Combustion optimization control system based on acoustically-measured hearth temperature field, and control method thereof

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

Technical field [0001] The invention relates to the field of combustion detection and control, and in particular to a combustion optimization control system and control method based on acoustic wave measurement of furnace temperature field. Background technique [0002] With the implementation of my country’s new thermal power plant air pollutant emission standards, more stringent requirements have been put forward for the emission of nitrogen oxides from thermal power plants. Therefore, the boilers of newly-built thermal power plants have adopted low-nitrogen combustion technology and put into production earlier The unit will also transform the original boiler burner into a low-nitrogen burner to reduce the level of nitrogen oxide emissions. Among the low-nitrogen burners currently used in our country, considering the investment cost and technological maturity, most of them adopt the air staged combustion technology. For the boiler with direct-flow tangential combustion, the main...

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Problems solved by technology

[0012] Chinese patent 201110107881.3 "Optimized measurement method for flue gas temperature at furnace outlet based on flue gas energy balance" introduces a method based on the balance of furnace combustion and radiation energy, the energy balance between the flue gas side of the superheater and the working medium side, and the flue gas side of the reheater and the The energy balance of the working fluid side and the energy balance of the exhaust gas, the optimized measurement of the furnace flue gas temperature from the positive and negative directions of the flue gas side, only introduces a measurement method of the flue gas temperature at the furnace outlet, and does not involve the content of combustion optimization

The limitations of flame image processing technology and radiant energy signals used in the field have been described in detail before and will not be described again. The combustion optimization involved in Chinese patent 200910273514.3 has great limitations in optimizing only the amount of oxygen, because the combustion adjustment variables also include There are many, such as the auxiliary air distribution mode, the operation mode of the coal mill, etc., and the concentration of nitrogen oxide emissions should also be included, and the radiant energy signal is a factor that has many influences and often distorts the signal, and its variation range and frequency are relatively high , using it to control the amount of desuperheating water will easily cause the desuperheating water regulating valve to be adjusted too frequently and be damaged; Chinese patent 01133648. Including the important variable of operating oxygen (operating oxygen has an impact on the economy of the boiler and the emission of nitrogen oxides), it does not include the burner swing angle, the ratio of the staged overfire air, the condition of the furnace soot blowing and the combustion The operation of the burner, etc. Another point is that for the boiler equipped with the direct-blowing pulverizing system, the fuel volume of the burners at each corner cannot be adjusted.

[0014] Chinese patent 200710069862.X "Method and device for power plant boiler combustion optimization based on infrared radiant energy signal". The near-infrared radiant energy sensor obtains the radiation intensity information in the furnace, and obtains the radiant energy deviation value through the artificial network. Regarding combustion optimization, it is only to insert the radiant energy deviation value into the DCS system of the power plant to control the boiler fuel module and improve the boiler. Coal feeding control logic, to increase the speed of load change of the corresponding unit of the boiler, is not a real combustion optimization to a certain extent

[0015] Chinese patent 200910184471.1 "on-line optimization control system for boiler pulverized coal layered combustion and its optimization", this patent optimization method uses the flue gas sampling and analysis data from the outlet of the air preheater and the furnace as the basis, and uses the support vector machine theory as the basis for automatic training and Optimizing, this method is firstly due to the large flue, if the number of sampling points is small, it cannot truly reflect the composition of the flue gas, if there are many points, the system will be too complicated, and fly ash needs to be used in training and learning Data such as carbon content, high-temperature corrosion conditions, etc. These data are greatly affected by man-made and coal quality changes. At present, the coal fired by boilers basically deviates from the designed coal type, and the system training and optimization process often cannot be completed, and the optimal goal cannot be found.

[0016] Chinese patent 201110205051.4 "A Generalized Boiler Combustion Overall Optimization and Energy Saving Composite System" introduces an optimized composite control system for grate boilers. This patent mainly emphasizes the improved addition system of fuel improvers. It is said that the combustion optimization control system uses fuzzy control and optimization self-optimization technology to adjust the air-to-coal ratio, and does not describe the method of overall combustion optimization in detail, and the patent is mainly applicable to small grate boilers

[0017] Chinese patent 201220029007.2 "A Boiler Furnace Combustion Optimization Device" introduces the addition of CO at the outlet of the tail flue economizer 2 probe, then conduct left and right side CO 2 For comparison, if there is a large deviation, the deviation can be eliminated by adjusting the secondary air. Another point is to use the measured CO 2 value with the calculated CO 2MAX compare if CO 2MAX than measured CO 2 If the value is less than 6%, it means that the oxygen measurement value is too large, and its claim only requires the addition of CO in the flue. 2 monitoring transmitter, so the patent does not address combustion optimization in the true sense

[0018] According to the above analysis, it can be found that for large-scale utility boilers, there are many defects in the boiler combustion control system based on the furnace temperature field or the simple combustion optimization control system, mainly in: (1). The temperature field measurement technology based on image processing technology, due to the dusty and high temperature environment of the sensor, the furnace temperature field measurement system does not work normally, often shuts down or the temperature field data is distorted; (2), the current simple combustion optimization control system or the combustion optimization control system based on the furnace temperature field measurement has the problem of incomplete combustion control factors. Most of the current combustion optimization control systems only improve a certain aspect, such as improving the response speed of the boiler to the load of the unit, etc.

(3) Another shortcoming of the current simple combustion optimization control system or the combustion optimization control system based on the measurement of the furnace temperature field is that the control system cannot automatically achieve combustion optimization and requires the participation of operators

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