Coal-fired unit screen type superheater over-temperature control system based on wall temperature prediction, and method thereof

Abstract

The invention relates to a coal-fired unit screen-type superheater over-temperature control system based on wall temperature prediction, and a method thereof. According to the system, on one hand, a maximum value of the wall temperature of a screen-type superheater is predicted in combination with an actual measurement signal and is combined with an amplitude limiting module and a rising rate speed limiting module, so that a predicted value participates in over-temperature control; and on the other hand, the actually-measured wall temperature signal of the screen type superheater is also combined with the amplitude limiting module and the rising rate speed limiting module to realize that an actually-measured value participates in a control scheme. By adjusting a burnout air baffle, a first-stage desuperheating water adjusting valve and other devices, the coal-fired unit screen type superheater over-temperature control system based on wall temperature prediction is formed, and screen type superheater wall temperature over-temperature active inhibition adjustment is achieved. According to the coal-fired unit screen-type superheater over-temperature control system based on wall temperature prediction, and the method thereof provided by the invention, the predicted wall temperature and the change trend of the current wall temperature are obtained at the same time, advanced wall temperature over-temperature active inhibition is achieved, and the system and the method have important significance in improving the operation reliability of a thermal power plant, effectively reducingthe pipe explosion risk, prolonging the service life of key equipment and reducing the maintenance and repair cost.

Description

technical field [0001] The invention relates to the field of automatic control of coal-fired units, in particular to an over-temperature control system and method for a wall-type superheater of a coal-fired unit based on wall temperature prediction. Background technique [0002] With the continuous improvement of the grade of thermal power units, increasing the power generation parameters such as steam temperature and pressure is an important way to improve the efficiency of ultra-supercritical units, but the increase in steam temperature puts forward higher requirements for steam pipe materials and wall temperature control. Limited by the creep strength and durable strength of the material, the temperature fluctuation must be within the safety margin. Due to the temperature measurement deviation of the water cooling wall, the parameters cannot be adjusted in time, and the long-term overtemperature operation of the water cooling wall will inevitably increase the risk of tube ...

AI Technical Summary

Problems solved by technology

Among them, the wall temperature is calculated through the mechanism modeling analysis of water-cooled walls, superheaters and other components. This method is more complicated, and there are many boundary parameters. The actual measurement points of the power plant cannot give all the boundary parameters, and the model needs to be continuously revised under different conditions. Therefore, It does not meet the requirements of online calculation, and cannot participate in the closed-loop control of the wall temperature of the power station in real time; based on the mathematical modeling analysis method, the wall temperature prediction method based on the artificial neural network is mostly used at present, only considering the influence of external factors on the wall temperature, using BP Prediction of Boiler Tube Wall Temperature Using Static Network Structures such as Neural Network

The historical data of the current wall temperature, the historical data of the upstream wall temperature, and the rate of change of related factors are not considered, and the time series prediction neural network structure, neural network activation function, etc. are not studied. The prediction structure is relatively backward and the calculation results are poor; And the current wall temperature prediction is only in the display stage, and the prediction results are not used to participate in the closed-loop control of thermal power

[0006] To sum up, the existing countermeasures and prediction methods for wall temperature overtemperature only stop at displaying alarms, so that parameters can be changed with the experience of operating personnel, and closed-loop control has not been realized.

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