Denitration ammonia injection self-adaptive control method and device and denitration system

The invention provides a denitration ammonia injection self-adaptive control method and device and a denitration system. The method comprises the steps of acquiring current working condition data; inputting the combustion data into a pre-trained reactor inlet nitrogen oxide concentration model to obtain a reactor inlet nitrogen oxide concentration; determining a first ammonia injection amount according to a reactor outlet nitrogen oxide concentration set value, the reactor inlet nitrogen oxide concentration, the denitration reaction data and the pre-trained reactor outlet nitrogen oxide concentration model; determining a second ammonia injection amount according to the measured reactor inlet nitrogen oxide concentration and the measured reactor outlet nitrogen oxide concentration; and determining the final ammonia injection amount according to the first ammonia injection amount, the second ammonia injection amount and the feedforward coefficient of the load interval corresponding to the current working condit