Improving Blast Furnace Raceway Blockage Detection. Part 1: Classification of Blockage Events and Processing Framework

Abstract

The present paper is the first part of a three paper series discussing raceway blockages in blast furnaces for ironmaking. During raceway blockages the hot blast flow rate can be reduced significantly and in such cases it is beneficial to shut down additional fuel systems like pulverized coal injection (PCI) on that specific tuyere. Currently this is mainly done by a simple threshold comparison of the hot blast flow rate data. Using a constant threshold level cannot account for drifting sensor levels or local changes in burden permeability around the raceway. Thus, the authors investigate various strategies to find more reliable solutions for blockage detection and the shutdown of PCI branches. Part 1 discusses the different nature of various blockage events on the basis of tuyere camera images and hot blast flow rate data. For the detailed testing of signal processing (part 2) and image processing algorithms (part 3) a universal test-bench is presented which also includes a common quality assessment of the results. Based on the collection of tuyere camera images a simple classification of blockage events is established. The analysis of 1500 hours of blast furnace operation data delivers a proper statistics about the frequency of occurrence of blockages on a small size blast furnace. The detailed analysis of hot blast signals and tuyere camera images presented in this paper series aims to improve the understanding of the raceway regions and their influence on optimal blast furnace operation.