RU2646438C1 - Photochemical treatment unit for water purification and disinfection plants - Google Patents

Abstract

FIELD: chemistry; optics.

SUBSTANCE: invention relates to purification and disinfection of water using ultraviolet radiation. Photochemical treatment unit for water purification and disinfection plants contains a cascade of continuous irradiation in the form of photochemical reactor 2 on the basis of one or more ultraviolet lamps on mercury vapor and a control unit connected to the lamps via commutator 5. In the treated water stream, there is at least one pulse irradiation cascade, connected to control unit 24, and contaminant analyzer 23. Pulsed irradiation cascade comprises photochemical reactor 2 based on ultraviolet radiation sources in the form of pulsed xenon lamps 8, power supply unit 9 with charging device 11, storage capacitor 10, ignition unit 12 and synchronization circuit 13. Contaminant analyzer 23 is configured to monitor the concentration of contaminants and transmit the output signals to control unit 24. Control unit 24 is configured to generate control pulses to the pulsed irradiation cascades with the possibility of increasing or decreasing their frequency, and also with the possibility of changing the frequency of the control pulses to pulsed irradiation cascades with a delay relative to the previous change in the frequency of the control pulses by an amount t_set, which is chosen from inequality

, where V_i∑ – total volume of photochemical reactors and connecting pipelines from the i-th pulsed irradiation cascade to the contaminat analyzer, m³; Q – volumetric flow of treated water, m³/s.

EFFECT: invention allows to increase the productivity, degree of water disinfection and purification, and also to increase the device functionality.

1 cl, 2 dwg

Description

The invention relates to technologies and devices for cleaning and disinfecting water using ultraviolet (UV) radiation.

A device for cleaning and disinfecting water, containing a photochemical reactor in the form of a sealed enclosure with fittings, inside which is placed a UV lamp in a quartz casing (Utility model RU 150233).

The known device has a low productivity and can be used only for water treatment with constant pollution and flow characteristics.

A device for disinfecting running water according to the patent RU 2288192, which is taken as a prototype and can be used to disinfect water from pathogenic microflora and purify dissolved organic impurities due to the photochemical initiation of oxidative reactions. The known device is a cascade of continuous irradiation, including a photochemical reactor based on one or more radiation sources in the form of ultraviolet lamps on low-pressure mercury vapor and a control unit connected to the radiation sources through a switch in the form of a ballasts (ballasts).

The known device, in contrast to the analogue, can change the magnitude of the flux of UV radiation by changing the number of simultaneously operating lamps.

The disadvantages of the known device are as follows.

Firstly, the performance of the known device is small due to the fact that the used lamps using low-pressure mercury vapor (even the most powerful amalgam lamps) generate continuous narrow-band UV radiation with low intensity (up to 0.1 W / cm ² ), which, in its in turn, it leads to a low rate of ongoing photochemical oxidative reactions and, as a result, to low productivity and the degree of purification and disinfection of treated water;

Secondly, such lamps require considerable time (up to 10 minutes) to warm up and reach the optimum operating mode, and any adjustment of the UV radiation power by changing the parameters of the electrical operating mode is practically impossible, since the lamp operates in a very narrow range of electrical parameters and thermal conditions. For this reason, in the known device, the change in the total flux of UV radiation is carried out by changing the number of working lamps, which does not allow you to quickly change the emitted dose of UV radiation when changing the characteristics of the water at the entrance to the device.

The problem solved by the proposed device is to disinfect and purify water from various dissolved organic impurities.

The technical result achieved by using the proposed device is to increase the productivity and degree of disinfection and purification of water by increasing the depth and intensification of photochemical oxidative reactions, as well as expanding the functionality of the device.

The specified technical result is achieved by the fact that at least one cascade of pulsed irradiation connected to the control unit and a pollution analyzer are additionally installed in the stream of treated water, and the cascade of pulsed irradiation contains a photochemical reactor based on ultraviolet radiation sources in the form of xenon flash pulses, a unit power supply with a charger, storage capacitor, ignition unit and synchronization circuit, while the pollution analyzer is configured to monitoring the concentration of contaminants and transmitting the output signals to the control unit, and the control unit is configured to generate control pulses on the cascades of pulsed irradiation, with the possibility of increasing or decreasing their frequency, as well as the ability to change the frequency of the control pulses on cascades of pulsed irradiation with a delay relative to the previous change the frequency of the control pulses by the value of t _ass , which is selected from the inequality

- суммарный объем фотохимических реакторов и соединительных трубопроводов от i-го каскада импульсного облучения до анализатора загрязнений, м³;Where

- the total volume of photochemical reactors and connecting pipelines from the i-th cascade of pulsed irradiation to the pollution analyzer, m ³ ;

Q - volumetric flow rate of treated water, m ³ / s.

In an embodiment, a flow meter connected to a control unit may be additionally installed in the flow of treated water.

The invention is illustrated by graphic materials, where in FIG. 1 shows a schematic block diagram of a photochemical treatment device for water treatment and disinfection plants; FIG. 2 - plot signals illustrating the operation of the proposed device:

a) the concentration of water pollution With _I at the entrance to the device;

b) the concentration of water pollution With _output at the exit of the device;

c) the total average radiation power P _ная over all stages;

g) the average radiation power of the cascade of continuous exposure P _nep ;

d) the average radiation power of the first cascade of pulsed irradiation P _{imp 1} ;

e) the average radiation power of the second stage of pulsed irradiation P _{imp. 2}

In accordance with the claims, a photochemical treatment device for water purification and disinfection systems can be implemented in a multi-stage design. As an example of execution in FIG. 1 shows a block diagram of a device consisting of 3 cascades, the first of which is a cascade of continuous irradiation, and the second and third cascades of pulsed irradiation, and the second and third cascades are made on different types of pulsed UV radiation sources.

The inlet pipe 1 is connected to the casing 2 of a photochemical reactor based on a source of continuous UV radiation of constant intensity in the form, for example, of an amalgam mercury lamp 3. Lamp 3 is placed in a sealed quartz cylindrical casing transparent to UV radiation 4. The electrodes of llama 3 are connected to the switch 5 , which is used as a ballast (PRA).

A photochemical reactor with a casing 2, a lamp 3, a casing 4, and a switch 5 form a cascade of continuous irradiation.

The pipeline 6 connects the output of the photochemical reactor 2 with the input of the photochemical reactor 7 based on a wide spectrum pulsed UV radiation source in the form of a tube-type xenon lamp 8 with an inner diameter of 7 mm and an interelectrode gap of 300 mm. The inner cavity of the lamp 8 is filled with an inert gas xenon at an initial pressure of 200 ... 450 mm Hg.

The electrodes of a pulsed xenon lamp 8 are connected to a power supply 9, consisting of a storage capacitor 10 with a capacity of, for example, 100 μF, a charger 11, an ignition unit 12, and a synchronization circuit 13.

The charger 11 is made in the form of, for example, a voltage-current converter. As part of the charger there is a circuit for monitoring the voltage of the charging voltage of the capacitor 10.

The ignition unit 12 of the discharge can be made in various ways, for example, in the form of a thyristor switch key or in the form of a pulse step-up transformer, the secondary step-up winding of which is included in the discharge circuit "storage capacitor 10 - lamp 8".

A photochemical reactor with a housing 7, a lamp 8 and a power supply 9 form the first cascade of pulsed irradiation.

A pipe 14 connects the output of the photochemical reactor 7 to the input of the photochemical reactor 15 based on a wide spectrum pulsed UV radiation source in the form of a pulsed short-arc xenon lamp 16 of a spherical type with an electrode gap of 7 mm. The inner cavity of the ball lamp 16 is filled with xenon at an initial pressure of 6 ... 7 atm.

The electrodes of a pulsed xenon ball lamp 16 are connected to a power supply 17 from a storage capacitor 18 with a capacity of, for example, 4 μF, a charger 19, an ignition unit 20, and a synchronization circuit 21.

The implementation of the charger 19, the ignition unit 20 and the synchronization circuit 21 is basically similar to the implementation of the components 11, 12, 13 in the power supply 9, the differences are only in the choice of ratings of the components and specific technical parameters of the components (power, operating voltage, etc. .).

The photochemical reactor 15 with a pulsed ball lamp 16 and a power supply 17 form a second cascade of pulsed irradiation.

A pollution analyzer 23 is installed in the output pipe 22. Depending on the specific conditions and features, the pollution analyzer 23 can be installed directly in the output pipe 22, or in a bypass branch (as shown in Fig. 1).

As a pollution analyzer 23, various photoelectric, electrochemical, and other devices can be used to monitor the concentration of oxen contamination in real time. In a specific example of the implementation of a photochemical processing device for water purification and disinfection systems, S :: CAN (http://www.s-can.at/) immersion spectrometers can be used that determine the optical absorption of contaminated water at different wavelengths, which allows calculate the concentration of a pollutant with known optical absorption properties, and in some cases it becomes possible to determine the qualitative composition of pollutants.

The cascade of continuous irradiation, the first and second cascades of pulsed irradiation, as well as the pollution analyzer 23 are connected to a control unit 24, which can be performed, for example, on the basis of a microprocessor and peripheral units: matching nodes, pulse shapers, threshold devices, actuators, etc. d. A specific technical implementation of the control unit should ensure the implementation of the functional features described in the claims.

In a specific example of a photochemical treatment device for water purification and disinfection, a flow meter 25 is placed in the inlet pipe 1, which can be used as a water meter with a measuring pulse sensor. The number of pulses generated by such a device for a time interval is proportional to the volumetric flow rate of water Q. The flow meter 25 is connected to the control unit and can be installed anywhere in the device, for example, in pipelines 6, 14 or 22.

A photochemical treatment device for water purification and disinfection works as follows.

Waste water from a technological object (for example, chemical, pharmaceutical and other production) enters the inlet pipe 1 and then flows sequentially through a flow meter 25, body 2 of the continuous irradiation cascade, pipeline 6, housing 7 of the first pulse irradiation cascade, pipeline 14, housing 15 the second cascade of pulsed irradiation, the output pipe 22 with the installed pollution analyzer 23.

The initial level of pollution concentration is removed by a working cascade of continuous irradiation (building 2, quartz casing 4, mercury amalgam lamp 3, connected through switch 5 to control unit 24. Ultraviolet radiation of lamp 3 with radiation power P _np initiates photochemical oxidation reactions contained in it in water impurities up to the moment t _{1, the} concentration of pollution is low and the cascade of continuous irradiation completely copes with the decomposition of pollutants. The first and second cascades of pulsed irradiation in The concentration of contaminants in the outlet pipe is continuously monitored by the pollution analyzer 23 and does not exceed the set threshold value From _{p. 1} .

At time t _{1, the} concentration of contaminants, for example, as a result of volley discharge, begins to increase. At time t _{2, the} concentration of pollution reaches the threshold value With _{then. 1} , the pollution analyzer 23 records the threshold and transmits the corresponding signal to the control unit 24.

The control unit 24 generates a sequence of control pulses to the first cascade of pulsed irradiation with an initial frequency of, for example, 0.5 Hz. Each pulse received at the synchronization circuit 13 causes the charger 11 to turn on, upon reaching a predetermined charging voltage (in the example of 2.7 kV), the charger 11 is turned off. The synchronization circuit 13 includes an ignition unit 12, which generates a high-voltage (15 ... 20 kV) pulse, which provides a primary electrical breakdown of the interelectrode gap of a pulsed xenon lamp 8 and the formation of a primary discharge channel. A storage capacitor 10 is discharged through the primary primary channel with the formation of an electric discharge xenon plasma that is intensively emitting in the UV range of the spectrum (at the maximum of the radiation pulse, the brightness temperature is 8000 ... 8400 K, the maximum radiation density in the spectral range is 200 ... 400 nm on the lamp surface (7 ... 9.2) ⋅10 ³ W / cm ² , the duration of the radiation pulse at half maximum 100 ... 140 μs). Such radiation has a powerful effect on the treated water, activates and intensifies the photochemical reactions of the oxidation of impurities. As a result of this effect, the concentration of contaminants in the treated water immediately after time t ₂ decreases, but then, due to the increasing concentration of C _in at the inlet of the device, it again increases and the concentration of C _out at the output recorded by the pollution analyzer 23. At time t _{3, the} output concentration of contaminants again reaches a threshold value C _{then. 1} , the control unit 24 again receives a signal from the pollution analyzer 23 and increases the repetition rate of the control pulses supplied to the input of the synchronization circuit 13. Accordingly, charge-discharge cycles in the power supply 9 and UV radiation pulses from the lamp 8 in the photochemical reactor 7 are repeated with increased frequency, resulting in immediately after the moment t _{3 the} concentration of C _o decreases.

But since the concentration of C _in continues to increase, according to a similar algorithm, an increase in the frequency of control pulses occurs at time t ₄ . At time t _{4, the} average power of UV radiation P _imp . 1 generated by the first cascade of pulsed irradiation reaches its maximum (in a specific example, this corresponds to a frequency of 2.5 ... 3 Hz) and cannot increase anymore. Therefore, at time t ₅ , corresponding to the next achievement of the threshold value of the concentration of pollution With _{then. 1} , the control unit 24 includes a second cascade of pulsed irradiation from a photochemical reactor 15 with a pulsed xenon ball lamp 16 and a power supply 17 with components 18 ... 21 (while the first cascade of pulsed irradiation from components 7-9 continues to operate at maximum power). The second cascade of pulsed irradiation is characterized by parameters: a charging voltage of 4 kV, a brightness temperature at the maximum of a radiation pulse of 14000 ... 16000 K, a maximum radiation density in the spectral range of 200 ... 400 nm on the surface of the luminous body (1 ... 1.7) ⋅10 ⁵ W / cm ² , the duration of the radiation pulse at half maximum 7 ... 14 μs, the repetition frequency of the radiation pulses is up to 500 Hz.

With a further increase in the concentration of C _{in, a} similar increase in the repetition rate of radiation pulses generated by the second cascade of pulsed irradiation occurs (in Fig. 2 this is time t ₆ ).

Further, at time t _{7, the} increase in the concentration of pollution ceases, the operation mode of the device is stabilized at the achieved values of the total average power of UV radiation generated by all stages of the device, the concentration of pollution at the output is set below the threshold C _{pore 1} .

This pattern persists until t ₈ , when the salvo discharge of pollutants ceases and the concentration at the inlet begins to decrease. In this case, the concentration of contaminants at the output of the device With _o also decreases and reaches the lower threshold level C _por.2 , which is recorded by the pollution analyzer 23 and through the control unit 24 leads to a sequential decrease in the frequency of operation of the second cascade of pulsed irradiation from components 15-17 at times t ₉ and t ₁₀ , and then the first cascade of pulsed irradiation from components 7-9 at time instants t ₁₁ , t ₁₂ and t ₁₃ until the first and then the first cascades of pulsed irradiation are completely turned off.

Thus, during the operation of the proposed device, the concentration of contaminants at the outlet is automatically maintained within the limits specified by the threshold values C _{pore 1} and C _{pore 2} . In this case, the change in the frequency of control pulses generated by the control unit 24 can be performed both stepwise and continuously, with a constant rate of change or proportional to the rate of change of the input concentration C _in , etc.

To simplify the understanding in the diagrams of FIG. 2 and in the previous description of the work, the delay of the moment of changing the frequency of the control signals to each cascade of pulse irradiation provided for by the claims was not taken into account relative to the moment of the previous change in the frequency of the control signals. In a specific example of the implementation of the proposed photochemical processing device for water treatment and disinfection, the control unit 24 changes the frequency of the control pulses with a delay relative to the moment of the previous change in the frequency of the control pulses in accordance with inequality (1), in which:

- суммарный объем фотохимического реактора 7, трубопровода 14, фотохимического реактора 15 и трубопровода 22;

- the total volume of the photochemical reactor 7, pipe 14, photochemical reactor 15 and pipe 22;

- суммарный объем фотохимического реактора 15 и трубопровода 22.

- the total volume of the photochemical reactor 15 and the pipe 22.

The execution of the control unit 24 so that the formation of control signals (pulses) for each cascade of pulsed irradiation is carried out with the specified delay ensures the stability of the proposed device in the conditions of changing the characteristics of the source water (pollution concentrations and costs).

Moreover, the delay value for each cascade of pulsed processing in the form of a fixed value (determined from inequality (1) for the minimum operating flow rate) can be stored in the memory of the control unit 24, but the best dynamic properties of the proposed device will be obtained when the delay value is calculated the microprocessor of the control unit 24, taking into account the actual flow rate of the treated water, information about which is contained in the output signal of the flow meter 25.

The proposed photochemical processing device for water purification and disinfection plants similarly works when the flow rate of the treated water changes. So, with an increase in water flow with a constant concentration of contaminants, the dose of UV radiation per each elementary volume of water is not enough to oxidize the contained contaminants and their concentration at the output of the device increases. Further, according to the operation logic already described, the cascades of pulsed irradiation and their frequency are connected in turn, as a result of which a cascade operation mode is established that ensures the concentration of contaminants at the output of the device within the specified threshold values.

The application of the proposed device can increase the degree of disinfection and purification of water from impurities by increasing the total intensity of UV radiation, which leads to an increase in the depth and intensification of photochemical oxidative reactions.

In addition, the functionality of the device is expanded in terms of automatically ensuring the quality of water treatment when the initial concentration of pollution and volumetric flow are changed.

The proposed device can be used as a stand-alone unit for the reagent-free purification and disinfection of water with automatic selection of the operating mode, as well as as part of integrated wastewater treatment plants, including those containing liquid radioactive waste (for example, as part of the installation according to patent RU 2560837).

Claims (5)

1. A photochemical processing device for water treatment and disinfection systems, comprising a cascade of continuous irradiation, including a photochemical reactor based on one or more radiation sources in the form of ultraviolet lamps based on mercury vapor and a control unit connected to the radiation sources through a switch, characterized in that at least one cascade of pulsed irradiation connected to the control unit, and a pollution analyzer are installed in the flow of the treated water, and a cascade of impu The ice irradiation contains a photochemical reactor based on ultraviolet radiation sources in the form of flash xenon lamps, a power supply with a charger, a storage capacitor, an ignition unit and a synchronization circuit, while the pollution analyzer is configured to control the concentration of pollution and transmit output signals to the control unit, and the control unit is configured to generate control pulses in cascades of pulsed irradiation with the possibility of increasing or decreasing them often you, as well as with the possibility of changing the frequency of control pulses to cascades of pulsed irradiation with a delay relative to the previous change in the frequency of control pulses by a value of t _ass , which is selected from the inequality

where V _i∑ is the total volume of photochemical reactors and connecting pipelines from the i-th cascade of pulsed irradiation to the pollution analyzer, m ³ ; Q - volumetric flow rate of treated water, m ³ / s. 2. The device according to p. 1, characterized in that in the stream of treated water an additional flow meter is connected to the control unit.

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