Online analysis of bubbling phenomena

Abstract

Bubbling is commonly used in the chemical and mineral refining processes to enhance temperature and chemical composition homogeneity, and control mass transfer and heat transfer. In the case of high temperature operations, it is very difficult to measure directly the effect of stirring on the system and thus the control of such processes is dominated by manual procedures. In the case of bottom bubbling processes involving two fluids (e.g. steel and slag in ladle refining operations), the disturbance of the surface of the top layer ('spout eye') provides a visual indication of the bubbling process and is accompanied by sound and vibration signals that all originate from the same phenomena and are clearly closely related to each other. In this study, we construct an experimental rig using five depths of the secondary layer (5-25mm) and 10 flow gas rates (2-20lpm) to simulate the secondary steelmaking process. Images from the top view, sound and vibration signals were collected simultaneously and they were manipulated into a state matrix after pre-treatment. The state matrix carries all the information which can be reliably measured from the bubbling phenomena. In this study, we propose to analyse the matrix using the PCA technique as means to reduce the dimensions of the matrix and hopefully produce a useful control signal