Device system and method for cooperative control of boiler ammonia escape and NOx and product treatment

Abstract

The invention provides a boiler ammonia escape and NOx cooperative control and product treatment device system and method. The device system comprises an adsorption and catalytic conversion module, a combustion process feedback control module and a product collection and treatment module. All the modules cooperate with one another, changes of various parameters in the filtering combustion process are monitored in real time, the ammonia escape and NOx emission conditions are comprehensively analyzed, and cooperative control and optimization control of ammonia escape and NOx are achieved by automatically adjusting operation parameters of a combustor. Chemical products obtained through catalytic treatment are recycled through the product collection and treatment module, pollutant emission is reduced, additional economic benefits are brought, and the device has good application and popularization prospects.

Description

Technical Field

[0001] This invention relates to the field of boiler combustion technology, and in particular to a device system and method for the coordinated control of ammonia escape and NOx in boilers and the treatment of byproducts. Background Technology

[0002] In the energy sector, ammonia-infused combustion technology in pulverized coal boilers has gained increasing attention and application as a means to improve combustion efficiency and reduce emissions of traditional pollutants. However, in actual operation, this technology has given rise to two prominent problems: ammonia slip and NOx emissions. Ammonia slip not only wastes resources but also reacts with acidic gases in the atmosphere to generate secondary particulate matter, exacerbating smog pollution. NOx, as one of the major air pollutants, can cause environmental problems such as acid rain and photochemical smog, posing serious threats to the ecological environment and human health.

[0003] Currently, most existing technologies employ single methods to address ammonia slip and NOx emissions separately. For example, ammonia slip is mainly controlled by optimizing the burner structure and adjusting the ammonia injection rate; while NOx emissions rely on denitrification technologies such as selective catalytic reduction (SCR) and selective non-catalytic reduction (SNR). These methods not only fail to achieve synergistic control of both emissions but also fail to effectively utilize the potential resources generated during combustion, resulting in energy waste.

[0004] CN105953259A discloses a method for synergistic optimization of the operation of a coal-fired power plant boiler system and a denitrification system, including the following steps: optimizing and adjusting the operation of the pulverizing system; optimizing and adjusting the operation of the combustion system; optimizing and adjusting the operation of the denitrification system; coupling and optimizing the NOx emission control of the coal-fired boiler with the ammonia slip control of the SCR denitrification system, and determining the optimal oxygen content range for the coal-fired boiler under different loads and the optimal opening range of the burnout air nozzles within the optimal oxygen content range, based on the distribution characteristics of the reducing atmosphere in the near-wall zone of the furnace water-cooled wall and the ammonia slip situation during denitrification; and determining the optimal denitrification efficiency range of the denitrification system under different loads.

[0005] CN108870384A discloses a method for synergistic optimization of combustion and SNCR denitrification in a low-NOx combustion circulating fluidized bed boiler. The method involves laying insulation material in the water-cooled wall area of ​​the boiler furnace. First, a full-system numerical simulation of the boiler's combustion in the furnace and the SNCR denitrification reaction at the cyclone separator is performed using CFD software. Then, an insulation material layout scheme is formulated based on the actual boiler operating conditions and verified in the CFD software. While meeting ultra-low emission requirements, the final placement and area of ​​the insulation material are determined using the coke mass concentration at the furnace outlet and the ammonia escape rate at the cyclone separator outlet as evaluation indicators. By laying insulation material in the water-cooled wall area of ​​the circulating fluidized bed boiler, the temperature of the flue gas entering the cyclone separator is increased, which improves the SNCR denitrification efficiency and avoids excessive ammonia injection. Simultaneously, the insulation material installation raises the temperature, reducing the carbon content of the fly ash at the furnace outlet, thus achieving synergistic optimization of combustion and denitrification.

[0006] CN115930220A discloses a plasma-assisted ammonia combustion and ultra-low NOx emission system and method for a coal-fired boiler. It employs plasma-assisted combustion, online pyrolysis technology, and integrated ammonia-hydrogen reburning denitrification technology to achieve stable and efficient ammonia combustion and ultra-low NOx emissions at the furnace outlet. Ammonia gas enters the furnace in two paths. One path passes through an ammonia-coal mixed burner located two layers below the main combustion zone to achieve ammonia-coal co-combustion, utilizing plasma torch technology for ignition and combustion support. The plasma torch is loaded on the combustion air side. The other path undergoes online pyrolysis into an ammonia-hydrogen mixture via a plasma-thermal co-pyrolysis unit, and then enters the furnace through an ammonia-hydrogen reburning injector located in the reburning zone for combustion and NOx reduction.

[0007] However, the methods mentioned above for controlling NOx emissions during boiler combustion still have problems such as high processing costs and low level of intelligence. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a device system and method for the coordinated control of ammonia slip and NOx in boilers and the treatment of byproducts. Through the synergistic action of an adsorption and catalytic conversion module, a combustion process feedback control module, and a product collection and treatment module, the changes of various parameters during the combustion process are monitored in real time, the ammonia slip and NOx emission status are comprehensively analyzed, and the optimized control of ammonia slip and NOx is achieved by automatically adjusting the burner operating parameters. The treated chemical products are recovered through the product collection and treatment module, which not only reduces pollutant emissions but also brings additional economic benefits, reduces production costs, and improves resource utilization efficiency.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a device system for the coordinated control of boiler ammonia escape and NOx and the treatment of products, the device system comprising an adsorption and catalytic conversion module, a combustion process feedback control module and a product collection and treatment module;

[0011] The adsorption and catalytic conversion module is installed inside the boiler flue; the adsorption and catalytic conversion module is connected to the product collection and processing module; the combustion process feedback control module is connected to the boiler.

[0012] The combustion process feedback control module includes a multi-parameter real-time monitoring unit and an intelligent control algorithm and parameter adjustment unit connected in sequence; the multi-parameter real-time monitoring unit monitors the boiler's combustion parameters and transmits them to the intelligent control algorithm and parameter adjustment unit; the intelligent control algorithm and parameter adjustment unit regulates the boiler's combustion after model analysis and calculation.

[0013] The intelligent control algorithm and parameter adjustment unit includes a physical mechanism model, a data-driven prediction model, and a multi-objective optimization control function. The intelligent control algorithm and parameter adjustment unit utilizes a parameter adaptive learning mechanism to optimize the control of the physical mechanism model and the data-driven prediction model.

[0014] The device system for coordinated control of ammonia slip and NOx emissions and product treatment in boilers described in this invention is applicable to pulverized coal boilers. The adsorption and catalytic conversion module is installed in the boiler flue. Flue gas generated by the boiler enters the adsorption and catalytic conversion module, which converts escaped ammonia and incompletely converted NOx into valuable chemical products. Subsequently, the product collection and treatment module collects, purifies, and stores the chemical products. A combustion process feedback control module monitors parameters such as temperature, pressure, ammonia to pulverized coal ratio, and flue gas composition during boiler combustion in real time. Based on this real-time monitoring data, an intelligent control algorithm and parameter adjustment unit employ a hybrid modeling strategy, combining the physicochemical mechanism of boiler combustion with a data-driven approach. Through multi-objective optimization control functions, coordinated control of ammonia slip and NOx emissions is achieved. This intelligent control algorithm and parameter adjustment unit can simulate the interrelationships and changes in various parameters during boiler combustion. By analyzing real-time monitoring data, it can quickly determine whether the current combustion state is at the optimal state for coordinated control of ammonia slip and NOx emissions. If a deviation is detected, the intelligent control algorithm and parameter adjustment unit will automatically generate adjustment commands to precisely adjust operating parameters such as the air distribution ratio, burner angle, and the delivery rates of ammonia and pulverized coal. This invention, through the coordinated operation of various system modules, improves the overall operational stability and reliability of boiler combustion, reduces equipment maintenance costs and downtime, and achieves a balance between environmental and economic benefits. It has significant application value in the fields of environmental protection and resource utilization in boiler combustion.

[0015] Preferably, the multi-parameter real-time monitoring unit includes a temperature sensor, a pressure sensor, and a gas composition analyzer to monitor the temperature, pressure, ammonia to pulverized coal ratio, and flue gas composition during the boiler combustion process in real time.

[0016] In this invention, a temperature sensor monitors the temperature distribution in different areas inside the boiler in real time, providing crucial data for determining the combustion state and reaction process; a pressure sensor monitors the furnace pressure and flue pressure, ensuring the combustion system operates within a safe and stable pressure range; and a gas composition analyzer accurately detects various components in the flue gas, such as ammonia, NOx, oxygen, and carbon monoxide concentrations. These sensors can quickly and accurately collect data and transmit it to the control center in real time via a high-speed data transmission network, providing a reliable basis for subsequent intelligent control. This invention does not impose specific limitations on the placement of the temperature sensor, pressure sensor, and gas composition analyzer; those skilled in the art can set them appropriately according to actual needs.

[0017] Preferably, the product collection and processing module includes a preliminary collection unit, a purification unit, and a storage unit connected in sequence.

[0018] Secondly, the present invention also provides a method for the coordinated control of boiler ammonia slip and NOx and the treatment of its byproducts, wherein the method is performed using the apparatus system for the coordinated control of boiler ammonia slip and NOx and the treatment of its byproducts as described in the first aspect; the method includes:

[0019] The flue gas generated by the boiler enters the adsorption and catalytic conversion module, which captures the escaped ammonia and NOx, and converts them into chemical products through adsorbents and catalysts, which then enter the product collection and treatment module. Throughout the process, the combustion process feedback control module monitors the boiler's combustion status through a multi-parameter real-time monitoring unit, and automatically adjusts the air distribution ratio, burner angle, and ammonia and pulverized coal delivery rates of the boiler burner through intelligent control algorithms and parameter adjustment units, thereby coordinating the control of ammonia escape and NOx emissions.

[0020] The method for synergistic control of boiler ammonia escape and NOx and product treatment described in this invention allows escaped ammonia, which is originally considered a pollutant, and incompletely converted NOx to undergo an oxidation-reduction reaction under the action of a catalyst, generating valuable chemical products such as ammonium nitrate. This improves resource utilization and reduces production costs. Through intelligent regulation of the combustion process feedback control module, the overall operational stability and reliability of the pulverized coal boiler combustion system are enhanced.

[0021] Preferably, the adsorbent in the adsorption and catalytic conversion module uses ZSM-5 molecular sieve as the main framework, loaded with CuO, Fe2O3, and CeO2. CuO and Fe2O3 form a Cu-Fe synergistic catalytic system, while CeO2 acts as an oxygen carrier, improving the efficiency of NO oxidation to NO2. The adsorbent possesses a hierarchical porous structure and bifunctional active sites, achieving selective enrichment of NH3 and NOx.

[0022] After the adsorbent described in this invention becomes saturated, it is purged with hot air at 180–220°C to release high concentrations of NH3 and NOx, which then enter the catalyst for resource-based conversion. The adsorbent is regenerated and recycled. The integrated design achieves coupling of the adsorption-catalysis process, improving the overall processing efficiency of the adsorption and catalytic conversion module.

[0023] Preferably, the average pore size of the ZSM-5 molecular sieve is 0.5 to 0.6 nm, for example, it can be 0.5 nm, 0.52 nm, 0.54 nm, 0.56 nm, 0.58 nm or 0.6 nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] The ZSM-5 molecular sieve of this invention preferably has an average pore size of 0.5-0.6 nm, which matches the molecular size of ammonia and NOx. This allows gas molecules to enter the pores smoothly, and the adsorbent can preferentially and efficiently capture these two gases, thereby enriching escaped ammonia and NOx and creating favorable conditions for subsequent catalytic conversion.

[0025] Preferably, the loading of CuO is 5 to 8 wt%, for example, it can be 5 wt%, 5.5 wt%, 6 wt%, 6.8 wt%, 7.5 wt%, or 8 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] The loading of Fe2O3 is 3 to 5 wt%, for example, it can be 3 wt%, 3.5 wt%, 4 wt%, 4.2 wt%, 4.8 wt%, or 5 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] The loading of CeO2 is 2 to 3 wt%, for example, it can be 2 wt%, 2.2 wt%, 2.4 wt%, 2.6 wt%, 2.8 wt%, or 3 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the catalyst in the adsorption and catalytic conversion module adopts a V2O5-WO3-TiO2 ternary system, wherein V2O5 provides the main redox active sites, promotes the SCR reaction of NH3 and NOx to generate N2 and H2O, and some NH3 and NO2 further react to generate ammonium nitrate; WO3 acts as a structural stabilizer to prevent V2O5 grain growth and enhance surface acidity; TiO2 is anatase type with a large specific surface area, providing a highly dispersed support and enhancing the dispersion of active components.

[0029] Preferably, the V2O5 content in the catalyst is 3 to 5 wt%, for example, it can be 3 wt%, 3.5 wt%, 4 wt%, 4.2 wt%, 4.8 wt%, or 5 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] The WO3 content is 8 to 10 wt%, for example, it can be 8 wt%, 8.3 wt%, 8.6 wt%, 9 wt%, 9.5 wt%, or 10 wt%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] Preferably, the specific surface area of ​​the TiO2 is >100m². 2 / g, for example, could be 101m 2 / g, 105m 2 / g、110m 2 / g, 120m 2 / g, 130m 2 / g or 150m 2 / g, etc., but not limited to the listed values; other unlisted values ​​within this range also apply.

[0032] Preferably, the physicochemical mechanism model in the intelligent control algorithm and parameter adjustment unit includes a combustion efficiency model, a NOx emission reduction model, and an ammonia slip suppression model.

[0033] The combustion efficiency model described in this invention is based on the Arrhenius equation to describe the chemical reaction rate during the combustion of pulverized coal, taking into account the influence of factors such as temperature, pressure, and reactant concentration on the reaction rate.

[0034] Preferably, the combustion efficiency model is:

[0035]

[0036] Where r is the reaction rate of pulverized coal combustion with ammonia; A is the pre-exponential factor; E is the activation energy; [Fuel] concentration; [O2] is the oxygen concentration; R is the ideal gas constant; T is the reaction temperature; a is the first reaction order; and b is the second reaction order.

[0037] Preferably, the relationship between the fuel conversion rate x and the reaction rate r of pulverized coal combustion with ammonia is as follows:

[0038]

[0039] Where nf0 is the initial fuel quantity; V is the reaction volume.

[0040] Preferably, the combustion efficiency η is a function of fuel conversion rate x and heat loss as follows:

[0041]

[0042] Among them, Q loss Heat loss due to heat dissipation and smoke exhaust; Q theoretical denoted as , where is the total heat generated by the complete combustion of fuel; x represents the fuel conversion rate.

[0043] The NOx emission reduction model described in this invention considers thermal NOx based on the Zeldovich mechanism, describing the process of NOx formation from the reaction of nitrogen and oxygen at high temperatures. The formation rate of thermal NOx is affected by the reaction temperature T, oxygen concentration [O2], and residence time t. The empirical model for fuel-type NOx is as follows:

[0044] [NO x ] 燃料型 =f(N) fuel , α, T, t)

[0045] Where: N fuel denoted as α, where α is the mass fraction of nitrogen in the fuel; α is the excess air coefficient; T is the combustion temperature; and t is the gas residence time.

[0046] Preferably, the NOx emission reduction model is as follows:

[0047]

[0048] Where [NO] represents the concentration of NO generated; [NO] 平衡 t is the equilibrium concentration of NO at this temperature; k is the reaction rate constant; t is the residence time of the gas in the high-temperature region. The partial pressure of oxygen;

[0049] The ammonia escape suppression model described in this invention is based on the adsorption-desorption kinetics theory, describing the adsorption behavior of ammonia on the catalyst surface, the reaction process with NOx, and the escape law of unreacted ammonia; it considers the influence of factors such as temperature, catalyst activity, and NH3 / NOx molar ratio on ammonia escape.

[0050] Preferably, the ammonia escape inhibition model is as follows:

[0051]

[0052] Where, k ads [NH3] represents the adsorption rate; [NH3] represents the NH3 concentration; θ represents the adsorption coverage; k des k is the desorption rate. react is the reaction rate; [NOx] is the NOx concentration; K is the adsorption equilibrium constant.

[0053] Preferably, the intelligent control algorithm and the data-driven prediction model in the parameter adjustment unit treat the boiler combustion system as a dynamic system, and describe the evolution of the system state (such as NOx concentration, NH3 concentration and temperature) with control input (such as air distribution ratio and ammonia injection amount) and external disturbance (such as coal quality change) through state equations. The model parameters are identified through historical operating data (such as temperature, NOx concentration, ammonia injection amount, etc. recorded by DCS).

[0054] Then, a long short-term memory network is used to capture the nonlinear dynamic characteristics and temporal correlations of the combustion process to predict NOx concentration and ammonia slip. The model input includes historical measurement data and current control commands, and the output is the emission prediction values ​​for a future period.

[0055] Preferably, the state equation is:

[0056]

[0057] in, denoted as , where is the change of state variables over time; f(·) is a nonlinear function derived from chemical reaction kinetics and heat and mass transfer laws; u(t) is the change of wind speed over time; d(t) is the change of coal quality over time; and θ is the model parameter vector.

[0058] Preferably, the multi-objective optimization control function in the intelligent control algorithm and parameter adjustment unit includes a NOx emission deviation function, an NH3 emission deviation function, and a combustion thermal efficiency deviation function.

[0059] Preferably, the NOx emission deviation function is:

[0060]

[0061] in, C is the NOx emission deviation function; NOX-测量 The measured NOx concentration; C NOX-标准 The standard NOx concentration;

[0062] Preferably, the NH3 emission deviation function is:

[0063]

[0064] in, This is the NH3 emission deviation function; The calculated NH3 concentration; The permitted concentration of NH3 for emissions;

[0065] Preferably, the combustion thermal efficiency deviation function is:

[0066] e 热效率 =η 热效率-计算 -η 热效率-设定值

[0067] Among them, e 热效率 η is the combustion thermal efficiency deviation function; 热效率-计算 The calculated thermal efficiency; η 热效率-设定值 The set thermal efficiency.

[0068] Preferably, the intelligent control algorithm and parameter adjustment unit utilize a parameter adaptive learning mechanism to optimize the control of the physicochemical mechanism model and the data-driven prediction model, dynamically balancing the priorities of NOx control, ammonia slip suppression, and combustion efficiency.

[0069] The parameter adaptive learning mechanism described in this invention utilizes the forgetting factor recursive least squares method to update the relevant parameters of the physicochemical mechanism model online based on real-time data monitored by a multi-parameter real-time monitoring unit. This enables the physicochemical mechanism model to adapt to characteristic drift caused by factors such as coal quality changes and equipment aging. The weights of the long short-term memory network are periodically fine-tuned using the latest data to enhance the model's generalization ability to unknown operating conditions. An incremental learning strategy is employed to prevent the model from forgetting historical knowledge.

[0070] Preferably, the priority of NOx control and ammonia slip suppression is represented by dynamic weighting coefficients for NOx and NH3, respectively:

[0071]

[0072] in, For NOx, the dynamic weighting coefficients are used. β is the initial weight for NOx; β is the sensitivity coefficient, β>0; The measured value of NOx at time k; The reference value for NOx at time k;

[0073] For NH3, the dynamic weighting coefficient is used. The initial weights for NH3; The measured value of NH3 at time k; This is the reference value for NH3 at time k.

[0074] Preferably, the overall objective function for NOx control, ammonia slip suppression, and combustion efficiency is:

[0075]

[0076] Where J is the overall objective function; For NOx, the dynamic weighting coefficients are used. This is the NOx emission deviation function; For NH3, the dynamic weighting coefficient is used. ω is the NH3 emission deviation function; eff For efficiency weights; e eff This is the combustion efficiency deviation function.

[0077] Preferably, the preliminary collection unit in the product collection and processing module employs gravity settling, inertial separation, and filtration, combining multiple collection methods to significantly improve collection efficiency. When chemical products (such as ammonium nitrate particles) generated by the adsorption and catalytic conversion module flow with the flue gas, larger particles are first allowed to settle naturally to the bottom of the collection device under gravity. Smaller particles are separated from the flue gas using inertial separation. Finally, the remaining microparticles are filtered and collected using filter material, ensuring efficient and comprehensive collection of chemical products, reducing product loss, and improving resource recovery rate.

[0078] Preferably, the purification unit in the product collection and processing module employs a combination of at least two of the following: distillation, ion exchange, or crystallization, to achieve deep purification of chemical products.

[0079] The storage unit described in this invention has good sealing, corrosion resistance and thermal insulation properties, which can effectively prevent the product from getting damp, oxidized and contaminated, ensure stable product quality and facilitate subsequent transportation and sales.

[0080] Compared with the prior art, the present invention has at least the following beneficial effects:

[0081] (1) The combustion process feedback control module in the device system for boiler ammonia slip and NOx co-control and product treatment provided by the present invention includes a multi-parameter real-time monitoring unit and an intelligent control algorithm and parameter adjustment unit connected in sequence. It can monitor the changes of various parameters in the combustion process in real time, comprehensively analyze the status of ammonia slip and NOx emissions, and automatically adjust the burner operating parameters to achieve co-control of ammonia slip and NOx. This breaks the limitations of traditional single control, significantly improves the environmental protection effect, and enables pulverized coal boilers to meet strict environmental protection requirements more efficiently during ammonia-blended combustion.

[0082] (2) The adsorption and catalytic conversion module and the product collection and processing module in the device system for the coordinated control of boiler ammonia escape and NOx and the product treatment provided by the present invention are connected. Through adsorption and catalytic conversion technology, escaped ammonia and incompletely converted NOx are converted into chemical products with economic value and recycled and purified. This not only reduces the emission of pollutants, but also brings additional economic benefits, reduces production costs, and improves resource utilization efficiency, which is in line with the concept of sustainable development.

[0083] (3) The device system for boiler ammonia escape and NOx synergistic control and product treatment provided by the present invention organically integrates the adsorption and catalytic conversion module, the combustion process feedback control module and the product collection and treatment module to form a complete and efficient integrated system. The modules realize information sharing and collaborative work, which improves the operating efficiency, stability and reliability of the entire device system and provides a brand-new solution for the upgrading and transformation of pulverized coal boiler combustion system. Attached Figure Description

[0084] Figure 1 This is a schematic diagram of the device system for the coordinated control of boiler ammonia escape and NOx and the treatment of products in a specific embodiment of the present invention. Detailed Implementation

[0085] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0086] 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.

[0087] As a specific embodiment of the present invention, a device system for the coordinated control of boiler ammonia escape and NOx and the treatment of byproducts is provided, the schematic diagram of which is shown below. Figure 1 As shown.

[0088] The device system includes an adsorption and catalytic conversion module, a combustion process feedback control module, and a product collection and processing module;

[0089] The adsorption and catalytic conversion module is installed inside the boiler flue; the adsorption and catalytic conversion module is connected to the product collection and processing module; the combustion process feedback control module is connected to the boiler.

[0090] The combustion process feedback control module includes a multi-parameter real-time monitoring unit and an intelligent control algorithm and parameter adjustment unit connected in sequence; the multi-parameter real-time monitoring unit monitors the boiler's combustion parameters and transmits them to the intelligent control algorithm and parameter adjustment unit; the intelligent control algorithm and parameter adjustment unit regulates the boiler's combustion after model analysis and calculation.

[0091] The intelligent control algorithm and parameter adjustment unit includes a physical mechanism model, a data-driven prediction model, and a multi-objective optimization control function. The intelligent control algorithm and parameter adjustment unit utilizes a parameter adaptive learning mechanism to optimize the control of the physical mechanism model and the data-driven prediction model.

[0092] The multi-parameter real-time monitoring unit includes a temperature sensor, a pressure sensor, and a gas composition analyzer, which monitors the temperature, pressure, ammonia to pulverized coal ratio, and flue gas composition during the boiler combustion process in real time.

[0093] The product collection and processing module includes a preliminary collection unit, a purification unit, and a storage unit connected in sequence.

[0094] The installation steps of the boiler ammonia escape and NOx synergistic control and product treatment device system described in this specific embodiment include:

[0095] (1) Installation of Adsorption and Catalytic Conversion Module: The adsorption and catalytic conversion module is installed inside the flue of the pulverized coal boiler, according to the flue size and flue gas flow characteristics. During installation, ensure that the loading method and quantity of adsorbent and catalyst meet the design requirements, guaranteeing that the flue gas can contact the adsorbent and catalyst evenly and fully. Simultaneously, connect the inlet and outlet gas pipes of the module and perform a sealing test to prevent flue gas leakage from affecting system performance.

[0096] (2) Installation of the combustion process feedback control module: Temperature sensors, pressure sensors, and gas composition analyzers are installed in the boiler combustion zone and flue. High-speed data transmission lines are laid to connect the sensors to the data analysis and processing equipment in the control center, ensuring the accuracy and timeliness of data transmission. Control command execution equipment, such as electric valves and servo motors, are installed to execute the adjustment commands for burner operating parameters issued by the control center, and are debugged to ensure accurate and reliable equipment operation.

[0097] (3) Installation of product collection and processing module: Install the preliminary collection unit, purification unit and storage unit in sequence. The preliminary collection unit is installed at the outlet of the adsorption and catalytic conversion module to ensure that the generated chemical products can enter the preliminary collection device smoothly. Connect the pipelines and conveying devices between the various devices to ensure that the chemical products can be smoothly transferred between the devices. At the same time, install liquid level monitoring equipment and temperature monitoring equipment in the storage unit to ensure the safe and stable operation of the storage unit.

[0098] The commissioning steps of the boiler ammonia escape and NOx synergistic control and product treatment device system described in this specific embodiment include single-unit commissioning and linkage commissioning.

[0099] The individual unit commissioning includes performing individual unit commissioning on each device in the adsorption and catalytic conversion module, the combustion process feedback control module, and the product collection and processing module. The operating status of the equipment is checked, such as motor speed, valve opening and closing flexibility, and sensor signal output accuracy, to ensure that each device can operate normally. The adsorbent and catalyst are activated to achieve optimal working performance.

[0100] The integrated commissioning includes starting the pulverized coal boiler to bring the boiler ammonia slip and NOx coordinated control and product treatment system into operation, simulating different operating conditions and load changes, and observing the coordinated operation between various modules. It checks whether the combustion process feedback control module can accurately adjust the burner operating parameters based on monitoring data, whether the adsorption and catalytic conversion module can effectively capture and convert ammonia and NOx, and whether the product collection and treatment module can smoothly collect, purify, and store chemical products. Simultaneously, various performance indicators of the system are tested, such as ammonia slip rate, NOx removal rate, chemical product recovery rate, and purity. Based on the test results, the system is optimized and adjusted to ensure that the system performance meets design requirements.

[0101] This specific implementation also includes daily operation management and regular maintenance and repair of the device system for the coordinated control of boiler ammonia escape and NOx and the treatment of products.

[0102] As a specific embodiment of the present invention, a method for the coordinated control of boiler ammonia slip and NOx and the treatment of its byproducts is also provided. The method employs the aforementioned apparatus system for the coordinated control of boiler ammonia slip and NOx and the treatment of its byproducts. The method includes:

[0103] The flue gas generated by the boiler enters the adsorption and catalytic conversion module, which captures the escaped ammonia and NOx, and converts them into chemical products through adsorbents and catalysts, which then enter the product collection and treatment module. Throughout the process, the combustion process feedback control module monitors the boiler's combustion status through a multi-parameter real-time monitoring unit, and automatically adjusts the air distribution ratio, burner angle, and ammonia and pulverized coal delivery rates of the boiler burner through intelligent control algorithms and parameter adjustment units, thereby coordinating the control of ammonia escape and NOx emissions.

[0104] The adsorbent in the adsorption and catalytic conversion module uses ZSM-5 molecular sieve as the main framework and is loaded with CuO, Fe2O3 and CeO2; the loading of CuO is 6wt%, the loading of Fe2O3 is 4wt%, and the loading of CeO2 is 2.3wt%.

[0105] The catalyst in the adsorption and catalytic conversion module adopts a V2O5-WO3-TiO2 ternary system; the content of V2O5 in the catalyst is 3.5wt%, the content of WO3 is 9wt%, and the specific surface area of ​​TiO2 is 110m².2 / g.

[0106] The physicochemical mechanism models in the intelligent control algorithm and parameter adjustment unit include a combustion efficiency model, a NOx emission reduction model, and an ammonia slip suppression model.

[0107] The combustion efficiency model is as follows:

[0108]

[0109] Where r is the reaction rate of pulverized coal combustion with ammonia; A is the pre-exponential factor; E is the activation energy; [Fuel] concentration; [O2] is the oxygen concentration; R is the ideal gas constant; T is the reaction temperature; a is the first reaction order; b is the second reaction order;

[0110] The relationship between fuel conversion rate x and the reaction rate r of pulverized coal combustion with ammonia is as follows:

[0111]

[0112] Where nf0 is the initial fuel quantity; V is the reaction volume;

[0113] Combustion efficiency η is a function of fuel conversion rate x and heat loss:

[0114]

[0115] Among them, Q loss Heat loss due to heat dissipation and smoke exhaust; Q theoretical represents the total heat of complete combustion of fuel; x represents the fuel conversion rate.

[0116] The NOx emission reduction model is as follows:

[0117]

[0118] Where [NO] represents the concentration of NO generated; [NO] 平衡 t is the equilibrium concentration of NO at this temperature; k is the reaction rate constant; t is the residence time of the gas in the high-temperature region. The partial pressure of oxygen;

[0119] The ammonia escape inhibition model is as follows:

[0120]

[0121] Where, k ads [NH3] represents the adsorption rate; [NH3] represents the NH3 concentration; θ represents the adsorption coverage; k des k is the desorption rate. react [NOx] represents the reaction rate; [NOx] represents NO. X Concentration; K is the adsorption equilibrium constant.

[0122] The intelligent control algorithm and the data-driven prediction model in the parameter adjustment unit treat the boiler combustion system as a dynamic system, describe the evolution of the system state through state equations, and then use long short-term memory networks to capture the nonlinear dynamic characteristics and time-series correlation of the combustion process to predict NOx concentration and ammonia slip.

[0123] The state equation is:

[0124]

[0125] in, denoted as , where is the change of state variables over time; f(·) is a nonlinear function derived from chemical reaction kinetics and heat and mass transfer laws; u(t) is the change of wind speed over time; d(t) is the change of coal quality over time; and θ is the model parameter vector.

[0126] The intelligent control algorithm and the multi-objective optimization control function in the parameter adjustment unit include the NOx emission deviation function, the NH3 emission deviation function, and the combustion thermal efficiency deviation function;

[0127] The NOx emission deviation function is:

[0128]

[0129] in, C is the NOx emission deviation function; NOX-测量 The measured NOx concentration; C NOX-标准 The standard NOx concentration;

[0130] The NH3 emission deviation function is:

[0131]

[0132] in, This is the NH3 emission deviation function; The calculated NH3 concentration; The permitted concentration of NH3 for emissions;

[0133] The combustion thermal efficiency deviation function is:

[0134] e 热效率 =η 热效率-计算 -η 热效率-设定值

[0135] Among them, e 热效率 η is the combustion thermal efficiency deviation function; 热效率-计算 The calculated thermal efficiency; η 热效率-设定值 The set thermal efficiency.

[0136] The intelligent control algorithm and parameter adjustment unit utilize a parameter adaptive learning mechanism to optimize the control of the physicochemical mechanism model and the data-driven prediction model, dynamically balancing the priorities of NOx control, ammonia slip suppression, and combustion efficiency.

[0137] The priority of NOx control and ammonia slip suppression is represented by dynamic weighting coefficients for NOx and NH3, respectively:

[0138]

[0139] in, For NOx, the dynamic weighting coefficients are used. β is the initial weight for NOx; β is the sensitivity coefficient, β>0; The measured value of NOx at time k; The reference value for NOx at time k;

[0140] For NH3, the dynamic weighting coefficient is used. The initial weights for NH3; The measured value of NH3 at time k; Here is the reference value for NH3 at time k;

[0141] The overall objective optimization function for NOx control, ammonia slip suppression, and combustion efficiency is:

[0142]

[0143] Where J is the overall objective function; For NOx, the dynamic weighting coefficients are used. This is the NOx emission deviation function; For NH3, the dynamic weighting coefficient is used. ω is the NH3 emission deviation function; eff For efficiency weights; e eff This is the combustion efficiency deviation function.

[0144] The preliminary collection unit in the product collection and processing module employs gravity sedimentation, inertial separation, and filtration; the purification unit in the product collection and processing module employs distillation and ion exchange.

[0145] The boiler ammonia slip and NOx synergistic control and product treatment device system provided in this specific embodiment was applied to the pulverized coal boiler of a large thermal power plant. This resulted in a significant reduction in both ammonia slip and NOx emissions, meeting stringent local environmental emission standards and effectively reducing atmospheric pollution. The system converts escaped ammonia and incompletely converted NOx into ammonium nitrate, which is then processed by the product collection and treatment module to meet market sales standards, bringing considerable economic benefits to the power plant. Simultaneously, the combustion process feedback control module adjusts combustion parameters, significantly improving boiler operational stability, reducing equipment failures and downtime, and lowering equipment maintenance costs.

[0146] 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 device system for boiler ammonia slip and NOx co-control and product treatment, characterized by, The device system comprises an adsorption and catalytic conversion module, a combustion process feedback control module and a product collection and processing module; The adsorption and catalytic conversion module is arranged in the flue of the boiler; the adsorption and catalytic conversion module is connected with the product collection and processing module; the combustion process feedback control module is connected with the boiler; The combustion process feedback control module comprises a multi-parameter real-time monitoring unit and an intelligent control algorithm and parameter adjustment unit connected in sequence; after the multi-parameter real-time monitoring unit monitors the combustion parameters of the boiler, the combustion parameters are transmitted to the intelligent control algorithm and parameter adjustment unit; the intelligent control algorithm and parameter adjustment unit adjusts and controls the combustion of the boiler after model analysis and calculation; The intelligent control algorithm and parameter adjustment unit comprises a physicochemical mechanism model, a data-driven prediction model and a multi-objective optimization control function; the intelligent control algorithm and parameter adjustment unit optimizes and controls the physicochemical mechanism model and the data-driven prediction model by using a parameter self-adaptive learning mechanism.

2. The device system of claim 1, wherein, The multi-parameter real-time monitoring unit comprises a temperature sensor, a pressure sensor and a gas component analyzer, which monitors the temperature, pressure, ammonia and coal ratio and flue gas composition in the boiler combustion process in real time.

3. The device system of claim 1, wherein, The product collection and processing module comprises a preliminary collection unit, a purification unit and a storage unit connected in sequence.

4. A method of boiler ammonia slip and NOx co-control and product treatment, characterized by, The method is carried out by using the device system for ammonia escape and NOx collaborative control and product processing of the boiler according to any one of claims 1-3; the method comprises: The flue gas generated by the boiler enters the adsorption and catalytic conversion module, captures the escaped ammonia and NOx, and is converted into chemical products by the adsorbent and catalyst to enter the product collection and processing module; in the whole process, the combustion process feedback control module monitors the combustion of the boiler through the multi-parameter real-time monitoring unit, and automatically adjusts the air distribution ratio of the boiler burner, the angle of the burner, and the delivery amount of ammonia and coal powder through the intelligent control algorithm and parameter adjustment unit, to collaboratively control the ammonia escape and NOx emission.

5. The method of claim 4, wherein, The adsorbent in the adsorption and catalytic conversion module takes ZSM-5 molecular sieve as the main framework, and loads CuO, Fe2O3 and CeO2; The loading amount of CuO is 5-8wt%, the loading amount of Fe2O3 is 3-5wt%, and the loading amount of CeO2 is 2-3wt%; The catalyst in the adsorption and catalytic conversion module adopts a V2O5-WO3-TiO2 ternary system; The content of V2O5 in the catalyst is 3-5wt%, and the content of WO3 is 8-10wt%; The specific surface area of the TiO2 is > 100 m 2 / g.

6. The method of claim 4, wherein, The physicochemical mechanism model in the intelligent control algorithm and parameter adjustment unit comprises a combustion efficiency model, a NOx emission reduction model and an ammonia escape inhibition model; The combustion efficiency model is: Wherein, r is the reaction rate of coal powder mixed with ammonia combustion; A is the pre-exponential factor; E is the activation energy; [Fuel] is the concentration; [O2] is the oxygen concentration; R is the ideal gas constant; T is the reaction temperature; a is the first reaction order; b is the second reaction order; The relationship between the fuel conversion rate x and the reaction rate r of coal powder mixed with ammonia combustion is: Wherein, nf0 is the initial fuel amount; V is the reaction volume; The combustion efficiency η is a function of fuel conversion rate x and heat loss: where Q loss is the heat loss for heat dissipation and smoke exhaust; Q theoretical is the total heat of complete combustion of fuel; x is the fuel conversion rate; The NOx emission reduction model is: where [NO] is the concentration of NO produced; [NO]e is the equilibrium concentration of NO at the temperature; k is the rate constant for the reaction; and t is the residence time of the gas in the high temperature zone. 平衡 where [NO] is the concentration of NO produced; [NO]e is the equilibrium concentration of NO at the temperature; k is the rate constant for the reaction; and t is the residence time of the gas in the high temperature zone. where [O2] is the oxygen partial pressure; The ammonia escape inhibition model is: where k ads is the adsorption rate; [NH3] is the NH3 concentration; θ is the adsorption coverage; k des is the desorption rate; k react is the reaction rate; [NOx] is the NO X concentration; and K is the adsorption equilibrium constant.

7. The method of claim 4, wherein, The data-driven prediction model in the intelligent control algorithm and parameter adjustment unit regards the boiler combustion system as a dynamic system, describes the evolution law of system state through a state equation, and then uses a long short-term memory network to capture the nonlinear dynamic characteristics and time correlation of the combustion process to predict the NOx concentration and ammonia escape amount; The state equation is: wherein, is the change of the state variable over time; f(·) is a non-linear function derived from chemical reaction kinetics, heat and mass transfer laws; u(t) is the change of the wind speed over time; d(t) is the change of the coal quality over time; and Θ is a vector of model parameters.

8. The method of claim 4, wherein, The multi-objective optimization control function in the intelligent control algorithm and parameter adjustment unit includes a NOx emission deviation function, an NH3 emission deviation function, and a combustion heat efficiency deviation function; The NOx emission deviation function is: wherein, is a NOx emission bias function; C NOX-测量 is a measured NOx concentration; C NOX-标准 is a standard NOx concentration; The NH3 emission deviation function is: wherein, is a NH3emission bias function; is a calculated NH3concentration; is a NH3concentration allowed to be emitted; The combustion heat efficiency deviation function is: e 热效率 = η 热效率-计算 - η 热效率设定值 where e 热效率 is the combustion heat efficiency deviation function; η 热效率-计算 is the calculated heat efficiency; η 热效率 - 设定值 is the set heat efficiency.

9. The method of claim 4, wherein, The intelligent control algorithm and parameter adjustment unit uses a parameter self-adaptive learning mechanism to optimize control the physical and chemical mechanism model and the data-driven prediction model, and dynamically balances the priority of NOx control, ammonia escape inhibition, and combustion efficiency; The priority of NOx control and ammonia escape inhibition is represented by the dynamic weight coefficients of NOx and NH3, respectively: wherein, is a dynamic weight coefficient for NOx; is an initial weight for NOx; β is a sensitivity coefficient, β > 0; is a measured value of NOx at time k; is a reference value of NOx at time k; is a dynamic weight coefficient for NH3; is an initial weight for NH3; is a measured value of NH3 at time k; is a reference value of NH3 at time k; The total target optimization function of NOx control, ammonia escape inhibition, and combustion efficiency is: where J is the total objective optimization function; is a dynamic weight coefficient for NOx; is a NOx emission deviation function; is a dynamic weight coefficient for NH3; is a NH3 emission deviation function; ω eff is an efficiency weight; e eff is a combustion efficiency deviation function.

10. The method of claim 4, wherein, The preliminary collection unit in the product collection and processing module adopts gravity sedimentation, inertial separation, and filtration; The purification unit in the product collection and processing module adopts a combination of at least two of rectification, ion exchange, or crystallization.

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