Method for regulating and controlling ammonia spraying amount based on inlet NOx concentration prediction

Abstract

The invention belongs to the SCR system ammonia spraying amount regulation and control field and discloses a method for regulating and controlling an ammonia spraying amount based on inlet NOx concentration prediction. The method comprises the following steps of (a) measuring and acquiring a measured value of each correlation parameter at a current moment and an inlet NOx concentration respectively; (b) according to a relation between the correlation parameter and the inlet NOx concentration, constructing a prediction model and predicting the inlet NOx concentration of a next moment; (c) carrying out filtering processing on the inlet NOx concentration of the current moment, and taking a difference value of the filtered inlet NOx concentration and the inlet NOx concentration of the next moment as a predicted variation value; and (d) taking the predicted variation value and the like as input of a denitration system PID controller, and outputting an ammonia spraying valve opening degree so as to complete regulation and control of the ammonia spraying amount. In the invention, the prediction model is used to predict the inlet NOx concentration of the next moment, the ammonia spraying amount is optimized, a frequent fluctuation of an outlet NOx concentration is restrained and adjusting quality of the outlet NOx concentration is increased.

Description

technical field [0001] The invention belongs to the field of adjusting and controlling the amount of ammonia injection in an SCR system, and more specifically relates to a method for adjusting and controlling the amount of ammonia injection based on the prediction of inlet NOx concentration. Background technique [0002] Coal burning in thermal power plants is one of the main sources of NOx pollution. In order to reduce NOx emissions, Selective Catalytic Reduction (SCR) flue gas denitrification system has been widely used in thermal power plants. With the improvement of environmental protection requirements, in order to meet the national NOx emission standards and ensure the economic Benefits, the optimal control of ammonia injection in SCR systems has received widespread attention. [0003] As an important parameter of the SCR control system, the inlet NOx concentration plays an important role in the control of the amount of ammonia injection. However, the inlet flue of th...

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Problems solved by technology

[0004] Aiming at the above defects or improvement needs of the prior art, the present invention provides a method for adjusting and controlling the amount of ammonia injection based on inlet NOx concentration prediction, by using the inlet concentration at the current moment and related parameter values ​​to predict the inlet concentration at the next moment, and then using The filtering process uses the difference between the filtering value and the predicted value as the input of the PID control, the purpose of which is to make the interference of the feedforward signal of the PID control small, thereby solving the technical problem of low accuracy of ammonia injection

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