Ash Line Control

Abstract

For efficient firing in sloping grate bark furnaces, it is important to control the ash line position on the grate. The ash line is the border between burning fuel and fuel which is burned out (ash). Here, the problem of detecting the ash line with an image processing system is treated. The presentation of trend curves to the operator is of special interest. The process is slow and trend curves provide a memory that will assist the operator to improve the manual control of the process. In future development it may be possible to close the loop. An algorithm for detection of the ash line is presented. It is an optimization method where the position of the ash line is computed by maximizing a criterion. The criterion is tailored for the application and maximized by dynamic programming. The goal has been to obtain an algorithm suitable for a small computer e.g. IBM-PC. The algorithm has been tested on images taken from a video tape, showing the interior of an industrial bark furnace. Experimental results show that the algorithm can be used for the generation of trend curves.