MIMO Soft-sensor Model of Nutrient Content for Compound Fertil- izer Based on Hybrid Modeling Technique

In compound fertilizer production, several quality variables need to be monitored and controlled simultaneously. It is very diifficult to measure these variables on-line by existing instruments and sensors. So, soft-sensor technique becomes an indispensable method to implement real-time quality control. In this article, a new model of multi-inputs multi-outputs （MIMO） soft-sensor, which is constructed based on hybrid modeling technique, is proposed for these interactional variables. Data-driven modeling method and simplified first principle modelingmethod are combined in this model. Data-driven modeling method based on limited memory partial least squares（LM-PLS） al.gorithm is used to build soft-senor models for some secondary variables.then, the simplified first principle model is used to compute three primary variables on line. The proposed model has been used in practicalprocess; the results indicate that the proposed model is precise and efficient, and it is possible to realize on line quality control for compound fertilizer process.

In compound fertilizer production,several quality variables need to be monitored and controlled simul- taneously.It is very difficult to measure these variables on-line by existing instruments and sensors.So,soft-sensor technique becomes an indispensable method to implement real-time quality control.In this article,a new model of multi-inputs multi-outputs(MIMO)soft-sensor,which is constructed based on hybrid modeling technique,is pro- posed for these interactional variables.Data-driven modeling method and simplified first principle modeling method are combined in this model.Data-driven modeling method based on limited memory partial least squares (LM-PLS)algorithm is used to build soft-senor models for some secondary variables;then,the simplified first prin- ciple model is used to compute three primary variables on line.The proposed model has been used in practical process;the results indicate that the proposed model is precise and efficient,and it is possible to realize on line quality control for compound fertilizer process.