Soft measuring method for denitration control system

Abstract

The invention discloses a soft measuring method for a denitration control system. The method is characterized in that an auxiliary variable relevant to the outlet NOx concentrate value is analyzed; a field instrument records data; received data is uploaded into a DCS; then, the DCS inputs the data into a computer, and receives an outlet NOx concentration prediction value returned by the computer to form a closed loop; a support vector machine model analysis model is arranged in the computer; the modeling is performed through a support vector machine; the outlet NOx concentration value combining with a support vector machine regression algorithm is estimated to obtain the current moment prediction value; the current moment prediction value is returned into the DCS. The method provided by the invention has the advantages that the advanced support vector machine algorithm is used for regressing the SCR outlet NOx concentration value; the current value can be fast and effectively measured; in addition, the NOx change in a period of time in future can be obtained. Sample data used by the support vector machine are few; the calculation speed is high; the generalization capability is high; the SCR outlet NOx concentration value can be fast and effectively predicted.

Description

technical field [0001] The invention relates to a soft sensor method for a denitrification control system, belonging to the technical field of model prediction. Background technique [0002] At present, with the rapid development of China's electric power construction, air and acid rain pollution is becoming more and more serious. Especially in recent years, NOx pollution has been serious in big cities, and regional NOx pollution has gradually increased. According to the "Emission Standards of Air Pollutants for Thermal Power Plants" promulgated and implemented by China, the maximum allowable limit for nitrogen oxide emissions from thermal power boilers is 100mg / Nm3. Efficiently solving the emission of nitrogen oxides is already a very important issue. [0003] The NOx concentration at the SCR outlet is a very important control indicator. Excessive NOx at the outlet will lead to a high concentration of nitrogen oxides in the final exhausted flue gas. At present, convention...

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Problems solved by technology

At present, conventional PID is mostly used to control the outlet NOx concentration. For an accurate and constant mathematical model, PID can be effectively controlled. However, the denitrification control system is a large delay, nonlinear, and time-varying control system. When the controlled object When changes occur, PID control cannot effectively meet the performance of the object

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