Coal-fired unit denitration ammonia spraying control method

Abstract

The invention belongs to the technical field of thermal generator set flue gas denitration control and discloses a coal-fired unit denitration ammonia spraying control method. The method includes the steps that an outlet nitric oxide concentration measured value of an SCR reactor and an outlet nitric oxide concentration set value of the SCR reactor are acquired; the outlet nitric oxide concentration measured value and the outlet nitric oxide concentration set value are subtracted to obtain a nitric oxide concentration deviation value; the nitric oxide concentration deviation value is input in the input end of a main PID controller, and an ammonia flow required value output by the main PID controller is obtained; the ammonia flow required value is corrected, and an ammonia flow set value is obtained; an ammonia flow measured value is obtained, and the ammonia flow measured value and the ammonia flow set value are subtracted to obtain an ammonia flow deviation value; the ammonia flow deviation value is input in the input end of an auxiliary PID controller, and an ammonia spraying flow control instruction output by the auxiliary PID controller is obtained. The problem that the automatic adjusting quality of an original flue gas denitration ammonia spraying system is poor due to inaccurate flue gas flow measurement in the prior art can be solved.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitrification control of thermal power generating units, and in particular relates to a control method for denitrification and ammonia injection of coal-fired units, which can be used for the control of denitrification and ammonia injection of general coal-fired units. Background technique [0002] At present, the design scheme of the SCR denitrification and ammonia injection control system for coal-fired units is basically: use the flue gas flow rate at the SCR inlet and the concentration of nitrogen oxides to calculate the content of nitrogen oxides to be removed, and then multiply it by NH3 / NOx x The molar ratio yields the ammonia flow setpoint. The deviation between the set value and the measured value of the ammonia gas flow is calculated by the PID to generate an output command to control the opening of the ammonia injection regulating valve, and finally achieve the purpose of controlling...

AI Technical Summary

Problems solved by technology

[0008] In view of the above problems, the purpose of the present invention is to provide a control method for denitrification and ammonia injection of coal-fired units, which can solve the problem of poor automatic adjustment quality of the original flue gas denitrification and ammonia injection system caused by inaccurate flue gas flow measurement in the prior art

Images