Research For Aluminum Reduction Cells On Unsteady Heterogeneous Models And Technology Of Energy Saving By Key Anode

Novel technology of energy saving is a hot topic for research in the filed of aluminum reduction and an important way for our country to save energy. This new technology of energy saving of aluminum reduction is based on the unsteady and heterogeneous models. This paper is focus on establishment of integrated intelligent decision support system (IIDSS) by,integrating the unsteady and heterogeneous models. The paper is aimed at realizing energy saving by key anode. The theory and methodof developing the unsteady and heterogeneous models, and an online monitoring system are studied in detail through application of wavelet packets transform (WPT), adaptive-neural-fuzzy-inference-system (ANFIS), numerical simulation, soft sensor, multiple neural networks, fuzzy C-means (FCM), multidatabase, visualization and object-oriented integration. The main content includes seven parts: information elements analysis model of voltage fluctuating in aluminum reduction cells, dynamic conditions diagnosis system of aluminum reduction cells, liquid metal wave model, soft sensor model for heterogeneous anode-cathode-distance (ACD), real-time monitoring system of ACD and liquid metal wave, multipledatabase system, IIDSS for operationaloptimization of aluminum reduction cells and its application. Based on these studies, this paper presents a technology of energy saving by key anode and its corresponding novel technics.This paper presents an information elements analysis model of fluctuating of voltage in aluminum reduction cells based on WPT and ANFIS according to the frequency spectrum characteristics of voltage vibration signal. The energy characteristic vectors related to the five types of aluminum reduction cells working conditions are extracted through WPT of the voltage vibration signals. The extracted features are inputted into ANFIS for diagnosing working conditions. Based on these studies, the paper puts forward the structure of real-time monitoring system and its applications.The liquid metal wave is the main factor of aluminum reduction cells instabilities. This paper puts forward a soft sensor model of heterogeneous ACD of aluminum reduction cells based on FCM and neural networks through numerical and experimental study on the liquid metal wave. By analyzing the mechanism of liquid metal wave instabilities, a method of tracking liquid metal interface based on Level Set technology. The governing equations for liquid metal wave had been established. Theresults of numerical study indicate that interfacial wave of 320kA prebaked anode aluminum reduction cell has a good magneto hydrodynamic (MHD) stability. The paper discusses selection of determination of complementary variables of soft sensor models. The results of numerical simulation for variation of anode current and anode resistance, distribution of anode current are discussed. After analyzing a lot of samples using FCM, soft sensor model for heterogeneous ACD is established based on multiple neural networks. Based on these studies, the design and realization of software and hardware for monitoring ACD and liquid metal wave are investigated in detail, and the three reasons of liquid metal wave are given.Based on unsteady and heterogeneous model of aluminum reduction cells, IIDSS was established through integration of information elements analysis model of voltage fluctuating, soft sensor model for heterogeneous ACD, decision support system for optimizing operation on aluminum reduction cells. This paper puts forward a method of object-oriented knowledge representation, object-oriented knowledge base model, technology of integrating model base based on goal-driven. A examination in a working cell of Guangxi Branch of China Aluminum Ltd is introduced, and the results of test are most satisfactory.This paper presents a new technology of energy saving by key anode based on development of unsteady and heterogeneous model and integrated intelligent decision support mode. The characteristic and technical scheme of energy saving by key anode are described. In the end, the experiment with 320kA prebaked anode aluminum reduction cell is performed in Guangxi Branch, China Aluminum Ltd, and the results of test indicate that an optimal goal of reducing voltage drop of 40my and maintaining the current efficiency unchanged is achieved...