Boiler flue gas denitrification control method based on self-adaptive fuzzy PID algorithm

Abstract

The invention discloses a boiler flue gas denitrification control method based on a self-adaptive fuzzy PID algorithm. The implementation processes comprises the following steps of collecting an actual measured value of the nitrogen oxide at a flue gas outlet, and calculating a deviation value and a change rate of the nitrogen oxide at the flue gas outlet; determining membership functions of nitrogen oxide deviation, a deviation change rate, a proportion change value, an integral change value and a differential change value; outputting a new fuzzy set membership function according to a fuzzy control rule, calculating the proportional change value, the integral change value and the differential change value according to the fuzzy set membership function, and adjusting corresponding parameters in the PID in real time to obtain new PID parameters; and controlling the ammonia spraying amount according to the new PID parameters. According to the denitrification control method disclosed by the invention, the PID control parameters can be adjusted by adopting a fuzzy control algorithm, on one hand, the condition that the content of nitrogen oxide at the outlet exceeds the standard irregularly can be avoided; on the other hand, the usage amount of ammonia gas can be more reasonably and efficiently controlled.

Description

technical field [0001] The invention belongs to the technical field of boiler denitrification systems, and in particular relates to a boiler flue gas denitrification control method based on an adaptive fuzzy PID algorithm. Background technique [0002] At present, the SCR denitrification system for boiler flue gas treatment mostly adopts the selective catalytic reduction method; ammonia gas is selected as the reducing agent, so that the nitrogen oxides in the boiler flue gas and ammonia gas undergo oxidation-reduction reactions under the action of the catalyst, and the formation will not Nitrogen and water that have an impact on the environment. The control principle of boiler flue gas nitrogen oxides is as follows: Calculate the actual ammonia demand according to the boiler flue gas flow rate (determined by the boiler load), the content of nitrogen oxides and oxygen in the inlet flue gas, and the set value of outlet nitrogen oxides, and finally pass Control the opening of ...

AI Technical Summary

Problems solved by technology

The large overshoot is mainly due to the delay in the system, and the traditional parameter tuning principle is based on obtaining an accurate mathematical model of the object, but when dealing with time-varying parameters and numerous interference controlled objects, the parameters of the PID controller are not easy to determine

Therefore, the tuning method of PID parameters has certain limitations and cannot solve the fundamental contradiction between dynamic performance and steady-state accuracy

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