An external circulating simulation reactor system and an external circulating simulation reaction method for a boiler furnace of a coal-fired power plant

Abstract

This invention provides a simulated external circulation reactor system and a simulated external circulation reaction method for a coal-fired power plant boiler furnace. The simulated external circulation reactor system includes a furnace partitioned reactor unit and an external circulation flue gas duct. The furnace partitioned reactor unit is used to simulate the lower part, middle part, upper part, lower part, and upper part of the main combustion zone in the furnace of a prototype boiler. The furnace partitioned reactor unit is connected to the external circulation flue gas duct and the furnace outlet respectively through a first distributor. The outlet of the external circulation flue gas duct returns the flue gas to the main combustion zone through a second distributor. This invention establishes a one-dimensional reactor network system for deep air staged combustion in a coal-fired power plant boiler furnace with dimensions and tuyeres highly matched to the prototype boiler and employing external flue gas circulation technology. This system is used to obtain the influence of different flue gas recirculation ratios under deep air staged combustion on the combustion performance and component conversion mechanism of the coal combustion process, especially the influence on the migration and conversion characteristics of nitrogen element.

Description

Technical Field

[0001] This invention belongs to the field of combustion technology, specifically relating to an external circulation simulation reactor system and an external circulation simulation reaction method for a coal-fired power plant boiler furnace. Background Technology

[0002] With increasing global emphasis on environmental protection, reducing nitrogen oxide (NOx) emissions from coal-fired power plants has become a crucial research area. Traditional coal-fired power plants generate significant amounts of NOx during combustion, and these gases are a major contributor to acid rain and photochemical smog, posing serious threats to the environment and human health. Therefore, developing effective combustion optimization technologies to reduce NOx emissions is of significant practical importance.

[0003] As a widely used low-NOx combustion technology, flue gas recirculation (FGR) introduces flue gas into the combustion zone of the furnace. By reducing the furnace temperature and decreasing the oxygen partial pressure in the reaction zone, it controls the combustion reaction rate and thus reduces NOx emissions. FGR is divided into two types: external recirculation and internal recirculation. External recirculation, which sends flue gas from the boiler outlet to the burner air inlet through external pipes, achieves good NOx emission reduction. This technology is also relatively simple to modify for boilers and can be used in conjunction with other low-NOx combustion technologies, thus showing promising application prospects in coal-fired boilers.

[0004] Currently, existing flue gas recirculation (FGR) technologies mostly use two or three reactors to simulate the main combustion zone and burnout zone of a boiler furnace. The simple furnace reactor networks with FGR devices built upon this foundation, due to the limited number of reactors, cannot simulate the actual operating conditions where flue gas is injected into the furnace from burners at different heights in varying distribution ratios. Furthermore, the dimensions of these models, especially the positions of the burners and tuyeres, have a low correlation with actual furnace dimensions, thus failing to simulate the actual combustion conditions of combustion gases within the furnace.

[0005] Therefore, it can be seen that the existing technology lacks a one-dimensional reactor model system and equipment with an external flue gas circulation device that corresponds to the boiler furnace size and tuyer position and can simulate flue gas being injected into the furnace in stages from burners at different heights with different distribution ratios. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a simulated reactor system and method for external circulation in a coal-fired power plant boiler furnace. Based on a numerical simulation method of a one-dimensional reactor at the chemical kinetics level, this invention studies the pulverized coal combustion performance and NOx emission performance of a (super)critical single-furnace, counter-current combustion once-through boiler with flue gas external circulation. Specifically, based on the furnace structure, the temperature characteristics and combustion characteristics of pulverized coal within the furnace, a one-dimensional reactor network system with deep air staged combustion in a coal-fired power plant boiler furnace, with dimensions and tuyeres highly matched to the prototype boiler and employing external flue gas circulation technology, is established. This system is used to obtain the influence of different flue gas recirculation ratios under deep air staged combustion on the combustion performance and component conversion mechanism of the coal combustion process, especially its influence on the migration and conversion characteristics of nitrogen.

[0007] To achieve this objective, the present invention employs the following technical solution: In a first aspect, the present invention provides a simulated external circulation reactor system for a coal-fired power plant boiler furnace, the simulated external circulation reactor system comprising a furnace zoned reactor unit and an external circulation flue gas pipeline; The furnace zone reactor unit includes a first PSR reactor, a second PSR reactor, a third PSR reactor, a fourth PSR reactor and a fifth PSR reactor arranged in series, which are used to simulate the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone and the upper part of the burnout zone in the furnace of the prototype boiler, respectively. The fifth PSR reactor is connected to the external circulation flue gas pipeline and the furnace outlet respectively through the first splitter, and is used to adjust the injection ratio of flue gas delivered to the external circulation flue gas pipeline; The outlet of the external circulation flue gas duct is connected to a second diverter that redirects the flue gas to the lower part of the main combustion zone, the middle part of the main combustion zone, and the upper part of the main combustion zone, respectively, in order to adjust the injection ratio of the flue gas redirected to the lower part of the main combustion zone, the middle part of the main combustion zone, and the upper part of the main combustion zone.

[0008] In this invention, both the furnace partition reactor unit and the reactor in the external circulating flue gas pipeline are fully stirred reaction reactors (PSR reactors). Two distributors are used to adjust the ratio of recirculated flue gas to outlet flue gas and the ratio of recirculated flue gas injected into the furnace from the lower, middle, and upper parts of the main combustion zone, respectively. This accurately simulates the operating conditions of flue gas injected into the furnace from various tuyeres in different stages and flow rates. Furthermore, it yields the mechanisms of ammonia-coal mixed combustion performance (such as temperature and pressure) and the migration and transformation paths of various components (such as O2, CO, NO, and NOx) and elements at the reaction network level under different flue gas recirculation rates, especially the influence of staged air injection into the furnace on the migration and transformation characteristics of nitrogen.

[0009] As a preferred embodiment of the present invention, a first burner mixer is provided between the first PSR reactor and the second PSR reactor.

[0010] Preferably, a second burner mixer is provided between the second PSR reactor and the third PSR reactor.

[0011] Preferably, a side burnout air mixer is provided between the third PSR reactor and the fourth PSR reactor.

[0012] Preferably, a burnout air mixer is provided between the fourth PSR reactor and the fifth PSR reactor.

[0013] Preferably, the external circulating flue gas duct is a PSR reactor.

[0014] As a preferred embodiment of the present invention, the outlet of the second distributor is divided into three branches, which are respectively connected to the first PSR reactor, the first burner mixer, and the second burner mixer.

[0015] As a preferred embodiment of the present invention, the inlet of the first PSR reactor is provided with a first fuel delivery pipe and a first air delivery pipe.

[0016] Preferably, the inlet of the first burner mixer is provided with a second fuel delivery pipe and a second air delivery pipe.

[0017] Preferably, the inlet of the second burner mixer is provided with a third fuel delivery pipe and a third air delivery pipe.

[0018] As a preferred embodiment of the present invention, the inlet of the side burnout air mixer is provided with a side burnout air delivery pipe.

[0019] Preferably, the inlet of the burnout air mixer is provided with a burnout air delivery pipe.

[0020] This invention uses six fully premixed reactors, six burner inlets, two burnout air inlets, and three flue gas recirculation paths to accurately simulate the furnace of a boiler with an external flue gas recirculation device. The size of each reactor, the position of the burner and the tuyeres are scaled down proportionally according to the prototype boiler. This allows for accurate simulation of the actual operating conditions where fuel / air / flue gas is injected from various tuyeres in the furnace in different stages and flow rates. This enables the simulation of boiler furnace combustion under different flue gas recirculation rates.

[0021] As a preferred embodiment of the present invention, the size ratio of each PSR reactor in the furnace zone reactor unit to the size of the prototype boiler furnace is 1:40~50, for example, it can be 1:40, 1:42, 1:44, 1:46, 1:48 or 1:50, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the length of the external circulating flue gas duct is the sum of the lengths of each PSR reactor in the furnace zone reactor unit.

[0023] In this invention, the dimensions of each PSR reactor in the furnace zone reactor unit are obtained by proportionally reducing the actual furnace dimensions of the prototype boiler. This is used to simulate the five zones of the boiler furnace, and their positions are matched with the burner and tuyer positions of the prototype unit. This can accurately simulate the working conditions of air being injected from each tuyer in the furnace with different components, flow rates, and staged patterns.

[0024] Secondly, the present invention provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, the method comprising: (1) Obtain target parameters: The target parameters are the coal type parameters, air volume parameters, flue gas recirculation rate, flue gas recirculation ratio and temperature parameters of the target coal-fired power plant; (2) Based on the target parameters described in step (1) and combined with the external circulation simulation reactor system provided in the first aspect, the predicted value of nitrogen oxide emissions at the furnace outlet is obtained.

[0025] As a preferred technical solution of the present invention, the coal type parameters in step (1) are extracted from the real-time monitoring system of the target coal-fired power plant, and the coal type parameters are: the nitrogen content and volatile matter characteristics of the coal under the current load.

[0026] Preferably, the air volume parameters include: fuel flow rate, fuel composition, and air flow rate extracted from the real-time monitoring system for the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, and the upper part of the burnout zone.

[0027] Preferably, the temperature parameters include the temperatures of the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, and the upper part of the burnout zone extracted from the real-time monitoring system.

[0028] Preferably, the target parameter in step (1) further includes heat loss parameters, which are: heat loss parameters of the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct, obtained according to the flue gas circulation rate and the recirculation ratio.

[0029] In this invention, the air volume parameter is delivered via a fuel delivery pipeline, an air delivery pipeline, a side burnout air delivery pipeline, or a burnout air delivery pipeline. Any component gas included in the combustion mechanism can be input, such as atmospheres other than air, such as CO, N2, O2, or O2 / CO2 mixtures, to simulate pulverized coal combustion in the boiler furnace under different atmospheres. Alternatively, other component gaseous fuels besides ammonia, such as H2, HCN, NCO, HNCO, and C2H2, can be injected to simulate the combustion of fuels with different components. In addition, the temperature, pressure and heat loss parameters of the fully premixed reactor in this invention can be adjusted according to the load differences of the boiler, thereby simulating the combustion in the boiler furnace under different load conditions.

[0030] As a preferred technical solution of the present invention, the calculation process of the predicted value of nitrogen oxide emissions at the furnace outlet in step (2) is as follows: The target parameters are input into a pre-trained external circulation simulated reactor system, so that the external circulation simulated reactor system calculates the amount of nitrogen oxides generated in the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct, respectively, through the combustion process of the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct.

[0031] The sum of nitrogen oxide generation in the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct is used as the predicted value of nitrogen oxide emissions at the furnace outlet.

[0032] More specifically, in the external circulation simulation reactor system of this invention, a suitable combustion mechanism file is selected and imported based on the differences in the fuel composition used. The flow rate, composition, and temperature parameters of fuel, air, and burnout air are input according to the required operating conditions (e.g., full load under air atmosphere). Based on the required flue gas recirculation rate, the flow ratios (i.e., the ratio of recirculated flue gas to outlet flue gas) entering the external circulation flue gas duct and outlet are input in the first distributor. According to the load conditions, the flow ratios of flue gas entering the lower, middle, and upper parts of the main combustion zone are input in the second distributor. The heat loss parameters of the six fully premixed reactors are adjusted. Clicking "Calculate" will cause the model to sequentially calculate the combustion / chemical reaction processes in the lower, middle, and upper parts of the main combustion zone, the lower and upper parts of the burnout zone, and the external circulation flue gas duct, ultimately obtaining the calculated results of the combustion characteristics and composition parameters for the lower, middle, and upper parts of the main combustion zone, the lower and upper parts of the burnout zone.

[0033] Combustion mechanism packages used for calculations typically include two files: gas-phase kinetics and surface kinetics. Some more comprehensive packages also include transport files. Currently, numerous combustion mechanism packages with varying application ranges have been developed by laboratories both domestically and internationally. Appropriate packages can be directly selected based on differences in fuel composition and imported into the model settings. For example, the widely used GRI 3.0 mechanism includes many common gas components, containing 53 components and 325 elementary reactions, suitable for syngas combustion processes; TIAN and other mechanisms include detailed NH3 / CH4 flame kinetic data, containing 84 components and 703 elementary reactions, suitable for calculating ammonia-doped low-pressure premixed flames; MEI and other mechanism packages include ammonia combustion kinetic data, containing 38 components and 265 elementary reactions, suitable for calculating ammonia-doped laminar flames under oxygen-rich and high-pressure environments.

[0034] It is worth noting that when the predicted value of nitrogen oxide emissions at the furnace outlet obtained in step (2) is ≥300 mg / m³, 3 At that time, the target parameters of the target coal-fired power plant need to be adjusted to ensure that nitrogen oxide emissions meet environmental standards.

[0035] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0036] Compared with the prior art, the present invention has the following beneficial effects: (1) Existing technologies often use two or three reactors to simulate the main combustion zone and burnout zone of a boiler furnace. Based on this, the simple furnace reactor network with flue gas external circulation device is established. Due to the small number of reactors, it is impossible to simulate the actual working conditions of flue gas being injected into the furnace from burners at different heights with different distribution ratios. This invention uses two diverters to adjust the ratio of recirculated flue gas to outlet flue gas and the ratio of recirculated flue gas being injected into the furnace from the lower part of the main combustion zone, the middle part of the main combustion zone, and the upper part of the main combustion zone, respectively. This allows for the accurate simulation of the working conditions of flue gas being injected into the furnace from various tuyeres with different staged modes and flow rates. This leads to the discovery of the ammonia-coal mixed combustion performance (such as temperature and pressure) and the migration and conversion paths of various components (such as O2, CO, NO and NOx) and elements at the reaction network level under different flue gas recirculation rates. In particular, it shows the influence of staged air injection into the furnace on the migration and conversion characteristics of N elements. (2) Existing technologies often use two or three reactors to simulate the main combustion zone and burnout zone of a boiler furnace. Based on this, the reactor dimensions, burner and tuyer positions in the simple furnace reactor network with flue gas external circulation device are significantly different from the actual situation of the boiler furnace. Compared with the existing technologies, the present invention uses 6 fully premixed reactors, 6 burner inlets, 2 burnout air inlets and 3 flue gas recirculation paths to accurately simulate the boiler furnace with flue gas external circulation device. The reactor dimensions, burner and tuyer positions are scaled down proportionally according to the prototype boiler, which can accurately simulate the actual working conditions of fuel / air / flue gas being injected from each tuyer in the furnace in different stages and flow rates, and thus be used to simulate the boiler furnace combustion under different flue gas recirculation rates. (3) Existing technologies lack a one-dimensional reactor model system with a flue gas recirculation device that injects different fuels, gas compositions, and flow rates into the furnace from different burners and tuyeres in stages. Compared with existing technologies, the simulated reactor system provided by this invention can simulate the combustion of boiler furnaces under different fuels and atmospheres by adjusting the fuel / gas composition input at the fuel inlet, air inlet, side burnout air inlet, or burnout air inlet. (4) The simulated reactor system provided by the present invention can simulate the combustion of boiler furnace under different load conditions by optimizing and adjusting the temperature, pressure and heat loss parameters of the PSR reactor in the furnace zone reactor unit. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the simulated reactor system for external circulation in a coal-fired power plant boiler furnace provided in Embodiment 1 of the present invention; Figure 2 A schematic diagram of the NOx concentration at the outlet of the fifth PSR reactor provided as an application example of the present invention; Figure 3 A schematic diagram of the NO generation / consumption reaction intensity at the outlet of the fifth PSR reactor, provided as an application example of the present invention; Figure 4 A schematic diagram of the main migration and conversion pathway of N element from NH3 to NO in the fifth PSR reactor provided as an application example of the present invention; Wherein, 1 is the first fuel delivery pipeline, 2 is the first air delivery pipeline, 3 is the first PSR reactor, 4 is the second fuel delivery pipeline, 5 is the second air delivery pipeline, 6 is the first burner mixer, 7 is the second PSR reactor, 8 is the third fuel delivery pipeline, 9 is the third air delivery pipeline, 10 is the second burner mixer, 11 is the third PSR reactor, 12 is the side burnout air delivery pipeline, 13 is the side burnout air mixer, 14 is the fourth PSR reactor, 15 is the burnout air delivery pipeline, 16 is the burnout air mixer, 17 is the fifth PSR reactor, 18 is the first distributor, 19 is the external circulating flue gas pipeline, 20 is the furnace outlet, and 21 is the second distributor. Detailed Implementation

[0038] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0039] In the prototype boiler described in the following embodiments, the 10-15m area inside the furnace is the main combustion zone, and the 30-35m area is the burnout zone; in the direction perpendicular to the ground upward, the lower part, the middle part and the upper part of the main combustion zone are equally divided into the main combustion zone, and the lower part and the upper part of the burnout zone are equally divided into the burnout zone.

[0040] Example 1 This embodiment provides a simulated reactor system for external circulation in a coal-fired power plant boiler furnace, such as... Figure 1 As shown, the external circulation simulated reactor system includes a furnace zoned reactor unit and an external circulation flue gas duct 19; The furnace zone reactor unit includes a first PSR reactor 3, a second PSR reactor 7, a third PSR reactor 11, a fourth PSR reactor 14 and a fifth PSR reactor 17 arranged in series, which are used to simulate the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone and the upper part of the burnout zone in the furnace of the prototype boiler, respectively. The inlet of the first PSR reactor 3 is directly provided with a first fuel delivery pipe 1 and a first air delivery pipe 2 to simulate the process of fuel and air being injected from the first and second air inlets of the lower burner nozzle; The first PSR reactor 3 and the second PSR reactor 7 are connected by a first combustor mixer 6, which is also connected to a second fuel delivery pipe 4 and a second air delivery pipe 5 to simulate the process of fuel and air being injected from the first and second air inlets of the middle layer burner nozzle. The second PSR reactor 7 and the third PSR reactor 11 are connected by a second burner mixer 10, which is also connected to a third fuel delivery pipe 8 and a third air delivery pipe 9 to simulate the process of fuel and air being injected from the first and second air inlets of the upper burner nozzle. The third PSR reactor 11 and the fourth PSR reactor 14 are connected by a side burnout air mixer 13, which is connected to a side burnout air delivery pipe 12 to simulate the process of burnout air being injected into the combustion mixture from the side burnout air nozzle. The fourth PSR reactor 14 and the fifth PSR reactor 17 are connected by a burnout air mixer 16, which is connected to a burnout air delivery pipe 15 to simulate the process of burnout air being injected into the combustion mixture from the burnout air nozzle. The fifth PSR reactor 17 is connected to the external circulating flue gas duct 19 and the furnace outlet 20 respectively through the first diverter 18; the outlet of the external circulating flue gas duct 19 is connected to the first PSR reactor 3, the first burner mixer 6 and the second burner mixer 10 respectively through the second diverter 21, so as to adjust the proportion of circulating flue gas injected into the furnace from the lower part of the main combustion zone, the middle part of the main combustion zone and the upper part of the main combustion zone respectively.

[0041] The dimensions of the first PSR reactor 3, the second PSR reactor 7, the third PSR reactor 11, the fourth PSR reactor 14, and the fifth PSR reactor 17 are all obtained by scaling down the actual furnace size of the prototype boiler by 1 / 45.8, and the cross-sectional dimensions of all five reactors are set to 48.4 × 33.7 cm. 2 The first PSR reactor 3 is 10cm long, the second PSR reactor 7 is 10cm long, the third PSR reactor 11 is 7.2cm long, the fourth PSR reactor 14 is 5.8cm long, and the fifth PSR reactor 17 is 10.4cm long. These reactors are used to accurately simulate the positions of the three rows of burners and the two rows of burnout air at the furnace height. The external circulating flue gas duct 19, which connects the flue gas outlet and the fuel inlet, has a length of 43.4cm, which is the total length of the furnace, and a cross-sectional dimension of 10×10cm². The temperature of the first PSR reactor 3 is set to 1173.15 K, the temperature of the first burner mixer 6 is set to 1273.15 K, the temperature of the second PSR reactor 7 is set to 1473.15 K, the temperature of the second burner mixer 10 is set to 1673.15 K, the temperature of the third PSR reactor 11 is set to 1473.15 K, the temperature of the side burnout air mixer 13 is set to 1273.15 K, the temperature of the fourth PSR reactor 14 is set to 1173.15 K, the temperature of the burnout air mixer 16 is set to 1273.15 K, the temperature of the fifth PSR reactor 17 is set to 1273.15 K, the temperature of the external circulation flue gas duct 19 is set to 873.15 K, and the pressure of all reactors is set to 1 atm.

[0042] Application Example 1 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; Taking a 600kW ultra-supercritical furnace variable-pressure once-through boiler as an example, the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler includes: (1) Obtain target parameters: The target parameters are the coal type parameters, air volume parameters, flue gas recirculation rate and recirculation ratio, temperature parameters and heat loss parameters of the target coal-fired power plant; The coal parameters include: the nitrogen content of the coke of bituminous coal is 0.75%, and the nitrogen content of the volatile matter is 1.74%. The airflow parameters include: fuel flow rate, fuel composition, and air flow rate extracted from the real-time monitoring system for the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, and the upper part of the burnout zone; The fuel components are CH4, HCN and NH3; the composition, content, temperature parameters and pressure of the inlet fuel and air under full load conditions are shown in Table 1. Table 1 The flue gas recirculation rate and recirculation ratio include: a flue gas recirculation rate of 5%; a recirculated flue gas ratio of 5% distributed to the external recirculated flue gas duct 19 through the first distributor 18, and a recirculated flue gas ratio of 95% distributed to the main combustion zone; The proportion of flue gas distributed to the first PSR reactor through the second distributor is 40%, the proportion of flue gas distributed to the second PSR reactor is 40%, and the proportion of flue gas distributed to the third PSR reactor is 20%. (2) Based on the target parameters described in step (1) and the external circulation simulated reactor system provided in Example 1, the predicted value of nitrogen oxide emissions at the furnace outlet is obtained; The combustion process in the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct was calculated using a numerical simulation method based on chemical kinetics. The calculation results for the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct were obtained.

[0043] Application Example 2 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 10%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 10%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 90%.

[0044] Application Example 2 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 10%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 10%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 90%.

[0045] Application Example 3 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 15%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 15%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 85%.

[0046] Application Example 4 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 20%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first diverter 18 is adjusted to 20%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 80%.

[0047] Application Example 5 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 25%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 25%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 75%.

[0048] Application Example 6 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 30%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 30%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 70%.

[0049] Application Example 7 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 35%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first diverter 18 is adjusted to 35%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 65%.

[0050] Application Example 8 This application example provides a method for simulating external circulation reaction in a coal-fired power plant boiler furnace, wherein the external circulation simulation reaction method is carried out using the coal-fired power plant boiler furnace external circulation simulation reactor system provided in Example 1; The difference between the simulated reaction method for external circulation in the furnace of a coal-fired power plant boiler and Application Example 1 is only that: In this application example, the flue gas recirculation rate is adjusted to 40%; and the proportion of recirculated flue gas distributed to the external recirculated flue gas duct 19 through the first distributor 18 is adjusted to 40%, and the proportion of recirculated flue gas distributed to the main combustion zone is adjusted to 60%.

[0051] By comparing the calculated NOx concentration at the outlet of the fifth PSR reactor obtained using the method provided in the above application example, the influence of the degree of non-premixing on the NOx concentration in each region of the furnace is obtained, such as... Figure 2 As shown; The calculation results of the NO generation / consumption elementary reactions at the outlet of the fifth PSR reactor, obtained by using the method provided in the above application example, yielded the main NO generation / consumption reactions in the upper part of the burnout zone, such as... Figure 3 As shown; Taking the fifth PSR reactor as an example, the calculation results of the main NO generation / consumption pathways were statistically analyzed, and the main migration and conversion pathways of N element from NH3 to NO in the upper part of the burnout zone were obtained, such as... Figure 4 As shown.

[0052] In summary, this invention establishes a one-dimensional reactor network system for deep air staged combustion in a coal-fired power plant boiler, with dimensions and tuyeres that are highly matched to the prototype boiler and employing external flue gas recirculation technology. This system is used to obtain the influence of different flue gas recirculation ratios under deep air staged combustion on the combustion performance and component conversion mechanism of the coal combustion process, especially on the migration and conversion characteristics of nitrogen.

[0053] 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 simulated reactor system for external circulation in a coal-fired power plant boiler furnace, characterized in that, The external circulation simulated reactor system includes a furnace zoned reactor unit and an external circulation flue gas duct. The furnace zone reactor unit includes a first PSR reactor, a second PSR reactor, a third PSR reactor, a fourth PSR reactor and a fifth PSR reactor arranged in series, which are used to simulate the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone and the upper part of the burnout zone in the furnace of the prototype boiler, respectively. The fifth PSR reactor is connected to the external circulation flue gas pipeline and the furnace outlet respectively through the first splitter, and is used to adjust the injection ratio of flue gas delivered to the external circulation flue gas pipeline; The outlet of the external circulation flue gas duct is connected to a second diverter that redirects the flue gas to the lower part of the main combustion zone, the middle part of the main combustion zone, and the upper part of the main combustion zone, respectively, in order to adjust the injection ratio of the flue gas redirected to the lower part of the main combustion zone, the middle part of the main combustion zone, and the upper part of the main combustion zone.

2. The external circulation simulation reactor system for coal-fired power plant boilers according to claim 1, characterized in that, A first burner mixer is provided between the first PSR reactor and the second PSR reactor; Preferably, a second burner mixer is provided between the second PSR reactor and the third PSR reactor; Preferably, a side burnout air mixer is provided between the third PSR reactor and the fourth PSR reactor; Preferably, a burnout air mixer is provided between the fourth PSR reactor and the fifth PSR reactor.

3. The coal-fired power plant boiler furnace external circulation simulation reactor system according to claim 2, characterized in that, The outlet of the second splitter is divided into three branches, which are respectively connected to the first PSR reactor, the first burner mixer, and the second burner mixer.

4. The coal-fired power plant boiler furnace external circulation simulation reactor system according to claim 3, characterized in that, The inlet of the first PSR reactor is provided with a first fuel delivery pipe and a first air delivery pipe; Preferably, the inlet of the first burner mixer is provided with a second fuel delivery pipe and a second air delivery pipe; Preferably, the inlet of the second burner mixer is provided with a third fuel delivery pipe and a third air delivery pipe.

5. The coal-fired power plant boiler furnace external circulation simulation reactor system according to claim 2, characterized in that, The inlet of the side burnout air mixer is provided with a side burnout air delivery pipe; Preferably, the inlet of the burnout air mixer is provided with a burnout air delivery pipe.

6. The simulated reactor system for external circulation in a coal-fired power plant boiler furnace according to any one of claims 1-5, characterized in that, The size ratio of each PSR reactor in the furnace zone reactor unit to the size of the prototype boiler furnace is 1:(40~50); Preferably, the length of the external circulating flue gas duct is the sum of the lengths of each PSR reactor in the furnace zone reactor unit.

7. A method for simulating external circulation reaction in a coal-fired power plant boiler furnace, characterized in that, The external circulation simulation reaction method includes: (1) Obtain target parameters: The target parameters are the coal type parameters, air volume parameters, flue gas recirculation rate, flue gas recirculation ratio and temperature parameters of the target coal-fired power plant; (2) Based on the target parameters described in step (1) and in conjunction with the external circulation simulation reactor system described in any one of claims 1-6, the predicted value of nitrogen oxide emissions at the furnace outlet is obtained.

8. The external circulation simulation reaction method according to claim 7, characterized in that, The coal type parameters mentioned in step (1) are extracted from the real-time monitoring system of the target coal-fired power plant. The coal type parameters are: the nitrogen content and volatile matter characteristics of the coal under the current load.

9. The external circulation simulation reaction method according to claim 8, characterized in that, The airflow parameters include: fuel flow rate, fuel composition, and air flow rate extracted from the real-time monitoring system for the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, and the upper part of the burnout zone; Preferably, the temperature parameters include the temperatures of the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, and the upper part of the burnout zone extracted from the real-time monitoring system.

10. The external circulation simulation reaction method according to any one of claims 7-9, characterized in that, The calculation process for the predicted nitrogen oxide emissions at the furnace outlet in step (2) is as follows: The target parameters are input into a pre-trained external circulation simulated reactor system, so that the external circulation simulated reactor system can calculate the amount of nitrogen oxides generated in the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct, respectively, through the combustion process of the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct. The sum of nitrogen oxide generation in the lower part of the main combustion zone, the middle part of the main combustion zone, the upper part of the main combustion zone, the lower part of the burnout zone, the upper part of the burnout zone, and the external circulation flue gas duct is used as the predicted value of nitrogen oxide emissions at the furnace outlet.

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