Control method and system of adjustable primary combustion thermal kinetic energy and flame gas phase combustor

Abstract

The invention relates to the technical field of boiler burner devices, in particular to a control method and system of an adjustable primary combustion thermal kinetic energy and flame gas phase burner. The method comprises the steps that S1, a combustor thermal kinetic energy real-time measurement technology is adopted, a novel combustor thermal kinetic energy model is established, and a four-corner tangential flame center position real-time graph is established; s2, solving the thermal kinetic energy adjustment problem of the combustor in a real-time closed-loop manner by adopting an elliptical turnover type servo balance adjusting valve, S3, researching a correlation model of thermal kinetic energy control parameters of the combustor and energy efficiency indexes in an unbalanced state and an equilibrium state, and S4, calculating the thermal kinetic energy of the combustor according to the correlation model. The measurement sensor based on the electrostatic ion radiation technology principle is introduced to accurately measure the primary air powder in real time, and the combustor thermal kinetic energy sensor plays a key role in optimizing the boiler combustion process. According to the technology, the primary air powder state in the combustor, the thermal kinetic energy parameters of the combustor and the flame gas phase state can be monitored in real time, and powerful support is provided for fine control of the combustion process.

Description

Technical Field

[0001] The invention relates to the technical field of boiler burner devices, and in particular to a control method and a system for an adjustable primary combustion heat kinetic energy and flame gas phase burner. Background Art

[0002] Under boiler operating conditions, the temperature deviation of the walls on both sides of the high-temperature superheater heating surface is large, and the cooling water consumption has exceeded the boiler feed water volume by more than 6%. During the overhaul, the high-temperature superheater heating surface was inspected and it was found that there was a lot of oxide scale accumulation on the high-temperature superheater tube screen. The peeling and accumulation of oxide scale caused by the deviation of the heating surface under the variable load operation of the boiler has brought great challenges to the safe operation of the unit, and there is even a risk of emergency shutdown due to tube burst on the heating surface; however, the lack of refined research on coal-fired boiler combustion has caused the boiler's operating level to lag far behind during low load and frequent peak regulation, making it impossible for coal-fired boilers to perform their normal efficiency in low-load and frequently fluctuating load production, especially for ultra-supercritical boilers at low load. Due to the lack of primary air powder flow parameters and burner thermal kinetic energy data and burner combustion thermal kinetic energy control technology, the deviation of the burner flame in the furnace during frequent peak regulation or low load causes the primary of each burner in the boiler to be Unbalanced thermal energy, flame deflection and inconsistent rigidity lead to dynamic imbalance of flue gas (excessive temperature difference of the heating surface causes a series of problems), high precipitation of nitrogen oxides, high exhaust temperature, increased loss of thermal efficiency, and safety hazards such as coking and pipe burst; the level of boiler combustion efficiency, whether the fuel entering the furnace can be fully burned, the balanced distribution of combustion in each layer of the boiler, and the real-time dynamic leveling of primary thermal energy will directly affect the overall safe operation of the boiler, flue gas temperature deviation, nitrogen oxide reduction, efficiency and economy; achieving the most efficient combustion of the boiler through real-time burner combustion control is an effective way to improve the overall efficiency of the boiler, improve boiler safety production, and reduce unplanned shutdowns.

[0003] However, most thermal power plants lack key combustion monitoring and control methods on the boiler side, which makes it impossible to fully carry out refined operation control, which easily leads to insufficient air supply and uneven air-powder mixing, and brings troubles to boiler operation. Whether from the perspective of boiler safe operation or boiler combustion efficiency, technical research on refined and balanced combustion of coal-fired boilers is of great significance. Summary of the invention

[0004] Technical issues solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a control method and system for an adjustable primary combustion thermal energy and flame gas phase burner, which can effectively solve the problem in the prior art that requires technical research on refined and balanced combustion of coal-fired boilers.

[0006] Technical Solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] The present invention provides a control method for an adjustable primary combustion thermal energy and flame gas phase burner, comprising: S1: adopting a real-time measurement technology for the thermal energy of a burner, establishing a new type of thermal energy model for the burner, and establishing a real-time graphic of the center position of a four-corner cut-circle flame; S2: adopting an elliptical flip-type servo balancing regulating valve to solve the problem of adjusting the thermal energy of the burner in a real-time closed loop; S3: studying the thermal energy control parameters of the burner, and the correlation model of energy efficiency indicators under non-equilibrium and equilibrium states, studying and compiling a dynamic control software for the dynamic balance of the primary combustion of the boiler, systematically analyzing the combustion status of the boiler, and applying the control software to correct the biased burning in time, and establishing a complex control system that solves the problem of the system being easily disturbed by multiple factors and has high requirements for the dynamic process.

[0009] Furthermore, the real-time measurement technology in S1 includes six measurements of primary air powder, namely velocity, concentration, flow rate, particle fineness, calorific value, water content and burner thermal energy, and the burner thermal model is for burner thermal energy and flame gas phase analysis. According to the furnace structure, burner layout, coal powder flow characteristics and airflow organization during combustion, an accurate gas phase state model is established.

[0010] Furthermore, in S2, the servo balancing control valve adopts an expanded diameter design, with constant flow velocity inside, and does not increase the outlet resistance of the coal mill.

[0011] Furthermore, in S2, the correlation model of the energy efficiency index under the non-equilibrium and equilibrium states of the thermal kinetic energy control quantity of the burner is studied, and the real-time dynamic model parameters are dynamically optimized by using short-cycle data.

[0012] Furthermore, the control system effect principle in S3 is a method that draws on the regulation mechanism of the biological anti-shock feedback response process and the characteristics of fuzzy reasoning logic that can approximate nonlinear functions.

[0013] Furthermore, the burner thermal kinetic energy adaptive balance control logic is coordinated with the DCS system.

[0014] Furthermore, among all the burners in the mill, the difference between the maximum and minimum thermal kinetic energy values ​​and the average thermal kinetic energy of this layer is less than 2MW; the imbalance of the burner burnout capacity and flame rigidity is not greater than 5%; the difference between the maximum and minimum values ​​of the primary air powder velocity in each air duct in the mill and the average flow velocity of this layer is less than 3m / s; the difference between the maximum and minimum values ​​of the primary air powder flow in each air duct in the mill and the average flow of this layer is less than 1.5t / h; the difference between the maximum and minimum values ​​of the primary air powder concentration in each air duct in the mill and the average concentration of this layer is less than 100g / m3.

[0015] To achieve the above objectives, the present invention also provides a control system, which is implemented through the following technical solutions:

[0016] An adjustable primary combustion heat kinetic energy and flame gas phase burner system, which consists of a six-parameter measurement system for primary air powder flow state, a burner heat kinetic energy and flame gas phase measurement system, an SES data center cabinet, system software, a communication system, a burner balanced combustion control system and a VF series servo balance valve closed-loop adjustment system.

[0017] First, the six-parameter measurement system of the primary air-powder flow state is equipped with at least four sets of integrated flow, flow velocity, concentration, particle fineness and water content sensors, all of which are arranged on the outside of the pipeline. It adopts the measurement technology of electrostatic ion radiation principle (static electricity + capacitance) and space containment structure. The burner thermal kinetic energy and flame gas phase measurement system includes: ① integrated measurement sensor device, ② data acquisition module, ③ data processing module and ④ real-time thermal kinetic energy mathematical model. The functions that can be realized in the system software include: initial configuration, data analysis, function calculation, status display, display monitoring, combustion control logic, data storage; the communication system is connected to the industrial Modbus RTU bus mode and DCS communication.

[0018] Afterwards, the VF series servo balance valve closed-loop regulation system is provided with a VF servo air-powder balance regulating valve, and the regulating valve is installed on the coal mill outlet separator. The real-time thermal kinetic energy mathematical model is:

[0019]

[0020] Among them: α-carbon film resistance; δ-medium pressure; C-burner radiation heat energy; G-insulation resistance difference; A-coal powder flow rate; е-radiation temperature difference absorption coefficient; γ-thermal kinetic energy coefficient.

[0021] Beneficial Effects

[0022] Compared with the known public technology, the technical solution provided by the present invention has the following beneficial effects:

[0023] The invention plays a key role in optimizing the boiler combustion process by introducing a measurement sensor based on the principle of electrostatic ion radiation technology to measure the primary air powder in real time and accurately and a burner thermal kinetic energy sensor. This technology can monitor the primary air powder state, burner thermal kinetic energy parameters and flame gas phase state in real time in the burner, providing strong support for the fine control of the combustion process.

[0024] Combined with servo-balanced regulating valve technology, this technology can dynamically adjust the primary combustion heat energy and flame gas phase state of each burner in real time. This closed-loop adjustment mechanism ensures that the combustion process is always in the best state, significantly improving the combustion efficiency of the boiler;

[0025] In addition, by compiling advanced combustion optimization software, the uniform control of combustion gas distribution is achieved, further improving the uniformity of heat absorption of the heating surface, making the temperature field distribution in the furnace more balanced. This not only effectively reduces the occurrence of partial burning, coking and other phenomena, but also reduces the exhaust temperature of the air preheater, which is of great significance for improving the thermal efficiency of the boiler and reducing pollutant gas emissions; at the same time, this technology can also understand and balance the deviations of flow velocity, flow rate and concentration between the primary air ducts of the coal mill in real time. This balance adjustment can ensure the uniform distribution of coal powder in the burner, further improving the stability and efficiency of combustion;

[0026] Based on the measurement of six groups of parameters of the primary air powder of a four-corner tangential circle boiler, the study conducts real-time quantitative analysis of the combustion thermal kinetic energy state of each burner, as well as the logical relationship among flame rigidity, flame burnout ability, coal powder concentration, flame thermal kinetic energy and NOx precipitation. An application model of the gas phase state related to four-corner tangential circle combustion is established to lay a data foundation for optimizing the boiler combustion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is the technical roadmap of the present invention;

[0029] Figure 2 It is a device connection diagram of the present invention;

[0030] Figure 3 It is a schematic diagram of boiler combustion and its external control structure in the present invention;

[0031] Figure 4 It is a two-dimensional gas phase diagram and flame position diagram of the burner flame in the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention will be further described below in conjunction with the embodiments.

[0034] Embodiment 1: Figure 1-4 As shown, a control method for an adjustable primary combustion thermal energy and flame gas phase burner includes: S1: using the real-time measurement technology of the thermal energy of the burner, establishing a new type of thermal energy model of the burner, and establishing a real-time graph of the center position of the four-corner tangential circle flame; S2: using an elliptical flip-type servo balancing regulating valve to solve the problem of adjusting the thermal energy of the burner in a real-time closed loop; S3: studying the thermal energy control parameters of the burner, the correlation model of the energy efficiency index under the non-equilibrium and equilibrium states, studying and compiling the dynamic balance control software for the primary combustion of the boiler, systematically analyzing the combustion status of the boiler, and using the control software to correct the biased burning in time, and establishing a complex control system that can solve the problem of the system being easily disturbed by multiple factors and has high requirements for the dynamic process;

[0035] The real-time measurement technology in S1 includes six types of primary air powder measurements, namely velocity, concentration, flow rate, particle fineness, calorific value, moisture content and burner thermal kinetic energy. The establishment and application of the flame combustion gas phase state model of the four-corner tangential combustion boiler based on the six-parameter measurement technology of primary air powder and the burner thermal kinetic energy measurement technology is a complex and important field. The combustion mode of this boiler involves many factors, including furnace structure, burner layout, coal powder flow characteristics and airflow organization during combustion. Therefore, establishing an accurate gas phase state model is of great significance for optimizing the combustion process, improving boiler efficiency and reducing pollutant emissions.

[0036] In S2, the servo balance control valve adopts an expanded diameter design, with constant flow rate inside, without increasing the outlet resistance of the coal mill, and solves the problem of burner thermal kinetic energy adjustment in real time closed loop. The structural design of the elliptical valve plate, an internal component of the control valve, is a technical difficulty. The design of the appropriate ellipticity, guide strips, powder slots, and center hole structure is the key technology of the control valve. The problem of uneven combustion distribution is solved through the reasonable selection of the structure of the valve plate and the material.

[0037] In S2, the correlation model of the energy efficiency index under the non-equilibrium and equilibrium states of the burner thermal kinetic energy control quantity is studied, and the real-time dynamic model parameters are dynamically optimized by using short-cycle data.

[0038] The control system effect principle in S3 is to learn from the adjustment mechanism of biological anti-oscillation feedback response process and the method that fuzzy reasoning logic can approximate the characteristics of nonlinear functions. On the basis of the control technology based on the adaptive directional adjustment of the thermal kinetic energy of the burner, we study and compile the dynamic control software for the dynamic balance of the primary combustion of the boiler. The system can timely analyze the combustion status of the boiler and can use this set of control software to correct the biased burning in time. To solve the complex control system that is easily disturbed by multiple factors and has high requirements for dynamic processes, the biological adjustment mechanism and fuzzy reasoning logic method can be used to meet the verification needs.

[0039] The burner thermal energy adaptive balance control logic and DCS system coordinated control; the research combines advanced control theory, real-time monitoring technology and the powerful functions of the DCS system, bringing new breakthroughs to boiler combustion control; the research and innovation of burner thermal energy adaptive balance control logic and strategy has brought new ideas and methods to boiler combustion control. Through in-depth research and practical application, the combustion efficiency and environmental performance of the boiler can be further improved, making greater contributions to energy utilization and environmental protection.

[0040] Among all the burners in the mill, the difference between the maximum and minimum thermal kinetic energy values ​​and the average thermal kinetic energy of this layer is less than 2MW; the imbalance of the burner's burnout capacity and flame rigidity is not greater than 5%; the difference between the maximum and minimum values ​​of the primary air powder velocity in each air duct in the mill and the average flow velocity of this layer is less than 3m / s; the difference between the maximum and minimum values ​​of the primary air powder flow in each air duct in the mill and the average flow of this layer is less than 1.5t / h; the difference between the maximum and minimum values ​​of the primary air powder concentration in each air duct in the mill and the average concentration of this layer is less than 100g / m3.

[0041] Performance guarantee value after system commissioning:

[0042] 1) After adjustment, the boiler achieves balanced combustion, and the boiler efficiency is increased by more than 0.3% (0.3% is the minimum guaranteed value written in the contract) under the three load test conditions of 40%, 60% and 80% of the unit;

[0043] 2) After adjustment, the experimental load reduces the NOx generation at the SCR inlet by more than 5% (written into the contract);

[0044] 3) After adjustment, the boiler exhaust temperature, fly ash carbon content, slag carbon content, CO concentration, etc. are lower than the test values ​​before the transformation;

[0045] 4) The desuperheating water consumption of the first and second level superheaters and reheaters is greatly reduced compared with the test value before the transformation;

[0046] 5) Reduce coking on the heated surface in the combustion area and reduce high-temperature corrosion of the water-cooled wall.

[0047] Embodiment 2: Based on Embodiment 1, this embodiment further introduces a control system: the details are as follows:

[0048] An adjustable primary combustion thermal kinetic energy and flame gas phase burner system, which consists of a six-parameter measurement system for primary air powder flow state, a burner thermal kinetic energy and flame gas phase measurement system, an SES data center cabinet, system software, a communication system, a burner balanced combustion control system and a VF series servo balance valve closed-loop adjustment system;

[0049] The six-parameter measurement system of the primary air-powder flow state is provided with at least four sets of integrated flow rate, flow velocity, concentration, particle fineness and water content sensors, all of which are arranged on the outside of the pipeline. It adopts the measurement technology of electrostatic ion radiation principle (static electricity + capacitance) and space containment structure. The burner thermal kinetic energy and flame gas phase measurement system includes: ① integrated measurement sensor device, ② data acquisition module, ③ data processing module and ④ real-time thermal kinetic energy mathematical model. The functions that can be realized in the system software include: initial configuration, data analysis, function calculation, status display, display monitoring, combustion control logic, data storage; the communication system adopts industrial Modbus RTU bus mode to communicate with DCS, and the operating personnel can monitor and operate the boiler furnace combustion state in real time.

[0050] The VF series servo balance valve closed-loop regulation system is equipped with a VF servo air-powder balance regulating valve. The regulation of the burner thermal energy and the gas phase state of the burner flame (air-powder flow rate, flow rate, concentration) is completed by the VF servo air-powder balance regulating valve installed at the outlet separator of the coal mill. The angle of the inlet valve plate of each primary air duct is adjusted through the servo control mechanism, so that the flow rate, speed and concentration of the coal powder entering the primary air duct change, thereby changing the thermal energy of each burner and the gas phase state of the burner flame. The real-time thermal energy mathematical model is:

[0051]

[0052] Among them: α-carbon film resistance; δ-medium pressure; C-burner radiation heat energy; G-insulation resistance difference; A-coal powder flow rate; е-radiation temperature difference absorption coefficient; γ-thermal kinetic energy coefficient.

[0053] The SES data center cabinet is mainly composed of data transmission system, data decomposition, PLC and display, combustion control software and data communication module with DCS. The burner balanced combustion control system obtains the two-dimensional state data of the primary combustion heat and kinetic energy distribution of all burners in the coal-fired boiler through the analysis of monitoring data, compiles the control program, and uses the new balanced regulating valve technology to adjust the flow state of coal powder in the primary air duct in real time in a closed loop while improving the ratio of secondary air. Combined with the boiler power field experiment, it realizes the balanced combustion of the boiler.

[0054] Summary: The research and application of intelligent control systems based on burner thermal kinetic energy will effectively reduce NOx pollution emissions and save coal consumption. It belongs to the National Development and Reform Commission, Ministry of Environmental Protection, National Energy Administration (2014) No. 2093 document, item 12 of the implementation of optimized boiler combustion engineering technology. Reducing the use of urea and catalysts for denitrification and reducing carbon emissions plays an important role in the quality of the atmospheric environment, with significant environmental and social benefits.

[0055] The large-scale development of new energy is the basic path for the low-carbon transformation of the power system, and the transformation and development of coal-fired power is an important support for the power system to absorb new energy. As for the thermal power units that bear the basic peak-shaving capacity in the "Three North Regions", the annual peak-shaving hours are about 1,000 hours; the project results can solve the problem that coal-fired power generating units cannot operate at low load for a long time, and improve the reliability of long-term low-load safety and economic operation of coal-fired units. It will truly play the role of coal-fired power as a basic guarantee and system regulation power source, and further consolidate the role of coal-fired power as the "ballast stone" of power supply. The market prospects are broad and the social significance is great.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for an adjustable primary combustion heat and flame gas phase burner, characterized in that: include; S1: Use the real-time measurement technology of burner thermal energy to establish a new burner thermal energy model and a real-time graphic of the center position of the four-corner tangential circle flame; S2: Use an elliptical flip-type servo balancing control valve to solve the problem of burner thermal energy adjustment in a real-time closed loop; S3: Study the thermal energy control parameters of the burner, the correlation model of energy efficiency indicators under non-equilibrium and equilibrium states, study and compile the dynamic balance control software for the primary combustion of the boiler, systematically analyze the combustion status of the boiler, and use the control software to correct the biased burning in time, and establish a complex control system that can solve the problem of the system being easily disturbed by multiple factors and has high requirements for the dynamic process.

2. A control method for an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 1, characterized in that: The real-time measurement technology in S1 includes six measurements of primary air powder, namely velocity, concentration, flow rate, particle fineness, calorific value, moisture content and burner thermal energy. The burner thermal model is for burner thermal energy and flame gas phase analysis. According to the furnace structure, burner layout, coal powder flow characteristics and airflow organization during combustion, an accurate gas phase state model is established.

3. The control method of an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 1, characterized in that: In S2, the servo balancing control valve adopts an expanded diameter design, with constant flow rate inside, which does not increase the outlet resistance of the coal mill.

4. The control method of an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 1, characterized in that: In S2, the correlation model of the energy efficiency index under the non-equilibrium and equilibrium states of the burner thermal kinetic energy control quantity is studied, and the real-time dynamic model parameters are dynamically optimized by using short-cycle data.

5. A control method for an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 4, characterized in that: The control system effect principle in S3 is a method that draws on the regulation mechanism of the biological anti-shock feedback response process and the characteristics of fuzzy reasoning logic that can approximate nonlinear functions.

6. A control method for an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 1, characterized in that: The burner thermal kinetic energy adaptive balance control logic is controlled in coordination with the DCS system.

7. A control method for an adjustable primary combustion heat kinetic energy and flame gas phase burner according to claim 1, characterized in that: Among all the burners in the mill, the difference between the maximum and minimum thermal kinetic energy values ​​and the average thermal kinetic energy of the layer is less than 2MW; the imbalance of the burner's burnout capacity and flame rigidity is not greater than 5%; The difference between the maximum and minimum values ​​of the primary air powder velocity in each air duct in the mill and the average flow velocity of the layer is <3m / s; the difference between the maximum and minimum values ​​of the primary air powder flow rate in each air duct in the mill and the average flow rate of the layer is <1.5t / h; the difference between the maximum and minimum values ​​of the primary air powder concentration in each air duct in the mill and the average concentration of the layer is <100g / m3.

8. A system of an adjustable primary combustion heat kinetic energy and flame gas phase burner, comprising any one of the control methods of the adjustable primary combustion heat kinetic energy and flame gas phase burner according to claims 1 to 7, characterized in that: The system consists of a six-parameter measurement system for primary air powder flow state, a burner thermal kinetic energy and flame gas phase measurement system, an SES data center cabinet, system software, a communication system, a burner balanced combustion control system and a VF series servo balancing valve closed-loop adjustment system.

9. The adjustable primary combustion heat and flame gas phase burner system according to claim 8, characterized in that: The six-parameter measurement system of the primary air-powder flow state is provided with at least four sets of integrated flow rate, flow velocity, concentration, particle fineness and water content sensors, all of which are arranged on the outside of the pipeline. It adopts the measurement technology of electrostatic ion radiation principle (static electricity + capacitance) and space containment structure. The burner thermal kinetic energy and flame gas phase measurement system includes: ① integrated measurement sensor device, ② data acquisition module, ③ data processing module and ④ real-time thermal kinetic energy mathematical model. The functions that can be realized in the system software include: initial configuration, data analysis, function calculation, status display, display monitoring, combustion control logic, data storage; the communication system is connected to the industrial Modbus RTU bus mode and DCS communication.

10. The adjustable primary combustion heat and flame gas phase burner system according to claim 8, characterized in that: The VF series servo balance valve closed-loop regulation system is provided with a VF servo air-powder balance regulating valve, and the regulating valve is installed on the coal mill outlet separator. The real-time thermal kinetic energy mathematical model is: Among them: α-carbon film resistance; δ-medium pressure; C-burner radiation heat energy; G-insulation resistance difference; A-coal powder flow rate; е-radiation temperature difference absorption coefficient; γ-thermal kinetic energy coefficient.

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