WO2014172818A1

WO2014172818A1 - Combustion optimization and control system based on measurement of furnace temperature field via sound wave and control method therefor

Info

Publication number: WO2014172818A1
Application number: PCT/CN2013/001401
Authority: WO
Inventors: 董信光; 胡志宏; 郝卫东; 刘福国; 杨兴森
Original assignee: 国家电网公司; 山东电力研究院
Priority date: 2013-04-27
Filing date: 2013-11-18
Publication date: 2014-10-30
Also published as: CN103244964B; CN103244964A

Abstract

A combustion optimization and control system based on measurement of furnace temperature field via sound wave and a control method therefor, comprising a data collecting device (10), a data processing device (12), an operation mode selecting module (11), an execution instruction output module (13), wherein the data processing device (12) is encapsulated with a coal quality processing module (1), a soot-blowing mode processing module (2), an air distribution mode processing module (3) for auxiliary air flow, a furnace temperature field data processing module (4), a furnace temperature field homogenising module (5), a boiler auxiliary operation mode processing module (6), a module (7) for processing the boiler coal mill commissioning manner, the execution instruction output module (13) comprising an oxygen amount adjustment module (8) and a furnace temperature adjustment module (9). The system constructs a combustion automatic adjustment system which improves the efficiency of combustion of the boiler.

Description

Combustion optimization control system and control method based on acoustic wave measuring furnace temperature field

The invention relates to the field of combustion detection and control, and in particular relates to a combustion optimization control system and a control method based on acoustic wave measuring furnace temperature field.

Background technique

With the implementation of air pollutant emission standards for new thermal power plants in China, more stringent requirements are imposed on the emission of nitrogen oxides from various thermal power plants. Therefore, the boilers of new thermal power plants have adopted low-nitrogen combustion technology, which is put into production earlier. The unit also converted the original boiler burner to a low-nitrogen burner to reduce nitrogen oxide emissions. In the low-nitrogen burners currently used in China, most of them adopt the air-graded combustion technology in consideration of the investment cost and the maturity of the technology. For the boiler with DC tangential combustion, that is, the combustion in the main combustion area is anoxic A part of the over-combustion air is arranged on the upper part of the main burner to achieve air staged combustion. In the current air-staged combustion technology, since a part of the air is separated and placed on the burner as a burn-out wind, the burning time of the pulverized coal particles is elongated, and the flame center is moved upward, such as the boiler is stable under a certain load. When running and the coal quality is stable, the boiler can be operated at a relatively economical level with a low level of nitrogen oxide emission through a certain combustion adjustment method, but when the unit needs to meet the AGC command of the response grid, it needs to quickly increase or decrease. When the load changes, or when the coal type changes, the combustion process is elongated due to the air staged combustion technology. The situation will be: When the boiler is under load, the superheater wall temperature and the reheater will have a large area super short time. Temperature, the amount of desuperheated water is not enough; and when the load is reduced, the phenomenon of low steam temperature appears. The variation/degradation of coal types is the same as that of boilers with reduced load/load increase.

This situation is more obvious in the retrofit unit, such as #2 boiler of Guodian Penglai Power Plant, #4 boiler of Huadian Zhangqiu Power Plant, etc. Due to the above situation, the AGC of some units cannot be used and the economy of the boiler The performance is also poor. Therefore, these conditions affect not only the adaptability of the boiler to load changes, but also the use of lower oxygen to fly ash and slag combustibles in order to meet boiler NOx emission standards. Boiler economy The reduction of the nature, here is the problem of an optimal operating state, in the best operating conditions, the boiler maintains the most appropriate oxygen, fi good air distribution, etc., in this state, the boiler's nitrogen oxide emissions Qualified and the boiler is economical.

In recent years, some units in China have installed boiler furnace smoke temperature measurement systems. Some of the measurement methods use laser measurement and some use acoustic wave measurement. As far as the measurement of the smoke temperature at the exit of the furnace is concerned, its accuracy is industrially acceptable. However, the results measured by this measuring system are only for the operator to observe the change of the temperature of the furnace, and do not participate in any automatic adjustment, and the utilization rate is extremely low.

The temperature field of the flue gas in the furnace is the most direct and fastest variable reflecting the combustion condition of the boiler, and its reaction speed is far. Faster than the temperature of the superheater wall and the amount of desuperheated water. If the temperature field of the flue gas in the furnace can be used to form a combustion-optimized control system, according to the optimized furnace flue gas temperature field, the burner damper flap, the burner swing angle, etc. The variables are adjusted so that the boiler can smoothly transition when lifting the load, avoiding the phenomenon that the wall temperature of the superheater and the reheater will have a large area of over-temperature, insufficient desuperheating water and low steam temperature. The economic optimization control system improves the boiler thermal efficiency and reduces the thermal efficiency of the boiler by adjusting the temperature field of the flue gas in the furnace evenly, adjusting the damper baffle, operating oxygen volume, and air distribution mode. The NOx emission of the boiler is the same, ensuring that the boiler operation is in a state of good economy and environmental protection.

The literature found to be relevant through search includes:

Wang Fei, Ma Gai, Wei Chengye, et al. "Study on the measurement of the temperature field of pulverized coal furnace section based on flame image", Journal of China Electrical Engineering 2000 (7), 20 (7): 41-43. Based on the flame treatment technology, algebraic reconstruction techniques are used to process the data and calculate the temperature field of the section. This document does not further relate to how to adjust and control the combustion in the furnace to optimize the temperature field. The calculation of the temperature field is only discussed algorithmically.

Huang Qunxing, Ma Gai, Yan Jianhua, et al. "Real-time monitoring of the temperature field center of boiler furnace section of 300MWe power plant", Journal of China Electrical Engineering 2003 (3), 23 (3): 156-160. Based on the temperature field of the section, the concept of the temperature field center is proposed. The temperature field center is used to reflect the distribution of the combustion tangential circle of the tangentially fired boiler, which provides a basis for combustion adjustment. This document only constructs the position of the burning circle, and if there is a skew, it does not propose how to solve the problem.

Zhang Shishi, Zhou Huaichun, Huang Yongli et al., “Study on the simulation of the load control system of thermal power unit using radiant energy feedback signal”, Journal of China Electrical Engineering, 2001 (2), 21 (2) 85-88. (The radiant energy of this paper is also the radiant energy signal extracted from the flame image processing technology) and Chang Ruili, Wang Fei, Huang Qunxing, etc., "Study on the optimization control of flame monitoring and combustion diagnosis of pulverized coal boilers in power stations", Energy Engineering, 2006 (4) : 10-13. These two papers are based on the 3⁄4 technology of the flame image, using BP neural network for self-learning and stability analysis, and a feedforward signal is obtained to adjust and correct the fuel quantity to the main steam pressure and the fuel quantity to the unit. Pure delay of power, large hysteresis characteristics. There are two major defects in this control system, which are also the main reasons for the inability to apply. One is the imperfection of the flame image processing technology. Due to the high temperature, ash, boiler coking and slag, etc., it is collected from the scene. Flame images tend to be more distorted, and there is a large delay in image processing, resulting in errors in BP neural network learning. The other is that the diagnostic control system only corrects the load control system, which is beneficial to improve the load response speed of the unit. There is no need to improve the efficiency of the boiler by controlling the combustion controllable factors.

Literature Gao Xiayu, Cheng Xueyong, Zang Hairui et al. "Optimized operation of boilers based on flue gas temperature monitoring of furnace outlets" 《Gas and Power》, 2010 (10), 30 (11): 12- 14 The author introduces infrared temperature measurement The instrument tests the flue temperature of the boiler furnace exit (the author defines the furnace exit as the entrance to the convective heating surface, ie, the flame exit angle, the horizontal flue inlet), and uses the measured furnace exit smoke. The temperature is re-calculated to provide a basis for the optimal operation of the boiler. Then the computer software calculates the boiler thermal efficiency and provides the operating personnel with the best operation mode, such as the main steam operation mode, the coal mill operation mode, etc. The best way to operate. The shortcoming of this method is that the infrared temperature measurement technology has a large error, and it is affected by factors such as ash collection and slagging of the boiler. Especially when the domestic power plant burns non-designed coal, the deviation will be greater. Sometimes it will not be used directly. The temperature measuring instrument of the power plant is basically in the exit state; the optimized operation of the boiler is only to provide a better operation mode for the operating personnel, and the operation personnel must operate to achieve the best operating state, and cannot directly adjust the damper flap. Make the boiler work best.

The patents found through patent search are as follows - Chinese patent 201110107881. 3 "Optimization measurement method for flue gas outlet temperature based on flue gas energy balance", introduces a method based on furnace combustion and radiant energy balance, superheater flue gas side The energy balance on the working side, the energy balance between the flue gas side and the working side of the reheater, and the energy balance of the tail flue gas. The flue gas temperature is optimized from both the flue gas side and the opposite direction. Only one furnace exit is introduced. The method of measuring the temperature of the smoke does not involve the content of combustion optimization.

Chinese Patent 200910273514. 3 "Method for detecting radiant energy signal of furnace and its method for controlling combustion of boiler", Chinese patent 01133648. X "Boiler multi-fire burner furnace combustion optimization control method", these two patents and the literature mentioned above Similar to the research on the flame monitoring and combustion diagnosis optimization control of pulverized coal boilers in power stations, the flame image processing technology is used to obtain the radiant energy signals and then the radiant energy signals are used for combustion control. Among them, Chinese patent 200910273514. 3 is controlled by radiant energy signals. The amount of oxygen, and the heat signal to control the amount of desuperheated water in the superheater; Chinese patent 01133648. X uses the flame image detector to obtain the three-dimensional temperature field distribution of the furnace, and then through the data processing to fit the radiant energy signal to find out the relationship with the unit's electrical load, The relationship between the center of the flame and the center of the section and the fuel amount and the air volume distribution ratio of each layer are optimized for combustion. The limitation of flame image processing technology and radiant energy signal in the field has not been described in detail. The combustion optimization involved in Chinese patent 200910273514. 3 has only a large limitation in the optimization of oxygen content because of the combustion adjustment variable. It also includes many, such as auxiliary wind distribution, coal mill operation, etc., and should also include nitrogen oxide emission concentration, etc., and the radiant energy signal is a factor that affects many factors and often distorts the signal, and its amplitude and frequency of change. Higher, using it to control the amount of desuperheating water is easy to cause the desuperheating water regulating valve to adjust excessive frequency and damage; Chinese patent 01133648. X In addition to the radiant energy acquisition method and the inherent defects in the field, the combustion optimization adjustment variables include incomplete , does not include the important variable of operating oxygen (operating oxygen has an impact on boiler economy and nitrogen oxide emissions), does not include burner swing angle, graded burnout ratio, furnace blowdown And the operation of the burner, etc., and another point is for the boiler with the direct-blowing pulverizing system. In other words, the fuel ffi of the burners at each corner is not adjustable.

Chinese patent 200710069862. X "Initiative method and device for power plant boiler combustion based on infrared radiant energy signal", the method proposed by this patent is consistent with the literature "Boiler optimization operation based on furnace outlet flue gas temperature monitoring", this patent The method of obtaining the radiation intensity information in the furnace by the near-infrared radiant energy sensor and obtaining the radiant energy deviation value through the artificial network is mainly emphasized. Regarding the combustion optimization, the radiant energy deviation value is only involved in the DCS system of the power plant to control the boiler fuel. Module, improve boiler feed control logic, || The speed of load change of the corresponding unit of high boiler, to a certain extent, is not true combustion optimization.

China Patent 200910184471. 1 "On-line optimization control system for boiler pulverized coal combustion and its optimization", this patent optimization method is based on the analysis of smoke sampling and analysis of the air preheater outlet and the furnace, using the support vector machine theory as the basis for automatic Training and optimization, this method is first of all because the flue is large. If the sampling point is small, the smoke component cannot be truly reflected. If there are more points, the system is too complicated, and it needs to be used in training and learning. The data of fly ash carbon content, high temperature corrosion status and other data are greatly affected by man-made and coal quality changes. At present, boiler coal-fired wood is deviated from the design of coal, and the system training and optimization process can not be completed. Excellent goal.

China Patent 201110205051. 4 "-Generalized Boiler Combustion Integrated Optimization Energy-Saving Composite System", introduced an optimized composite control system for use in grate boilers, this patent mainly emphasizes the improved addition system of fuel improver, patent specification It is only a simple statement that the combustion optimization control system uses fuzzy control and optimized self-optimizing technology to adjust the wind-to-coal ratio. The method of overall combustion optimization is not described in detail, and the patent is mainly applicable to small grate boilers.

Chinese patent 201220029007. 2 "-Boiler furnace combustion optimization device", introduced the addition of C0 ₂ probe at the exit of the tail flue economizer, and then compare the C0 ₂ on the left and right sides. If there is a large deviation, it is considered to be adjusted. The secondary wind eliminates the deviation. Another point is that the measured C0 ₂ value is compared with the calculated CC. If C0 _2SHX is 6% or more smaller than the measured C0 ₂ value, the oxygen measurement value is too large, and the power requirement is only required. The C0 ₂ monitoring transmitter is added to the flue, so the patent does not address the true combustion optimization. ,

According to the above analysis, for large power station boilers, the current boiler combustion control system based on the furnace temperature field or the simple combustion optimization control system has many defects, mainly in: (1), with radiant energy or flame Image processing technology-based temperature field measurement technology in the working environment of the sensor is gray, high temperature environment makes the furnace temperature field measurement system work abnormally, often outage or temperature field data distortion; (2), the current simple combustion optimization Control systems or combustion optimization control systems based on furnace temperature field measurement have problems of incomplete combustion control factors. Most of the current combustion optimization control systems only improve one aspect, such as improving the reaction speed of the boiler to the unit load. (3) Another shortcoming of the current combustion optimization control system or the combustion optimization control system based on the furnace temperature field measurement is that the optimization of the control system that cannot automatically achieve combustion requires the participation of the operating personnel.

Summary of the invention

The object of the present invention is to solve the above problems, and to provide a combustion optimization control system and a control method based on acoustic wave measuring furnace temperature field, which can quickly and directly reflect the combustion condition in the furnace by using the furnace temperature field, and establish a Under the condition of accurately measuring the temperature field of the furnace, comprehensively consider all the control factors affecting combustion to construct a system for automatic regulation of combustion. It has the advantages of improving boiler combustion efficiency and making the boiler safe, stable, economical and reliable. .

In order to achieve the above object, the present invention adopts the following scheme:

A combustion optimization control system based on acoustic wave measuring furnace temperature field, comprising a data acquisition module, wherein the data acquisition module transmits the collected data to a data processing device, and the data processing device transmits the processed data to a running mode selection module The operation mode selection module transmits the selected result to the execution instruction output module;

The data acquisition module is used to collect power plant operating state data;

The data processing device is configured to analyze and process the collected operational status data;

The operation mode selection module is used to select the optimal operation mode according to the commissioning state of the coal mill and the soot blowing;

Execution command output module is used to issue instructions to the field actuator according to the optimal operation mode to adjust the boiler to the optimal operating state;

The data processing device is packaged with a coal processing module, a soot blowing processing module, an auxiliary wind distribution mode processing module, a furnace temperature field data processing module, a furnace temperature field leveling module, a boiler auxiliary machine operation mode processing module, and a boiler coal grinding Machine operation mode processing module;

The execution instruction output module includes an oxygen amount adjustment module and a furnace temperature adjustment module;

The coal quality processing module is used for quantitatively analyzing and analyzing the coal quality of the boiler into the furnace, so as to adjust the corresponding operation mode according to the coal quality;

The soot blowing method processing module is used for digitally processing the boiler soot blowing state for convenient control and adjustment; the auxiliary wind distribution mode processing module is used for digital processing of the boiler auxiliary wind distribution mode, which is convenient for control and adjustment;

The furnace temperature field data processing module is configured to preprocess data of the temperature field measurement system;

The furnace temperature field leveling module is configured to perform uniformity adjustment of the furnace temperature field by an actuator;

The boiler auxiliary machine operation mode module is used for digitally processing and optimizing the operation mode of the boiler auxiliary machine; the boiler coal mill operation mode module is used for digitizing the operation state of the coal mill, and is convenient for control , Adjustment;

The oxygen amount adjustment module is used for adjusting and optimizing the oxygen amount of the boiler operation;

The furnace temperature adjustment module is used for adjustment and optimization of boiler furnace temperature.

The above control method for the combustion optimization control system based on the acoustic wave measuring furnace temperature field mainly comprises the following steps _: Step (1): performing comprehensive performance test and combustion optimization adjustment on the boiler to find the optimal operating condition of the boiler, and The range of variation of each controllable variable under the optimal operating conditions, the data acquisition module is for boiler load, auxiliary wind condition, Data collection for separation of burnout wind conditions, furnace temperature field conditions, soot blowing conditions and coal mill operating conditions; Step (2): Mathematical treatment based on the above comprehensive test results, mainly to establish boiler thermal efficiency, nitrogen oxide emissions The relationship between the concentration and the controllable variables of each combustion, the data processing of the temperature value outputted by the data acquisition module is processed to become a variable capable of participating in the combustion control, the coal processing module of the data processing module, the soot blowing processing module, and the auxiliary The wind distribution mode processing module, the furnace temperature field data processing module, the furnace temperature field leveling module, the boiler auxiliary machine operation mode module, and the boiler coal mill operation mode module process the data of the data acquisition device;

Step (3): The operation mode selection module selects the corresponding operation mode;

Step (4): The oxygen amount adjustment module compares the operating oxygen amount with the optimal oxygen amount. When there is a deviation between the two, the operating oxygen amount is made close to or equal to the optimal oxygen amount by adjusting the air supply amount. The furnace temperature adjustment module compares the average temperature of the real-time furnace with the average temperature of the optimal furnace. When there is a deviation between the two, the SOFA (Separated Over Fire Air) swing angle, the output of each coal mill, etc. The average temperature is close to or equal to the optimum furnace average temperature.

The comprehensive performance test of the boiler in the step (1) includes: adjustment and testing of the boiler auxiliary system, combustion optimization adjustment test under various load of the boiler, and variable coal test under the economic load of the boiler;

The step (1) combustion optimization adjustment includes: performing a variable oxygen amount test under different loads, an auxiliary wind distribution mode change test, a variable coal mill operation mode test, a change soot frequency test, and a variable separation burnout air volume Test, variable burner swing angle test, coal mill separator rotation speed test;

The step (2) temperature value processing includes: a bad value judgment and processing of the temperature measurement value, and a regionalization process of the temperature measurement value;

The mathematical treatment of the step (2) comprises: establishing a mathematical model of the coal quality factor according to the analysis result of the coal quality in the furnace, and establishing an optimum furnace average temperature, boiler load, and coal quality factor according to the comprehensive performance test and the boiler combustion adjustment test. Mathematical relationship, establish the mathematical relationship between optimal oxygen quantity and boiler load and coal quality factor, find out the change SOFA swing angle, burner swing angle, the output distribution of each coal mill and the average temperature change of the furnace as the oxygen quantity adjustment module. And furnace temperature adjustment preparation.

The basic working principle of the invention - based on the comprehensive optimization test of the boiler and the measurement of the acoustic wave temperature measurement system, the acoustic wave measurement data is processed, and the uniformity adjustment of the furnace temperature field is performed according to the temperature measurement data of the acoustic wave measurement system, so that the whole boiler is The temperature field of the entire combustion section uniformly reduces the amount of nitrogen oxides generated and the incomplete combustion of coke due to the uneven temperature field. According to the actual comprehensive measurement results of the boiler site, the controllable factors and boiler economy of the boiler are established. A mathematical model of NOx emission characteristics and furnace temperature is then used to achieve automatic adjustment of boiler combustion optimization using a mathematical model control system.

The key point of the technology of the present invention -

1), in order to truly reflect the actual situation of the boiler, but also to consider different coal types and different soot blowing conditions, different loads Under the operating condition of the boiler, the boiler is fully adjusted and optimized. Therefore, the work is quite complicated and the length of time can be used in advance according to the specific conditions of the site or some of the previous test data can be used.

2) The establishment of the mathematical model is not only based on the actual test data for numerical fitting, but also the operating habits of the plant operators and the safety and stability of the boiler operation.

The beneficial effects of the invention are -

1 Since the combustion optimization control system is developed on the basis of comprehensive adjustment and optimization of the boiler and using the acoustic wave temperature measurement system, and fully considers the actual coal burning condition of the power plant, the operation mode of the auxiliary system, the operation of the operating personnel Habits, can be very close to the actual, it can be said that tailored to a certain boiler, can ensure the stable operation of the boiler in a state of economy and NOx emission characteristics.

2 At present, the abnormal exit of more combustion optimization systems is caused by the change of coal combustion or the change of the operating state of the auxiliary machine, and the actual coal-fired condition of the power plant and the operating state of the auxiliary machine fully considered by the system are avoided. These two reasons lead to abnormal exit of the combustion optimization system and high reliability.

3 This system does not require the operation personnel to participate in the operation, and realizes completely intelligent, completely avoiding the negative influence of some unreasonable operating habits of the operating personnel on the combustion of the boiler.

DRAWINGS

1 is a schematic diagram of a system module of the present invention;

2 is a schematic diagram of a workflow of the present invention;

Figure 3 is a schematic diagram of the temperature signal of the TMS-2000 sonic temperature measurement system;

Among them, 1, coal quality processing module, 2, soot blowing mode processing module, 3, auxiliary wind distribution mode processing module, 4, furnace temperature field data processing module, 5, furnace temperature field mixing module, 6, boiler auxiliary machine operation Mode processing module, 7. Boiler coal mill operation mode processing module, 8, oxygen amount adjustment module, 9, furnace temperature adjustment module, 10, data acquisition device, 11, operation mode selection module, 12, data processing device, 13 Execute the instruction output module.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the actual embodiment of the Huaneng Power Plant #5 boiler and the drawings.

As shown in FIG. 1, a combustion optimization control system based on a sound wave measuring furnace temperature field includes a data acquisition module, and the data acquisition module transmits the collected data to the data processing device 12, and the data processing device 12 will process the data. The data is transmitted to the operation mode selection module 11, the operation mode selection module 11 transmits the selected result to the execution instruction output module 13;

The data acquisition module is configured to collect power plant operating state data; the data processing device 12 is configured to collect the collected operating states According to the analysis and processing; the operation mode selection module 11 is configured to select the optimal operation mode according to the commissioning state of the coal mill and the soot blowing; the execution command output module 13 is configured to issue an instruction to the field actuator according to the optimal operation mode. The boiler is adjusted to an optimal operating state; the data processing device 12 is packaged with a coal quality processing module 1, a soot blowing mode processing module 2, an auxiliary wind distribution mode processing module 3, a furnace temperature field data processing module 4, a furnace temperature The field leveling module 5, the boiler auxiliary machine operation mode processing module 6, and the boiler coal mill operation mode processing module 7.

The actuator includes an oxygen amount adjustment module 8 and a furnace temperature adjustment module 9; the coal quality processing module 1 is used for quantitatively analyzing and analyzing the coal quality of the boiler, so as to adjust the operation mode according to the coal quality. The soot blowing method processing module 2 is used for digitally processing the boiler soot blowing state for convenient control and adjustment; the auxiliary wind distribution mode processing module 3 is used for digital processing of the boiler auxiliary wind distribution mode, which is convenient for control and adjustment. The furnace temperature field data processing module 4 is configured to preprocess data of the temperature field measurement system; the furnace temperature field leveling module 5 is configured to perform uniformity adjustment of the furnace temperature field by the actuator; the boiler auxiliary machine The operation mode module is used for digitally processing and optimizing the operation mode of the boiler auxiliary machine: the boiler coal mill operation mode module is used for digitizing the operation state of the coal mill, which is convenient for control and adjustment; The oxygen amount adjusting module 8 is used for adjusting and optimizing the oxygen amount of the boiler operation; the furnace temperature adjusting module 9 Adjust and optimize the boiler furnace temperature.

As shown in FIG. 2, the above control method for the combustion optimization control system based on the acoustic wave measuring furnace temperature field mainly comprises the following steps:

Step (1): Perform comprehensive performance test and combustion optimization adjustment on the boiler to find out the optimal operating conditions of the boiler and the range of variation of the controllable variables of each combustion under the optimal operating conditions. The data acquisition module is for the boiler load. , data collection of auxiliary wind conditions, separation of burnout wind conditions, furnace temperature field conditions, soot blowing conditions, and coal mill operating conditions;

Step (2): According to the above comprehensive test results, the mathematical processing is mainly to establish the relationship between the boiler thermal efficiency, the concentration of nitrogen oxides and the controllable variables of each combustion, and the data processing of the temperature values output by the data acquisition module. It becomes a variable that can participate in combustion control, the coal processing module of the data processing module, the soot blowing processing module, the auxiliary wind distribution mode processing module, the furnace temperature field data processing module, the furnace temperature field leveling module, and the boiler auxiliary machine operation mode. The module and the boiler coal mill operation mode module process the data of the data acquisition device;

Huaneng Power Plant #5 Boiler ώ Shanghai Boiler Factory Co., Ltd., model SG-1025/17. 47- Μ880 subcritical Number of steam drum furnaces, control cycle, single furnace, one time reheating, open air layout, solid waste slag. The boiler is designed with the maximum continuous load (B-MCR) as the design parameter, and the maximum continuous evaporation is 1025t/h. The boiler adopts five medium-speed coal mill direct-blowing powder feeding system, five-layer primary air nozzle arrangement, four layers of operation with B-MCR, and three layers of ignition oil guns, and the lowermost layer is equipped with plasma ignition system. The fully oscillating DC burner with tangential arrangement of four corners, the burner should be able to operate for a long time, and the swinging device is flexible and reliable. In the hot state operation, the secondary air nozzle can swing up and down, and the maximum swing angle is about ±30° to meet the reheat steam temperature regulation requirements.

The sound wave temperature measurement system TMS-2000 is installed on the #5 boiler. The temperature signal output of the temperature measurement system is shown in Figure 1. In order to verify the accuracy of the sound wave temperature measurement, the suction type thermocouple is used for verification. Thermocouples are limited in length and can only be used with T-MS. ,, TMS. ₂ , TMS „ ₃ , TMSo TMS. ₅ , TMS. ₆ , TMS, „, TMS „, TMS, ₅ , TMS, ₆ , TMS ₁₇ , TMS, _a , TMS „ , TMS ₂ . For measurement and comparison, after multiple operating conditions and multiple measurements, the maximum deviation is 8%, the minimum deviation is 1%, and the data is repeatable, because it can be considered as temperature measurement. The system has good accuracy and stability and can be used for control and optimization of boiler combustion.

The first step is to perform a full performance test and combustion optimization adjustment of the boiler. For the #5 boiler, it includes:

(1) Adjustment of the auxiliary system. This includes the primary air leveling (measuring the wind speed of the air duct at the exit of each coal mill. If the wind speed of the coal mill is large, the wind speed is adjusted by the adjustable shrinkage hole. The wind speed of the primary air duct is less than ± 5%. ): The primary air volume calibration of the coal mill inlet (the wind inlet device is installed at the entrance of each coal mill. Under the habitual operation air volume, the primary air volume passing through the coal mill is measured with the calibrated backrest tube, and the air volume of the dial is compared. Whether the measured air volume is consistent, if the difference is large, the calibration coefficient of each coal mill can be used to adjust the air volume of the dial, so that the air volume indication of the coal mill is accurate, providing a reliable basis for the operation operation); Test (adjust the output of the coal mill to about 80% of the maximum output, carry out the load test of the grinding roller of the coal mill to determine the optimal loading pressure of the grinding roller); test the characteristics of the coal powder separator (adjust the output of the coal mill to the maximum About 80% of the output, the coal mill air volume is set according to the wind-coal ratio curve. Under different separator rotation speeds, the pulverized coal is sampled at the same speed on the four primary air ducts at the coal mill exit. Principles sectional opposing installation, etc. inch coal samples collected, analyzing coal fineness and R & lt .. ..) (Note: and are represented by R ₂ .. Method for Fineness of coal, coal by representation. The pore size is the percentage of 90 sieves, R ₂ . represents the percentage of pulverized coal passing through the pore size of 200 sieves; the characteristic test of the blower fan (testing the output characteristics of the blower fan at three load points to find out that the fan is different The efficiency at the working point, find out the resistance characteristics of the air intake system). The adjustment of this step is mainly for the next step to make a comprehensive adjustment of the boiler.

(2) Comprehensive combustion optimization of the boiler.

It mainly includes the following test items:

1 Comprehensively collect and analyze the coal quality of the boiler and the coal quality of the incoming coal, and determine the test coal according to the variation range of coal quality. The range of qualitative changes and test coal types.

2 coal mill separator characteristics test.

3 Determine the minimum steady combustion load of the boiler and the maximum continuous load of the boiler.

4 furnace temperature field adjustment uniform test.

5 The oxygenation test is carried out from the lowest steady-state load to the maximum continuous load, and the boiler efficiency, nitrogen oxide emission concentration and furnace temperature average are calculated for each oxygen amount.

6 change coal mill operation mode test. It is divided into four coal mills and five coal mills.

7 Optimized adjustment test under different soot frequency.

8 Optimized adjustment test under different air distribution modes.

9 Separate the relationship between the burnout baffle opening and the boiler efficiency / NOx emission concentration / furnace temperature average.

10 separate burnout wind swing angle and boiler efficiency / NOx emission concentration / furnace temperature average relationship.

11 main burner swing angle and boiler efficiency / NOx emission concentration / furnace temperature average relationship.

(3) In order to make the optimization program more concise and easy to upgrade, the function block will be processed to make the optimization system error and maintenance convenient.

1 Coal quality treatment

0) Calculate the comprehensive analysis index of coal quality according to the coal quality in the past two years, and then comprehensively determine the coal quality? _max , β _αν , y9 _min for future coal quality changes.

Where: y» _max - the maximum value of the comprehensive analysis index of coal quality: A „^ The average value of the comprehensive analysis index of coal quality; the minimum value of the comprehensive analysis index of 9 _m , _n -- coal quality; F _z " and F: 'The index of coal quality combustion characteristics of a design and actual coal type; F; = {V _ad "+ M. _d ") ² χ C _ai "x 10 , F _z ' ^- (V _ad '+ M _ad ' ² x C. _d 'x 10- ⁶ ; V _ad "and V _ad ' -- design and actual coal type air-dry basis volatiles, %: c _ad "and c _ad '-design and actual coal species δ Thousands of fixed carbon, %·'

Α "and A' a design and actual coal type of empty-based ash, %; Q _ne , _ad "and '-- design and actual coal type air dry heat generation, kj / kg _;

M _ad "and M _ad '- space design and actual dry coal moisture,%.

(2), according to the thermal calculation book fitting function = / (£>);

(3) Calculating the coal quality factor for coal supply quantity,

Where: Μγ - - design coal supply under coal, t / h;

HV—the amount of coal fed under actual coal, t/h;

Boiler evaporation, t/h; according to the value of ^), 9, for the #5 boiler, ^ > 0.9, the coal quality is selected? _max , 0.8 < ^ < 0.9 wf ^w f ^w f when β is selected, < At 0.8, choose j3 _mi „.

Wf

2 blowing method

The mode of soot blowing is two modes: modeb-Ι is the distance from the last soot time of less than 8 hours, and modeb-2 is the distance from the last soot time of more than 8 hours.

3 auxiliary wind distribution method

The three modes of boiler burner auxiliary wind distribution mode are modew-1 for pagoda type distribution, rnodew-2 for equal air distribution, and modew-3 for inverted pagoda type distribution. Different coal quality and load, the optimal air distribution method of the boiler is different, as for the #5 boiler,

D^75%BMCR and α >0. 8 distribution mode selection modew- 1 ;

D^75%BMCR and α <0. 8 distribution mode selection modew- 3 ;

D<75%BMCR air distribution mode select modew-2.

Where: boiler evaporation, t / h; α - - coal quality factor.

4 furnace temperature field data processing

(1), the definition of the central area includes: TMS. ₇ , TMS. ₈ , TMS. , TMS, ₂ , TMS, ₃ , TMS,"

The furnace temperature average is defined as Ta ge,

Taverage = average (TMS ₀₇ , TMS _m , TMS ₉ , TMS _{X 2} , TMS _{] 3} , TMS ₄ ); If: |7 - (07,08,09,12,13,14)

Then, the average temperature of the furnace is set to ⁷ ^, and the average value of the central area is calculated.

(2), furnace wall area definition: The front wall includes TMS _M , TMS. ₂ , TMS. ₃ , TMS _M , TS „ ₅ ,

The left wall includes TMS^ TMSoe> TMS„, TMS ₁₆

The rear wall includes TMS, ₆ , IMS 17, TMS ₁₈ , TMS ₁₉ , TMS ₂ . ,

The right wall includes TMS „ ₅ , TS, „ TMS, ₅ , TMS ₂ „o

For the average value of the front wall area, the data less than the average value of 100 中 in the temperature data of the front wall is removed;

For the average value of the left wall area, the data smaller than the average value 100 'C in the temperature data of the left wall is removed;

For the average value of the back wall area, the data less than the average value of 100 °C in the temperature data of the back wall is removed;

For the average value of the right wall area, the data of less than the average value of 100 中 in the temperature data of the right wall is removed;

(3), corner area definition: #1 corner includes TMS. , TMS„ ₂ , TMS„ ₆ , TMS ₀₇ ;

#2角 includes TMS„, TMS.2, TMS, ₆ , TMS ₁₇ ;

The #3 corner includes TMS ₂ . , TMS _l9 , TMS, ₅ , TMS";

The #4 corner includes TMS. ₅ , TMS _M , TS _I0 , TMS. ₉ .

After the data processing of the four-wall area, the average temperature of each corner is obtained, wherein the average temperature of the angle #1 is T _m average, the average temperature of the angle is 7 ₂ flverage, and the average temperature of the angle #3 is ^average , The average temperature of the #4 angle is T _M average.

(4), the module finally outputs the average furnace temperature - - 73⁄4 _Vera ge and the average temperature of each corner r _#l awrage,

T _#1 average , T _#i average » T _M avemge. 5 furnace temperature field adjustment hook

(1), find Γ max = averag, Τ _#2 averag, Γ _#3 averag, Τ _#4 averag), πώι = (T _m averag, T _#2 averag, Γ _#3 averag, T _#4 averag)

Where, rmax - the maximum temperature of the four corners of the boiler, Γηιίη - the minimum temperature of the four corners of the boiler.

(2) If rmax- Γπώι < 70 ° _C , no adjustment command will be issued to the damper flap.

(3) If Tinax-r min ≥ 70 _O , an adjustment command is issued to the damper flap. The specific adjustment method is as follows (for the convenience of description, #1 is the maximum value, and #3 angle is the minimum value):

1. Open the #1 corner SOFA baffle until the full opening and close the #3 corner SOFA baffle. The baffle change step is 3%, while closing When the NOx emission concentration is greater than 300 tiig/ _m ³ , the #3 angle SOFA baffle is stopped.

After ②, SOFA adjustment is completed, rmax- rmin≥70 _'C adjustment _0FA1 _{(0ver fire} _Airl first overfire air layer) and 0FA2 (second layer 0ver fire Air2 overfire air), the large open angle # 1 and 0FA1 0FA2 baffle until the full opening and close the #3 corner 0FA1/2 baffle, the baffle change step size is 3%.

3. After 0FA1 and 0FA2 are adjusted, Tmax- min≥70 ' _C performs _EE / _DE / _CD layer auxiliary wind adjustment, open #1 angle EE/DE/CD (represents the EE layer, DE layer and CD layer auxiliary Wind baffle until the full opening and closing the #3 angle EE/DE/CD baffle, the baffle change length is 3%, when closing the auxiliary baffle, when the baffle opening is closed to 15%, then Stop closing.

4. After the adjustment of EE/DE/CD is completed, max- Γηιΐη > 70. _C performs _BC / _AB (representing the _B C layer and AB layer auxiliary wind) layer auxiliary wind adjustment, open the #1 angle BC / AB baffle until fully open and close small #3 angle BC / AB baffle, baffle Change step

3%. When the auxiliary air baffle is closed, when the baffle opening is closed to 15%, the shutdown is stopped.

According to the actual test at the site, after the completion of 1 and 2, the furnace temperature field can be adjusted.

(4) When the above adjustment is completed, the furnace temperature field is still ^max- r _m in≥70 ' _C , then the alarm of "uneven temperature field of the furnace" is given, and the relevant personnel are required to check the temperature measurement system.

After the temperature field is adjusted, the temperature field of the whole section is relatively uniform, which reduces the excessive combustion in the high temperature region and the incomplete combustion of the coke in the low temperature region, reduces the carbon content of the fly ash and improves the thermal efficiency of the boiler; The uniformity of the field reduces the local high temperature in the boiler and reduces the generation of thermal nitrogen oxides, which is beneficial to reduce the nitrogen oxide emissions of the boiler.

6 boiler auxiliary machine operation mode processing

(1) The automatic tracking function of the relationship between the loading force of the coal mill and the coal volume P = f{w , a) , where: >- - coal mill grinding stick loading force, coal feeding amount, "- coal quality factor .

The function relationship is based on the optimization test results of the boiler auxiliary machine, and optimizes the relationship between the coal feeding amount of the coal feeder and the loading force of the grinding mill grinding rod, so that the coal mill receives the command of the coal quantity change, and automatically adjusts the coal mill. Loading power. It should be noted here that the coal mill manufacturer will provide a loading force as a function of the amount of coal, but this functional relationship is the ideal functional relationship derived from the design of the coal type. The functional relationship obtained through the optimization test is The function relationship is optimized after considering the factors of coal type change.

(2) When the boiler evaporation amount is greater than 90% BMCR (Boiler Maximum Continuous Rate boiler maximum continuous output), the induced draft fan A/B is automatically switched to the power frequency operation mode by the variable frequency operation mode. When the boiler evaporation amount is greater than 95% BMCR, Keep the flue gas pressure at the outlet of the induced draft fan constant, adjust the desulfurization booster fan to maintain the flue gas pressure at the outlet of the induced draft fan. The specific logic operation can increase the flue gas pressure at the outlet of the induced draft fan in the control loop of the desulfurization booster fan. When raised, then Increase the output of the desulfurization booster fan; when the flue gas pressure at the outlet of the induced draft fan decreases, the adjustment of the desulfurization booster fan or the adjustment of the induced draft fan is not performed.

(3), the automatic speed tracking function of the best separator speed of the coal mill

(«), where: the best separator speed of the coal mill, tf - coal quality factor

7 boiler coal mill operation mode

(1), #5 boiler runs 5 sets of milling system when the heat load is greater than 80% BMCR; runs 4 sets of milling system when 50% BMCR-100%BMCR, and the boiler is put into operation when less than 50% BMCR Stable combustion, this is the main task is the stable combustion of the boiler, combustion optimization is in a secondary position.

(2) For the five sets of milling system, the operation mode of the coal mill is defined as three types: _m ode5-1, mode5-2 and mode5-3. Among them, m ₀ de5-l is the second two layers with large grinding force, the upper two layers have small grinding force, mode 5-2 is the average output of five sets of mills, mod _e 5-3 is the upper two layers with large output, and the lower two layers have small output.

(3), four sets of milling system operation 吋, also defined as three operating modes mod _e 4-l, mode4-2 and m ₀ d _e 4- 3, where mode4-1 is the lower four grinding operation, mode4_2 is the upper Four-mill operation, mode 4-3 is a four-grind operation with a fault.

8 operating mode selection

This module is mainly used to deal with the combination of different milling system operation mode and soot blowing method, and then according to the boiler combustion adjustment test data to obtain the optimal operating oxygen content of the boiler 0 ₂ / optimal furnace temperature T and boiler load / coal quality Relational function. The specific operation mode of #5 boiler of Huaneng Power Plant can be seen in the following table.

Table 1 Selection of specific operation modes of 5 boilers in Huaneng Power Plant

No. Milling system operation mode, soot blowing operation mode, optimal furnace average temperature and optimal oxygen quantity function

11 modem4-3 modeb - 1 T=f (D, a ) , 0 ₂ =f (D, a )

12 modem4-3 modeb - 2 T=f (D,a ), 0 ₂ =f (D, a )

For an example of the above table, for example, the third row indicates that the average furnace temperature function of the boiler is T=f (D, a ) when the milling system is operated modems-2 and modeb-1 is used during soot operation. , the optimal oxygen function is 0 ₂ =f (D, a ). Where: T-one optimal furnace average temperature, °C, D-boiler load, t/h, 0 ₂ - optimum oxygen amount, %.

9 oxygen adjustment

(1) Compare the optimal operating oxygen amount 0 ₂ calculated by different coal _pulverizer operation modes and soot blowing mode with the real-time operating oxygen amount 0 _{2rea/ of the} boiler, and obtain the deviation value.

(2) If I 0 ₂ - O _2rra , I > 0.5% (indicating the absolute value of the difference between the optimal operating oxygen and the real-time operating oxygen), in order to reduce the DCS (Distributed Control System distribution) of the optimization program Control system) The influence of the control, the oxygen control in the optimization program will use the offset adjustment, if I 0 ₂ - O _{2re; i /} I> 0. 5% will 0 ₂ - O ₂ , _ra , as the offset Change the operating oxygen volume. During the process of changing the oxygen content, the emission concentration of NOx (representing nitrogen oxides) should be detected at any time. When the NOx emission concentration is greater than 300 _mg / m ³ , the SOFA baffle is opened until the SOFA baffle Fully open, then reduce the opening of all auxiliary winds in the same proportion until the NOx emission concentration is less than Omg/m^

Note: This module takes precedence if the adjustment of the SOFA baffle in the module conflicts with the adjustment of the SOFA baffle in the furnace temperature field data processing module 4.

10 furnace temperature adjustment

(1) The optimum average temperature T of the furnace temperature and the average value of the real-time furnace temperature calculated by different coal mill operating modes and soot blowing modes. , compare, and find the deviation value.

(2) If T- r _wa , >15. C, first swing the SOFA up until the SOFA is fully placed, then proceed to the upper burner, until the main burner is fully in place, then reduce the upper three layers of the auxiliary wind opening by the same proportion. Auxiliary wind opening, and then increase the output of the upper two-layer coal mill while reducing the output of the next two-layer coal mill in the same proportion. According to the experience, after the current two measures are completed, the average temperature of the furnace can reach the optimal temperature. When all four measures are completed, there are still Τ-7 _σ , 〉 15'C, then the program gives the information "optimization program failure", and Exit the optimizer automatically.

(3) If Tr _rea/ <15O, first swing the SOFA down until the SOFA is fully seated, then proceed to the hem of the main burner until the main burner is fully seated, then add the upper three layers of auxiliary wind opening The same proportion of the reduction of the next three The layer assists the wind opening, and then reduces the output of the upper two-layer coal mill while increasing the output of the two-layer coal mill by the same proportion. According to the experience, after the current two measures are completed, the average temperature of the furnace can reach the optimal temperature. When all four measures are completed, there is still Τ- Γ„., <15Ό, then the program gives the information "for furnace ash blowing", The optimizer automatically exits to start the furnace soot blowing.

(4), combustion optimization closed-loop control

Detailed description is made in conjunction with Figure 3: TMSi is the temperature value of the temperature field measurement system output, and the subscript i ' ranges from 01-20.

Step 1 is mainly to read the current operating state of the boiler, including: boiler load, burner auxiliary wind distribution, SOFA opening condition, furnace temperature field condition, soot blower, coal mill operating condition;

Step 2 performs 7 modular treatments on the collected boiler operating conditions, including: coal quality processing of coal quality processing module 1, soot blowing frequency processing of soot blowing method processing module 2, auxiliary wind distribution mode processing module 3 The burner assists the wind distribution method, the furnace temperature field data processing module 4 and the furnace temperature field leveling module 5 are the furnace temperature field data processing and the temperature field homogenization processing, and the boiler auxiliary machine operation mode processing module 6 the boiler auxiliary machine operation mode processing The coal mill operation mode of the boiler coal mill operation mode processing module 7 is processed, and the seven processing modules output the response operation mode and the parameter information; Step 3 selects according to the result of the process in step 2, and finds the corresponding operation mode. The optimum operating oxygen volume and the optimum furnace temperature average;

Step 4: The oxygen amount adjustment module is performed according to the optimal operating oxygen amount 0 ₂ and the optimal furnace temperature average value T processed in step 3.

8 and the calculation of the furnace temperature adjustment module 9 and the adjustment command of the burner swing angle, oxygen amount and other parameters to make the boiler reach a new operating state.

In the new operating state, the boiler is re-executed in steps 1-4 to achieve optimum operation of the boiler.

The above description of the specific embodiments of the present invention has been described with reference to the accompanying drawings, but is not intended to limit the scope of the present invention. Those skilled in the art should understand that the skilled in the art does not require the creative work on the basis of the technical solutions of the present invention. Various modifications or variations that can be made are still within the scope of the invention.

Claims

A combustion optimization control system based on acoustic wave measuring furnace temperature field, comprising: a data acquisition module, wherein the data acquisition module transmits the collected data to a data processing device, and the data processing device processes the processed data Transmitted to the operation mode selection module, the operation mode selection module transmits the selected result to the execution instruction output module; the data collection module is configured to collect the power plant operation state data;

The execution command output module includes an oxygen amount adjustment module and a furnace temperature adjustment module.

2. The combustion optimization control system based on acoustic wave measuring furnace temperature field according to claim 1, wherein the coal quality processing module is used for quantitatively analyzing and analyzing the coal quality of the boiler into the furnace, so as to According to the coal quality, the corresponding operation mode adjustment;

The furnace temperature field grading module is configured to perform uniformity adjustment of the furnace temperature field by an actuator;

The boiler auxiliary machine operation mode module is used for digitally processing and optimizing the operation mode of the boiler auxiliary machine; the boiler coal mill operation mode module is used for digitizing the operation state of the coal mill, and is convenient for control , Adjustment; .

3. A control method for a combustion optimization control system based on acoustic wave measuring furnace temperature field according to any of the preceding claims, characterized in that it comprises the following steps:

Step (1): Perform comprehensive performance test and combustion optimization adjustment on the boiler to find the optimal operating conditions of the boiler, and the range of variation of the controllable variables of each combustion under the optimal operating conditions. The data acquisition module is for the boiler load. , data collection of auxiliary wind conditions, separation of burnout wind conditions, furnace temperature field conditions, soot blowing conditions, and coal mill operating conditions; Step (2): According to the above comprehensive test results, the mathematical processing is mainly to establish the relationship between the boiler thermal efficiency, the concentration of nitrogen oxides and the controllable variables of each combustion, and the data processing of the temperature values output by the data acquisition module. It becomes a variable that can participate in combustion control, the coal processing module of the data processing module, the soot blowing processing module, the auxiliary wind distribution mode processing module, the furnace temperature field data processing module, the furnace temperature field leveling module, and the boiler auxiliary machine operation mode. The module and the boiler coal mill operation mode module process the data of the data acquisition device;

Step (3): The operation mode selection module selects a corresponding operation mode;

Step (4): The oxygen quantity adjustment module compares the operating oxygen quantity with the optimal oxygen quantity. When the deviation occurs between the two, the operating oxygen quantity is adjusted to be equal to or equal to the optimal oxygen quantity; the furnace temperature adjusting module is a real-time furnace The average temperature is compared with the average furnace average temperature. When the deviation occurs between the two, by adjusting the SOFA swing angle, the output of each coal mill makes the average temperature of the real-time furnace close to or equal to the average furnace average temperature.

4. A control method for a combustion optimization control system based on acoustic wave measuring furnace temperature field according to claim 3, wherein:

The comprehensive performance test of the boiler in the step (1) includes: adjustment and test of the boiler auxiliary system, combustion optimization adjustment test under the various loads of the boiler, and variable coal test under the economic load of the boiler.

5. A control method for a combustion optimization control system based on acoustic wave measuring furnace temperature field according to claim 3, wherein:

The step (1) combustion optimization adjustment includes: performing a variable oxygen amount test under different loads, an auxiliary wind distribution mode change test, a variable coal mill operation mode test, a variable blow ash frequency test, and a variable separation burnout wind volume Test, variable burner swing angle test, coal mill separator speed test.

6. A control method for a combustion optimization control system based on acoustic wave measuring furnace temperature field according to claim 3, wherein:

The step (2) temperature value processing includes: bad value judgment and processing of the temperature measurement value, and localization processing of the temperature measurement value.

7. A control method for a combustion optimization control system based on acoustic wave measuring furnace temperature field according to claim 3, wherein:

The mathematical treatment of the step (2) comprises: establishing a mathematical model of the coal quality factor according to the analysis result of the coal quality in the furnace, and establishing an optimum furnace average temperature, a boiler load, and a coal quality factor according to the comprehensive performance test and the boiler combustion adjustment test. Mathematical relationship, establish the mathematical relationship between optimal oxygen quantity and boiler load and coal quality factor, find out the change SOFA swing angle, burner swing angle, the output distribution of each coal mill and the average temperature change of the furnace as the oxygen quantity adjustment module. And furnace temperature adjustment preparation.