Denitration ammonia spraying control method based on multi-variable correction

Abstract

The invention relates to a denitration ammonia spraying control method based on multi-variable correction, belongs to the technical field of ammonia spraying control of a denitration system of a thermal power generating set, and solves the problem that NOx fluctuation in an outlet of an SCR system in the prior art is severe. The method comprises the steps of acquiring measurement data and workingcondition information of a denitration system instrument in real time; constructing a NOx content prediction model at the inlet of the SCR denitration system, and predicting the NOx content at the inlet of the SCR system at the current moment; and carrying out ammonia spraying amount feedforward control and prediction correction on the basis of the predicted NOx content at the inlet of the SCR system and the measured data, generating an ammonia spraying amount control instruction at the current moment, controlling an ammonia spraying adjusting valve and adjusting the ammonia spraying amount. According to the method, the NOx content precision prediction model of the SCR inlet denitration system and the intelligent feedforward control method are adopted, so that NOx fluctuation at the outletof the SCR denitration system and space deviation are greatly reduced under the premise that smoke NOx emission satisfies the environmental protection index, the average value of the outlet NOx is increased, the ammonia spraying amount is reduced, the ammonia escape level is reduced, and the denitration cost is lowered.

Description

technical field [0001] The invention relates to the technical field of ammonia injection control for a denitrification system of a thermal power generation unit, in particular to a method for controlling ammonia injection for denitrification based on multivariable correction. Background technique [0002] For a long time, people's research on the SCR (Selective Catalytic Reduction, Selective Catalytic Reduction) denitrification system has mainly focused on its physical principles, equipment structure and operation mode. The research on the automatic control strategy of denitrification has not yet been carried out, and the automatic control quality of the denitrification system It is closely related to the long-term operation cost of the power plant. Due to the denitrification controlled object (NH 3 The response pure delay time of flow rate - chimney inlet NOx concentration) is close to 3 minutes, and the whole response process lasts for more than ten minutes, which is a ty...

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Problems solved by technology

[0004] In view of the above analysis, the present invention aims to provide a denitrification and ammonia injection control method based on multivariate correction, to solve the problem that the ammonia injection control loop cannot adapt to the denitrification process due to the huge lag of NOx measurement at the inlet and outlet of the SCR system in the prior art. The problem of drastic fluctuation of outlet NOx caused by nonlinear, large lag and fast time-varying characteristics

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