SNCR (selective non-catalytic reduction) and SCR (selective catalytic reduction) combined coordinated denitration system of W flame boiler

Abstract

The invention provides an SNCR (selective non-catalytic reduction) and SCR (selective catalytic reduction) combined coordinated denitration system for a W-flame boiler, and relates to the technical field of boiler flue gas denitration devices. A reducing agent diluting and metering system sprays a reducing agent into a burnout chamber, a precise ammonia spraying adjusting system sprays ammonia gas into a flue, an SCR inlet flue partition measuring device monitors concentration distribution of nitric oxide in the flue, and an SCR outlet grid sampling and measuring device monitors concentration distribution of nitric oxide at an outlet of an SCR reactor. The denitration control system collects data of the low-nitrogen combustor, the SNCR temperature measurement set, the SCR inlet flue partition measurement device and the SCR outlet grid sampling measurement device, so that an SNCR control module controls the concentration and distribution of a reducing agent sprayed by the reducing agent dilution metering system, and an SCR control module controls the concentration and distribution of ammonia sprayed by the precise ammonia spraying adjusting system. According to the invention, SNCR + SCR combined coordinated denitration can be realized.

Description

Technical Field

[0001] The present application relates to the technical field of boiler flue gas denitration devices, and particularly relates to a W-flame boiler SNCR+SCR combined coordinated denitration system. Background Art

[0002] A W-flame boiler is a type of boiler that includes a lower combustion chamber and an upper burnout chamber. The volume of the lower combustion chamber is enlarged by about one time, and the fuel combustion process is basically carried out in the lower combustion chamber. The W-flame boiler can effectively improve the coal combustion adaptability, low-load steady combustion ability, and fly ash burnout rate, and has significant advantages in fuel ignition, flame stability, and fuel burnout. With its special combustion organization method and high furnace volume heat load, it has become the main furnace type for difficult-to-burn coal combustion in China.

[0003] The flue gas generated during the combustion of a W-flame boiler contains nitrogen oxides (NO x ), and NO x needs to be denitrified. Currently, the main denitrification technologies used in W-flame boilers include low-nitrogen combustion, selective catalytic reduction (SCR), and selective non-catalytic reduction (SNCR), etc. However, it is difficult to meet the low-emission requirements by using a single low-nitrogen combustion, SNCR, SCR, or SNCR+SCR coupled denitrification technology. To meet the national low-emission standard requirements, after the transformation of the low-nitrogen burner in a W-flame boiler, the SNCR+SCR combined denitrification technology can be adopted to improve the denitrification efficiency. Among them, the set SNCR denitrification system is mainly used to reduce costs and relieve the treatment pressure of the subsequent SCR denitrification system, ensuring the economic and efficient operation of the entire denitrification system.

[0004] Adopting the combined denitrification technology of low-nitrogen burner+SNCR+SCR to achieve low-content emission of NO x in a W-flame boiler. Due to the lack of coordination and even interference between technologies, the overall system cannot operate in the best state. In severe cases, the ammonia escape concentration is much higher than that of a conventional SCR denitrification device, causing serious corrosion and blockage of the air preheater of the unit, and having a serious impact on the safe and stable operation of the unit. The specific problems are as follows: 1. The temperature range of the SNCR denitrification reaction is relatively narrow, and NO in the flue gas can be effectively removed only in the range of 850-1100°C. x When the reaction temperature is too high, a large amount of reducing agent is oxidized, not only unable to achieve the denitrification purpose, but also may increase the NO x content in the flue gas; when the flue gas temperature is too low, the reaction rate is slow, and the SNCR denitrification reaction hardly proceeds below 800°C. The temperature in the furnace of a W-flame boiler is high, and the temperature section that meets the SNCR reducing agent injection point is located in the area of the burnout chamber heating surface, where the temperature gradient changes greatly.

[0005] 2. The furnace of the W-flame boiler is wide, and the burner layout structure is special. The combustion in the furnace is unevenly distributed, and the SNCR ammonia injection requirements vary in different regions. At the same time, the coverage of the SNCR spray gun is limited, resulting in uneven ammonia injection of the SNCR spray gun in the furnace, and thus the ammonia concentration of the unreacted SNCR and the NO concentration distribution at the SCR denitration inlet are uneven, seriously affecting the stable operation of the SCR denitration system. x The concentration distribution is uneven, seriously affecting the stable operation of the SCR denitration system. Summary of the Invention

[0006] In order to enable the SNCR+SCR combined and coordinated denitration, the present application provides a W-flame boiler SNCR+SCR combined and coordinated denitration system.

[0007] The present application provides a W-flame boiler SNCR+SCR combined and coordinated denitration system, adopting the following technical solutions: A W-flame boiler SNCR+SCR combined and coordinated denitration system includes a boiler, the boiler includes a combustion chamber, a burnout chamber and a flue, and further includes: A low-nitrogen burner installed on the combustion chamber; A reducing agent dilution metering system that sprays the reducing agent into the burnout chamber; An SNCR temperature measurement group arranged on the burnout chamber, and the SNCR temperature measurement group monitors the temperature distribution in the burnout chamber; A precise ammonia injection adjustment system that sprays ammonia into the flue; An SCR inlet flue partition measurement device that monitors the concentration distribution of nitrogen oxides in the flue; An SCR reactor communicated with the flue; An SCR outlet grid sampling measurement device arranged on one side of the outlet of the SCR reactor, and the SCR outlet grid sampling measurement device monitors the concentration distribution of nitrogen oxides at the outlet of the SCR reactor; A denitration control system provided with an SNCR control module and an SCR control module; the denitration control system respectively collects the parameters of the low-nitrogen burner, the data of the SNCR temperature measurement group, the data of the SCR inlet flue partition measurement device and the data of the SCR outlet grid sampling measurement device, so that the SNCR control module controls the injection amount, concentration and distribution of the reducing agent sprayed by the reducing agent dilution metering system, and the SCR control module controls the injection amount, concentration and distribution of the ammonia sprayed by the precise ammonia injection adjustment system.

[0008] By adopting the above technical solution, the setting of low nitrogen burner can effectively reduce the initial NO x The amount of ammonia generated lays the foundation for the subsequent denitrification process. The reducing agent dilution and metering system can accurately control the concentration and distribution of the reducing agent sprayed into the burnout chamber. Combined with the real-time monitoring of the temperature distribution by the SNCR temperature measurement group, it ensures that the reducing agent reacts within the appropriate temperature range and reduces the overoxidation problem caused by inappropriate temperature. The precise ammonia injection adjustment system is responsible for injecting an appropriate amount of ammonia into the flue. In conjunction with the concentration distribution data provided by the SCR inlet flue partition measurement device, it realizes the fine control of the ammonia injection amount and spatial distribution, which helps to improve the denitrification efficiency. The flue gas undergoes catalytic reduction reaction inside the SCR reactor, while the SCR outlet grid sampling and measuring device measures NO at the outlet of the SCR reactor. x / O 2 The concentration value is collected and analyzed, and the ammonia injection amount of the precise ammonia injection adjustment system is feedback-adjusted. The denitration control system collects various data, and adjusts the reducing agent dilution metering system through the SNCR control module, and adjusts the precise ammonia injection adjustment system through the SCR control module, so that SNCR+SCR jointly coordinates denitration, reduces the overoxidation of the reducing agent and ammonia escape, saves the reducing agent consumption, and correspondingly saves the operating cost, and finally realizes the coordinated, stable and efficient operation of the denitration system.

[0009] Optionally, the reductant dilution and metering system includes a dilution and metering pipeline network and an SNCR injector group, the SNCR control module is electrically connected to the dilution and metering pipeline network, and the dilution and metering pipeline network includes a dilution water pipeline assembly and a urea solution pipeline assembly; The dilution water pipeline assembly is fed with dilution water, the urea solution pipeline assembly is fed with urea solution, the dilution water pipeline assembly and the urea solution pipeline assembly are mixed and then connected with the SNCR injector group, the SNCR injector group is installed in the burnout chamber, and the SNCR injector group sprays the mixture of dilution water and urea solution into different areas in the burnout chamber.

[0010] By adopting the above technical solution, by setting up a dilution water pipeline and a urea solution pipeline, and mixing the two and connecting them to the SNCR injector group, the concentration and distribution of the reducing agent can be accurately controlled, reducing the low denitrification efficiency or secondary pollution caused by too high or too low concentration of the reducing agent. The SNCR injector group is installed in the burnout chamber, and can accurately spray the mixture of dilution water and urea solution into the designated area according to actual needs, ensuring that the reducing agent reacts within the appropriate temperature range, improving the denitrification efficiency while reducing the waste of reducing agent. Under the action of the SNCR control module, by regulating the dilution metering pipeline network, the injection amount and concentration distribution of the reducing agent can be adjusted according to the real-time monitored temperature distribution data, further optimizing the denitrification process, reducing the risk of ammonia escape, and improving the stability and economy of the system.

[0011] Optionally, the dilution water pipeline assembly includes a dilution water pipeline, on which a dilution water switch valve, a dilution water regulating valve and a dilution water flowmeter are provided; The urea solution pipeline assembly includes a urea solution pipeline, on which a urea solution switch valve, a urea solution regulating valve and a urea solution flowmeter are provided; the SNCR control module is electrically connected to the dilution water switch valve, the dilution water regulating valve, the dilution water flowmeter, the urea solution switch valve, the urea solution regulating valve and the urea solution flowmeter respectively.

[0012] By adopting the above technical solution, the SNCR control module controls the dilution water switch valve and the urea solution switch valve, and can open or close the mixing of the dilution water and the urea solution. The SNCR control module controls the dilution water regulating valve and the urea solution regulating valve, and can adjust the mixing ratio of the dilution water and the urea solution to ensure that the ratio after mixing the dilution water and the urea solution is appropriate, and reduce the reaction abnormality caused by insufficient or excessive dilution. The dilution water flowmeter can measure the flow rate of the dilution water, and the urea solution flowmeter can measure the flow rate of the urea solution, so as to feedback information to the SNCR control module. The denitration control system collects data in real time and feedbacks for adjustment, so as to realize automatic operation, improve the system response speed and stability, optimize the SNCR reaction conditions, and enhance the denitration efficiency.

[0013] Optionally, the precise ammonia injection regulation system includes an ammonia dilution pipe network, an ammonia injection grid and a urea hydrolyzer, and the SCR control module is electrically connected to the ammonia dilution pipe network; the urea hydrolyzer is communicated with the ammonia dilution pipe network, and the ammonia injection grid is communicated with the ammonia dilution pipe network, The ammonia dilution pipe network is provided with two inlets, one inlet of the ammonia dilution pipe network is introduced with dilution air, and the urea hydrolyzer processes the urea solution to obtain ammonia and inputs it to the other inlet of the ammonia dilution pipe network; The ammonia injection grid is arranged in the flue, and the ammonia injection grid is used for injecting the mixed gas of ammonia and dilution air into different areas in the flue.

[0014] By adopting the above technical solution, the urea hydrolyzer processes the urea solution to obtain ammonia, the ammonia and the dilution air are introduced into the ammonia dilution pipe network, and the ammonia dilution pipe network mixes the ammonia and the dilution air, and the SCR control module can control the mixing ratio of the ammonia dilution pipe network.

[0015] Optionally, the ammonia dilution pipe network includes an input main pipe, a gas mixer, branch pipes, and an output pipe; a plurality of the input main pipes are respectively communicated with the gas mixer, and ammonia gas and dilution air are respectively introduced into the input main pipes; a spray ammonia main pipe on-off valve and a spray ammonia main pipe regulating valve are connected to the input main pipe, the branch pipes are respectively communicated with the gas mixer and a plurality of the output pipes, a spray ammonia branch leveling valve is connected to the branch pipes, a spray ammonia branch manual valve is connected to the output pipes, and the output pipes are communicated with the spray ammonia grid.

[0016] By adopting the above technical solution, ammonia gas and dilution air respectively enter the gas mixer through the input main pipe for sufficient mixing, ensuring uniform ammonia gas concentration sprayed into the flue, and reducing the problems of too high or too low local concentration. The spray ammonia main pipe on-off valve and the spray ammonia main pipe regulating valve can control the total flow of ammonia gas and dilution air, realizing precise regulation of the ammonia gas supply amount by the system, reducing ammonia gas waste and lowering the operation cost. The spray ammonia branch leveling valve on the branch pipe further refines the ammonia gas distribution process, and can flexibly adjust the ammonia gas flow of each branch pipe according to the actual requirements of different regions in the flue, ensuring relatively high uniformity of the ammonia-nitrogen molar ratio in each region of the flue. The spray ammonia branch manual valve on the output pipe provides additional manual adjustment ability, increasing the possibility of manual intervention in addition to automatic control, and enhancing the flexibility and reliability of the system. It improves the operation efficiency of the SNCR+SCR combined denitration system of the W-flame boiler, reduces the ammonia slip phenomenon, saves the consumption of reducing agent, and finally promotes the stable and efficient operation of the denitration system.

[0017] Optionally, the SCR reactor includes a catalyst layer, a rectifying grid, and a reactor shell, the reactor shell is communicated with the flue, the rectifying grid is arranged at the inlet of the reactor shell, and the catalyst layer is arranged inside the reactor shell.

[0018] By adopting the above technical solution, the rectifying grid can preliminarily rectify the flue gas entering the SCR reactor, optimize the flue gas flow state, and make it more uniformly distributed inside the reactor shell, thereby improving the effect of subsequent denitration reactions. The catalyst layer can increase the reaction rate of nitrogen oxides and ammonia gas in the flue gas, significantly improving the removal efficiency of NO x . This design helps to reduce the NO x concentration at the outlet of the SCR reactor, reduce the occurrence of ammonia slip phenomenon, and finally achieve the goal of efficient denitration and save the operation cost.

[0019] Optionally, the catalyst layer includes a dynamic catalyst layer and a static catalyst layer, the static catalyst layer is connected inside the reactor shell, and the flue gas sequentially passes through the dynamic catalyst layer and the static catalyst layer; a driving device is connected to the reactor shell, and the driving device drives the dynamic catalyst layer to rotate.

[0020] By adopting the above technical solution, the combined design of the dynamic catalyst layer and the static catalyst layer can extend the residence time of the flue gas in the catalyst layer and improve the denitration efficiency. The driving device rotates the dynamic catalyst layer, which helps to make the contact between the flue gas and the dynamic catalyst layer more sufficient and uniform, reduce the situation of local overload or deficiency, and thus improve the overall reaction stability. It can also reduce the blockage phenomenon caused by dust accumulation in the local area on the surface of the dynamic catalyst layer, maintain the catalyst activity, and reduce the maintenance frequency and cost.

[0021] Optionally, the driving device includes a rotation driving source and a connecting rod. The output end of the rotation driving source is connected to the connecting rod, and the connecting rod is connected to the dynamic catalyst layer. The rotation driving source drives the dynamic catalyst layer to rotate through the connecting rod.

[0022] By adopting the above technical solution, the rotation driving source drives the dynamic catalyst layer to rotate through the connecting rod, so that the flue gas can contact the catalyst surface more evenly when passing through the dynamic catalyst layer, improving the denitration efficiency. At the same time, the rotation of the dynamic catalyst layer helps to reduce the ash accumulation phenomenon in the local area on the catalyst surface and extend the service life of the catalyst.

[0023] Optionally, the driving device further includes a support base, a moving driving source, a sliding seat and a dust-brushing rod. The moving driving source is arranged on the support base. The sliding seat is slidably connected to the support base, and the rotation driving source is connected to the sliding seat. The dust-brushing rod is connected inside the reactor housing. The moving driving source drives the sliding seat to slide, so that the dynamic catalyst layer contacts the dust-brushing rod, and the dust-brushing rod brushes the dynamic catalyst layer.

[0024] By adopting the above technical solution, the moving driving source drives the sliding seat to slide on the support base, thereby driving the dynamic catalyst layer to move, so that the dynamic catalyst layer can contact the dust-brushing rod. Then the rotation driving source rotates the dynamic catalyst layer, enabling the dust-brushing rod to physically clean the dynamic catalyst layer, and the dust attached to the dynamic catalyst layer can be removed in time, thus improving the denitration efficiency and extending the service life of the catalyst.

[0025] Optionally, the SCR control module is electrically connected to the moving driving source and the rotation driving source respectively, and the SCR control module controls the start of the moving driving source and the rotation speed of the rotation driving source respectively.

[0026] By adopting the above technical solution, the SCR control module is electrically connected to and controls the mobile drive source and the rotational drive source respectively. On the one hand, it can start the mobile drive source to drive the sliding seat to slide, so that the ash brushing rod contacts the dynamic catalyst layer and realizes brushing and cleaning of it. On the other hand, it can adjust the rotation speed of the rotational drive source, thereby changing the rotation speed of the dynamic catalyst layer to optimize the contact effect between the flue gas and the catalyst. This design not only helps to maintain the activity of the catalyst surface, reduce the situation of catalytic efficiency decline caused by dust accumulation, but also can improve the overall denitration performance and stability, and reduce the maintenance frequency and cost caused by catalyst blockage or failure.

[0027] In summary, the present application includes at least one of the following beneficial effects: 1. By using the SNCR temperature measurement group to monitor the temperature distribution in the burnout chamber in real time, accurately locate the temperature range suitable for the SNCR reaction, and selectively turn on the SNCR injector group according to the temperature distribution data, reducing the situation of injecting reducing agent in areas with too high or too low temperature, thereby improving the denitration efficiency and reducing the waste of reducing agent; 2. Using the SCR inlet flue gas partition measurement device to monitor the nitrogen oxide concentration in the flue gas in partitions, and cooperating with the precise ammonia injection adjustment system to achieve refined control of the ammonia injection volume and distribution, improving the problem of uneven ammonia injection, and ensuring the stable and efficient operation of the SCR system; 3. Setting the SCR outlet grid sampling measurement device to comprehensively master the concentration distribution of NO in the flue gas after denitration x can feedback information to dynamically adjust the ammonia injection volume, greatly reducing the ammonia slip risk, and reducing the reducing agent consumption and operation cost while ensuring the denitration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of the SNCR+SCR combined coordinated denitration system of the W-flame boiler in Embodiment 1 of the present application; Figure 2 is a schematic structural diagram of unfolding the left wall and the right wall and looking directly at the front wall in Embodiment 1 of the present application; Figure 3 is a schematic structural diagram of the dilution metering pipe network and the SNCR spray gun in Embodiment 1 of the present application; Figure 4 is a schematic structural diagram of the ammonia dilution pipe network in Embodiment 1 of the present application; Figure 5 is a top view structural diagram of the SCR inlet flue gas partition measurement device in Embodiment 1 of the present application; Figure 6 is a top view structural diagram of the SCR outlet grid sampling measurement device in Embodiment 1 of the present application; Figure 7It is a schematic structural diagram of the driving device and the SCR reactor in Embodiment 2 of the present application.

[0029] Description of the reference numerals: 1, low-NOx burner; 11, secondary air nozzle; 12, main burner; 2, reductant dilution metering system; 21, dilution metering pipe network; 211, dilution water shut-off valve; 212, dilution water regulating valve; 213, dilution water flowmeter; 214, flushing valve; 215, urea solution shut-off valve; 216, urea solution regulating valve; 217, urea solution flowmeter; 22, SNCR spray gun; 3, SNCR temperature measurement group; 4, denitration inlet flue gas partition mixer; 5, precise ammonia injection regulation system; 51, ammonia dilution pipe network; 511, main ammonia injection pipe shut-off valve; 512, main ammonia injection pipe regulating valve; 513, gas mixer; 514, ammonia injection branch leveling valve; 515, manual valve for ammonia injection branch pipe; 52, ammonia injection grid; 53, urea hydrolyzer; 6, SCR inlet flue gas partition measurement device; 61, partition measurement sampler; 62, partition measurement detector; 7, SCR reactor; 71, catalyst layer; 711, dynamic catalyst layer; 712, static catalyst layer; 72, rectifying grid; 73, reactor shell; 8, SCR outlet grid sampling and measurement device; 81, grid sampler; 82, switching valve; 83, grid sampling and measurement detector; 9, boiler; 91, combustion chamber; 92, burnout chamber; 93, front wall; 94, left side wall; 95, right side wall; 96, horizontal flue; 97, rising flue; 10, denitration control system; 101, SNCR control module; 102, SCR control module; 20, driving device; 201, support base; 202, mobile driving source; 203, sliding seat; 204, rotational driving source; 205, connecting rod; 206, ash brushing rod; 30, economizer; 40, static mixer. Detailed implementation manners

[0030] The following Figures 1 to 7 further elaborates on the present application in detail.

[0031] Embodiment 1:

[0032] Embodiment 1 of the present application provides a W-flame boiler SNCR+SCR combined coordinated denitration system.

[0033] Refer to Figure 1 and Figure 2, the SNCR+SCR combined coordinated denitration system for W-flame boilers includes a boiler 9, low-NOx burners 1, a reductant dilution metering system 2, and an SNCR temperature measurement group 3. The boiler 9 includes a furnace and a flue. The furnace includes a front wall 93, a rear wall, a left side wall 94, and a right side wall 95. The front wall 93, the rear wall, the left side wall 94, and the right side wall 95 enclose to form a combustion chamber 91 and a burnout chamber 92. The combustion chamber 91 is located at the bottom of the furnace, and the burnout chamber 92 is located at the top of the furnace. The low-NOx burner 1 includes secondary air nozzles 11 and main burners 12. The main burners 12 are installed on the arch top of the combustion chamber 91, and the secondary air nozzles 11 are installed on the side walls of the combustion chamber 91. During combustion, the main burners 12 spray pulverized coal downward for combustion, and the secondary air nozzles 11 spray horizontally, thus forming a W-shaped flame in the combustion chamber 91.

[0034] Reference Figure 1 and Figure 3 , the reductant dilution metering system 2 includes a dilution metering pipe network 21 and an SNCR injector group. The dilution metering pipe network 21 includes a dilution water pipeline assembly and a urea solution pipeline assembly. The dilution water pipeline assembly includes a dilution water pipeline, and a dilution water shut-off valve 211, a dilution water regulating valve 212, and a dilution water flowmeter 213 are sequentially connected to the dilution water pipeline. The dilution water shut-off valve 211 controls the on / off of the dilution water pipeline, the dilution water regulating valve 212 controls the flow rate of the dilution water pipeline, and the dilution water flowmeter 213 measures the flow rate of the dilution water pipeline.

[0035] Reference Figure 1 and Figure 3 , the urea solution pipeline assembly includes a urea solution pipeline, and a urea solution shut-off valve 215, a urea solution regulating valve 216, a urea solution flowmeter 217, and a flushing valve 214 are sequentially connected to the urea solution pipeline. The urea solution shut-off valve 215 controls the on / off of the urea solution pipeline, the urea solution regulating valve 216 controls the flow rate of the urea solution pipeline, and the urea solution flowmeter 217 measures the flow rate of the urea solution pipeline. The end of the urea solution pipeline is connected to the dilution water pipeline at the end, so that the dilution water and the urea solution are mixed to obtain a mixed solution.

[0036] Reference Figure 1 and Figure 3 , a connecting pipeline is connected between the dilution water pipeline and the urea solution pipeline. One end of the connecting pipeline is located between the dilution water shut-off valve 211 and the dilution water regulating valve 212, and the other end of the connecting pipeline is located between the urea solution shut-off valve 215 and the urea solution regulating valve 216. The flushing valve 214 is installed on the connecting pipeline. When the urea solution shut-off valve 215 is closed, the dilution water shut-off valve 211 and the flushing valve 214 are opened, and the dilution water can enter the urea solution pipeline from the dilution water pipeline through the connecting pipeline, thereby flushing the inner wall of the urea solution pipeline and reducing the deposition of urea solution on the inner wall of the urea solution pipeline.

[0037] Reference Figure 1 and Figure 3 In this embodiment, a dilution water pipeline and a urea solution pipeline form a set of mixed liquid pipelines, and there are four sets of mixed liquid pipelines. That is, after dilution water and urea solution are introduced, four portions of the mixed liquid after mixing of dilution water and urea solution can be obtained.

[0038] Reference Figure 1 and Figure 2 The SNCR injector group includes a plurality of SNCR spray guns 22, and the SNCR temperature measurement group 3 includes a plurality of pyrometers. The plurality of SNCR spray guns 22 are installed on the front wall 93 of the burnout chamber 92. The plurality of SNCR spray guns 22 are arranged in four layers, and the elevations are 47m, 51m, 55m, and 59m respectively. 16 SNCR spray guns 22 are evenly arranged on each layer, with a total of 64. The plurality of pyrometers are also arranged in four layers, and the four layers of SNCR spray guns 22 correspond to the four layers of pyrometers one by one. 5 pyrometers are arranged on the front wall 93 of each layer, and 3 pyrometers are arranged on each of the left side wall 94 and the right side wall 95. There are 44 pyrometers in total for 4 layers.

[0039] Reference Figure 1 and Figure 3 The four sets of mixed liquid pipelines of the dilution metering pipe network 21 correspond to the four layers of SNCR spray guns 22 one by one and are connected. The mixed liquid after mixing of dilution water and urea solution can be sprayed from the SNCR spray gun 22 into the burnout chamber 92. The dilution water dilutes the urea solution to reduce the concentration. Since the SNCR spray guns 22 are evenly arranged, the diluted mixed liquid can be sprayed into the burnout chamber 92 more evenly, reducing the uneven reaction caused by too high local concentration. When the diluted mixed liquid is sprayed out through the SNCR spray gun 22, it is easier to be atomized into fine droplets, and these fine droplets can quickly evaporate and disperse in the flue gas, thereby increasing the contact area between the mixed liquid and NO x in the flue gas and enhancing the denitrification effect.

[0040] Reference Figure 1 and Figure 2 Each pyrometer can detect the temperature of the corresponding detection point. According to the temperature data detected by the pyrometers on the same layer, the two-dimensional temperature field distribution of this layer can be obtained. The cross-section of the burnout chamber 92 is divided into multiple temperature regions, and the average temperature of each region is calculated according to the two-dimensional temperature field. Then, according to the temperature data measured by the multi-layer pyrometers, the three-dimensional temperature field distribution can be obtained.

[0041] Reference Figure 1, the denitration control system 10 is provided with an SNCR control module 101 and an SCR control module 102. The parameters of the low-nitrogen burner 1 (such as the working load of the low-nitrogen burner 1) are uploaded to the processor of the denitration control system 10, and the three-dimensional temperature field distribution data obtained by the SNCR temperature measurement group 3 is uploaded to the processor of the denitration control system 10. Based on the parameters of the low-nitrogen burner 1 and the three-dimensional temperature field distribution data, the denitration control system 10 controls the reductant dilution metering system 2 through the SNCR control module 101, so as to control the spraying conditions of each SNCR spray gun 22. It can be used to control the opening of the SNCR spray gun 22 suitable for the SNCR reaction temperature range, and control the spraying flow rate of the SNCR spray gun 22, thereby reducing the problems of overoxidation or non-reaction of the reductant.

[0042] Reference Figure 1 And Figure 3 , specifically, the SNCR control module 101 controls the opening and closing of the dilution water switch valve 211 and the urea solution switch valve 215, and can control the opening and closing of the mixed liquid pipeline, so as to control whether the mixed liquid is sprayed by the SNCR spray gun 22 of the corresponding layer. The SNCR control module 101 can also control the opening degrees of the dilution water regulating valve 212 and the urea solution regulating valve 216, and can control the flow rate of the mixed liquid pipeline, so as to control the spraying amount of the SNCR spray gun 22 of the corresponding layer. The SNCR control module 101 can more accurately control the mixing ratio of the dilution water and the urea solution based on the flow data of the dilution water flowmeter 213 and the urea solution flowmeter 217.

[0043] Reference Figure 1 , the flue includes a horizontal flue 96 and a rising flue 97. The horizontal flue 96 is communicated with the burnout chamber 92, and the rising flue 97 is communicated with the horizontal flue 96. A economizer 30 is installed at the inlet of the horizontal flue 96, and a denitration inlet flue gas partition mixer 4 is installed in the horizontal flue 96. The horizontal flue 96 is a pipe with a rectangular cross-section, and the flue gas flows along the length direction of the horizontal flue 96. The horizontal flue 96 is divided into four zones along the width direction, and there are four denitration inlet flue gas partition mixers 4. The four denitration inlet flue gas partition mixers 4 are respectively located in the four zones of the horizontal flue 96. After passing through the economizer 30, the flue gas passes through the denitration inlet flue gas partition mixer 4, and the denitration inlet flue gas partition mixer 4 makes the temperature field and NO x concentration field in each zone tend to be uniform.

[0044] Reference Figure 1 And Figure 4, the SNCR+SCR combined coordinated denitration system of the W-flame boiler further includes a precise ammonia injection regulation system 5. The precise ammonia injection regulation system 5 includes an ammonia dilution pipe network 51, an ammonia injection grid 52, and a urea hydrolyzer 53. The ammonia dilution pipe network 51 includes an input main pipe, an ammonia injection main pipe shut-off valve 511, an ammonia injection main pipe regulating valve 512, a gas mixer 513, an ammonia injection branch leveling valve 514, and an ammonia injection branch manual valve 515. There are two sets of ammonia dilution pipe networks 51. For each set of ammonia dilution pipe networks 51, there are two input main pipes. One of the input main pipes is used to introduce dilution air. The other input main pipe is connected to the urea hydrolyzer 53. After the urea solution flows through the urea hydrolyzer 53, ammonia gas is obtained and introduced into the input main pipe. In the flowing direction of the ammonia gas, the ammonia injection main pipe shut-off valve 511 and the ammonia injection main pipe regulating valve 512 are sequentially installed on the input main pipe into which the ammonia gas is introduced. The ammonia injection main pipe shut-off valve 511 controls the on / off of the ammonia gas input, and the ammonia injection main pipe regulating valve 512 controls the flow rate of the ammonia gas input. Both input main pipes are connected to the gas mixer 513, and the gas mixer 513 mixes the ammonia gas and the dilution air to obtain a mixed gas. The gas mixer 513 is connected with four branch pipes, and the ammonia injection branch leveling valve 514 is installed on each branch pipe. The ammonia injection branch leveling valve 514 is used to adjust the flow rate of each branch pipe. Each branch pipe is connected with eight output pipes, and an ammonia injection branch manual valve 515 is installed on each output pipe. The eight output pipes are in a group, that is, there are a total of four groups of output pipes.

[0045] Reference Figure 1 , in the flowing direction of the flue gas, an ammonia injection grid 52, a static mixer 40, and an SCR inlet flue gas partition measurement device 6 are sequentially installed in the rising flue 97. There are two ammonia injection grids 52, and the two ammonia injection grids 52 correspond to the two sets of ammonia dilution pipe networks 51 one by one. Each ammonia injection grid 52 is divided into four partitions, and the four partitions of the ammonia injection grid 52 correspond to the four groups of output pipes one by one. The mixed gas of ammonia and air is finally sprayed into the rising flue 97 from the ammonia injection grid 52. The static mixer 40 mixes the mixed gas of ammonia and air with the flue gas to improve the uniformity of the distribution of the mixed gas of ammonia and air in the rising flue 97.

[0046] Reference Figure 1 and Figure 5 , the SCR inlet flue gas partition measurement device 6 includes a partition measurement sampler 61 and a partition measurement detector 62. The partition measurement sampler 61 and the partition measurement detector 62 are connected. The partition measurement detector 62 is located outside the rising flue 97, and the partition measurement sampler 61 extends into the rising flue 97. In this embodiment, there are four groups of SCR inlet flue gas partition measurement devices 6 arranged at equal intervals. The SCR inlet flue gas partition measurement device 6 can detect the O 2 content and NO x concentration distribution in the flue gas.

[0047] Reference Figure 1 At the end of the upcomer 97, an SCR reactor 7 is provided. The SCR reactor 7 includes a catalyst layer 71, a rectifying grid 72, and a reactor housing 73. The reactor housing communicates with the end of the upcomer 97. The rectifying grid 72 is connected to the inlet of the reactor housing. The catalyst layer 71 is installed inside the reactor housing 73, and the catalyst layer 71 catalytically treats the flue gas inside the reactor housing 73. The rectifying grid 72 helps to reduce the vortex and backflow phenomena of the flue gas when it enters the catalyst layer 71, thereby improving the uniformity and stability of the flue gas flow.

[0048] Reference Figure 1 and Figure 5 , the SCR inlet duct partition measurement device 6 is electrically connected to the denitration control system 10. The partition measurement detector 62 uploads the data of the detected O 2 content and NO x concentration to the processor of the denitration control system 10. Through the partition measurement of the SCR inlet duct partition measurement device 6, the concentration distribution of NO x in the flue gas entering the SCR reactor 7 is obtained. According to the NO x concentration measured by partition, the SCR control module 102 adjusts the partition ammonia injection amount of the precise ammonia injection regulation system 5 to ensure that the ammonia injection amount in each area of the upcomer 97 matches the NO x concentration, reducing the situation of local excessive ammonia injection or insufficient ammonia injection.

[0049] Reference Figure 1 and Figure 6 , an SCR outlet grid sampling and measurement device 8 is installed at the outlet of the SCR reactor 7. The SCR outlet grid sampling and measurement device 8 includes a grid sampler 81, a switching valve 82, and a grid sampling and measurement detector 83. There are 12 grid samplers 81, which divide the cross-section of the SCR reactor 7 into 12 areas. The grid samplers 81 extend into the reactor housing 73, and the 12 grid samplers 81 correspond to the 12 areas of the reactor housing 73 one by one. The SCR outlet grid sampling and measurement device 8 is provided with four groups. The switching valve 82 and the grid sampling and measurement detector 83 are located outside the reactor housing 73. Three grid samplers 81 are in a group, and the grid samplers 81 within a group are all connected to the switching valve 82, and the switching valve 82 is connected to the grid sampling and measurement detector 83. The switching valve 82 is used to switch between different grid samplers 81, enabling the SCR outlet grid sampling and measurement device 8 to sequentially measure the NO x concentration and ammonia slip concentration of each grid area.

[0050] Reference Figure 1, the SCR outlet grid sampling measurement device 8 is electrically connected to the denitration control system 10, and the SCR outlet grid sampling measurement device 8 uploads the detected data to the denitration control system 10. According to the data detected by the SCR outlet grid sampling measurement device 8, the denitration control system 10 controls the total ammonia injection amount of the precise ammonia injection regulation system 5 through the SCR control module 102 to ensure that the outlet NO x concentration meets the standard.

[0051] Reference Figure 1 , specifically, the SCR control module 102 can control the ammonia injection main pipe on-off valve 511, the ammonia injection main pipe regulating valve 512, and the ammonia injection branch leveling valve 514 to ensure the uniform distribution of the molar ratio of ammonia to NO x , thereby improving the denitration efficiency and reducing ammonia escape.

[0052] The implementation principle of the W-flame boiler SNCR+SCR combined coordinated denitration system in Embodiment 1 of this application is as follows: The denitration control system 10 obtains the working parameters of the low-nitrogen burner 1 and controls the injection amount and concentration of the reducing agent of the reducing agent dilution metering system 2 through the SNCR control module 101. The SNCR temperature measurement group 3 monitors the temperature field in the area corresponding to the SNCR spray gun 22, opens the SNCR spray gun 22 with a temperature in the range of 850-1100°C, and adjusts the injection concentration and distribution of the reducing agent so that the average concentration of NO x in the burnout chamber 92 is not higher than 600 mg / m 3 . The SCR inlet flue gas partition measurement device 6 is used to evaluate the flue gas characteristics entering the SCR reactor 7 and provide data support for the partition adjustment of the precise ammonia injection regulation system 5. The SCR outlet grid sampling measurement device 8 is used to evaluate the flue gas characteristics after being treated by the SCR reactor 7, verify the overall performance of the denitration system, and provide feedback for optimizing the ammonia injection amount and uniformity. The denitration control system 10 collects the feedback data, so that the SNCR control module 101 controls the injection amount, concentration, and distribution of the reducing agent dilution metering system 2, so that the SCR control module 102 controls the injection amount, concentration, and distribution of the precise ammonia injection regulation system 5, so that the SNCR and SCR processes can be combined and coordinated for denitration.

[0053] Embodiment 2:

[0054] The W-flame boiler SNCR+SCR combined coordinated denitration system provided in Embodiment 2 of this application is different from Embodiment 1 in that: Reference Figure 7, the SNCR+SCR combined coordinated denitration system of the W-flame boiler further includes a driving device 20, and the driving device 20 includes a support base 201, a moving driving source 202, a sliding seat 203, a rotating driving source 204 and a connecting rod 205. The support base 201 is fixedly connected to the top side of the reactor shell 73. The moving driving source 202 is specifically a cylinder. The body of the moving driving source 202 is fixedly connected to the support base 201, and the output end of the moving driving source 202 is fixedly connected to the sliding seat 203. The sliding seat 203 is slidably connected to the support base 201, and the connecting rod 205 is rotatably connected to the sliding seat 203. The rotating driving source 204 is specifically a motor. The body of the rotating driving source 204 is fixedly connected to the sliding seat 203, and the output end of the rotating driving source 204 drives the connecting rod 205 to rotate, and the connecting rod 205 extends into the reactor shell 73.

[0055] Reference Figure 7 , in this embodiment, the catalyst layer 71 includes a dynamic catalyst layer 711 and a static catalyst layer 712. The static catalyst layer 712 is fixedly connected to one side of the reactor shell 73 close to the outlet, and the dynamic catalyst layer 711 is located on the side of the static catalyst layer 712 away from the outlet of the reactor shell 73. There are two dynamic catalyst layers 711, and the two dynamic catalyst layers 711 are arranged at intervals, and both of the two dynamic catalyst layers 711 are fixedly connected to the connecting rod 205. When the rotating driving source 204 drives the connecting rod 205 to rotate, the connecting rod 205 drives the two dynamic catalyst layers 711 to rotate, so that the surface of the catalyst layer 71 can contact the flue gas more evenly and fully, reducing the possibility of local ash accumulation and blockage. It can also increase the relative movement between the flue gas and the surface of the catalyst layer 71, enabling the active sites of the catalyst to participate in the reaction more evenly and reducing local overload.

[0056] Reference Figure 7 , in this embodiment, when the dynamic catalyst layer 711 rotates, a small amount of flue gas will escape from between the dynamic catalyst layer 711 and the inner wall of the reactor shell 73, while the static catalyst layer 712 fits with the inner wall of the reactor shell 73, which can reduce the problem of flue gas escape.

[0057] Reference Figure 7 , a dust-brushing rod 206 is fixedly connected inside the reactor shell 73. The dust-brushing rod 206 is horizontally arranged. When the moving driving source 202 drives the sliding seat 203 to move, the dynamic catalyst layer 711 can be brought into contact with the dust-brushing rod 206. The dynamic catalyst layer 711 rotates, enabling the dust-brushing rod 206 to brush off the dust on the surface of the dynamic catalyst layer 711, reducing the problem of blockage on the surface of the dynamic catalyst layer 711 and improving the service life of the dynamic catalyst layer 711.

[0058] Reference Figure 7In this embodiment, the SCR control module 102 is electrically connected to the mobile drive source 202 and the rotating drive source 204 respectively. The SCR control module 102 can control the rotation speed of the dynamic catalyst layer 711 to balance the power consumption of the rotating drive source 204 and the adequacy of the contact between the dynamic catalyst layer 711 and the flue gas. As time goes by, the dynamic catalyst layer 711 will gradually accumulate dust, causing the reaction rate to decrease. The SCR outlet grid sampling and measuring device 8 monitors the NO at the outlet of the SCR reactor 7. x Concentration, if the outlet NO of SCR reactor 7 x The concentration gradually increases, indicating that the denitration efficiency of the catalyst layer 71 decreases. The decrease in reaction rate can be compensated by appropriately increasing the amount of ammonia injection to maintain the outlet NO x The concentration reaches the standard, and the distribution of ammonia in the flue is optimized through the ammonia spray grid 52 and the ammonia spray branch leveling valve 514 to ensure that the ammonia and NO x If the SCR outlet grid sampling and measuring device 8 detects the NO at the outlet of the SCR reactor 7 x When the concentration rises to a predetermined value, the SCR control module 102 controls the mobile driving source 202 to drive the sliding seat 203 to move, so that the dynamic catalyst layer 711 contacts the dust brushing rod 206, thereby performing a dust cleaning operation on the dynamic catalyst layer 711. After a certain period of use, the dynamic catalyst layer 711 and the static catalyst layer 712 are promptly inspected and replaced to restore the denitration efficiency.

[0059] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A W-flame boiler SNCR+SCR combined coordinated denitration system, comprising a boiler (9), wherein the boiler (9) comprises a combustion chamber (91), a burnout chamber (92) and a flue, characterized in that: Also includes: A low-nitrogen burner (1), the low-nitrogen burner (1) being mounted on the combustion chamber (91); A reducing agent dilution and metering system (2), wherein the reducing agent dilution and metering system (2) sprays the reducing agent into the burnout chamber (92); an SNCR temperature measurement group (3), the SNCR temperature measurement group (3) being arranged on the burnout chamber (92), the SNCR temperature measurement group (3) monitoring the temperature distribution in the burnout chamber (92); A precise ammonia injection regulating system (5), wherein the precise ammonia injection regulating system (5) injects ammonia gas into the flue; An SCR inlet flue partition measurement device (6), wherein the SCR inlet flue partition measurement device (6) monitors the concentration distribution of nitrogen oxides in the flue; An SCR reactor (7), the SCR reactor (7) being in communication with the flue; An SCR outlet grid sampling and measuring device (8), the SCR outlet grid sampling and measuring device (8) being arranged at an outlet side of the SCR reactor (7), the SCR outlet grid sampling and measuring device (8) monitoring the concentration distribution of nitrogen oxides at the outlet of the SCR reactor (7); A denitration control system (10), wherein the denitration control system (10) is provided with an SNCR control module (101) and an SCR control module (102); the denitration control system (10) respectively collects parameters of the low-nitrogen burner (1), data of the SNCR temperature measurement group (3), data of the SCR inlet flue partition measurement device (6), and data of the SCR outlet grid sampling measurement device (8), so that the SNCR control module (101) controls the concentration and distribution of the reducing agent sprayed by the reducing agent dilution metering system (2), and the SCR control module (102) controls the concentration and distribution of ammonia sprayed by the precise ammonia spray adjustment system (5).

2. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 1, characterized in that: The reducing agent dilution and metering system (2) comprises a dilution and metering pipeline network (21) and an SNCR injector group, the SNCR control module (101) is electrically connected to the dilution and metering pipeline network (21), and the dilution and metering pipeline network (21) comprises a dilution water pipeline assembly and a urea solution pipeline assembly; The dilution water pipeline assembly is fed with dilution water, the urea solution pipeline assembly is fed with urea solution, the dilution water pipeline assembly and the urea solution pipeline assembly are mixed and then communicated with the SNCR injector assembly, the SNCR injector assembly is installed in the burnout chamber (92), and the SNCR injector assembly injects a mixture of dilution water and urea solution into different areas in the burnout chamber (92).

3. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 2, characterized in that: The dilution water pipeline assembly comprises a dilution water pipeline, on which a dilution water switch valve (211), a dilution water regulating valve (212) and a dilution water flow meter (213) are provided; The urea solution pipeline assembly comprises a urea solution pipeline, on which a urea solution switch valve (215), a urea solution regulating valve (216) and a urea solution flow meter (217) are arranged; the SNCR control module (101) is electrically connected to the dilution water switch valve (211), the dilution water regulating valve (212), the dilution water flow meter (213), the urea solution switch valve (215), the urea solution regulating valve (216) and the urea solution flow meter (217), respectively.

4. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 1, characterized in that: The precise ammonia injection regulation system (5) comprises an ammonia dilution pipeline network (51), an ammonia injection grid (52) and a urea hydrolyzer (53); the SCR control module (102) is electrically connected to the ammonia dilution pipeline network (51); the urea hydrolyzer (53) is in communication with the ammonia dilution pipeline network (51); the ammonia injection grid (52) is in communication with the ammonia dilution pipeline network (51); The ammonia dilution pipe network (51) is provided with two input ends, dilution air is introduced into one input end of the ammonia dilution pipe network (51), and the urea hydrolyzer (53) processes the urea solution to obtain ammonia and inputs the ammonia into the other input end of the ammonia dilution pipe network (51); The ammonia injection grid (52) is arranged in the flue, and the ammonia injection grid (52) is used to inject a mixed gas of ammonia and dilution air into different areas in the flue.

5. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 4, characterized in that: The ammonia dilution pipe network (51) comprises an input main pipe, a gas mixer (513), a branch pipe and an output pipe; a plurality of the input main pipes are respectively connected to the gas mixer (513), and ammonia and dilution air are respectively introduced into the input main pipes; an ammonia injection main pipe switch valve (511) and an ammonia injection main pipe regulating valve (512) are connected to the input main pipe, the branch pipes are respectively connected to the gas mixer (513) and the plurality of the output pipes, the branch pipes are connected to an ammonia injection branch leveling valve (514), the output pipes are connected to an ammonia injection branch pipe manual valve (515), and the output pipes are connected to the ammonia injection grid (52).

6. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 1, characterized in that: The SCR reactor (7) comprises a catalyst layer (71), a rectifying grid (72) and a reactor shell (73); the reactor shell (73) is in communication with the flue; the rectifying grid (72) is arranged at the inlet of the reactor shell (73); and the catalyst layer (71) is arranged in the reactor shell (73).

7. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 6, characterized in that: The catalyst layer (71) comprises a dynamic catalyst layer (711) and a static catalyst layer (712); the static catalyst layer (712) is connected to the reactor shell (73); the flue gas passes through the dynamic catalyst layer (711) and the static catalyst layer (712) in sequence; the reactor shell (73) is connected to a driving device (20); the driving device (20) drives the dynamic catalyst layer (711) to rotate.

8. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 7, characterized in that: The driving device (20) comprises a rotational driving source (204) and a connecting rod (205); the output end of the rotational driving source (204) is connected to the connecting rod (205); the connecting rod (205) is connected to the dynamic catalyst layer (711); and the rotational driving source (204) drives the dynamic catalyst layer (711) to rotate via the connecting rod (205).

9. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 8, characterized in that: The driving device (20) further comprises a supporting base (201), a movable driving source (202), a sliding seat (203) and a dust brushing rod (206), wherein the movable driving source (202) is arranged on the supporting base (201), the sliding seat (203) is slidably connected to the supporting base (201), and the rotating driving source (204) is connected to the sliding seat (203); the dust brushing rod (206) is connected to the reactor shell (73); the movable driving source (202) drives the sliding seat (203) to slide, so that the dynamic catalyst layer (711) contacts the dust brushing rod (206), and the dust brushing rod (206) brushes the dynamic catalyst layer (711).

10. A W-flame boiler SNCR+SCR combined coordinated denitration system according to claim 9, characterized in that: The SCR control module (102) is electrically connected to the mobile drive source (202) and the rotation drive source (204), respectively, and the SCR control module (102) controls the start-up of the mobile drive source (202) and the rotation speed of the rotation drive source (204), respectively.

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