CN116020253A - Photocatalyst pretreatment type flue gas denitration device and intelligent monitoring method thereof - Google Patents

Abstract

The application relates to a photocatalyst pretreatment formula flue gas denitrification facility and intelligent monitoring method thereof belongs to the technical field of flue gas treatment facility, and this flue gas denitrification facility includes: the pretreatment tower is provided with an air inlet pipe, and a photocatalyst catalytic system is arranged in the pretreatment tower and is used for oxidizing nitrogen oxides in the flue gas; the wet absorption box is internally provided with denitration absorption liquid, and is provided with an exhaust pipe and a liquid discharge pipe; and the flue gas air pipe assembly is used for communicating the pretreatment tower and the wet absorption box, and the air outlet end of the flue gas air pipe assembly is arranged below the liquid level of the denitration absorption liquid. The method has the effect of improving the wet flue gas denitration treatment efficiency; and fuzzy control is introduced, and the fuzzy control is combined with the parameter adjustment of PID to form a self-adaptive fuzzy PID algorithm, so that the intelligent monitoring of the flue gas after denitration and the functions of data acquisition, processing, analysis and feedback are realized.

Description

Photocatalyst pretreatment type flue gas denitration device and intelligent monitoring method thereof

Technical Field

The application relates to the field of flue gas treatment devices, in particular to a photocatalyst pretreatment type flue gas denitration device and an intelligent monitoring method thereof.

Background

The method is mainly used for coal production and consumption in the world, the environmental pollution caused by coal-fired power generation is a constraint factor of the power development industry in China, and strict requirements are placed on the emission of nitrogen oxides of thermal power generating units and the like according to related standards.

The wet flue gas treatment technology is a traditional flue gas treatment technology, has simple process, less investment and good treatment effect, and can be used as a plurality of absorbents. However, wet flue gas denitration technology has been slow to develop, and the main reason is the special properties of flue gas. O in flue gas ₂ The content is only 6-9%, NO _x The concentration is also relatively low, so that NO in the flue gas _x Has very low oxidation degree, namely, 90 to 95 percent of NO in the flue gas _x Is NO by reacting NO _x Research on liquid phase reaction mechanism shows that NO _x The liquid phase absorption of (2) is first transferred from the gaseous state to the aqueous phase, which is mainly achieved by the absorption equilibrium of the gas in solution, which complies with henry's law.

The solubility of NO in water is very low, which greatly increases the mass transfer resistance of liquid phase absorption, and the solubility of NO in water cannot be obviously improved by means of changing the temperature, the pH value of the solution and the like. The characteristic causes a series of problems of low removal efficiency, high energy consumption and the like in the existing wet flue gas denitration technology, and the wet flue gas denitration technology is difficult to realize real industrial application.

Disclosure of Invention

In order to improve the treatment efficiency of wet flue gas denitration, the application provides a photocatalyst pretreatment type flue gas denitration device and an intelligent monitoring method thereof.

In a first aspect, the application provides a photocatalyst pretreatment formula flue gas denitrification facility adopts following technical scheme: a photocatalyst pretreatment type flue gas denitration device, comprising: the pretreatment tower is provided with an air inlet pipe, and a photocatalyst catalytic system is arranged in the pretreatment tower and is used for oxidizing nitrogen oxides in the flue gas; the wet absorption box is internally provided with denitration absorption liquid, and is provided with an exhaust pipe and a liquid discharge pipe; and the flue gas air pipe assembly is used for communicating the pretreatment tower and the wet absorption box, and the air outlet end of the flue gas air pipe assembly is arranged below the liquid level of the denitration absorption liquid.

Through adopting above-mentioned technical scheme, let into the flue gas of waiting to handle at first pretreatment tower, the photocatalyst catalytic system in the pretreatment tower carries out catalytic oxidation to the nitrogen oxide in the flue gas, and the flue gas after the oxidation gets into wet process absorption case, fully contacts with denitration absorption liquid after, denitration absorption liquid absorbs the nitrogen oxide in the flue gas, and the flue gas after handling is finally discharged from the blast pipe. NO which is difficult to dissolve in water is oxidized into a high valence state through a photocatalyst catalytic system, so that the water solubility of nitrogen oxides in the flue gas is improved, and the treatment efficiency of wet flue gas denitration is improved.

Optionally, the photocatalyst catalysis system comprises a catalysis support plate and an ultraviolet light source which are arranged in the pretreatment tower, and a photocatalyst coating is arranged on the surface of the catalysis support plate.

Through adopting above-mentioned technical scheme, the flue gas gets into in the pretreatment tower and contacts with the catalysis carrier plate, and the photocatalyst coating on the catalysis carrier plate carries out catalytic oxidation under the irradiation of ultraviolet light source to the nitrogen oxide in the flue gas, realizes the purpose that improves the oxidation degree of nitrogen oxide in the flue gas.

Optionally, the inside cavity of catalysis carrier plate just be equipped with a plurality of air vents on the catalysis carrier plate, the catalysis carrier plate is equipped with a plurality of, and a plurality of the one end of catalysis carrier plate is connected with same pivot, be equipped with drive pivot pivoted drive assembly on the pretreatment column.

By adopting the technical scheme, after the inside of the catalytic support plate is hollow and the vent holes are arranged, the surface area for the photocatalyst coating to attach and the contact area with the flue gas are increased; when the driving component drives the rotating shaft to rotate, the turbulence degree of the flue gas in the pretreatment tower can be increased, and the flue gas can enter the catalytic carrier plate more easily through the vent holes; in addition, in the rotation process of the catalytic support plate, the rotation angle of the catalytic support plate is continuously changed, the ultraviolet light received by each part is more balanced, and the ultraviolet light is easier to irradiate the inside of the catalytic support plate through the vent holes, so that the photocatalyst coating is triggered to catalyze and oxidize nitrogen oxides in the flue gas, and the oxidation efficiency of the nitrogen oxides in the flue gas is improved.

Optionally, a reflective film is arranged on the inner wall of the pretreatment tower.

By adopting the technical scheme, the reflecting film is used for reflecting ultraviolet light, and reflecting ultraviolet light irradiated on the inner wall of the pretreatment tower onto the catalytic carrier plate, so that the utilization efficiency of the ultraviolet light is improved.

Optionally, be equipped with the dust fall subassembly in the pretreatment tower, the dust fall subassembly is located between intake pipe and the photocatalyst catalytic system, the dust fall subassembly includes the dust board, the dust board is located on the inner wall of pretreatment tower, the dust board is kept away from the one end downward sloping setting of pretreatment tower inner wall.

By adopting the technical scheme, the dust baffle can block the upward movement path of the flue gas, and simultaneously block the larger fly ash contained in the flue gas, so that the content of the fly ash in the flue gas is reduced, the condition that the photo-catalyst coating is covered by deposited ash on the catalytic carrier plate is reduced, and the contact area between the photo-catalyst coating and the flue gas is ensured; when more fly ash is attached to the dust plate, because one end of the flow baffle plate is inclined downwards, the accumulated fly ash can slide downwards by self weight along the inclination trend of the dust plate, so that dust is not easy to be accumulated on the dust plate too much.

Optionally, be equipped with the cyclone subassembly in the pretreatment tower, the cyclone subassembly is located between intake pipe and the dust board, the cyclone subassembly includes interior annular plate, guide plate and outer annular plate, the one end and the interior annular plate of guide plate are fixed and evenly provided with a plurality ofly along the global of interior annular plate, and the other end is fixed with outer annular plate, and is a plurality of the guide plate stacks the slope setting, outer annular plate is fixed with the inner wall of pretreatment tower.

Through adopting above-mentioned technical scheme, when flue gas passes through cyclone subassembly, can receive the direction effect of guide plate and rotatory formation cyclone, and the guide plate can block the motion path of flying dust in the flue gas to increased its contact time with the flue gas, thereby made the flying dust can be kept out whereabouts by the cyclone, reached the purpose that the flue gas was dust removed, can fall into the dust hopper by the flying dust that dust fall subassembly i.e. cyclone subassembly kept off in order to follow-up concentrated processing.

Optionally, the dust fall subassembly still includes the filter screen that is arranged in filtering the flying dust in the flue gas, the filter screen is located between dust board and the photocatalyst catalytic system, the lower surface of filter screen is equipped with first self-cleaning coating, the slope top surface of dust board and guide plate is equipped with the second self-cleaning coating.

By adopting the technical scheme, the flue gas is further filtered through the filter screen, so that the content of fly ash in the flue gas is effectively reduced; the fly ash is attached to the bottom of the filter screen when contacting the filter screen, and because the flue gas is accompanied with water vapor, the water vapor is condensed into water drops when meeting the filter screen, and the water drops are easy to drop from the filter screen and take away the fly ash on the filter screen at the same time through the arrangement of the first self-cleaning coating, so that the surface cleaning of the filter screen is ensured, the excessive surface area ash is prevented, and the filtering efficiency of the filter screen to the flue gas is ensured.

Optionally, be equipped with the cold source subassembly on the filter screen, the cold source subassembly is including locating the cold flow pipe on the filter screen, the cold flow pipe is the setting of buckling in succession, the one end of cold flow pipe is equipped with the inlet, and the other end is equipped with the liquid outlet, inlet and outside running water pipe intercommunication, the filter screen top is located to the liquid outlet.

By adopting the technical scheme, through the arrangement of the cold source component, the water vapor in the smoke is easier to condense when encountering the filter screen, and the first self-cleaning coating is easier to achieve the self-cleaning effect; simultaneously, liquid outlet exhaust water can rinse filter screen and dust fall subassembly of below through the filter screen, reduces filter screen and dust board and appears the condition that the deposition is more.

Optionally, the flue gas tuber pipe subassembly is including the main tuber pipe, connect tuber pipe and a plurality of sub tuber pipe that communicate in proper order, the one end and the preliminary treatment top of the tower intercommunication of sub tuber pipe are kept away from to the main tuber pipe, the one end that the main tuber pipe was kept away from to the sub tuber pipe stretches into the liquid level below of wet process absorption case, the bottom of sub tuber pipe is equipped with waterproof ventilated membrane.

By adopting the technical scheme, the oxidized flue gas sequentially passes through the main air pipe, the connecting air pipe and the sub air pipes, and the denitration efficiency of the flue gas is improved by additionally arranging a plurality of sub air pipes; in addition, the flue gas can enter into denitration absorption liquid through waterproof ventilated membrane, and denitration absorption liquid can't enter into in the sub-tuber pipe through waterproof ventilated membrane, has increased the path that the flue gas from denitration absorption liquid to emit for nitrogen oxide in the flue gas fully contacts with denitration absorption liquid, thereby makes the denitration of flue gas more thorough.

In a second aspect, the application further provides an intelligent monitoring method for denitration of photocatalyst pretreatment type flue gas, which adopts the following technical scheme:

an intelligent monitoring method for photocatalyst pretreatment type flue gas denitration comprises the following steps:

s1: collecting an actual measurement value of the nitrogen oxide detector in real time, comparing the actual measurement value with a set safe emission value, and calculating a deviation value of nitrogen oxide in exhaust gas of the exhaust pipe and a change rate of the deviation value;

s2: variation of the deviation value and variation of the deviation of nitrogen oxides in exhaust gas of exhaust pipeThe rate is input into a fuzzy controller to determine the deviation of nitrogen oxides, the deviation change rate and the proportion change value delta k _p Integral change value delta k _i Differential change value Deltak _d Membership functions of (2);

s3: according to the fuzzy control rule, outputting new fuzzy set membership function, and calculating proportional change value delta k according to the new fuzzy set membership function _p Integral change value delta k _i Differential change value Deltak _d ；

S4: by a proportional change value Deltak _p Integral change value delta k _i Differential change value Deltak _d Respectively carrying out real-time adjustment on corresponding proportional parameters, integral parameters and derivative parameters in the PID to obtain new PID parameters;

s5: and controlling the opening and closing degree of the valve body at the air inlet pipe according to the new PID parameters so as to control the flow of the flue gas in the air inlet pipe.

By adopting the technical scheme, the parameters of PID control are adjusted by adopting a fuzzy control algorithm, and the condition that the content of nitrogen oxides in the gas exhausted by the exhaust pipe exceeds the standard at an irregular period can be avoided by combining the PID control algorithm; on the other hand, the flue gas flow in the air inlet pipe can be controlled more reasonably and efficiently, so that the efficiency of flue gas treatment is improved.

In summary, the present application includes at least one of the following beneficial technical effects:

1. through the arrangement of the photocatalyst catalytic system, NO which is difficult to dissolve in water is oxidized into a high valence state, so that the water solubility of nitrogen oxides in the flue gas is improved, and the treatment efficiency of wet flue gas denitration is improved;

2. the reflective film is used for reflecting ultraviolet light, and reflecting ultraviolet light irradiated on the inner wall of the pretreatment tower to the catalytic support plate, so that the utilization efficiency of the ultraviolet light is improved;

3. through the setting of waterproof ventilated membrane, the flue gas can get into denitration absorption liquid through waterproof ventilated membrane, and denitration absorption liquid can't enter into in the sub-tuber pipe through waterproof ventilated membrane, has increased the path that the flue gas from the denitration absorption liquid emerge for nitrogen oxide in the flue gas fully contacts with denitration absorption liquid, thereby makes the denitration of flue gas more thoroughly.

Drawings

Fig. 1 is a schematic overall structure of an embodiment of the present application.

FIG. 2 is a cutaway view of the internal configuration of a pretreatment column embodying embodiments of the present application.

Fig. 3 is a cut-away view showing the internal construction of the wet absorption tank in the embodiment of the present application.

FIG. 4 is a schematic diagram of a dust suppression assembly and a cold source assembly embodying embodiments of the present application.

Figure 5 is a schematic view of a cyclone assembly embodying an embodiment of the present application.

Fig. 6 is a schematic structural view of a photocatalyst catalytic system and a driving assembly in an embodiment of the present application.

Fig. 7 is a cut-away view showing a specific structure of a catalytic support plate in an embodiment of the present application.

FIG. 8 is a cut-away view of a NOx detector embodying embodiments of the present application.

Reference numerals illustrate: 1. a pretreatment tower; 11. an air inlet pipe; 12. an ash collecting hopper; 121. a discharge valve; 13. a mounting frame; 14. a reflective film; 2. a wet absorption box; 21. an exhaust pipe; 211. a nitrogen oxide detector; 22. a liquid discharge pipe; 3. a flue gas duct assembly; 31. a main air pipe; 32. connecting an air pipe; 33. a sub-air pipe; 331. a waterproof breathable film; 4. a photocatalyst catalytic system; 41. a catalytic support plate; 411. a photocatalyst coating; 412. a vent hole; 42. an ultraviolet light source; 43. a rotating shaft; 431. a second bevel gear; 5. a dust fall assembly; 51. a dust-blocking plate; 511. a second self-cleaning coating; 52. a filter screen; 521. a first self-cleaning coating; 6. a cyclone assembly; 61. an inner ring plate; 62. a deflector; 63. an outer ring plate; 7. a cold source assembly; 71. a cold flow tube; 711. a liquid inlet; 712. a liquid outlet; 8. a drive assembly; 81. a driving motor; 82. a drive shaft; 821. a first bevel gear.

Detailed Description

The present application is described in further detail below in conjunction with figures 1-8.

In a first aspect, embodiments of the present application disclose a photocatalyst pretreatment type flue gas denitration device.

Referring to fig. 1 and 2, a photocatalyst pretreatment type flue gas denitration device comprises a pretreatment tower 1 and a wet absorption box 2, wherein the pretreatment tower 1 is communicated with the wet absorption box 2 through a flue gas air pipe assembly 3. The side wall of the pretreatment tower 1 is fixedly communicated with an air inlet pipe 11, a photocatalyst catalysis system 4 is arranged in the pretreatment tower 1, and the photocatalyst catalysis system 4 is used for oxidizing nitrogen oxides in the flue gas. The wet absorption box 2 is internally stored with denitration absorption liquid, the air outlet end of the flue gas air pipe assembly 3 is arranged below the liquid level of the denitration absorption liquid, the side wall of the wet absorption box 2 is fixedly communicated with an exhaust pipe 21, the exhaust pipe 21 is used for discharging treated flue gas, the denitration absorption liquid can be supplemented into the wet absorption box 2 through the exhaust pipe 21, and the exhaust pipe 21 is arranged above the liquid level of the denitration absorption liquid; the bottom end of the side wall of the wet absorption box 2 is fixedly communicated with a liquid discharge pipe 22 for discharging the denitration absorption liquid after the flue gas is absorbed.

Referring to fig. 3, in this embodiment, the denitration absorbing liquid may be a conventional absorbing liquid for wet absorption: the inner bottom wall of the wet absorption tank 2 is gradually inclined downwards along the direction approaching the liquid discharge pipe 22 in order to facilitate the discharge of the denitration absorption liquid after absorbing the nitrogen oxides.

Referring to fig. 2 and 4, a dust settling assembly 5 is provided in the pretreatment tower 1, the dust settling assembly 5 includes a plurality of dust plates 51, the dust plates 51 are arranged on the inner wall of the pretreatment tower 1 from bottom to top, the dust plates 51 are arranged above the air inlet pipe 11, and one end of the dust plates 51 away from the inner wall of the pretreatment tower 1 is inclined downwards.

Referring to fig. 2 and 5, the cyclone assembly 6 is further disposed between the air inlet pipe 11 and the dust baffle 51 in the pretreatment tower 1, the cyclone assembly 6 includes an inner ring plate 61, a plurality of guide plates 62, and an outer ring plate 63 mounted on the inner wall of the pretreatment tower 1, the inner ring plate 61 is concentrically disposed on the outer ring plate 63, one end of the guide plates 62 is fixedly connected with the inner ring plate 61 and uniformly disposed along the circumferential surface of the inner ring plate 61, the other end is fixedly connected with the outer ring plate 63, and the plurality of guide plates 62 are obliquely disposed in a stacked manner.

Referring to fig. 1 and 2, a dust hopper 12 is installed at the bottom of the pretreatment tower 1, the dust hopper 12 communicates with the inside of the pretreatment tower 1, and a discharge valve 121 is installed at the bottom of the dust hopper 12. After the flue gas lets in pretreatment tower 1 from intake pipe 11, when the flue gas when cyclone assembly 6 is passed through to the flue gas, great flying ash granule in the flue gas receives the dead weight influence and whereabouts after the baffle 62 blocks, can form the cyclone through cyclone assembly 6 along the incline direction of baffle 62 when upwards moving again to receive the further of dust board 51 to can effectively reduce the content of flying ash in the flue gas, realize the dust fall to the flue gas, the one end downward sloping of the inner wall of pretreatment tower 1 is kept away from to dust board 51 simultaneously, can make the flying ash that its slope bottom surface gathered fall into dust hopper 12 fast.

Referring to fig. 2 and 4, the dust settling assembly 5 further includes a filter screen 52 provided above the dust plate 51, and a lower surface of the filter screen 52 is coated with a first self-cleaning coating 521. In this embodiment, first self-cleaning coating 521 is a fluorinated titanium dioxide nanoparticle coating. When the flue gas passes through the filter screen 52, the residual fly ash particles in the flue gas are filtered by the filter screen 52, so that the dust settling effect on the flue gas is further improved, and the dust particles in the flue gas are prevented from being attached to the photocatalyst catalytic system 4, so that the oxidation efficiency of nitrogen oxides in the flue gas is influenced. Meanwhile, water vapor is often accompanied in the flue gas, and through the arrangement of the first self-cleaning coating 521, water drops easily drop from the filter screen 52 and simultaneously take away the fly ash on the filter screen 52, so that the surface cleaning of the filter screen 52 is ensured, the excessive surface area ash is prevented, and the filtration efficiency of the filter screen 52 to the flue gas is ensured.

Referring to fig. 2 and 4, in order to prevent dust particles accompanying water droplets from adhering to the lower dust plate 51 and the deflector 62, which affect the deflector 62's deflector action, the inclined top surfaces of the dust plate 51 and the deflector 62 are coated with a second self-cleaning coating 511. In this embodiment, the second self-cleaning coating 511 also employs a fluorinated titanium dioxide nanoparticle coating.

Referring to fig. 2 and 4, in order to make the water vapor in the flue gas more easily condense when the flue gas passes through the filter screen 52, so that the filter screen 52 is more easily self-cleaned, the filter screen 52 is made of a metal material with higher heat conductivity, the filter screen 52 is provided with a cold source assembly 7, the cold source assembly 7 comprises a cold flow pipe 71 fixed at the top of the filter screen 52, and the cold flow pipe 71 is continuously bent in an S-shape to increase the effective cooling path of the cold flow pipe 71. One end of the cold flow pipe 71 is provided with a liquid inlet 711, the other end is provided with a liquid outlet 712, the liquid inlet 711 is communicated with an external tap water pipe, and the liquid outlet 712 is arranged in the pretreatment tower 1 and is positioned above the filter screen 52. In this way, tap water entering the condensing pipe through the liquid inlet 711 absorbs heat and cools the filter screen 52, so that water vapor in the flue gas is condensed and then is discharged from the liquid outlet 712; the water discharged from the liquid outlet 712 can permeate the filter screen 52 to clean the filter screen 52, the dust baffle 51 and the deflector 62 below, and the self-cleaning effect of the dust baffle 51 and the deflector 62 is realized by matching with the strong water-repellent performance of the second self-cleaning coating 511.

Referring to fig. 2, 6 and 7, the photocatalyst catalytic system 4 includes a catalytic carrier 41 and an ultraviolet light source 42 disposed in the pretreatment tower 1, a photocatalyst coating 411 is coated on the surface of the catalytic carrier 41, the catalytic carrier 41 is provided with a plurality of catalytic carriers, one end of the catalytic carrier 41 is fixedly connected with the same rotating shaft 43, and the rotating shaft 43 is disposed along the vertical direction. The inner wall of the pretreatment tower 1 is fixedly provided with a mounting frame 13, a rotating shaft 43 is rotatably connected to the mounting frame 13, and the pretreatment tower 1 is provided with a driving assembly 8 for driving the rotating shaft 43 to rotate. The driving assembly 8 comprises a driving motor 81 and a driving shaft 82, wherein the driving motor 81 is arranged on the outer wall of the pretreatment tower 1, the driving shaft 82 is rotatably connected to the side wall of the pretreatment tower 1, a first bevel gear 821 is coaxially fixed at one end of the driving shaft 82, and the other end of the driving shaft penetrates out of the side wall of the pretreatment tower 1 to be coaxially fixed with the output end of the driving motor 81. A second bevel gear 431 is coaxially fixed to the tip of the rotating shaft 43, and the second bevel gear 431 is engaged with the first bevel gear 821. In this embodiment, the ultraviolet light source 42 is a high-power ultraviolet lamp, such as a xenon lamp, a high-pressure mercury lamp, etc.; the photocatalyst coating 411 is a titanium dioxide nano coating.

When the driving motor 81 rotates, the driving shaft 82 is driven to rotate, the driving shaft 82 rotates to drive the first bevel gear 821 to rotate, the first bevel gear 821 rotates to drive the second bevel gear 431 to rotate, and the second bevel gear 431 rotates to drive the rotating shaft 43 to rotate, so that the catalytic carrier 41 is driven to rotate. However, too many coating areas of the photocatalyst coating 411 are not needed to be set, so that the coating area of the photocatalyst coating 411 overflows, the oxidation rate of the nitrogen oxides is not obviously improved, and the layout cost of the catalyst carrier 41 and the photocatalyst coating 411 and the burden of the driving motor 81 are increased.

Referring to fig. 2, 6 and 7, the catalytic support 41 is hollow and a plurality of ventilation holes 412 are densely distributed on the catalytic support 41. Thus, the surface area to which the photocatalyst coating 411 can be attached and the contact area with the flue gas can be increased; and when the rotating shaft 43 rotates, a part of flue gas around the catalytic carrier plate 41 is rippled around along with the stirring of the catalytic carrier plate 41, and the other part of flue gas can directly pass through the vent holes 412 to enter the hollow structure inside the catalytic carrier plate 41, so that the turbulence degree of the flue gas in the pretreatment tower 1 is increased, the flue gas can enter the catalytic carrier plate 41 through the vent holes 412 more easily, the residence time of the flue gas entering the catalytic carrier plate 41 is longer, and the nitrogen oxides therein can be catalyzed and oxidized by the photocatalyst coating 411 more thoroughly. In addition, in the rotation process of the catalytic carrier plate 41, the rotation angle of the catalytic carrier plate 41 is continuously changed, the ultraviolet light received everywhere is more balanced, and the overall oxidation efficiency of nitrogen oxides in the flue gas can be improved.

Referring to fig. 2 and 6, in order to make full use of ultraviolet light in the pretreatment tower 1, a reflective film 14 is attached to the inner wall of the pretreatment tower 1, and the reflective film 14 is disposed around the catalytic carrier 41. In this embodiment, the aluminum reflective film 14 is used as the reflective film 14, so that the ultraviolet light diffused onto the inner wall of the pretreatment tower 1 can be reflected onto the catalytic carrier 41, thereby fully improving the utilization rate of the ultraviolet light.

Referring to fig. 2 and 3, after the nitrogen oxides in the flue gas are subjected to catalytic oxidation, the nitrogen oxides are introduced into the wet absorption box 2 through the flue gas air pipe assembly 3. Wherein, flue gas tuber pipe subassembly 3 is including the main tuber pipe 31 that communicates in proper order, connect tuber pipe 32 and a plurality of sub-tuber pipe 33, and the one end that main tuber pipe 31 kept away from ion tuber pipe 33 is fixed to be linked together with pretreatment tower 1 top, and the one end that main tuber pipe 31 was kept away from to sub-tuber pipe 33 stretches into wet process absorption case 2 below the liquid level, and the bottom of sub-tuber pipe 33 is fixed with waterproof ventilated membrane 331.

The oxidized flue gas sequentially passes through the main air pipe 31, the connecting air pipe 32 and the sub air pipes 33 and is finally discharged into denitration absorption liquid in the wet absorption box 2, and the denitration efficiency of the flue gas is improved by additionally arranging a plurality of sub air pipes 33; in addition, the flue gas can enter into denitration absorption liquid through waterproof ventilated membrane 331, and denitration absorption liquid can't enter into sub-tuber pipe 33 through waterproof ventilated membrane 331, has increased the path that the flue gas from denitration absorption liquid to emit for nitrogen oxide in the flue gas fully contacts with denitration absorption liquid, thereby makes the denitration of flue gas more thorough.

Referring to fig. 8, in order to detect the content of nitrogen oxides in the flue gas discharged after the final denitration treatment, a nitrogen oxide detector 211 is mounted on the inner wall of the exhaust pipe 21. When the detected value does not meet the set safe emission value, the nox detector 211 gives a warning, and at this time, the operator needs to change and supplement the denitration absorbing liquid according to the actual situation on site or by reducing the rate of introducing the flue gas to be treated into the air inlet pipe 11, or by enhancing the illumination intensity of the uv light source 42.

The implementation principle of the photocatalyst pretreatment type flue gas denitration device is as follows: when the flue gas to be treated passes through the cyclone assembly 6 from the air inlet pipe 11, larger fly ash particles in the flue gas fall under the influence of dead weight after being blocked by the guide plate 62, and then pass through the cyclone assembly 6 along the inclined direction of the guide plate 62 to form a cyclone when moving upwards, and are further blocked by the dust baffle 51, so that dust fall of the flue gas is realized.

Subsequently, when the flue gas continues to flow upwards and passes through the filter screen 52, the residual fly ash particles in the flue gas are filtered by the filter screen 52, meanwhile, the filter screen 52 is subjected to heat absorption and temperature reduction through the condensation component, water vapor in the flue gas is condensed into water drops on the filter screen 52, and the self-cleaning effect of the filter screen 52 is realized through the strong hydrophobicity of the first self-cleaning coating 521.

When the flue gas subjected to layer-by-layer dust fall treatment flows to the photocatalyst catalysis system 4, the photocatalyst catalysis system 4 carries out catalytic oxidation on nitrogen oxides in the flue gas, then the flue gas is introduced into the wet absorption box 2 through the flue gas air pipe assembly 3, and after the flue gas is fully contacted with the denitration absorption liquid, the denitration absorption liquid absorbs the nitrogen oxides in the flue gas, and the treated flue gas is finally discharged from the exhaust pipe 21.

NO which is difficult to dissolve in water is oxidized into a high valence state through the photocatalyst catalysis system 4, so that the water solubility of nitrogen oxides in the flue gas is improved, and the treatment efficiency of wet flue gas denitration is improved.

In a second aspect, the embodiment of the present application further discloses an intelligent monitoring method for flue gas denitration, which is configured to calculate and analyze a value detected by a nitrogen oxide detector 211 and control a flue gas flow of an air inlet pipe 11, so that the flue gas flow is maximized on the premise that a content of nitrogen oxide in exhaust gas discharged by an exhaust pipe reaches a standard, thereby improving a treatment efficiency of flue gas denitration, and the method includes the following steps:

step 1, acquiring an actual measurement value of the nitrogen oxide detector 211 in real time, comparing the actual measurement value with a set safe emission value, and calculating a deviation value of nitrogen oxides in exhaust gas discharged by the exhaust pipe 21 and a change rate of the deviation value;

setting the safe emission value set by the nox detector 211 as r (t), and the actual measurement value as n (t), the deviation value is e (t) =r (t) -n (t); the change rate of the deviation value is

Wherein t is time.

Step 2, inputting the deviation value and the deviation change rate of the nitrogen oxides in the exhaust gas of the exhaust pipe 21 into a fuzzy controller, and determining the deviation, the deviation change rate and the proportion change value delta k of the nitrogen oxides according to the preset corresponding relation according to the inputted deviation value and the deviation change rate of the nitrogen oxides at the smoke outlet _p Integral change value delta k _i Differential change value Deltak _d Membership functions of (a) are provided.

Step 3, outputting a new fuzzy set membership function according to a fuzzy control rule, and calculating a proportion change value delta k according to the new fuzzy set membership function _p Integral change value delta k _i Differential change value Deltak _d ；

The fuzzy control rule can be preliminarily determined after analysis and summarization according to the historical data of the operation of the out-of-stock system under PID control; with the operation of the improved new system (system introducing the fuzzy control), the preliminarily determined fuzzy control rule can be corrected. The specific fuzzy control rule is as follows:

(a) When the deviation e between the actual measurement value of the nox detector 211 and the set safe emission value is large, the proportional coefficient k of PID is reduced or even eliminated in order to increase the response speed of the system _p The value is larger; to prevent differential oversaturation which may be caused by an instantaneous increase in the deviation signal e, the PID differential parameter k _d The value is smaller; to prevent saturation of the integral due to large overshoot of the system response, the integral contribution is limited, usually by taking k _i ＝0。

(b) When the actual measurement value of the NOx detector 211 deviates from the set safe emission value e and the rate of change e of the deviation _c In order to reduce overshoot, the proportional parameter k of the PID controller is in the medium range _p The value is smaller, and the integral parameter k _i The value of the differential parameter k is moderate _d The value of the (2) has larger influence on the output response of the system, and the value is required to be moderate;

(c) When the deviation e between the actual measurement value of the nox detector 211 and the set safe emission value is small, k should be moderately increased to provide the system with good steady-state performance _p And k _i Taking the anti-interference performance of the system into consideration, and coping with the differential coefficient k of the PID controller _d And (3) carrying out proper value taking: when the deviation change rate e of the actual measurement value of the nitrogen oxide detector 211 from the set safe emission value _c Smaller, k _d The value is larger; when e _c When larger, k _d The value is smaller. e, e _c The magnitude of (e) indicates the rate of change of the deviation _c The larger the value, k _p The smaller the value of k _i The larger the value is.

Step 4, adopting the proportional change value delta k _p Integral change value delta k _i Differential change value Deltak _d Respectively carrying out real-time adjustment on corresponding proportional parameters, integral parameters and derivative parameters in the PID to obtain new PID parameters;

the above ratio change value Deltak _p Integral change value delta k _i Differential change value Deltak _d By communication or by hardThe wiring is transmitted to a DCS system of Honiweil, and PID parameters are adjusted. Using the variation of the proportional parameter Deltak _p Integral parameter variation value delta k _i Differential parameter variation value Deltak _d The proportional parameter, integral parameter and differential parameter corresponding to PID are respectively adjusted in real time, which is as follows: k (k) _p ＝k _p′ +Δk _p ；

k _i ＝k _i′ +Δk _i ；

k _d ＝k _d′ +Δk _d ；

In the above, k _p′ For proportional parameters, k, before adjustment of the PID controller _p K is a new ratio parameter after adjustment _i′ The integral parameter, k, before being adjusted for the PID controller _i K is the new integral parameter after adjustment _d′ Differential parameters, k, before adjustment for PID controllers _d Is the new differential parameter after adjustment.

Step 5, according to the new proportion parameter k _p New integral parameter k _i New differential parameter k _d The operation outputs a control signal u (t),

wherein k is _i ＝k _p /T _i 、k _d ＝k _p T _d ；/>

The control signal u (t) is output to the valve body control end of the flue gas flow of the air inlet pipe 11, the speed of the flue gas flowing into the air inlet pipe 11 is controlled, the content of nitrogen oxides in the denitrated flue gas is further controlled in real time, and the actual measured value of the adjusted nitrogen oxide detector 211 is collected to realize circulation control.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims (10)

1. The utility model provides a photocatalyst pretreatment formula flue gas denitrification facility which characterized in that includes:

the pretreatment device comprises a pretreatment tower (1), wherein an air inlet pipe (11) is arranged on the pretreatment tower (1), a photocatalyst catalysis system (4) is arranged in the pretreatment tower (1), and the photocatalyst catalysis system (4) is used for oxidizing nitrogen oxides in flue gas;

the wet absorption box (2), the wet absorption box (2) is internally provided with denitration absorption liquid, the wet absorption box (2) is provided with an exhaust pipe (21) and a liquid discharge pipe (22), and the exhaust pipe (21) is internally provided with a nitrogen oxide detector (211);

the flue gas air pipe assembly (3) is used for communicating the pretreatment tower (1) and the wet absorption box (2), and the air outlet end of the flue gas air pipe assembly (3) is arranged below the liquid level of the denitration absorption liquid.

2. The photocatalyst pretreatment type flue gas denitration device according to claim 1, wherein: the photocatalyst catalyzing system (4) comprises a catalyzing carrier plate (41) and an ultraviolet light source (42) which are arranged in the pretreatment tower (1), and a photocatalyst coating (411) is arranged on the surface of the catalyzing carrier plate (41).

3. The photocatalyst pretreatment type flue gas denitration device according to claim 2, wherein: the catalytic support plate (41) is hollow, a plurality of ventilation holes (412) are formed in the catalytic support plate (41), the catalytic support plate (41) is provided with a plurality of ventilation holes, one end of the catalytic support plate (41) is connected with the same rotating shaft (43), and a driving assembly (8) for driving the rotating shaft (43) to rotate is arranged on the pretreatment tower (1).

4. The photocatalyst pretreatment type flue gas denitration device according to claim 1, wherein: the inner wall of the pretreatment tower (1) is provided with a reflecting film (14).

5. The photocatalyst pretreatment type flue gas denitration device according to claim 1, wherein: be equipped with dust fall subassembly (5) in pretreatment tower (1), dust fall subassembly (5) are located between intake pipe (11) and photocatalyst catalytic system (4), dust fall subassembly (5) include dust board (51), on the inner wall of pretreatment tower (1) was located in dust board (51), the one end downward sloping setting of pretreatment tower (1) inner wall is kept away from in dust board (51).

6. The photocatalyst pretreatment type flue gas denitration device according to claim 5, wherein: be equipped with cyclone subassembly (6) in pretreatment tower (1), between intake pipe (11) and dust board (51) are located to cyclone subassembly (6), cyclone subassembly (6) are including interior annular plate (61), guide plate (62) and outer annular plate (63), the one end and the inner annular plate (61) of guide plate (62) are fixed and evenly are provided with a plurality ofly along the global of inner annular plate (61), and the other end is fixed with outer annular plate (63), and is a plurality of guide plate (62) range upon range of slope setting, outer annular plate (63) are fixed with the inner wall of pretreatment tower (1), the bottom of pretreatment tower (1) is equipped with album ash bucket (12), album ash bucket (12) are equipped with discharge valve (121) with the inside intercommunication of pretreatment tower (1) bottom of album ash bucket (12).

7. The photocatalyst pretreatment type flue gas denitration device according to claim 5, wherein: the dust settling assembly (5) further comprises a filter screen (52) for filtering fly ash in flue gas, the filter screen (52) is arranged between the dust baffle (51) and the photocatalyst catalysis system (4), a first self-cleaning coating (521) is arranged on the lower surface of the filter screen (52), and a second self-cleaning coating (511) is arranged on the inclined top surfaces of the dust baffle (51) and the guide plate (62).

8. The photocatalyst pretreatment type flue gas denitration device according to claim 7, wherein: be equipped with cold source subassembly (7) on filter screen (52), cold source subassembly (7) are including locating cold flow pipe (71) on filter screen (52), cold flow pipe (71) are the setting of buckling in succession, one end of cold flow pipe (71) is equipped with inlet (711), and the other end is equipped with liquid outlet (712), inlet (711) and outside running water pipe intercommunication, filter screen (52) top is located to liquid outlet (712).

9. The photocatalyst pretreatment type flue gas denitration device according to claim 1, wherein: the flue gas tuber pipe subassembly (3) is including main tuber pipe (31), connection tuber pipe (32) and sub tuber pipe (33) that communicate in proper order, the one end and pretreatment tower (1) top intercommunication of sub tuber pipe (33) are kept away from to main tuber pipe (31), the one end that main tuber pipe (31) was kept away from to sub tuber pipe (33) stretches into below the liquid level of wet process absorption case (2), the bottom of sub tuber pipe (33) is equipped with waterproof ventilated membrane (331).

10. An intelligent monitoring method for denitration of photocatalyst pretreatment type flue gas according to any one of claims 1 to 9, comprising the following steps:

s1: collecting an actual measurement value of the nitrogen oxide detector (211) in real time, comparing the actual measurement value with a set safe emission value, and calculating a deviation value of nitrogen oxide in exhaust gas of the exhaust pipe (21) and a change rate of the deviation value;

s2: inputting the deviation value and the change rate of the deviation of the nitrogen oxides in the exhaust gas of the exhaust pipe (21) into a fuzzy controller to determine the deviation, the change rate of the deviation and the change value delta k of the proportion of the nitrogen oxides _p Integral change value delta k _i Differential change value Deltak _d Membership functions of (2);

s3: according to the fuzzy control rule, outputting new fuzzy set membership function, and calculating proportional change value delta k according to the new fuzzy set membership function _p Integral change value delta k _i Differential change value Deltak _d ；

S4: by a proportional change value Deltak _p Integral change value delta k _i Differential change value Deltak _d Respectively carrying out real-time adjustment on corresponding proportional parameters, integral parameters and derivative parameters in the PID to obtain new PID parameters;

s5: and controlling the opening and closing degree of the valve body at the air inlet pipe (11) according to the new PID parameters so as to control the flue gas flow in the air inlet pipe (11).

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