3) water supplement amount calculation:
Qb＝Qe+Qp+Qw
then Qb is 2.4m3/h
(II) water balance of system
1. Water balance for existing systems
According to the water supplement amount of 2.4m3The total water supplement amount is 24m when the working time is 10 hours per day3/d
Wherein: evaporation capacity 1.5m310h evaporation of 15mm3/d；
Discharge capacity of 0.87m3The discharge capacity of the sewage per hour and 10 hours is 8.7m3/d；
The amount of drift was 0.02m3/h, and the amount of drift was 0.2m3/d for 10 h.
Referring to fig. 5, which is a water balance diagram, the water supply amount is approximately equal to the evaporation amount, the sewage discharge amount and the drift amount.
2. Water balance of the system
And (3) condensation water: 0.59m3The water supplement amount of the condensate water is 5.9m in 10h3/d；
Ion balancer (ion balancer treatment scale is 0.5m/h, fresh water yield is calculated according to 80%), water quantity of 10h is 5m3D, wherein the fresh water is 4m3D, concentrated water is 1m3/d。
Referring to fig. 6, a water balance diagram is shown, in which the condensed water amount + the external water supply amount is equal to the evaporation amount + the sewage discharge amount + the dispersion amount.
Water saving amount: 24m3/d-10.3m3/d＝13.7m3Water saving 2055m in/d, 150 sky-conditioned operation cycle3Reduce the sewage discharge amount 1150m3。
Salt balance
1. Salt balance of existing systems
①35m3Total dissolved solids of 35m with water retention3x210g/m3＝7350g；
②24m3Total dissolved solids of 24m after water supplement3x210g/m3＝5040g；
(N3) 8.7m sewage system3x210g/m3x3＝5481g；
The system has the following salt content: 7350+ 5040-;
wherein, N is 3, and the total salt content in the system balance is 6909 g.
2. Salt balance of the system
①35m3Water retention and total dissolution and solidification: 35x210g/m3＝7350g
② ion balancer concentrated water total dissolved solids 5x630g/m3x85％＝2678g
③10.3m3Make-up water total dissolved solids: 10.3X210g/m3＝2163g
④5.9m3Total dissolution of condensed water: 5.9X20g/m3＝118g
When N is 3, the total salt content of the system in balance is as follows: 7350+2163+118-
That is, when the treatment scale of the ion balancer is 0.5m/h and the desalination efficiency is 85%, the concentration ratio of the cooling circulation water can be completely controlled to be 3 by the double functions of the condensate water dilution and the ion balancer.
When the operation cycle time of the cooling water system is 10 hours and the ion balancer is operated for 24 hours, the concentration ratio can be controlled.
When the ion balancer was operated for 24 hours, the amount of treated water: the salt discharge amount is 12x630x85 percent to 6426g, the concentration ratio (N) is 2-3, and the running time of the ion balancer can be determined according to the actual index of water quality.
(IV) accounting for operating power consumption
Ion balance treatment circulating water system compares with conventional circulating water system, needs electrical equipment such as newly-increased ion balance treatment equipment, fresh water elevator pump, dense water flushing constant voltage water supply equipment, comdenstion water elevator pump, calculates the power consumption of above equipment:
1. the ion balance device is used for balancing the electricity consumption. The average power consumption of the ion balance equipment is 0.6kWh/m per ton of fresh water3. From the above calculation, it is known that the fresh water production amount is 0.40m3Hourly, daily transportThe line power consumption is 0.40 × 24 × 0.6 ═ 5.76 kWh.
2. And a fresh water pump, wherein a lift pump of 0.37kW is selected according to the yield of fresh water, and the running time of the water pump per day is 5 hours, so that the power consumption per day is 0.37 multiplied by 5-1.85 kWh.
3. A constant-pressure water supply device for flushing a toilet by using concentrated water is characterized in that a constant-pressure water supply device with a water pump of 0.55kW multiplied by 2 is selected, the water pump is used for one time and is used for one time, the average running time is calculated according to 8 hours, and the value of 0.55 multiplied by 8 is 4.4 kWh.
4. The power consumption of the condensed water system is calculated according to the power of a water pump of 0.37kw, the condensed water system runs for 3 hours every day, and the power consumption is 0.37 multiplied by 3 to 1.11kWh every day.
5. In summary, the daily power consumption of the ion balance system is 5.76+1.85+4.4+1.11 ═ 13.12 kWh.
6. The electricity price is calculated as 0.84 yuan/kWh, and the electricity fee per day is 13.12 × 0.84 ═ 11.02 yuan. (1653 yuan/year)
7. In the existing subway station 416 seats in Beijing (assuming that the air conditioning systems are all in a cooling circulating water mode), the daily electric charge is 12.87 × 416-5,353.92 yuan.
8. The operation time is calculated according to 150 days/year, and the annual electric charge 1653 x 150 ═ 687,648 Yuan/year
9. The equipment can be operated in the trough time period of the electricity price as far as possible, and the operation electricity fee is saved.
(V) Water saving amount calculation
From the above calculation, it can be seen that the amount of the supplemented tap water per day of the ion balance treatment cooling circulation water system of the present invention is reduced by 13.20m compared with the conventional cooling circulation water system3D, simultaneously reducing the discharged sewage by 7.66m3/d。
416 seats of the existing subway station in Beijing (assuming that the air conditioning systems are all in a cooling circulating water mode), the water saving amount of tap water is 13.20 multiplied by 416-5491 m each day3D, reducing the sewage discharge by 7.66 multiplied by 416 to 3187m3/d。
The operating time is calculated according to 150 days/year, and the amount of tap water saved every year is 5491 multiplied by 135 to 823,680m3A, reducing the sewage discharge capacity 3187 multiplied by 150 to 478,050m3/a.
The water cost is 9.5 yuan/m3The running water fee 823 can be saved every year680 × 9.5 ═ 7,824,960 yuan/year.
Annual cost saving accounting
The items saved by a single station include water cost and medicament cost of tap water; increased electricity charges with ion balancing. The conventional circulating water system (200 tons/hour circulation rate) has the medicament cost of about 6000 yuan/year per year, and the specification is calculated as the following formula:
the cost saved by one station is (saving water cost-increasing electricity cost per day) x operation days + saved medicament cost
＝(13.20m3/d×9.5-13.12×0.84)*150+6000
23157 yuan/year
The cost of each subway station can be saved by 23157 yuan/year; the cost can be saved by adopting the technology at the existing subway station 416 in Beijing (assuming that all air-conditioning systems are in a cooling circulating water mode), namely 23157 × 416-9,633,312 yuan/year.
(VII) carbon saving emissions calculation
According to the calculation in the above section, the ion balance circulating water treatment equipment saves 13.2 tons of tap water per day, reduces 7.66 tons of sewage discharge and simultaneously uses 13.12kWh of electricity.
1 ton of tap water is saved, the carbon emission of 0.91kg can be reduced, 0.997kg of carbon can be generated by using 1 DEG of electricity, the sewage emission of 1 ton can be reduced, and the carbon emission of 0.47kg can be reduced by taking a sewage treatment plant using an A2/O process in the northern area of China as an example.
The carbon emission per day can be reduced by 0.54kg/d (13.7 × 0.91+7.66 × 0.47-13.2 × 0.997), i.e., by 2.91 kg/d. The operation time is calculated according to 150 days/year, and the annual carbon emission reduction is 2.91 multiplied by 150 to 437 kg/a.
In the conventional subway station 416 in Beijing (assuming that air-conditioning systems are all in a cooling circulating water mode), the carbon emission is reduced by 437 × 416 to 181584kg/a to 182t/a each year.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and shall cover the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (10)
1. A water quality control method for a cooling circulating water system is characterized by comprising the following steps:
concentrating and enriching anions and cations in the cooling circulating water;
releasing the concentrated and enriched anions and cations to form concentrated water out of the system;
the concentration of the concentrated water is greater than the required value of the system operating concentration, the required value of the system operating concentration is the required value of the circulating water ion concentration when the cooling circulating water system normally operates, namely, the discharge capacity and the water replenishing capacity of the cooling circulating water system are reduced by increasing the concentration of the concentrated water discharged out of the system.
2. The method according to claim 1, wherein a bypass line is formed in the cooling circulation water system, a deionization system is provided in the bypass line, a part of the cooling water discharged from the cooling tower is purified by the deionization system, and fresh water generated by the purification process is returned to the cooling tower to be discharged out of the concentrated water discharge system.
3. The method according to claim 2, wherein the ion concentration of the circulating water in the cooling circulating water system is monitored, and the flow rate of the circulating water to the deionization system is controlled, or the deionization efficiency of the deionization system is controlled, or the operation time of the deionization system is controlled.
4. The method as claimed in claim 2, wherein the deionization system adopts electrodialysis method, electro-adsorption method, reverse osmosis method or distillation method.
5. Cooling according to any of claims 1-4The water quality control method of the circulating water system is characterized in that the concentration multiple N of cooling circulating water is controlled to be 1.5-3, wherein the concentration of water externally supplemented to the system is C1The required value of the system operation concentration is C2Concentration factor N ═ C2/C1。
6. A method for controlling the quality of water in a cooling circulation water system according to any one of claims 1 to 4, wherein the concentrated water discharged to the outside of the system is reused.
7. A water quality control method for a cooling circulation water system according to claim 6, wherein the generated concentrated water is used for flushing a toilet or for street watering.
8. The method for controlling the water quality of a cooling circulation water system according to any one of claims 1 to 4, wherein the cooling circulation water system is a cooling circulation water system of an air conditioning apparatus, and the method for controlling the water quality further comprises the following steps: collecting condensed water generated when the air conditioning equipment is operated, and then guiding the collected condensed water to a cooling tower for supplementing water to the cooling tower.
9. The method as claimed in claim 8, wherein the amount of water in the cooling tower is monitored, and when the cooling tower needs to be replenished, the condensed water is preferentially introduced into the cooling tower, and if the cooling tower still needs to be replenished, the water outside the system is introduced into the cooling tower, wherein the water outside the system is tap water, rainwater or reclaimed water.
10. The method for controlling the water quality of a cooling circulation water system according to any one of claims 1 to 4, further comprising:
and purifying the circulating water in the cooling circulating water system by adopting a physical method and a physical and chemical method.
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| WO2004028978A1 (en) * | 2002-09-27 | 2004-04-08 | Snyder Milton W | Low or zero bleed water discharge cooling tower system |
| CN101734743A (en) * | 2008-11-18 | 2010-06-16 | 中国科学院生态环境研究中心 | Method for circulating industrial cooling water and producing demineralized water |
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