Coal-fired boiler pollutant control system and method

Abstract

The application discloses a coal-fired boiler pollutant control system and method, which comprises a flue gas passage, a temperature control assembly, a denitration device, an exhaust gas passage, a recirculation passage and a fan. The flue gas passage is adapted to communicate with a furnace chamber to discharge flue gas in the furnace chamber. The temperature control assembly comprises a flue gas temperature detection unit and a spraying unit. The flue gas temperature detection unit and the spraying unit are both connected in the flue gas passage. The flue gas temperature detection unit is used for detecting the temperature of the flue gas in the flue gas passage. The spraying unit is used for spraying fluid into the flue gas passage. The denitration device is connected in the flue gas passage. The inlet of the exhaust gas passage communicates with the outlet of the flue gas passage. The inlet of the recirculation passage communicates with the outlet of the exhaust gas passage. The outlet of the recirculation passage communicates with the outlet of the flue gas passage. The fan is connected in the recirculation passage. The coal-fired boiler pollutant control system of the application can quickly avoid the secondary synthesis temperature range of dioxin and ensure that the flue gas temperature is in the active temperature range of the denitration catalyst.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal-fired boilers, and particularly relates to a coal-fired boiler pollutant control system and method. BACKGROUND

[0002] City solid waste includes household garbage, general industrial solid waste, and domestic sludge, and has a certain calorific value. Coupling and co-firing of the city solid waste and the coal-fired boiler can utilize the dust removal system, desulfurization system, and denitration system of the power plant itself, realize comprehensive utilization of the garbage, save valuable fossil fuels, and ensure that the dust, SO2, and NOx emissions generated by the solid waste burning meet the national environmental protection standards.

[0003] Since solid waste incineration is the main source of dioxin generation, the dioxin emission during the coupling and co-firing of the solid waste and the coal cannot be ignored. However, the existing equipment and arrangement mode is difficult to control the secondary synthesis of dioxin. Taking a 300 MW unit boiler as an example, the outlet flue gas temperature is about 350 DEG C under full load condition, and the flue gas flow rate is about 7-8 m / s. The flue gas temperature is in the secondary synthesis temperature range (250 DEG C to 500 DEG C) of dioxin, which is easy to cause the secondary synthesis of dioxin. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, the embodiments of the present application propose a coal-fired boiler pollutant control system. The coal-fired boiler pollutant control system preliminarily cools the flue gas through a temperature control assembly, and returns the cooled flue gas to the inlet of the flue gas discharge channel through a recirculation channel and a fan and mixes the flue gas with the hot flue gas discharged by a denitration device to reduce the temperature of the hot flue gas. This not only quickly avoids the secondary synthesis temperature range of dioxin, but also ensures that the flue gas temperature is in the catalyst activity temperature range of the denitration device.

[0005] The embodiments of the present application also propose a coal-fired boiler pollutant control method.

[0006] The coal-fired boiler pollutant control system of the embodiments of the present application includes a flue gas channel, a temperature control assembly, a denitration device, a flue gas discharge channel, a recirculation channel, and a fan.

[0007] The flue gas channel is adapted to communicate with a furnace chamber to discharge the flue gas in the furnace chamber.

[0008] The temperature control assembly includes a flue gas temperature detection unit and a spraying unit. The flue gas temperature detection unit and the spraying unit are both connected in the flue gas channel. The flue gas temperature detection unit is used to detect the temperature of the flue gas in the flue gas channel to obtain a flue gas temperature field. The spraying unit is used to spray a fluid into the flue gas channel and control the flow of the sprayed fluid according to the flue gas temperature field detected by the flue gas temperature detection unit to reduce the flue gas temperature in the flue gas channel to a set temperature.

[0009] The denitration device is connected in the flue gas passage, and the temperature control assembly and the denitration device are arranged in sequence along the flue gas flow direction in the flue gas passage.

[0010] The inlet of the flue gas exhaust passage is communicated with the outlet of the flue gas passage, the flue gas exhaust passage is used for exhausting the flue gas in the flue gas passage, the inlet of the recirculation passage is communicated with the outlet of the flue gas exhaust passage, and the outlet of the recirculation passage is communicated with the outlet of the flue gas passage, so that part of the flue gas at the outlet of the flue gas exhaust passage flows back to the recirculation passage and flows back to the inlet of the flue gas exhaust passage and / or the outlet of the flue gas passage through the recirculation passage, and the fan is connected in the recirculation passage.

[0011] The coal-fired boiler pollutant control system of the embodiment of the present application effectively utilizes solid waste while quickly avoiding the dioxin secondary synthesis temperature interval, inhibits dioxin secondary synthesis, and reduces environmental pollution through the arrangement of the temperature control assembly and the recirculation flue.

[0012] In some embodiments, the flue gas temperature detection unit is configured to detect the temperature of the flue gas at different positions in the flue gas passage at the same cross section of the flue gas passage to obtain a temperature field of the flue gas, and the injection unit is configured to control the flow of the injection fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detection unit.

[0013] In some embodiments, the flue gas detection unit includes a plurality of detectors, the plurality of detectors are spaced apart along the circumference of the flue gas passage, the injection unit includes a plurality of atomizing nozzles, the plurality of atomizing nozzles are spaced apart along the circumference of the flue gas passage, the plurality of atomizing nozzles correspond to the plurality of detectors one-to-one, and the atomizing nozzle controls the flow of the injection fluid according to the temperature detected by the corresponding detector.

[0014] In some embodiments, the temperature control assembly further includes a support pipe, an axis of the support pipe is arranged along the flue gas flow direction in the flue gas passage, the plurality of detectors are connected to the support pipe and spaced apart along the circumference of the support pipe, the plurality of atomizing nozzles are connected to the support pipe and spaced apart along the circumference of the support pipe, and the detector and the corresponding atomizing nozzle are spaced apart along the flue gas flow direction.

[0015] In some embodiments, the coal-fired boiler pollutant control system further comprises a baffle connected in the recirculation passage and movable relative to the recirculation passage, the baffle being moved in the recirculation passage to change the opening of the baffle, thereby adjusting the amount of flue gas flowing back to the inlet of the flue gas passage and / or the outlet of the flue gas passage.

[0016] In some embodiments, the flue gas passage comprises, in sequence, a heat recovery section, a transition section, a quenching section and a denitration section, the heat recovery section and the denitration section each having a cross-sectional area greater than that of the quenching section, and the transition section gradually decreases in cross-sectional area in the direction of flue gas flow.

[0017] In some embodiments, the coal-fired boiler pollutant control system further comprises an air preheater, a portion of the air preheater being located in the flue gas passage, the air preheater being used to reduce the temperature of the flue gas in the flue gas passage.

[0018] In some embodiments, the coal-fired boiler pollutant control system further comprises a reheater, a superheater and an economizer, the reheater, the superheater and the economizer each being connected in the flue gas passage and located upstream of the temperature control assembly, the superheater and the economizer being connected in series, and the superheater being located upstream of the economizer.

[0019] In some embodiments, the coal-fired boiler pollutant control system further comprises a horizontal flue, the flue gas passage being connected to the furnace through the horizontal flue, the horizontal flue being located above the furnace and the flue gas passage, respectively.

[0020] The coal-fired boiler pollutant control method according to the second aspect of the present application comprises:

[0021] After the coal and the solid waste are mixed and burned in the furnace, the flue gas generated enters the flue gas passage;

[0022] A flue gas temperature detection unit detects the temperature of the flue gas at different positions in the flue gas passage at the same cross section of the flue gas passage to obtain a temperature field of the flue gas;

[0023] A spraying unit sprays fluid into the flue gas passage and controls the flow rate of the sprayed fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detection unit, so as to reduce the temperature of the flue gas in the flue gas passage to a set temperature, thereby achieving preliminary cooling of the flue gas in the flue gas passage;

[0024] After preliminary cooling, the flue gas enters the denitration device, and the denitration device catalytically reduces NOx in the flue gas to reduce the content of NOx in the flue gas;

[0025] The flue gas after denitration treatment is discharged from the denitration device and enters the flue gas discharge channel, and the flue gas discharge channel is used to discharge the flue gas in the flue gas channel;

[0026] The fan guides the flue gas at the outlet of the flue gas discharge channel to the recirculation channel, and enters the inlet of the flue gas discharge channel and / or the outlet of the flue gas channel through the recirculation channel;

[0027] The backflow flue gas is mixed with the flue gas from the inlet of the flue gas discharge channel and / or the outlet of the flue gas channel to reduce the temperature of the flue gas at the inlet of the flue gas discharge channel, thereby further reducing the temperature of the flue gas to inhibit the formation of dioxin.

[0028] The coal-fired boiler pollutant control method of the embodiment of the present application effectively utilizes solid waste while quickly avoiding the dioxin secondary synthesis temperature range, inhibits dioxin secondary synthesis, and reduces environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of a coal-fired boiler pollutant control system of the embodiment of the present application.

[0030] Figure 2 is a schematic diagram of a temperature control assembly of the embodiment of the present application.

[0031] Figure 3 is a schematic diagram of a coal-fired boiler pollutant control method of the embodiment of the present application.

[0032] REFERENCE SIGNS:

[0033] furnace 100;

[0034] flue gas channel 1; heat recovery section 11; transition section 12; quenching section 13; denitration section 14;

[0035] temperature control assembly 2; detector 21; atomizing nozzle 22; support pipe 23;

[0036] denitration device 3;

[0037] flue gas discharge channel 4;

[0038] recirculation channel 51; fan 52; baffle 53;

[0039] air preheater 6;

[0040] reheater 71; superheater 72; economizer 73;

[0041] horizontal flue 8. DETAILED DESCRIPTION

[0042] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the embodiments described are examples of the present application and are not intended to limit the present application.

[0043] A coal-fired boiler pollutant control system and method according to an embodiment of the present application is described below with reference to the accompanying drawings.

[0044] As shown in Figure 1 and Figure 2 A coal-fired boiler pollutant control system according to an embodiment of the present application includes a flue gas passage 1, a temperature control assembly 2, a denitration device 3, an exhaust gas passage 4, a recirculation passage 51, and a fan 52.

[0045] The flue gas passage 1 is configured to communicate with a furnace 100 to discharge flue gas in the furnace 100. Specifically, an inlet of the flue gas passage 1 is configured to communicate with an upper end of the furnace 100. Coal and solid waste are mixed and then put into the furnace 100 for mixed combustion. Flue gas generated by the mixed combustion flows upward and enters the flue gas passage 1 from the inlet of the flue gas passage 1, thereby discharging the flue gas in the furnace 100.

[0046] The temperature control assembly 2 includes a flue gas temperature detection unit and a spraying unit. Both the flue gas temperature detection unit and the spraying unit are connected in the flue gas passage 1. The flue gas temperature detection unit is configured to detect a temperature of the flue gas in the flue gas passage 1 to obtain a temperature field of the flue gas. The spraying unit is configured to spray a fluid into the flue gas passage 1 and control a flow rate of the fluid according to the temperature field of the flue gas detected by the flue gas temperature detection unit, so as to reduce the temperature of the flue gas in the flue gas passage 1 to a set temperature. In other words, the flow rate of the fluid sprayed by the spraying unit into the flue gas passage 1 is determined by the temperature field of the flue gas detected by the flue gas temperature detection unit.

[0047] It should be noted that when the flue gas flows through the flue gas temperature detection unit, the flue gas temperature detection unit detects the temperature of the flue gas at multiple positions and feeds back the temperature field of the flue gas to the spraying unit according to the detection result. The spraying unit adaptively adjusts the spraying amount of the fluid according to the temperature field of the flue gas, so that the flue gas flowing through the spraying unit is kept at the set temperature. For example, the temperature of the flue gas flowing through the flue gas temperature detection unit increases over time. The flue gas temperature detection unit feeds back the change of the temperature of the flue gas to the spraying unit. The spraying unit adaptively adjusts the spraying amount of the fluid according to the change of the temperature of the flue gas, so as to ensure that the temperature of the mixed gas after the fluid is mixed with the flue gas is reduced to the set temperature.

[0048] The denitration device 3 is connected in the flue gas passage 1. The temperature control assembly 2 and the denitration device 3 are arranged in sequence along the flow direction of the flue gas in the flue gas passage 1. The flue gas in the flue gas passage 1 is preliminarily cooled by the temperature control assembly 2 and then enters the denitration device 3. The denitration device 3 reduces NOx in the flue gas to N2, thereby reducing the pollution of the flue gas to the environment.

[0049] The inlet of the smoke exhaust channel 4 is connected to the outlet of the smoke channel 1, and the smoke exhaust channel 4 is used to discharge the smoke in the smoke channel 1. The inlet of the recirculation channel 51 is connected to the outlet of the smoke exhaust channel 4, and the outlet of the recirculation channel 51 is connected to the outlet of the smoke channel 1, so that a part of the smoke at the outlet of the smoke exhaust channel 4 flows back to the recirculation channel 51, and flows back to the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1 through the recirculation channel 51. The fan 52 is connected to the recirculation channel 51.

[0050] It should be noted that the flue gas after denitrification treatment is discharged from the denitrification device 3 and enters the exhaust channel 4. A part of the flue gas at the outlet of the exhaust channel 4 enters the recirculation channel 51 under the action of the fan 52. The flue gas in the recirculation channel 51 is discharged into the inlet of the exhaust channel 4 and / or the outlet of the flue gas channel 1, so that the cold flue gas in the circulation channel is mixed with the hot flue gas at the inlet of the exhaust channel 4 and / or the outlet of the flue gas channel 1 to reduce the smoke temperature of the flue gas at the inlet of the exhaust channel 4 and / or the outlet of the flue gas channel 1, thereby further cooling the flue gas to inhibit the formation of dioxins.

[0051] The coal-fired boiler pollutant control system of the embodiment of the present invention effectively utilizes solid waste while quickly avoiding the dioxin secondary synthesis temperature range through the arrangement of the temperature control component 2 and the recirculation flue, thereby inhibiting the dioxin secondary synthesis and reducing environmental pollution.

[0052] like Figures 1 to 3 As shown, the coal-fired boiler pollutant control method according to the second embodiment of the present invention includes:

[0053] S1. After coal and solid waste are mixed and burned in the furnace 100, the generated flue gas enters the flue gas channel 1.

[0054] S2. The smoke temperature detection unit detects the temperature of the smoke at different locations within the smoke channel 1 on the same cross-section of the smoke channel 1 to obtain the smoke temperature field. Specifically, the smoke temperature detection unit includes multiple detectors 21, and the multiple detectors 21 are distributed on the same cross-section of the smoke channel 1 and arranged along the axial direction of the smoke channel 1. The multiple detectors 21 simultaneously measure the smoke temperature on the same cross-section of the smoke channel 1 to obtain the smoke temperature field.

[0055] S3, the injection unit injects fluid into the flue gas passage 1 and controls the flow of the injected fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detection unit, so as to reduce the temperature of the flue gas in the flue gas passage 1 to a set temperature, thereby achieving preliminary cooling of the flue gas in the flue gas passage 1. Specifically, the injection unit includes a plurality of atomizing nozzles 22, and after receiving the temperature field of the flue gas fed back by the flue gas temperature detection unit, the atomizing nozzles 22 adaptively change their injection amount according to their own position and the temperature field of the flue gas. For example, if the temperature of the flue gas at one position in the temperature field of the flue gas increases while the temperatures of the flue gas at other positions remain unchanged, the fluid injection amount of the atomizing nozzle 22 corresponding to the one position is adaptively increased, while the fluid injection amount of the atomizing nozzle 22 corresponding to the other positions remains unchanged.

[0056] S4, the flue gas after preliminary cooling enters the denitration device 3, and the denitration device 3 catalytically reduces NOx in the flue gas to reduce the content of NOx in the flue gas.

[0057] S5, the flue gas after denitration treatment is discharged from the denitration device 3 and enters the smoke exhaust passage 4, and the smoke exhaust passage 4 is used to exhaust the flue gas in the flue gas passage 1. It should be noted that the flue gas exhausted from the smoke exhaust passage 4 enters the subsequent environmental protection equipment for treatment and then enters the chimney for emission, so as to reduce the pollution of the flue gas to the environment.

[0058] S6, the fan 52 guides a part of the flue gas at the outlet of the smoke exhaust passage 4 to the recirculation passage 51, and the flue gas enters the inlet of the smoke exhaust passage 4 and / or the outlet of the flue gas passage 1 through the recirculation passage 51. In other words, a part of the flue gas at the outlet of the smoke exhaust passage 4 enters the recirculation passage 51 under the action of the fan 52, and then returns to the inlet of the smoke exhaust passage 4 and / or the outlet of the flue gas passage 1 through the recirculation passage 51, and the other part of the flue gas at the outlet of the smoke exhaust passage 4 enters the subsequent environmental protection equipment for treatment and then enters the chimney for emission.

[0059] S7, the backflow flue gas is mixed with the flue gas from the inlet of the smoke exhaust passage 4 and / or the outlet of the flue gas passage 1 to reduce the temperature of the flue gas at the inlet of the smoke exhaust passage 4, so as to further reduce the temperature of the flue gas to inhibit the generation of dioxin.

[0060] The coal-fired boiler pollutant control method of the embodiment of the present application effectively utilizes solid waste while quickly avoiding the secondary synthesis temperature range of dioxin, thereby inhibiting the secondary synthesis of dioxin and reducing environmental pollution.

[0061] In some embodiments, the injection unit is in communication with an external cooling device, and the cooling device is used to provide fluid for cooling the flue gas temperature to the injection unit.

[0062] Preferably, the injection unit is in communication with a wastewater collection device for collecting the wastewater generated by the furnace 100 and delivering the wastewater to the injection unit. After the wastewater of the furnace 100 is injected into the flue gas passage 1 and mixed with the flue gas, the wastewater of the furnace 100 flows downstream with the flue gas and shares the downstream environmental protection equipment with the flue gas, which reduces the investment in cooling equipment and treats the wastewater generated by the coal-fired boiler, thereby improving the economy of the pollutant control system of the coal-fired boiler.

[0063] Optionally, the denitration device 3 is an SCR denitration device 3.

[0064] In some embodiments, the flue gas temperature detection unit is configured to detect the temperature of the flue gas at different positions in the flue gas passage 1 at the same cross section of the flue gas passage 1 to obtain a temperature field of the flue gas, and the injection unit controls the flow rate of the injection fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detection unit. The detection of the temperature of the flue gas at different positions in the flue gas passage 1 at the same cross section of the flue gas passage 1 ensures the accuracy of the temperature field of the flue gas, so as to ensure that the injection unit accurately adjusts the amount of fluid injection to ensure that the flue gas at different positions is cooled to the set temperature.

[0065] As shown in Figure 1 and Figure 2 In some embodiments, the flue gas detection unit includes a plurality of detectors 21, and the plurality of detectors 21 are spaced apart along the circumference of the flue gas passage 1. The injection unit includes a plurality of atomizing nozzles 22, and the plurality of atomizing nozzles 22 are spaced apart along the circumference of the flue gas passage 1. The plurality of atomizing nozzles 22 correspond to the plurality of detectors 21 one-to-one, and the atomizing nozzle 22 controls the flow rate of the injection fluid according to the temperature detected by the corresponding detector 21. For example, as shown in Figure 1 The flue gas detection unit and the injection unit are arranged on a section of the flue gas passage 1 along the left-right direction, and the plurality of detectors 21 are spaced apart along the axis direction of the flue gas passage 1 at this section, and the plurality of atomizing nozzles 22 are spaced apart along the axis direction of the flue gas passage 1 at this section.

[0066] It should be noted that since the plurality of atomizing nozzles 22 correspond to the plurality of detectors 21 one-to-one, when one of the detectors 21 detects a change in the temperature of the flue gas at the position corresponding to the detector 21, the detector 21 feeds back the temperature change information to the atomizing nozzle 22 corresponding to the detector 21. The atomizing nozzle 22 adjusts the flow rate of the injection fluid according to the change in the temperature of the flue gas to reduce the temperature of the flue gas flowing through the atomizing nozzle 22 to the set temperature.

[0067] As shown in Figure 2As shown, in some embodiments, the temperature control component further includes a support tube 23, the support tube 23 is connected to the flue gas channel 1 and the axis of the support tube 23 is arranged along the flue gas flow direction in the flue gas channel 1, a plurality of detectors 21 are connected to the support tube 23 and are distributed at intervals along the circumference of the support tube 23, a plurality of atomizing nozzles 22 are connected to the support tube 23 and are distributed at intervals along the circumference of the support tube 23, and the detectors 21 and the corresponding atomizing nozzles 22 are arranged at intervals along the flue gas flow direction.

[0068] It should be noted that the support tube 23 is arranged at a section of the smoke channel 1 , and the axial direction of the support tube 23 is the smoke flow direction in the smoke channel 1 at that section.

[0069] In some embodiments, the coal-fired boiler pollutant control system also includes a baffle 53, which is connected to the recirculation channel 51 and is movable relative to the recirculation channel 51. The baffle 53 moves in the recirculation channel 51 to change the opening of the baffle 53, thereby adjusting the amount of flue gas flowing back to the inlet of the exhaust channel 4 and / or the outlet of the flue gas channel 1.

[0070] It should be noted that a temperature sensor is provided at the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1. The temperature sensor is used to measure the temperature of the smoke at the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1 and feed it back to the control system. The control system controls the movement of the baffle 53 relative to the recirculation channel 51 according to the smoke temperature to change the opening of the baffle 53. When the smoke temperature at the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1 increases, the opening of the baffle 53 increases to increase the cold smoke flowing back to the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1. When the smoke temperature at the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1 decreases, the opening of the baffle 53 decreases to reduce the cold smoke flowing back to the inlet of the smoke exhaust channel 4 and / or the outlet of the smoke channel 1.

[0071] Optionally, the baffle 53 is rotatable within the recirculation passage 51 .

[0072] Optionally, the baffle 53 may be slidable in the radial direction of the recirculation passage 51 .

[0073] like Figure 1 As shown, in some embodiments, the flue gas channel 1 includes a heat recovery section 11, a transition section 12, a quenching section 13, and a denitrification section 14, which are sequentially connected. The cross-sectional areas of the heat recovery section 11 and the denitrification section 14 are both larger than the cross-sectional area of ​​the quenching section 13. The cross-sectional area of ​​the transition section 12 gradually decreases in the direction of flue gas flow. The temperature control assembly 2 is connected to the quenching section 13. It is understood that the smaller cross-sectional area of ​​the quenching section 13 requires fewer sampling points for the flue gas temperature detection unit, and the injection unit can more easily cool the flue gas when injecting fluid into the flue gas channel 1, thereby improving the flue gas cooling effect of the fluid injected by the injection unit.

[0074] In some embodiments, the coal-fired boiler pollutant control system further comprises an air preheater 6, a portion of the air preheater 6 being located in the flue gas passage 4, the air preheater 6 being used to reduce the temperature of the flue gas in the flue gas passage 4 and recycle the heat, thereby absorbing the waste heat of the flue gas and improving the efficiency of the boiler.

[0075] In some embodiments, the coal-fired boiler pollutant control system further comprises a reheater 71, a superheater 72 and an economizer 73, the reheater 71, the superheater 72 and the economizer 73 being connected in the flue gas passage 1 and located upstream of the temperature control assembly 2, the superheater 72 and the economizer 73 being connected in series and the superheater 72 being located upstream of the economizer 73. The reheater 71, the superheater 72 and the economizer 73 recycle the heat in the flue gas, thereby improving the energy utilization rate of the system.

[0076] As shown in Figure 1 In some embodiments, the coal-fired boiler pollutant control system further comprises a horizontal flue 8, the flue gas passage 1 being communicated with the furnace 100 through the horizontal flue 8, the horizontal flue 8 being located above the furnace 100 and the flue gas passage 1. The flue gas generated by the mixed combustion of the coal and the solid waste in the boiler moves upward and enters the horizontal flue 8. During the movement of the flue gas in the horizontal flue 8, the solid particles and dust mixed in the flue gas are deposited in the horizontal flue 8, thereby reducing the influence of the solid particles and dust in the flue gas on the downstream equipment.

[0077] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0078] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0079] In the present application, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", "fixedly connected", "connection", "fixedly connected", "connected", "fixed", and the like should be construed broadly, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, can be electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0080] In the present application, unless specifically defined otherwise, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be the first feature directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "under" and "under" the second feature can be the first feature directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0081] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification and the features of different embodiments or examples without contradiction.

[0082] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and cannot be construed as limiting the present application, and the changes, modifications, replacements and variations of the above embodiments made by those skilled in the art are within the scope of the present application.

Claims

1. A coal-fired boiler pollution control system, characterized by, The application relates to a flue gas temperature control device for a furnace, comprising: a flue gas passage adapted to communicate with a furnace chamber to discharge flue gas in the furnace chamber; a temperature control assembly comprising a flue gas temperature detecting unit and a spraying unit, both of which are connected in the flue gas passage, the flue gas temperature detecting unit is used to detect the temperature of the flue gas in the flue gas passage to obtain a flue gas temperature field, and the spraying unit is used to spray fluid into the flue gas passage and control the flow of the sprayed fluid according to the flue gas temperature field detected by the flue gas temperature detecting unit to reduce the flue gas temperature in the flue gas passage to a set temperature, the spraying unit communicates with an external cooling device which is used to provide fluid for cooling the flue gas temperature for the spraying unit; a denitration device connected in the flue gas passage, and the temperature control assembly and the denitration device are arranged in sequence along the flue gas flow direction in the flue gas passage; a flue gas discharge passage, the inlet of the flue gas discharge passage communicates with the outlet of the flue gas passage, and the flue gas discharge passage is used to discharge the flue gas in the flue gas passage; a recirculation passage, the inlet of the recirculation passage communicates with the outlet of the flue gas discharge passage, and the outlet of the recirculation passage communicates with the outlet of the flue gas passage, so that a part of the flue gas at the outlet of the flue gas discharge passage flows back to the recirculation passage and then flows back to the inlet of the flue gas discharge passage and / or the outlet of the flue gas passage through the recirculation passage; a fan connected in the recirculation passage.

2. The coal-fired boiler pollution control system of claim 1, wherein, The flue gas temperature detecting unit is used to detect the temperature of the flue gas at different positions in the flue gas passage at the same cross section of the flue gas passage to obtain a flue gas temperature field, and the spraying unit controls the flow of the sprayed fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detecting unit.

3. The coal-fired boiler pollution control system according to claim 2, wherein, The flue gas temperature detecting unit comprises a plurality of detectors which are distributed at intervals along the circumference of the flue gas passage, and the spraying unit comprises a plurality of atomizing nozzles which are also distributed at intervals along the circumference of the flue gas passage, the atomizing nozzles correspond to the detectors one by one, and the flow of the fluid sprayed by the atomizing nozzles is controlled according to the temperature detected by the corresponding detectors.

4. The coal-fired boiler pollution control system according to claim 3, wherein, The temperature control assembly further comprises a support pipe, the axis of the support pipe is arranged along the flue gas flow direction in the flue gas passage, the detectors are connected to the support pipe and distributed at intervals along the circumference of the support pipe, and the atomizing nozzles are also connected to the support pipe and distributed at intervals along the circumference of the support pipe, and the detectors and the corresponding atomizing nozzles are arranged at intervals along the flue gas flow direction.

5. The coal-fired boiler pollution control system according to any one of claims 1-4, wherein, Further comprising a baffle connected in the recirculation passage and movable relative to the recirculation passage, the baffle moves in the recirculation passage to change the opening degree of the baffle so as to adjust the amount of the flue gas flowing back to the inlet of the flue gas discharge passage and / or the outlet of the flue gas passage.

6. The coal-fired boiler pollution control system according to any one of claims 1-4, wherein, The flue gas passage comprises a heat recovery section, a transition section, a quenching section and a denitration section connected in sequence, the cross-sectional area of the heat recovery section and the denitration section is greater than that of the quenching section, and the cross-sectional area of the transition section gradually decreases in the direction of flue gas flow.

7. The coal-fired boiler pollution control system according to any one of claims 1-4, wherein, The air preheater is also included, and a part of the air preheater is located in the flue gas passage, and the air preheater is used to reduce the temperature of the flue gas in the flue gas passage.

8. The coal-fired boiler pollution control system according to any one of claims 1-4, wherein, The reheater, the superheater and the economizer are also included, and the reheater, the superheater and the economizer are connected in the flue gas passage and located upstream of the temperature control assembly, the superheater and the economizer are connected in series, and the superheater is located upstream of the economizer.

9. The coal-fired boiler pollution control system according to any one of claims 1-4, wherein, The horizontal flue is also included, and the flue gas passage communicates with the furnace through the horizontal flue, and the horizontal flue is located above the furnace and the flue gas passage respectively.

10. A method of coal-fired boiler pollution control, characterized by, The coal-fired boiler pollutant control system according to any one of claims 1-9 is used, and the control method comprises: After the coal and the solid waste are mixed and burned in the furnace, the flue gas generated enters the flue gas passage; The flue gas temperature detection unit detects the temperature of the flue gas at different positions in the flue gas passage at the same cross section of the flue gas passage to obtain the temperature field of the flue gas; The injection unit injects fluid into the flue gas passage and controls the flow of the injected fluid according to the temperature of the flue gas at the corresponding position detected by the flue gas temperature detection unit to reduce the temperature of the flue gas in the flue gas passage to a set temperature, thereby achieving preliminary cooling of the flue gas in the flue gas passage; After the preliminary cooling, the flue gas enters the denitration device, and the denitration device catalytically reduces NOx in the flue gas to reduce the content of NOx in the flue gas; After the denitration treatment, the flue gas is discharged from the denitration device and enters the flue gas passage, and the flue gas passage is used to discharge the flue gas in the flue gas passage; The fan guides the flue gas at the outlet of the flue gas passage to the recirculation passage, and the flue gas enters the inlet of the flue gas passage and / or the outlet of the flue gas passage through the recirculation passage; The backflow flue gas mixes with the flue gas from the inlet of the flue gas passage and / or the outlet of the flue gas passage to reduce the temperature of the flue gas at the inlet of the flue gas passage, thereby further reducing the temperature of the flue gas to inhibit the formation of dioxin.

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