One-dimensional reactor network system for staged ammonia injection of hearth of ammonia-doped combustion boiler in coal-fired power plant

Abstract

The invention provides a one-dimensional reactor network system for staged ammonia injection of a hearth of an ammonia-doped combustion boiler in a coal-fired power plant. The one-dimensional reactor network system comprises a mixer, a main combustion zone front reactor, a main combustion zone tail reactor and a burn-out zone reactor which are connected in sequence, the mixer is respectively connected with the fuel conveyor and the gas conveyor; the main combustion area tail reactor is connected with an ammonia gas conveyor; the burnout zone reactor is connected with a burnout air conveyor; and the sizes of the main combustion zone front reactor, the main combustion zone tail reactor and the burnout zone reactor are all obtained by reducing the actual hearth size of the prototype boiler. The one-dimensional reactor network system for staged ammonia injection of the hearth of the ammonia-doped combustion boiler of the coal-fired power plant is established on the basis of a numerical simulation method, the association degree with the actual hearth size is high, the working condition that ammonia gas is injected along the hearth can be effectively simulated, and then the ammonia-coal co-combustion performance and migration and conversion path mechanisms of various components and elements are studied.

Description

Technical Field

[0001] This invention relates to the field of boiler combustion technology in coal-fired power plants, and more particularly to a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler. Background Technology

[0002] Ammonia, as a substitute or partial substitute for fossil fuels, plays a significant role in achieving carbon and NOx emission reduction in large-scale coal-fired power plants. Compared to hydrogen, ammonia has a higher volumetric energy density and exhibits better safety in storage and transportation, making it more suitable for large-scale industrial energy scenarios. However, ammonia's poor ignition performance and low reactivity significantly limit its practical application in production, especially in situations where high nitrogen input may lead to increased NOx emissions, easily causing NOx emissions from coal-fired power plants to exceed standards.

[0003] CN111581894A discloses an intelligent monitoring system and method for SCR ammonia injection, including an SCR inlet measurement module, an ammonia injection control module, a computational model simulation module, and a dynamic database monitoring system. The SCR inlet measurement module, located at the inlet of the SCR reactor, is connected to the input of the computational model simulation module, while the output of the computational model simulation module is connected to the dynamic database. The ammonia injection control module intelligently injects ammonia into the SCR reactor using NOx and NH3 distribution data from the dynamic database. The computational model simulation module determines the corresponding NOx and NH3 distribution data under various operating conditions based on the operating data collected by the SCR inlet measurement module and the computational simulation model. However, this SCR reactor has a low correlation with the actual furnace size and cannot accurately simulate the condition of ammonia gas being injected along the furnace.

[0004] CN116959594A discloses a method and system for predicting NOx concentration distribution at the economizer outlet based on CFD data. This includes establishing a full-furnace physical model; acquiring historical boiler operating parameters; performing batch CFD calculations on furnace combustion and pollutant generation processes; establishing a furnace combustion parameter database; developing a zoning scheme for the economizer outlet section; preprocessing and extracting feature vectors from boiler operating parameter data; determining the algorithm and parameters of the prediction model; establishing a NOx concentration prediction model for economizer outlet zones; acquiring real-time boiler operating parameters; predicting the NOx concentration distribution at the economizer outlet in real time; visualizing the NOx concentration distribution at the economizer outlet section; calculating the total ammonia injection amount and zoned ammonia injection amount to formulate an ammonia injection strategy; and executing the ammonia injection action. While this technology uses a three-dimensional CFD model to simulate the combustion process of ammonia mixed with pulverized coal, CFD models cannot be used to calculate the chemical kinetic reaction pathways of each component, nor can they be used to analyze the migration and transformation laws of nitrogen elements. Furthermore, the three-dimensional model involves a large computational load and is time-consuming.

[0005] Existing technologies lack reactor model systems and equipment that can rapidly calculate chemical kinetic reaction pathways and component migration and transformation laws, correspond to boiler furnace dimensions, and simulate ammonia injection conditions along the furnace.

[0006] Therefore, it is of great significance to develop a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler that can accurately simulate the ammonia injection conditions along the furnace. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler. It adopts a reactor at the front of the main combustion zone, a reactor at the tail of the main combustion zone, and a reactor in the burnout zone, which are obtained by scaling down the actual furnace size of the prototype boiler, to accurately simulate the combustion performance of ammonia-coal co-combustion at the one-dimensional reaction network level under the condition of ammonia injection along the furnace, as well as the mechanism of migration and transformation paths of various components and elements. The invention also studies the staged ammonia injection technology to improve the combustion performance of the mixed fuel and reduce the NOx emission level at the furnace outlet under ammonia-blended conditions.

[0008] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-infused combustion boiler, the one-dimensional reactor network system comprising a mixer, a front reactor of the main combustion zone, a tail reactor of the main combustion zone, and a burnout zone reactor connected in sequence. The mixer is connected to both the fuel delivery unit and the gas delivery unit. The tail reactor of the main combustion zone is connected to the ammonia conveyor. The burnout zone reactor is connected to the burnout air conveyor; The dimensions of the reactors at the front of the main combustion zone, the reactor at the rear of the main combustion zone, and the reactor in the burnout zone are all obtained by scaling down the actual furnace dimensions of the prototype boiler.

[0009] The one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler described in this invention is reasonable. It is derived by reducing the actual furnace size of the prototype boiler to obtain the front reactor of the main combustion zone, the tail reactor of the main combustion zone, and the burnout zone reactor. This makes the one-dimensional reactor network system highly correlated with the actual furnace size, and can accurately simulate the ammonia-coal co-combustion performance and the migration and transformation path mechanism of various components and elements at the reaction network level under the condition of ammonia injection along the furnace in an actual boiler.

[0010] Preferably, the front reactor of the main combustion zone, the tail reactor of the main combustion zone, and the burnout zone reactor are all fully stirred reactors.

[0011] Preferably, the total length of the reactor at the front of the main combustion zone and the reactor at the rear of the main combustion zone is 30-40 cm. Adjusting the length distribution of the two reactors simulates the injection of ammonia gas from different heights in the boiler furnace. Compared to existing simple one-dimensional reactor systems, which typically only have air inlet channels at the inlets of the main combustion zone and the burnout zone, this system can better simulate the injection of ammonia gas along the furnace, separating it from fuel or burnout air.

[0012] Preferably, the burnout zone reactor is connected to the flue gas outlet.

[0013] Secondly, the present invention also provides a simulation method for a staged ammonia injection one-dimensional reactor network system in the furnace of a coal-fired power plant ammonia-blended combustion boiler as described in the first aspect, the simulation method comprising: The fuel conveyor and gas conveyor deliver fuel and air to the mixer for premixing, and then send it to the reactor at the front of the main combustion zone to simulate the process of injecting the mixture into the furnace. Ammonia gas is delivered to the tail reactor of the main combustion zone by an ammonia gas conveyor, simulating the process of ammonia gas being injected separately from the middle of the furnace. The burnout air conveyor delivers burnout air to the burnout zone reactor, simulating the process of burnout air being injected separately from the center of the furnace.

[0014] The simulation method for a staged ammonia injection one-dimensional reactor network system in a coal-fired power plant ammonia-blended combustion boiler, as described in this invention, utilizes this system. Based on numerical simulation, it studies the ammonia injection location in a supercritical single-furnace, counter-current combustion once-through boiler. According to the furnace structure, the temperature and combustion characteristics of pulverized coal within the furnace, the method simulates the process of injecting the mixture into the furnace, the process of injecting ammonia gas separately from the center of the furnace, and the process of injecting burnout air separately from the center of the furnace. This allows for rapid determination of the impact of ammonia gas injection at different furnace heights on the combustion performance and component conversion mechanism of the ammonia-coal co-combustion process, as well as its influence on the migration and conversion pathway of nitrogen. Compared to existing technologies that use three-dimensional CFD models to simulate the combustion process of ammonia-blended pulverized coal, the simulation method of this invention significantly shortens the computation time of the numerical model.

[0015] Preferably, the simulation method further includes a gas conveyor supplying gases other than air to the mixer to simulate pulverized coal combustion in a boiler furnace under different atmospheres.

[0016] Preferably, the simulation method further includes selecting a combustion mechanism file package to simulate the combustion process of the staged ammonia injection one-dimensional reactor network system in the furnace of the coal-fired power plant ammonia-blended combustion boiler under different fuel composition conditions, and obtaining the calculation results of the combustion characteristics and component parameters of the reactor in the front of the main combustion zone, the reactor in the tail of the main combustion zone, and the reactor in the burnout zone.

[0017] Preferably, the combustion mechanism file package includes gas phase dynamics files, surface dynamics files, and transport files.

[0018] The combustion mechanism file package described in this invention can be the GRI 3.0 mechanism package, which contains many common gas components. This mechanism includes 53 components and 325 elementary reactions, and is applicable to the syngas combustion process; it can be a mechanism package such as TIAN, which contains detailed NH3 / CH4 flame kinetic data. This mechanism package contains 84 components and 703 elementary reactions, and is applicable to the calculation of ammonia-doped low-pressure premixed flames; it can be a mechanism package such as MEI, which contains ammonia combustion kinetic data. This mechanism package contains 38 components and 265 elementary reactions, and is applicable to the calculation of ammonia-doped laminar flames under oxygen-rich and high-pressure environments.

[0019] Preferably, the different fuel composition conditions include ammonia content in the fuel, air flow rate, burnout air flow rate, fuel composition, temperature, and pressure.

[0020] Preferably, the fuel components are simplified to CH4, HCN and NH3.

[0021] As a preferred technical solution of the present invention, the simulation method includes: The fuel conveyor and gas conveyor deliver fuel and air to the mixer for premixing, and then send it to the reactor at the front of the main combustion zone to simulate the process of injecting the mixture into the furnace. Ammonia gas is delivered to the tail reactor of the main combustion zone by an ammonia gas conveyor, simulating the process of ammonia gas being injected separately from the middle of the furnace. The burnout air conveyor delivers burnout air to the burnout zone reactor, simulating the process of burnout air being injected separately from the center of the furnace; The simulation method also includes a gas conveyor supplying gases other than air to the mixer to simulate pulverized coal combustion in a boiler furnace under different atmospheres; The simulation method also includes selecting a combustion mechanism file package to simulate the combustion process of the staged ammonia injection one-dimensional reactor network system in the furnace of the coal-fired power plant ammonia-blended combustion boiler under different fuel composition conditions, and obtaining the calculation results of the combustion characteristics and component parameters of the reactor in the front of the main combustion zone, the reactor in the tail of the main combustion zone, and the reactor in the burnout zone. The combustion mechanism documentation package includes gas phase kinetics documentation, surface kinetics documentation, and transport documentation; the different fuel composition conditions include ammonia content in the fuel, air flow rate, burnout air flow rate, fuel composition, temperature, and pressure; the fuel composition is simplified to CH4, HCN, and NH3.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The dimensions of the front reactor of the main combustion zone, the tail reactor of the main combustion zone, and the burnout zone reactor in the staged ammonia injection one-dimensional reactor network system of the coal-fired power plant ammonia-blended combustion boiler provided by the present invention are all obtained by proportionally reducing the actual furnace partition dimensions of the prototype boiler. It can simulate the ammonia-coal co-combustion performance and the migration and transformation path mechanism of various components and elements at the reaction network level under the condition of ammonia injection along the furnace of the actual boiler. It solves the problem that the existing one-dimensional reactor system uses two or three reactors to simulate the main combustion zone and burnout zone of the boiler furnace, resulting in a low correlation between the furnace reactor network size and the actual furnace size. (2) The one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant boiler provided by the present invention has a simple structure and reasonable design. It solves the problems that the existing technology cannot use three-dimensional CFD models to simulate and calculate the combustion process of ammonia mixed with pulverized coal, and cannot be used to calculate the chemical kinetic reaction paths of each component, let alone analyze the migration and transformation laws of elements in the combustion process, as well as the problems that the three-dimensional CFD model has a large amount of calculation and takes a long time. (3) The total length of the reactor at the front of the main combustion zone and the reactor at the tail of the main combustion zone in the one-dimensional reactor network system of the ammonia-infused combustion boiler furnace of the coal-fired power plant provided by the present invention remains unchanged. By adjusting the length distribution of the two, the ammonia-coal co-combustion condition of ammonia gas injected from different heights in the main combustion zone of the furnace can be simulated. This solves the problem that the simple one-dimensional reactor system of the prior art only has an air intake channel at the inlet of the main combustion zone and the burnout zone, and cannot simulate the condition of ammonia gas being injected separately from fuel or burnout air along the furnace. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler in Embodiment 1 of the present invention.

[0024] Figure 2 This is a comparison chart of the calculation results of the full-load operating condition model in Embodiment 1 of the present invention with the furnace temperature and NOx concentration of the prototype boiler.

[0025] Figure 3 This is a graph showing the temperature changes of each reactor at different ammonia injection heights in Embodiment 2 of the present invention.

[0026] Figure 4 This is a graph showing the NOx concentration changes in each reactor at different ammonia injection heights in Example 2 of the present invention.

[0027] Figure 5 This is a statistical chart of NO generation and ROP consumption in the front of the main combustion zone in Embodiment 2 of the present invention.

[0028] Figure 6 This is a diagram showing the main pathway of NO generation and consumption at the tail end of the main combustion zone in Embodiment 2 of the present invention under the condition of no ammonia addition.

[0029] Figure 7 This is a diagram showing the main pathway of NO generation and consumption at the tail end of the main combustion zone under the premixed ammonia condition in Embodiment 2 of the present invention.

[0030] Figure 8 This is a diagram showing the main pathways of NO generation and consumption at the tail of the main combustion zone under the conditions of 10 cm, 20 cm, and 30 cm length of the reactor at the front of the main combustion zone in Embodiment 2 of the present invention.

[0031] In the diagram: 1-Fuel conveyor; 2-Gas conveyor; 3-Mixer; 4-Front reactor of main combustion zone; 5-Ammonia conveyor; 6-Tail reactor of main combustion zone; 7-Burnout air conveyor; 8-Burnout zone reactor; 9-Flue gas outlet. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0034] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Example 1 This embodiment provides a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler, as shown in the schematic diagram below. Figure 1 As shown.

[0037] The ammonia-infused combustion boiler furnace staged ammonia injection one-dimensional reactor network system of the coal-fired power plant includes a mixer 3, a front reactor 4 of the main combustion zone, a tail reactor 6 of the main combustion zone, and a burnout zone reactor 8 connected in sequence. The mixer 3 is connected to the fuel conveyor 1 and the gas conveyor 2 respectively; The tail reactor 6 of the main combustion zone is connected to the ammonia conveyor 5; The burnout zone reactor 8 is connected to the burnout air conveyor 7; The dimensions of the front reactor 4, the rear reactor 6, and the burnout zone reactor 8 are all 1 / 45.8 of the actual furnace dimensions of the prototype boiler, and their cross-sectional dimensions are all 21.5 × 14.6 cm. 2 The length of the reactor 4 at the front of the main combustion zone and the reactor 6 at the rear of the main combustion zone are 35 cm. The lengths of the two can be freely allocated to simulate the working conditions of injecting ammonia gas from different heights in the boiler furnace.

[0038] The burnout zone reactor 8 is 20 cm long.

[0039] The reactor 4 at the front of the main combustion zone, the reactor 6 at the rear of the main combustion zone, and the reactor 8 in the burnout zone are all fully stirred reactors.

[0040] The burnout zone reactor 8 is connected to the flue gas outlet 9.

[0041] This embodiment also provides a simulation method for a staged ammonia injection one-dimensional reactor network system in a coal-fired power plant ammonia-blended combustion boiler furnace as described above, the simulation method comprising: Fuel conveyor 1 and gas conveyor 2 deliver fuel and air to mixer 3 for premixing, and then send it into reactor 4 at the front of the main combustion zone to simulate the process of injecting the mixture into the furnace. Ammonia conveyor 5 delivers ammonia to reactor 6 at the tail end of the main combustion zone, simulating the process of ammonia being injected separately from the middle of the furnace. The burnout air conveyor 7 delivers burnout air to the burnout zone reactor 8, simulating the process of burnout air being injected separately from the center of the furnace; The simulation method also includes selecting a combustion mechanism file package to simulate the combustion process of the staged ammonia injection one-dimensional reactor network system in the furnace of the coal-fired power plant ammonia-blended combustion boiler under different fuel composition conditions, and obtaining the calculation results of the combustion characteristics and component parameters of the main combustion zone front reactor 4, the main combustion zone tail reactor 6 and the burnout zone reactor 8. The combustion mechanism documentation package includes gas phase kinetics documentation, surface kinetics documentation, and transport documentation; the different fuel composition conditions include ammonia content in the fuel, air flow rate, burnout air flow rate, fuel composition, temperature, and pressure; the fuel composition is simplified to CH4, HCN, and NH3.

[0042] In this embodiment, the temperature of the reactor 4 at the front of the main combustion zone is set to 873.15 K, the temperature of the reactor 6 at the rear of the main combustion zone is set to 1173.15 K, and the temperature of the reactor 8 in the burnout zone is set to 873.15 K.

[0043] The pressure of all reactors was set to 1 atm.

[0044] This embodiment is for ammonia-free operation, and the commonly used combustion mechanism GRI 3.0 file is imported. The GRI 3.0 mechanism includes the following mechanism files: Since the GRI 3.0 mechanism does not cover the reaction pathways of pulverized coal and its pyrolysis-produced coke and volatile matter products, the imported fuel components are reasonably simplified: According to the classical coal pyrolysis model, the main nitrogen-containing product of volatile matter is HCN. At the same time, based on the fact that the volume ratio of HCN to total nitrogen-containing volatile matter (HCN+NH3) during bituminous coal pyrolysis is about 0.7, NH3 and HCN are selected to simulate the nitrogen-containing components after coal pyrolysis; in addition, considering that methane (CH4) is the main component in bituminous coal volatile matter, CH4 is used to replace the fuel components to create a high-temperature environment in the furnace.

[0045] According to the full-load combustion condition, the flow rate, composition, temperature and pressure parameters of fuel, air and burnout air are input into the inlet of fuel conveyor 1, gas conveyor 2, ammonia conveyor 5 and burnout air conveyor 7 respectively, as shown in Table 1. Adjust the length of the front reactor 4 in the main combustion zone to 10 cm and the length of the rear reactor 6 in the main combustion zone to 25 cm. Click Calculate, and the model will sequentially calculate the combustion process of the front reactor 4, the rear reactor 6, and the burnout reactor 8 in the main combustion zone. Finally, the calculated results of the combustion characteristics and component parameters of the front reactor 4, the rear reactor 6, and the burnout reactor 8 are obtained and compared with the corresponding parameters of the prototype boiler unit.

[0046] The comparison between the calculation results of the full-load operating condition model in this embodiment and the furnace temperature and NOx concentration of the prototype boiler is shown in the figure below. Figure 2 As shown. From Figure 2It can be observed that the one-dimensional reactor network system for staged ammonia injection in the furnace of the coal-fired power plant ammonia-blended combustion boiler in this embodiment shows a good correlation between the furnace temperature distribution and the prototype boiler in terms of both trend and numerical value. While the NOx distribution of the prototype boiler is consistent in trend with that of the one-dimensional reactor network system in this embodiment, the overall numerical value is lower. This is mainly due to the simplification of the inlet fuel composition, and the fact that the characteristics of the one-dimensional reactor model significantly reduce the oxidation reaction of pulverized coal during the pyrolysis stage. In summary, the reactors in the one-dimensional reactor network system of this embodiment can effectively reflect the temperature and NOx emission characteristics within the furnace of the prototype boiler unit.

[0047] Example 2 This embodiment provides a simulation method for a one-dimensional reactor network system of staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler as described in Embodiment 1. The simulation method is based on a 20% ammonia blending condition and analyzes the influence of varying ammonia injection locations.

[0048] Similar to Example 1, the commonly used combustion mechanism GRI 3.0 file was imported, and the composition of the imported fuel was simplified to CH4, HCN, and NH3. The fuel composition for the 20% ammonia blending condition under full load was calculated using the commonly used heat balance method, meaning the total heat of the fuel remained unchanged before and after ammonia blending. The specific ammonia blending ratio formula is as follows: In the formula: NP represents the ammonia doping ratio (%); The heat of combustion of NH3 in imported fuel / MJ; The total calorific value of the imported fuel is expressed in MJ.

[0049] The flow rate, composition, temperature, and pressure parameters of fuel, air, and burnout air under full-load conditions with 20% ammonia added were input at the inlet of fuel conveyor 1, gas conveyor 2, ammonia conveyor 5, and burnout air conveyor 7, respectively, as shown in Table 2. The lengths of the front reactor 4 and the rear reactor 6 of the main combustion zone are adjusted to the following four operating conditions: ① The length of reactor 4 at the front of the main combustion zone is 0 cm, and the length of reactor 6 at the rear of the main combustion zone is 35 cm; ②The length of reactor 4 at the front of the main combustion zone is 10 cm, and the length of reactor 6 at the rear of the main combustion zone is 25 cm; ③ The length of reactor 4 at the front of the main combustion zone is 20 cm, and the length of reactor 6 at the rear of the main combustion zone is 15 cm; ④ The length of reactor 4 at the front of the main combustion zone is 30 cm, and the length of reactor 6 at the rear of the main combustion zone is 5 cm.

[0050] The combustion processes of the four operating conditions were calculated separately. The model sequentially calculated the combustion processes of the reactor 4 at the front of the main combustion zone, the reactor 6 at the rear of the main combustion zone, and the reactor 8 in the burnout zone. Finally, the combustion characteristics and component parameters of the reactor 4 at the front of the main combustion zone, the reactor 6 at the rear of the main combustion zone, and the reactor 8 in the burnout zone were calculated and the temperature and NOx calculation results of the four operating conditions were statistically compared.

[0051] The temperature variation of each reactor at the ammonia injection height in this embodiment is shown in the following figure. Figure 3 As shown in the figure, the NOx concentration changes in each reactor at different ammonia injection heights are as follows: Figure 4 As shown. Figure 3 and Figure 4 In the diagram, PSR1, PSR2, and PSR3 represent reactor 4 at the front of the main combustion zone, reactor 6 at the rear of the main combustion zone, and reactor 8 in the burnout zone, respectively; the black line represents the ammonia blending condition.

[0052] from Figure 3 As can be seen, the temperatures of both the front and rear parts of the main combustion zone under different ammonia injection height conditions after ammonia addition are higher than those under the condition without ammonia addition.

[0053] As the ammonia injection position increases, the temperature at the front of the main combustion zone gradually rises. The temperature increase is particularly significant when the ammonia injection height increases from 0 cm to 10 cm. This is presumably because when ammonia is injected from the PSR1 inlet, it forms a premixed atmosphere with the fuel and air. The premixed conditions increase the oxygen concentration in the initial stage of the ammonia reaction, promoting the complete reaction of ammonia and thus increasing the combustion temperature.

[0054] At the tail end of the main combustion zone, the temperature decreases as the ammonia injection height increases from 0 cm to 20 cm; when the ammonia injection height is further increased to 30 cm, the temperature rises slightly. Overall, the temperature decrease at the tail end of the main combustion zone can be attributed to the shorter residence time of ammonia in the main combustion zone due to the higher ammonia injection position; while when the ammonia injection position is closer to the burnout zone, the temperature of the mixed gas at the front outlet is higher, which has a certain effect on increasing the temperature of the tail reactor.

[0055] In all ammonia-infused operating conditions, the burnout zone temperature at different ammonia injection heights was significantly lower than that in the non-ammonia-infused condition. Furthermore, as the ammonia injection position increased, the burnout zone temperature gradually decreased, but the decrease was relatively limited.

[0056] Depend on Figure 4 It can be seen that the NOx concentration in both the main combustion zone and the burnout zone after ammonia blending is higher than that in the non-ammonia blending condition, indicating that regardless of whether the ammonia is staged or how the injection location changes, ammonia blending combustion will bring higher NO and NOx emission risks.

[0057] In the front of the main combustion zone, NOx concentration gradually decreases with increasing ammonia injection position, while in the rear of the main combustion zone and the burnout zone, NOx concentration increases with increasing ammonia injection position. Notably, the changes in NOx concentration are particularly significant in the main combustion zone and burnout zone as the ammonia injection height increases from 0 cm to 10 cm. This phenomenon indicates that, under non-premixed conditions, mixing ammonia with fuel and air significantly suppresses NO formation in the initial combustion phase, but simultaneously leads to increased NO emissions in the rear of the main combustion zone and the burnout zone. The increase in NOx emissions in the rear of the main combustion zone and the burnout zone with increasing ammonia injection position suggests that placing the ammonia injection point closer to the fuel combustion zone and further away from the burnout air region is more conducive to achieving NOx emission reduction.

[0058] The Rate of Production (ROP) of NO generation / consumption in the front of the main combustion zone was statistically compared for four operating conditions. The statistical chart of NO generation and consumption ROP in the front of the main combustion zone in this embodiment is shown below. Figure 5 As shown.

[0059] according to Figure 5 The results show that, under conditions without ammonia, the main NO formation pathways are R214 and R212, indicating that HNO is a key intermediate product in the initial stage of NO formation under these conditions. Its main consumption pathways involve elementary reactions R249 and R255 related to the CH3 and CH2 combustion intermediates, as detailed below: By statistically comparing the NO conversion pathways at the tail end of the main combustion zone under four operating conditions, the main migration and conversion pathways of nitrogen element were obtained. In this embodiment, under the condition without ammonia doping, the main pathway diagram of NO generation and consumption at the tail end of the main combustion zone is shown below. Figure 6 As shown in the figure. In this embodiment, under the premixed ammonia condition, the main pathway diagram for NO generation and consumption at the tail end of the main combustion zone is as follows. Figure 7 As shown in the diagram. In this embodiment, the main pathway diagrams for NO generation and consumption at the tail end of the main combustion zone are shown under the conditions of 10 cm, 20 cm, and 30 cm reactor lengths at the front of the main combustion zone. Figure 8 As shown.

[0060] contrast Figure 6-8 It can be seen that under the condition of no ammonia addition, NO mainly comes from HNO and NH, and its conversion direction is mainly HCN, H2O and HNCO; while under the condition of ammonia-coal premixed combustion, NO mainly comes from NCO, indicating the enhancement of CN-type reactions, and its main conversion direction is N2O, HNO, CO, N free radicals and NH.

[0061] By comparison Figure 7 and Figure 8It can be seen that when ammonia is injected along the path, the main sources of NO become HNO and NH again, and the reaction intensity of the HNO→NO pathway is significantly higher than that of NH→NO. At this time, the main conversion directions of NO are N2O, CO2 and H2O.

[0062] It should be noted that NH3→NH2→NH→HNO→NO and NH3→NH2→NH→NO are two typical NO formation pathways in pure ammonia combustion. Compared to premixed combustion, HNO components again become one of the main sources of NO when ammonia is injected along the combustion path. The significant increase in CO2 and H2O in the conversion products indicates the formation of a strong oxidizing atmosphere at the tail end of the main combustion zone, reflecting the significant impact of staged ammonia-coal injection on the local reaction environment.

[0063] In summary, the reactors in this model can quickly obtain the effects of ammonia injection from different furnace heights on the combustion performance and component conversion path intensity of the ammonia-coal co-combustion process, and also the effects on the migration and conversion path of nitrogen.

[0064] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler, characterized in that, The ammonia-infused combustion boiler furnace staged ammonia injection one-dimensional reactor network system of the coal-fired power plant includes a mixer, a front reactor of the main combustion zone, a tail reactor of the main combustion zone, and a burnout zone reactor connected in sequence. The mixer is connected to both the fuel delivery unit and the gas delivery unit. The tail reactor of the main combustion zone is connected to the ammonia conveyor. The burnout zone reactor is connected to the burnout air conveyor; The dimensions of the reactors at the front of the main combustion zone, the reactor at the rear of the main combustion zone, and the reactor in the burnout zone are all obtained by scaling down the actual furnace dimensions of the prototype boiler.

2. The one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler according to claim 1, characterized in that, The reactors at the front of the main combustion zone, the reactor at the rear of the main combustion zone, and the reactor in the burnout zone are all fully stirred reactors.

3. The one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler according to claim 1 or 2, characterized in that, The total length of the reactor at the front of the main combustion zone and the reactor at the rear of the main combustion zone is 30-40 cm. The length distribution of the two is adjusted to simulate the working condition of injecting ammonia gas from different heights in the boiler furnace.

4. The one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler according to any one of claims 1 to 3, characterized in that, The burnout zone reactor is connected to the flue gas outlet.

5. A simulation method for a one-dimensional reactor network system of staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler as described in any one of claims 1 to 4, characterized in that, The simulation method includes: The fuel conveyor and gas conveyor deliver fuel and air to the mixer for premixing, and then send it to the reactor at the front of the main combustion zone to simulate the process of injecting the mixture into the furnace. Ammonia gas is delivered to the tail reactor of the main combustion zone by an ammonia gas conveyor, simulating the process of ammonia gas being injected separately from the middle of the furnace. The burnout air conveyor delivers burnout air to the burnout zone reactor, simulating the process of burnout air being injected separately from the center of the furnace.

6. The simulation method according to claim 5, characterized in that, The simulation method also includes selecting a combustion mechanism file package to simulate the combustion process of the staged ammonia injection one-dimensional reactor network system in the furnace of the coal-fired power plant ammonia-blended combustion boiler under different fuel composition conditions, and obtaining the calculation results of the combustion characteristics and component parameters of the reactor in the front of the main combustion zone, the reactor in the tail of the main combustion zone, and the reactor in the burnout zone.

7. The simulation method according to claim 6, characterized in that, The combustion mechanism documentation package includes gas phase dynamics documentation, surface dynamics documentation, and transport documentation.

8. The simulation method according to claim 6, characterized in that, The different fuel composition conditions include ammonia content in the fuel, air flow rate, burnout air flow rate, fuel composition, temperature, and pressure.

9. The simulation method according to claim 8, characterized in that, The fuel components are simplified to CH4, HCN and NH3.

10. The use of a one-dimensional reactor network system for staged ammonia injection in the furnace of a coal-fired power plant ammonia-blended combustion boiler as described in any one of claims 1 to 4, characterized in that, Air or other gases are supplied to the mixer via a gas conveyor to simulate the combustion of pulverized coal in a boiler furnace under different gas environments.

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