SNCR denitration control method and device for circulating fluidized bed unit and storage medium

Abstract

The invention discloses an SNCR denitration control method and device for a circulating fluidized bed unit and a storage medium. The method comprises the following steps: S1, oxygen amount control: designing an oxygen amount control model prediction controller by taking the total air amount of secondary air as a control variable, the total coal amount as an interference variable and the oxygen content in flue gas as a controlled variable, and controlling the opening degree of a baffle door of a secondary air fan according to an output result of the oxygen amount control model prediction controller; and S2, denitration control: designing a denitration control model prediction controller by taking the total ammonia spraying amount as a control variable, taking the NOx concentration of the clean flue gas as a controlled variable and taking the oxygen content in the flue gas as an interference variable, and controlling the opening degree of an ammonia spraying valve according to an outputresult of the denitration control model prediction controller. The fluctuation range of the NOx generation amount under the variable load working condition can be reduced through oxygen amount controloptimization, oxygen amount measuring points serve as feedforward control through denitration control optimization, the delay time of a control system can be shortened, and the ammonia spraying amount can be saved through combination of the oxygen amount control optimization and the denitration control optimization.

Description

technical field [0001] The invention relates to the technical field of denitration treatment, in particular to a method and device for controlling SNCR denitration of a circulating fluidized bed unit, and a storage medium. Background technique [0002] Boiler Selective Non-Catalytic Reduction (SNCR) denitrification technology has the advantages of low investment, low operating cost, and small amount of boiler modification, and has been applied in various boilers. The SNCR denitrification technology does not use a catalyst, and the reducing agent such as ammonia gas, ammonia water, urea dilute solution, etc. is sprayed into the flue gas at 850-1150°C to directly reduce NO, and the reducing agent rapidly thermally decomposes into NH 3 And react with NOx in flue gas to generate N2 and H 2 O. The spray gun of the SNCR denitrification system of the circulating fluidized bed unit is usually installed in the horizontal flue at the separator inlet. The SNCR denitrification system...

AI Technical Summary

Problems solved by technology

The existing SNCR control logic generally uses a PID controller to adjust the total amount of ammonia injection for feedback control. This traditional control strategy has defects, and it is difficult to stably control NOx emissions under large fluctuations in operating conditions.

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