Evaluation of Fluidized Bed Condition by Image Analysis and Modelling

Abstract

Circulating fluidized bed combustion (CFB) is a good example of an energy process in which monitoring the condition and performance is important, especially when inhomogeneous solid fuels such as biofuel is used. There are two main reasons for this: 1) information on the coarseness of the bed material would provide information on problematic phenomena such as agglomeration, and 2) it is not economical to replace the bed material too often, because it leads to excessive usage of sand and premature wearing of bottom ash conveyor and related devices, so optimization of the bed change interval would be useful. Nevertheless, the possibilities for performing sampling and measurements cost-efficiently in industrial-scale CFBs are difficult because of the demanding environment. In this paper we present a costefficient measurement system and a further developed, indirect modeling methodology for evaluating fluidized bed condition, which is based on capturing and analyzing digital images from bottom ash.