RU2502683C1 - Method of utilising blowdown water of circulating system - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be applied at thermal power plants. Method includes clarification filtration and deep demineralisation of blowdown water flow before utilisation, supply of additional water into circulating system and its preliminary demineralisation by reagent decarbonisation and sodium-cation exchange in alkaline medium, water demineralisation by sodium-cation exchange in the mode of primary and secondary cation exchange, prevention of continuous emission into atmospheric air of phenol from composition of circulating water in the process of its evaporation cooling and bactericidal processing of additional water flow by polyhexamethylene guanidine derivative. Blowdown water after clarification filtration is subjected to short-wave ultraviolet irradiation and is separated into two flows. One flow is processed with lime to pH=9.0-10.5, is demineralised by sodium-cation exchange in the mode of secondary cation exchange and directed to heating system feed. The other flow if successively subjected to deep demineralisation by sodium-cation exchange in the mode of secondary cation exchange, to primary and secondary reverse-osmosis filtering.

EFFECT: method ensures exclusion of uncontrolled emission of phenol into atmosphere in the process of evaporation cooling of blowdown water and growth of its corrosion activity, reduction of consumption of reagents for ensuring safety of blowdown water in circulatory cooling system of thermoelectric power plant and obtaining highly demineralised water.

2 cl, 17 ex, 1 tbl

Description

The invention relates to methods for utilizing purge water of a circulation system and can be used in a thermal power plant (TPP).

There is a method of disposing of purge water of the circulating cooling system of condensers of TPP turbines by feeding them into the heating system, including its clarification and softening before disposal, compensation of losses of circulating water by feeding makeup water to the circulation system - analogue (Moiseytsev Yu.V. Reducing water consumption and drainage in water treatment systems and of wastewater treatment at thermal power plants. Abstract of dissertation for the degree of candidate of technical sciences. M., 2001). The disadvantages of the analogue method are determined by the method of feeding makeup water to the circulation system from a surface water body without preliminary treatment. The use of make-up water from a surface water body without preliminary treatment causes a loss of the plant's electrical power during the summer period due to an increase in the temperature head in the turbine condensers due to precipitation on heat-transferring surfaces. This technique also makes it impossible to maintain the flow rate of purge water from the circulating system equal to the heat network's demand for recovered water. The purge water consumption, as a rule, is several times higher than the need of the heating network for make-up water and necessitates the discharge of part of the purge water into a surface water body for fishery purposes. The mentioned technological method limits the number of surface water bodies, the water of which can be used to feed circulating systems with cooling towers without violating the sanitary and epidemiological safety criteria. In general, the analogue method under consideration does not contain technological operations that prevent the uncontrolled release of phenol into the atmosphere during the process of evaporative cooling of the circulating water, as well as reduce the consumption of reagents for ensuring the sanitary and epidemic safety of the circulating cooling system of the thermal power plant and obtain deep demineralized water for its technological needs .

There is a method of disposing of purge water from a circulating cooling system of a power plant without discharging it into a water body by irrevocable use for technological needs, including clarification in the suspended layer of previously deposited particles, clarification by filtration and subsequent softening of the purge water flow by sodium cation before feeding to the heating network in the required to compensate for the loss of network water quantity, while part of the stream clarified by filtration of purge water is subjected to reverse osmotic filtration with the formation of a concentrate, then sequential H-cation and OH-anionation to obtain the required amount of deeply desalted water, which is irrevocably used in the composition of their regeneration products and to compensate for the loss of steam and condensate from the steam-water cycle, after which the concentrate and regeneration products are uniformly mixed with additional water in the circulating cooling system - analogue (Patent for utility model RU 95656 U1. Combined Water Management System). The main disadvantage of the analogue method is that it does not contain technological operations designed to prevent the uncontrolled release of phenol into the atmosphere during the evaporative cooling of the circulating water, which comes from the water supply as part of the additional water. This applies both to the uncontrolled release of phenol into the atmosphere due to the entrainment of cooled circulating water by the wind, and the loss of water by evaporation. In addition, the analogue method does not contain the operations necessary to ensure sanitary and epidemic safety of the circulation cooling system of a thermal power plant, which may be accompanied by an increased consumption of a bactericidal reagent, for example, one of the well-known chlorine-containing preparations. Another significant drawback of the analogue method is the increased consumption of reagents for the production of deep desalinated water for a power plant. It is associated with the need to use separate H-OH-ionization of water (Water treatment. Processes and devices. Edited by Doctor of Technical Sciences, Professor OI Martynova. Textbook for universities. M., Atomizdat, 1977, 352 p. ), requiring increased costs of acid and alkali for the regeneration of spent cation exchangers and anion exchangers.

The closest in technical essence and the achieved result is a method for the disposal of purge water from the circulation cooling system of a power plant without its discharge into a water body by irretrievable use for technological needs, including clarification by filtration and deep softening of the flow of purge water before disposal, compensation of losses of circulating water by feeding into the circulation additional water system, preliminary softening of the last sodium cation in alkaline media before feeding , Water softening, sodium-cationization in regimes of primary and secondary cationization, continuous disinfection of water used and removal of phenol recycled water is introduced into the circulation water Derivative polyhexamethyleneguanidine - prototype (patent RU 2279409 C2 recycling process blowdown water circulation system.).

Describing the disadvantages of the prototype method, first of all, it should be noted that the totality of the technological operations used in it is not able to prevent the uncontrolled release of phenol into the atmosphere during the evaporative cooling of circulating water, which comes from the source of water supply as part of additional water. This applies both to the uncontrolled release of phenol into the atmosphere due to the entrainment of cooled circulating water by the wind, and the loss of water by evaporation. According to the prototype method, uncontrolled emission of phenol into the atmosphere with water loss due to evaporation is prevented by deep softening in the alkaline medium of phenol-containing additional water, which causes the transformation of phenol into sodium phenolate C ₆ H ₅ ONa. This compound, unlike phenol, does not distill with water vapor. However, the prototype method does not take into account the fact that entering into the circulating water and then in its composition for evaporative cooling in the cooling tower, sodium phenolate, under the influence of carbon dioxide absorbed from the cooling air, is converted back to phenol. This is due to the fact that the acid properties of the latter are weakly expressed and phenolates are easily decomposed by carbonic acid according to the scheme:

C ₆ H ₅ ONa + H ₂ O + CO ₂ → C ₆ H ₅ ONa + H ₂ CO ₃ → C ₆ H ₅ OH + NaHCO ₃

The phenol that arises according to this scheme, in turn, forms an azeotropic phenol hydrate with water, which is volatile during its evaporative cooling, which has experimental confirmation. In this form, phenol enters from the circulating water into the cooling air and then as part of the discharge from the cooling tower into the atmosphere. It follows that natural water contaminated with phenol poses a sanitary and chemical hazard to humans when used as an additional circulating cooling system in the areas where thermal power plants are located, where the phenol content in atmospheric air is recorded at MPC levels and higher. According to the annual state reports “On the State and Environmental Protection of the Russian Federation”, this phenol content in the air is widespread and is recorded in more than 94 cities of Russia. In such cases, the state environmental standard GOST 17.2.3.02-78 prescribes to ensure sanitary standards by using the most modern technologies and technical means for protecting the atmosphere.

The disadvantages of the prototype method also include an increase in the corrosiveness of recycled water due to its evaporative cooling.

Another significant disadvantage of the prototype method is the increased consumption of reagents to ensure sanitary and epidemic safety of the circulation cooling system of a thermal power plant and to obtain deep demineralized water for its technological needs. For example, the increased consumption of reagent for ensuring sanitary and epidemic safety of the "circulating cooling system of a power plant is caused by the prototype method by continuously introducing a derivative of polyhexamethylene guanidine into the composition of the circulating water. The increased consumption of reagents for producing deep desalinated water for a power plant is connected, as already It was said above, with the need to use separate H-OH-ionization of water, requiring increased costs of acid and alkali for regenerator uw waste cation and anion exchangers.

The basis of the invention is the task to develop a method for recycling the purge water of the circulation system, which provides a technical result consisting in preventing the uncontrolled release of phenol into the atmosphere during evaporative cooling of the circulating water and increasing its corrosivity, reducing the consumption of reagents for ensuring sanitary and epidemic safety of circulating water circulation system for cooling a thermal power plant and getting deeply desalinated for its technological needs water, as well as increasing the degree of removal of the last silicon dioxide.

To solve the problem, in a known method of recycling the purge water of the circulation system, including clarifying filtering and deep softening the purge water flow before disposal, compensating for the losses of circulating water by adding additional water to the circulating system and pre-softening the latter before applying reagent decarbonization and sodium cation in alkaline environment, water softening by sodium cationization in the modes of primary and secondary cationization, prevention of continuous selection dew to atmospheric air of phenol from the composition of the circulating water during its evaporative cooling and bactericidal treatment of the additional water stream, introduction of the polyhexamethylene guanidine derivative into the circulating water, purge water irrevocably used for technological needs before clarification filtration is softened by preliminary reagent decarbonization and subsequent primary sodium cationization in alkaline medium additional water, and after clarification filtering is subjected to short-wave ultraviolet commercial irradiation and are divided into two streams, one of them is treated with lime to pH = 9.0-10.5 in the amount necessary to compensate for losses of network water, deeply softened with sodium cation in the secondary cation mode and sent to recharge the heating network, the other is subsequently subjected deep softening with sodium cation in the secondary cation mode, primary and secondary reverse osmosis filtration, with the formation of primary and secondary concentrates, then joint H-OH ionization to obtain not the required amount of deeply desalted water, which is irrevocably used in the composition of its regeneration product and to compensate for the losses of the working fluid from the steam-water cycle, after which the primary, secondary concentrates and the regeneration product are uniformly mixed with purge water before ultraviolet irradiation, while the flow of purge water directed for disposal, support the equal amount of losses of network water by the heating system and working fluid by the steam-water cycle of the thermal power plant, the introduction of the chlorine derivative into recycled water Ihe of polyhexamethylene guanidine is carried out periodically to the level of the maximum inactive concentration of 5-7 mg / l of its phosphate-containing derivative, this concentration is maintained for a day, after which the introduction of the polyhexamethylene guanidine derivative into the circulating water is stopped, and continuous emission of phenol into the atmospheric air from the circulating water is prevented due to the short-wave ultraviolet irradiation of additional water in an alkaline medium before applying to mix with the circulating, which is carried out immediately after ispa ritelny cooling of the last.

Moreover, to prevent the continuous release of phenol into the atmospheric air from the composition of the circulating water, the half-wave of additional water is predominantly subjected to short-wave ultraviolet irradiation, after which it is mixed with the unirradiated remaining water and, not earlier than 30 minutes after mixing, it is supplied as additional water to circulation system.

The technical result achieved by the proposed method is to prevent the uncontrolled release of phenol into the atmosphere during the evaporative cooling of the circulating water and the growth of its corrosive activity, reducing the consumption of reagents for ensuring the sanitary and epidemic safety of the circulating water of the cooling system of the thermal power plant and obtaining for its technological needs a deeply desalted water, as well as increasing the degree of removal from the last silicon dioxide.

Obtaining this result is ensured by the fact that the method is as follows.

The additional water before being mixed with recycled water is subsequently subjected to reagent decarbonization, primary sodium cation and short-wave ultraviolet softening in an alkaline medium, after which it is mixed with recycled water, and mixing is carried out immediately after the latter has evaporated cooling. Such a sequence of operations is not known from the prior art. It allows you to completely eliminate the influx of phenol and microorganisms from raw river into the composition of the circulating water and prevent the growth of its corrosive activity. At the same time, during the absence of microorganisms in the composition of decarbonized water, the half-wave flow is predominantly subjected to short-wave ultraviolet radiation, after which it is mixed with the unirradiated residue of decarbonized water and, not earlier than 30 minutes after mixing, is supplied as additional water to the circulation system. Such a technological technique is not known from the prior art. It is associated with the experimentally discovered effect of the complete destruction of phenol in contact with water previously exposed to ultraviolet radiation. Its advantage is obvious from economic considerations, since it leads to a half reduction in energy costs for ultraviolet irradiation. In addition to preventing the release of phenol from the cooling towers during the evaporative cooling of the circulating water, the above sequence of operations simultaneously reduces the reagent consumption to ensure its sanitary and epidemic safety, since in this case disinfection of the circulating water does not require the continuous introduction of a bactericidal agent into its composition. This is due to the fact that microorganisms entering the circulating water from atmospheric air are mainly saprophytes. Saprophytes do not pose an epidemic danger. They are removed from the circulating water almost completely together with the particles of air dust coming into it from the air by clarification filtering, since the particles of bacterial dust (their size varies from 10 to 1000 microns) are much larger than the particles of ordinary atmospheric dust (0.001-30 microns). Pathogenic bacteria are very rare in atmospheric air and the risk of infection is low due to the intensive dilution of microbes with air masses, the sun (ultraviolet rays) and temperature exposure. In the event that pathogenic microorganisms are still detected while monitoring the sanitary-epidemiological state of the circulating water, to prevent accidental infectious diseases during this period, the polyhexamethylene guanidine derivative is added to the level of the maximum inactive concentration of its phosphate-containing derivative, this concentration is maintained for 24 hours, after which derivative polyhexamethylene guanidine in the circulating water is stopped. This sequence of technological operations unknown from the prior art results in the death of all microorganisms of circulating water, both pathogenic and saprophytes.

It should be noted the special role played by the proposed sequence of technological operations for processing additional water due to the fact that it allows you to completely abandon the continuous introduction of a bactericidal agent into the composition of the circulating water, which, according to the prototype method, uses a polyhexamethylene guanidine derivative. The refusal from the continuous introduction of a bactericidal agent into the composition of the circulating water, first of all, leads to a reduction in the consumption of reagents for ensuring the sanitary and epidemic safety of the circulating water of the cooling system of the power plant. In turn, this entails the exclusion of the derivative of polyhexamethylene guanidine from the composition of the purge water as its permanent component. It is known that the derivative of polyhexamethylene guanidine in the composition of water subjected to ionization is irreversibly sorbed by acid cation exchanger (Grishin A.A., Malakhov I.A., Bogdanov M.V. Hygienic and technological aspects of the biocidal treatment of cooling water in the circulation systems of power plants // Thermal Power Engineering. 2001 - No. 8. - C.2-8), which over time leads to a complete loss of its ion-exchange ability and makes it impossible to use sodium cationization to soften such water. Therefore, the refusal to continuously introduce the polyhexamethylene guanidine derivative into the circulating water makes it possible to carry out a sequence of operations for treating purge water not known from the prior art, first with lime to pH = 9.0-10.5, and then with sodium cation in the secondary cation mode. It is designed to minimize the corrosive activity of utilized water relative to the main pipelines of the heating system under conditions of growth of corrosion activators (chlorides and sulfates) in the composition of recycled water.

It should be noted that the above-mentioned ranges of pH values of 9.0-10.5 correspond to the upper limits of pH values for open ones (9, 10, 15.5-34.20.501-2003 of the Ministry of Energy of the Russian Federation) 0) and closed heat supply systems (10.5). For closed heat supply systems with the permission of the power system, the upper limit of the pH value is allowed no more than 10.5 while reducing the value of the carbonate index to 0.1 (mEq / dm ³ ) ² . Tests have shown that an unknown sequence of purge water treatment operations provides a carbonate index in it that does not exceed the standard values for network water, and although it is insignificant, it decreases the rate of general corrosion against the background of an increase in the content of corrosion activators in it. At the same time, the tested samples of the material of the pipelines of the heating system and the tubes of the condensers retain metallic luster after testing, there are no pitting and ulcerative lesions on their surfaces.

In addition to the disposal of purge water in the heating network, the proposed method, in contrast to the known prototype method, further provides for its disposal by irretrievable use to compensate for the loss of the working fluid from the steam-water cycle. For this purpose, a set of operations of deep desalination of water unknown from the prior art is proposed, including independent sodium cationization in the secondary cationation mode, subsequent primary and secondary reverse osmosis filtration with the formation of primary and secondary concentrates, and joint H-OH ionization to obtain the required amount of deeply desalted water , which, along with replenishing the losses of steam and condensate from the steam-water cycle, is irrevocably used as part of the product radios, while the primary, secondary concentrates and the regeneration product are uniformly mixed with purge water, which ensures the removal of salts removed from the purge water during its desalination with softened make-up water of the heating system. It should be noted that in the aforementioned set of operations, sodium cation in the secondary cation mode increases the reliability of primary reverse osmosis filtering due to the complete removal of finely dispersed impurities from softened water, including the remains of saprophytic microorganisms surviving after ultraviolet exposure, performing a function unknown from the prior art, the presence of which established experimentally. This eliminates the consumption of reagents for chemical regeneration of membrane devices to remove deposits of calcium carbonate, iron hydroxide, organic and biological sediments accumulated on the membranes. Primary and secondary reverse osmosis filtration, in turn, without the cost of reagents provides desalted water with a specific electrical conductivity of 1 μS / cm, containing less than 3 μg / l of silicon dioxide. With subsequent joint H-OH ionization, this makes it possible to guaranteedly obtain deeply desalted water with a sodium content of less than 30 μg / L and silicon dioxide less than 3 μg / L. Such deeply desalted water is subsequently irrevocably used to compensate for the losses of the working fluid from the steam-water cycle directly. In addition, in the amount necessary for the regeneration of ion exchangers of joint H-OH-ionization, it is irrevocably sent to the heating system as a part of the regeneration product, for which purpose it is uniformly mixed with utilized purge water. The method of uniform mixing of the product of regeneration of joint H-OH-ionization with utilized purge water used in the proposed method determines an insignificant, within a few milligrams per liter, increase in the salinity of makeup water of the heating system. This is due to the fact that when the content of silicon dioxide is less than 3 μg / l in water entering the stage of joint H-OH-ionization according to the proposed method, the product of its regeneration measured in tens of kilograms is formed no more than once a month, and it is mixed with a stream of recyclable water measured in tens of tons per hour.

Example 1. At the CHPP-25 of the branch of MOSENERGO OJSC, samples of process water were taken, which went through the stages of softening with lime in clarifiers, subsequent clarification filtering and sodium cation, the pH of the water samples was measured by the standard method and the phenol content in them according to the PND F 14.1: 2.104 method -97. A 400 ml sample of water with a pH of 10.5 containing no phenol is taken, placed in a chemically clean heat-resistant measuring cup, a calibration solution of phenol is added to it, and a model solution of additional water containing 25 mg / m ^{3 of} phenol is obtained. A heat-resistant glass with a sample is placed in a water bath, the contents are heated to 40 ° C, after which an aerator is placed in the heated solution to saturate the aquarium water with air, through which air was passed using an air microcompressor (220 V, 50 Hz, 3 W) with a capacity of 30 l / hour, simulating the conditions of evaporative cooling of circulating water. The solution is aerated for 1 hour, while constantly monitoring the temperature, maintaining it at 40 ° C for the specified period of time. At the end of aeration, a pH of 8.3 is determined in the test sample and no phenol is detected. The experiment is repeated three times and get the same result. From example 1 it follows that the reception of deep softening of additional water in an alkaline environment is not able to prevent the intake of phenol from the circulating water into the cooling air during its evaporative cooling and then as part of the discharge from the cooling tower into the atmosphere. In addition, for the first time experimentally established the fact of the complete removal of phenol from recycled water under the influence of cooling air. This indicates that in those areas of the location of thermal power plants, where the phenol content is recorded at a maximum permissible concentration level or higher, any amounts of phenol are not admissible in the circulating water with additional water. The latter provides justification for the need for its complete removal from the composition of additional water before mixing it with recycled water.

Example 2. At the CHPP-25 of the branch of MOSENERGO OJSC, samples of process water are taken, which have passed the stages of liming by liming in clarifiers, subsequent clarification filtering and sodium cating in the primary cation mode, pH and total microbial number (TBC) are measured in the selected water samples according to standard methods, as well as the content of phenol in them according to the method PND F 14.1: 2.104-97. Take 500 ml of water sample with pH = 10.5, not containing phenol and bacteria (TBC = 0). The sample is placed in a sterile measuring cup and a phenol calibration solution is added to it in order to obtain its concentration at the upper limit of measurement using the used technique of 25 mg / m ³ . Thus, a model solution of additional water containing 25 mg / m ³ phenol (25 MPC in an aqueous medium) with a pH of 10.5 is obtained. Collect the ultraviolet installation. It includes a series of initial solution containers connected in series by flexible hoses, a peristaltic pump (with a flow rate of 7.5-8 l / h) for pumping the initial solution subjected to ultraviolet irradiation, a coil from a quartz tube with an inner diameter of 5 mm inside which the irradiated solution moves, and the capacity of the treated solution. A model solution of additional water is placed in the capacity of the initial solution. Inside the coil (whose inner diameter is 45 mm), formed by a quartz tube, a DRB-8 low-pressure mercury-quartz lamp coaxially located along its entire length provides a short-wavelength range of ultraviolet irradiation of the outer surface of the quartz tube. The peristaltic pump is turned on, electric power is supplied to the lamp and the irradiated solution is removed in the container of the treated solution. The collected working solution is subjected to three more similar cycles of ultraviolet irradiation in the installation used, after which the phenol content is determined in the four times irradiated solution. Phenol in four-time ultraviolet irradiation was not detected on the used model of the model solution of additional water. From example 2 it follows that the reception of short-wave ultraviolet irradiation of additional water containing phenol is able to ensure complete destruction of this volatile, toxic compound in its composition.

Example 3. At the CHPP-25 of the branch of MOSENERGO OJSC, a sample of lime water is taken for analysis: not filtered lime in the clarifiers, filtered lime in the clarifiers and filtered after sodium cation in the clarifiers. In the selected water samples, the total microbial number (TBC) is determined by a standard method. Samples of water are analyzed, which has passed the stage of softening by liming in clarifiers and when sowing from dilutions of 1 ml of water, 1000 grown colonies of bacteria are counted (OMC = 1000 CFU / ml). Samples of water are analyzed, which, after liming in the clarifiers, passed the filtration stage and, when sowing from dilutions of 1 ml of water, 20 colonies of bacteria are counted (TBC = 20 CFU / ml). Samples of water are analyzed, which, after liming in clarifiers and filtering, has passed the sodium-cating stage, and when cultures are diluted with 1 ml of water, the grown bacteria colonies are not detected (TBC = 0). From example 3 it follows that sodium cation simultaneously with deep softening of water provides an unknown result from the prior art, the complete removal of bacteria forming colonies from softened water.

Example 4. The method is carried out according to example 2. Phenol in exposed to four times ultraviolet radiation on the used installation model solution of additional water is not detected. Next, 200 ml of a model solution of additional water obtained after ultraviolet irradiation in the used ultraviolet unit is taken, mixed with the same volume of a model solution of additional water containing 25 mg / m ³ phenol, the flask containing the mixture is tightly closed, the mixture is kept for 30 minutes, after which it is determined phenol content. Phenol in the mixture of solutions after 30 minutes after mixing is not detected. From example 4 it follows that after the completion of the effect of ultraviolet radiation on the water stream, long-lived active photoionization products are formed in it, which have the previously unknown ability to completely degrade phenol molecules in an aqueous medium.

Example 5. The method is carried out according to example 4, but take 300 ml obtained after ultraviolet irradiation of the model solution of additional water used in the ultraviolet installation and mixed with the volume of the model solution of additional water containing 25 mg / m ³ phenol equal to 100 ml. Next, the flask containing the mixture is tightly closed, the mixture is kept for 30 minutes, after which the phenol content is determined in it. Phenol in the mixture of solutions after 30 minutes after mixing is not detected. From example 5 it follows that after the completion of the effect of ultraviolet radiation on the water stream, long-lived active photoionization products are formed in it, which have the previously unknown ability to completely degrade phenol molecules in an aqueous medium.

Example 6. The method is carried out according to example 4, but take 150 ml obtained after ultraviolet irradiation of the model solution of additional water used in the ultraviolet installation and mixed with the volume of the model solution of additional water containing 25 mg / m ³ phenol equal to 250 ml. Next, the flask containing the mixture is tightly closed, the mixture is kept for 30 minutes, after which the phenol content is determined in it. Phenol in a mixture of solutions after 30 minutes after mixing is detected in an amount of 2 mg / m ³ . From example 6, it follows that after the exposure to ultraviolet radiation on the water stream is completed, not enough long-lived active photoionization products are formed in it to undergo complete destruction of the phenol molecule in the aqueous medium.

Example 7. Summarize the results of the experiments presented in examples 4, 5 and 6, and conclude that the short-wave ultraviolet irradiation is predominantly subjected to half the flow of additional water, after which it is mixed with the unirradiated residue of the additional water and not earlier than 30 minutes after mixing serves as additional water in the circulation system.

Example 8. To sterile water, a suspension of E.Coli cultures, anaerobic bacteria, and fungi isolated from the circulating water of the equipment’s circulating cooling system was prepared using physiological saline. Model solutions are obtained containing cultures isolated from recycled water at a final concentration of 10 ⁹ CFU / ml. They are poured into sterile flasks; where then polyhexamethylene guanidine chloride is added as a derivative of polyhexamethylene guanidine at a dose of 5-8 mg / l. Flasks are incubated with the reagent for 24 hours at room temperature. The determination of E.Coli cultures is carried out by the standard method of seeding through membrane filters on the medium Endo. The following media are used to detect representatives of anaerobic bacteria: Schaedler-arape with 5% sheep blood, Schaedler-arape with kanamycin and bovine bile (Becton.), As well as semi-liquid thioglycol medium (Difco). Crops are cultivated in anaerobic systems at 37-42 ° C for 10 days. Mushrooms are detected using Saburo medium. Crops are kept at room temperature for 48-72 hours. After 24 hours of incubation in samples where a reagent concentration of 5 g / m ^{3 is created} , 10 ² CFU / ml of total coliform bacteria, 10 ³ CFU / ml of anaerobic bacteria and 10 ⁴ CFU / ml of mushrooms. In samples where the maximum concentration of the reagent is 6, 7 and 8 g / m ^{3 of} fungi, common coliform and anaerobic bacteria are not found. From example 8 it follows that the concentration of polyhexamethylene guanidine chloride in an aqueous medium of 5 g / m ³ does not provide disinfection of water simulating the infection of circulating water by microorganism strains that have formed under real conditions of the circulation system. The death of resistant strains of cultures of fungi, coliform and anaerobic bacteria is caused by a 24-hour increase in the concentration of the reagent in the water sample to at least 6 g / m ³ .

Example 9. The method is carried out according to example 8, but to obtain comparative data according to the prototype method, polyhexamethylene guanidine phosphate is used as a derivative of polyhexamethylene guanidine. After 24 hours of incubation, 10 ⁷ CFU / ml of total coliform bacteria, 10 ⁷ CFU / ml of anaerobic bacteria and 10 ⁸ CFU / ml of fungi were detected in samples where a reagent concentration of 5 g / m ^{3 was created} . In samples where a reagent concentration of 6 g / m ^{3 is created} , 10 ⁶ CFU / ml of total coliform bacteria, 10 ⁶ CFU / ml of anaerobic bacteria and 10 ⁷ CFU / ml of fungi are detected. In samples where a reagent concentration of 7 g / m ^{3 is created} , 10 ⁴ CFU / ml of total coliform bacteria, 10 ⁴ CFU / ml of anaerobic bacteria and 10 ⁵ CFU / ml of fungi are detected. In samples where a concentration of the reagent is 8 g / m ³ , fungi, common coliform and anaerobic bacteria are not found. From example 9 it follows that the concentration of polyhexamethylene guanidine phosphate in an aqueous medium of 5-7 g / m ³ does not provide disinfection of water simulating the infection of circulating water by microorganism strains that have formed under real conditions of the circulation system. The death of resistant strains of cultures of fungi, coliform and anaerobic bacteria is caused by a 24-hour increase in the reagent concentration in the water sample to not less than 8 g / m ³ .

Example 10. At the CHPP-25 of the branch of MOSENERGO OJSC, samples of the starting Moskvoretsk and process water, which passed the stages of softening by liming in clarifiers, subsequent clarification filtering and sodium cation, are taken, the pH of the selected water samples, the content of sodium and silicon dioxide in them by standard methods are measured. A 50 L sample of water with a pH of 10.5 containing 60 mg / L sodium, 3.2 mg / L silica was taken. Place it in the source water tank of a two-stage reverse osmosis unit, which is manufactured using FILMTEC XLE-2521 reverse osmosis membrane modules with a selectivity of 99% and a nominal capacity of 57.5 l / h. According to the logs of the engineering service of the CHPP-25, the minimum consumption of make-up water of the heating system is determined. The minimum consumption of make-up water of the heating network Q _TC = 192 t / h, which was observed in May 2003, is taken. It corresponded to: circulating water costs 143278 t / h, losses of circulating water due to evaporation in cooling towers (Q _ICP ) 1583 t / h, losses of circulating water due to drip removal from cooling towers (О _УОСО ) 43 t / h, working fluid (steam and condensate ) Q _PT = 120 t / h in the steam-water cycle of a thermal power plant. Then, it is determined by the formula K _kOV = (Q _ICP + Q _УОСО + Q _ТС + Q _РТ ) / (Q _УСОС + Q _ТС + Q _РТ ) the concentration coefficient (K _kOV ) of salts in the circulating water of the circulating system after its transfer to the closed water use mode . Its value is equal to K _kOV = 5,4. Then the selected sample with a pH of 10.5 containing 60 mg / l sodium, 4.9 mg / l silica in the source water tank is aerated until a pH of 8.3 is reached. After completion of aeration using the first stage of the reverse osmosis unit, operating at a flow rate of 30 l / h, the sample is concentrated 5.4 times and a model of purge water is supplied to the two-stage reverse osmosis unit according to the proposed method. In the resulting purge water model, the sodium and silica contents are determined at 259 mg / L and 26.5 mg / L, respectively. Then, the obtained purge water model is desalted using a two-stage reverse osmosis unit, and the permeate is used to determine the content of sodium and silicon dioxide at 30 μg / L and 3 μg / L, respectively. Then, the content of sodium and silicon dioxide in desalinated two-stage ion exchange make-up water of the energy boiler at the level of 28-54 μg / l and 72-108 μg / l is determined from the accounting books of the engineering service of the CHPP-25 and compared with the corresponding permeate indicators of the second stage of water desalination on the reverse osmosis installation. As a result of the comparison, they conclude that there is a significant (24-36 times) increase in the depth of removal of silicon dioxide from desalted water against the background of achieving the previous depth of removal of sodium from it by the proposed method in comparison with the known, traditional.

Example 11. According to the logs of the engineering service of the CHPP-25, the consumption of acid and alkali for one regeneration of the mixed-action filter (FSD) is determined at the level of 312.5 kg and 250.0 kg, respectively (with a water flow rate of 125 m ³ ). For simplicity, it is believed that after regeneration, 125 m of mineralized wastewater containing 312.5 + 250.0 = 562.5 kg of salts are discharged. At the same time, it is taken into account that water enters the FSD after the second stage of desalination of separate ionization containing 94-118 μg / L of silicon dioxide, and FSD is turned off for regeneration twice a month when the concentration of silicon dioxide in the filtrate reaches 20 μg / L, obtaining desalted water containing 11-20 μg / l of silicon dioxide. When implementing the proposed sequence of operations, it is proposed to supply water containing 3 μg / L of silicon dioxide to the FSD to obtain demineralized water containing less than 3 μg / L of silicon dioxide. Under these conditions, a priori, according to expert estimates, the number of FSD regenerations is taken once a month and the regeneration product (562.5 kg of salts in 30 days or 18.75 kg per day or 780 g per hour) is uniformly mixed with make-up water from the heating system. It is easy to calculate that if such a stream of salts is uniformly introduced into the heating water feed stream with a flow rate of 192 t / h (indicated in Example 10), the salt content of the make-up water will increase by 4 mg / l. Such an increase in salinity is insignificant from the point of view of the increase in the corrosion activity of network water. It can be neglected, especially against the background of increasing the pH of the make-up water to 9.0-10.5 before being fed into the heating system.

Example 12. To conduct corrosion tests using make-up water from the heating system of CHP-25 (model environment 1) with pH = 10.5, total hardness W ₀ = 0.2 mEq / l, total alkalinity Sh ₀ = 0.8 mg- equiv / l, the content of chlorides Cl ^- = 27.6 mg / l and sulfates SO ₄ ^2- = 19.7 mg / l. Corrosion tests are performed on rotating cylindrical samples of 3sp carbon steel, the most commonly used for the production of heating pipelines, at a temperature of 90 ° C. During the tests, water is deaerated with nitrogen to an oxygen concentration of 50 μg / L. The tests are carried out by two methods: gravimetric and polarization. During gravimetric tests, the total amount of steel corrosion products that have passed into water and remained on the surface of the samples during the experiment (4 hours) is determined, and the rate of total steel corrosion is calculated from these data. The rate of total corrosion of carbon steel is determined to be 0.27 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the corrosion potential of steel and the breakdown potential of a passive film is 320 mV, the zone of active dissolution of the metal is not detected and the conclusion is made that carbon steel is resistant to general and local corrosion.

Example 13. Corrosion tests are performed in accordance with example 12, but model medium 1 is aerated and the required amount of NaCl, Na ₂ SO ₄ and NaHCO ₃ solutions are added to it and circulating water is obtained under the water-chemical mode according to the prototype method (model medium 2) s pH = 8.4, total hardness W ₀ = 0.01 mEq / L, total alkalinity AH ₀ = 6.5 mEq / L, chloride content Cl ^- = 89.7 mg / L and SO4 ^2- = 50.2 mg / l. The rate of total corrosion of carbon steel is determined to be 0.32 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the steel corrosion potential and the passive film breakdown potential is 310 mV, the zone of active dissolution of the metal is detected and the carbon steel is resistant to local corrosion, as well as the need to prevent the growth of corrosive activity of recycled water under the chemical regime prototype method.

Example 14. Summarize the loss of recycled water for evaporation in the cooling towers (Q _ICP ) 1583 t / h, the loss of recycled water for drip entrainment from the cooling towers (Q _FOC ) 43 t / h, working fluid (steam and condensate) Q _RT = 120 t / h in the steam-water cycle of a thermal power plant and the charge flow rate of the heating network Q _TC = 192 t / h, the values of which are presented in Example 2, and thereby obtain the total flow of additional water to the circulating system according to the proposed method equal to 1938 t / h with a flow rate of circulating water 143278 t / h Based on the ratio of the costs of additional and circulating water, 1.9 ml of a model solution of additional water are obtained in accordance with Example 2 and 143 ml of model medium 2 in accordance with Example 13. Then, the model solution and model medium 2 are mixed in the volumes obtained and corrosion tests are performed. in accordance with example 12. The rate of total corrosion of carbon steel is determined equal to 0.29 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the corrosion potential of steel and the breakdown potential of a passive film is 290 mV, they do not detect the zone of active dissolution of the metal and conclude that carbon steel is resistant to general and local corrosion under these conditions.

Example 15. Corrosion tests are performed in accordance with example 12, but the necessary amount of NaCl, NaSO ₄ and NaHCO ₃ solutions are added to the model medium 1 and get make-up water corresponding to the proposed water-chemical regime (model medium 3) with pH = 10.5, total hardness W ₀ = 0.01 mEq / l, total alkalinity AH ₀ = 8.0 mEq / l, chloride content Cl ^- = 170 mg / l and sulfates SO ₄ ^2- = 140 mg / l. The rate of total corrosion of carbon steel is determined to be 0.29 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the corrosion potential of steel and the breakdown potential of a passive film is 290 mV, they do not detect the zone of active dissolution of the metal and conclude that carbon steel is resistant to general and local corrosion under these conditions.

Example 16. Corrosion tests are performed in accordance with example 12, but model medium 1 is aerated and the required amount of NaCl, Na ₂ SO ₄ and NaHCO ₃ solutions are added, and make-up water corresponding to the proposed water-chemical regime (model medium 4) with pH = 9.0, total hardness W ₀ = 0.2 mEq / l, total alkalinity UH ₀ = 8.0 mEq / l, chloride content Cl ^- = 170 mg / l and sulfates SO ₄ ^2- = 140 mg / l The rate of total corrosion of carbon steel is determined to be 0.29 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the corrosion potential of steel and the breakdown potential of a passive film is 300 mV, the zone of active dissolution of the metal is not detected and the conclusion is made that carbon steel is resistant to general and local corrosion under these conditions.

Example 17. Corrosion tests are performed in accordance with example 15, but model medium 1 is aerated to pH = 9.5. The rate of total corrosion of carbon steel is determined to be 0.29 mm / year. After testing, the samples retain a metallic luster; pitting and ulcerative lesions are absent on their surfaces. When carrying out polarization measurements, it is determined that the difference between the corrosion potential of steel and the breakdown potential of a passive film is 300 mV, the zone of active dissolution of the metal is not detected and the conclusion is made that carbon steel is resistant to general and local corrosion under these conditions.

The absence of a sharp change in the resistance of carbon steel to general and local corrosion in model environments of CHPP-25 with an increase in the concentration of sulfates and chlorides (within the studied limits) is explained by the high pH value of make-up water.

Below is a table of comparative data confirming the effectiveness of the proposed method compared to the known prototype method.

Table Indicators characterizing the methods Proposed Famous The degree of phenol removal from additional water of the circulating system,% one hundred 0 The corrosion rate of carbon steel in recycled water, mm / year 0.27-0.29 0.32 The expected annual consumption of bactericidal polyelectrolyte to ensure sanitary and epidemic safety of the circulating cooling system in the conditions of TPP-25, kg / year 340 6750 The expected annual consumption of reagents for the regeneration of ion exchangers in the conditions of CHP-25, kg / year: - acids 3852 261000 - alkalis 3000 192000 The content of silicon dioxide in demineralized water entering the steam-water cycle of a thermal power plant, μg / l less than 3 11-20

The data presented in the table, first of all, indicate that the proposed method, in contrast to the known method, allows to prevent uncontrolled emission of phenol into the atmosphere during evaporative cooling of the circulating water. This follows from a comparison of the degrees of phenol removal from the additional water of the circulating system according to the proposed and known methods presented on the first line of this table. According to the presented data, the proposed method provides a complete (100%) removal of phenol from additional water, the only source of its entry into the composition of recycled water, in contrast to the known method, which does not provide for the removal of phenol from additional water. In addition, the table draws attention to lower values of the rate of corrosion of steel in recycled water during the disposal of purge water proposed in comparison with the known method, presented in the second row of the table. This, in turn, indicates that the proposed method, in comparison with the known one, can prevent the growth of corrosive activity of circulating water when the circulating system is switched to a closed mode of water use. In addition, it follows from the data presented in the third and fourth row of the table that the proposed method, in contrast to the known one, requires significantly lower consumption of reagents for ensuring sanitary and epidemic safety of the circulating water of the cooling system of the power plant, as well as acid and alkali for the regeneration of ion exchangers in the process of obtaining deep demineralized water. Simple calculations show that the proposed method, compared to the known one, allows to reduce the consumption of bactericidal polyelectrolyte by approximately 95% in the first case and acid and alkali by more than 98% in the second. And finally, the data presented in the last row of the table show that, compared with the known method, the proposed method allows to reduce the content of silicon dioxide in demineralized water entering the steam-water cycle of a thermal power plant by more than three times. Due to its ability to enter the turbine together with steam from the high-pressure power boiler, this connection is dangerous for the turbines. It forms insoluble compounds on its blades, which lead to a deterioration in the efficiency and reliability of the turbine and the need to stop it to remove deposits.

Thus, the use of a combination of sequences of technological operations unknown from the prior art for purification of additional water by reagent decarbonization, primary sodium cationization, short-wave ultraviolet irradiation and subsequent mixing of purified water with recycled water immediately after evaporative cooling of the latter, as well as purge water at the beginning of sodium cationization account of preliminary softening of additional water in the mode of primary cationization and direct softer In the secondary cation mode, then primary and secondary reverse osmosis filtering and subsequent joint H-OH ionization, it provides a positive result, which is to prevent uncontrolled emission of phenol into the atmosphere and increase the corrosivity of recycled water during evaporative cooling, and reduce the consumption of reagents for providing sanitary and epidemic safety of the circulating cooling system of a thermal power plant and obtaining deeply for its technological needs of demineralized water, and increasing the degree of removal of the last silica.

Claims (2)

1. A method for utilizing purge water of a circulating cooling system for exhaust steam of turbines in a steam-water cycle of a power plant by irretrievable use for technological needs, including clarification filtering and deep softening of the purge water stream before disposal, compensation of losses of circulating water by adding additional water to the circulating system, preliminary softening prior to feeding the last reagent decarbonization and sodium cationization in an alkaline medium, softening of sodium cathy water by primary and secondary cationization modes, prevention of continuous phenol emission into the atmospheric air from the composition of the circulating water during its evaporative cooling, introduction of the polyhexamethylene guanidine derivative into circulating water, characterized in that the purge water irrevocably used for technological needs is preliminarily softened before clarification filtration due to reagent decarbonization and sodium cationization in an alkaline environment of additional water in the mode of primary cationization, and after clarification filtering, they are subjected to short-wave ultraviolet irradiation and divided into two streams, one of them is treated with lime to pH = 9.0-10.5 in order to compensate for network water losses, softened with sodium cation in the secondary cation mode and sent to recharge heating networks, the other is subsequently subjected to deep softening by sodium cationization in the secondary cationation mode, primary and secondary reverse osmosis filtration with the formation of primary and secondary concentrates, then joint H-OH-ionization to obtain the required amount of deeply desalted water, which is irrevocably used as a part of their regeneration product and to compensate for the losses of the working fluid from the steam-water cycle, after which the primary, secondary concentrates and the regeneration product are uniformly mixed with the purge water before its ultraviolet irradiation, while the flow rate of the purge water sent for disposal is maintained equal to the sum of the losses of the network water by the heating system and the working fluid of the steam in a single cycle of a thermal power plant, the introduction of the polyhexamethylene guanidine derivative into the circulating water is carried out periodically, the polyhexamethylene guanidine chloride being predominantly used as the derivative, its concentration in the circulating water of 5-7 mg / l is maintained for a day, after which the introduction of the polyhexamethylene guanidine derivative into the circulating water is stopped, and the continuous release of phenol into the atmospheric air from the composition of the circulating water is warned due to the short-wave ultraviolet irradiation of additional water in alkaline cf food before serving for mixing with the circulating, which is carried out immediately after evaporative cooling of the latter. 2. The method according to claim 1, characterized in that the half-wave of the additional water is predominantly subjected to short-wave ultraviolet irradiation, after which it is mixed with the unirradiated remaining water and, not earlier than 30 minutes after mixing, it is supplied as additional water to the circulating system.